|
Folks,
I have recently rebuilt my engine following what I now believe to have been an oil delivery problem to my exhaust camshaft.? I purchased a used cam carrier and a used camshaft to replace the failed ones but failed to notice my replacement camshaft was a "C" version while my original one was an "E" version.? As you all likely know (and I have now learned) they use different pulleys which are keyed to provide different MOP degrees.
I have at least three options to sort this out.? One is to obtain a replacement "E" camshaft and return everything to stock using my existing pulleys.? Two is to purchase a "red dot" pulley for the "C" camshaft and operate the engine with a mix of camshafts (Tim advises this is workable.)? Three is to purchase two "red dot" pulleys and convert the engine to full "C" camshaft spec (I actually already have two "C" camshafts.)
My question to the group is do any of you have any of these items (qty 1 "E" camshaft and/or qty 1 or 2 "red dot" pulleys) available for sale?
Thanks.
Ian Munro
JPS commemorative #32
|
Ian,
There may be another option...
As I also have an S4s with 910 engine which they make variable timing gears for, they might also make them for a 907 engine.? Tim E. would know.
--
Rich F
'79 JPS #040
'95 S4s ...SHF63000
|
Ian,
I don't have either an E-cam or 110 pulleys for you, but...
What is your preference for how the engine will run? Do you prefer higher performance at the top of the rev range, or milder manners/ easier driveability/ better low end torque? You can't have both stronger top-end power and better low-end torque. You must choose, and one comes at the expense of the other. If you're going to spend money to sort this out, then you should at least get what you want in the end.
The pre-1974 Lotus cars (Coventy-Climax, Lotus-Ford Twin Cam... etc) were meant to be flogged, and their owners were boy-racers rat-racing through the countryside. I think they would have loved the early 907. But I think Lotus failed to realize that buyers for the Jensen-Healey, and for the new 4-seat Elite 'Executive Express' were not going to be members of the previous crowd. And Lotus got a lot of complaints from early owners about the 907 being too high-strung, having to be driven hard in order to perform, and not having enough torque at low rpm.
In the 2nd & 3rd years of production, Lotus made some relatively minor carb changes aimed at taming the 907. But it wasn't until later that they actually made an internal change. The E-cam was Lotus first attempt to de-tune the 907. It helped, but the silk scarf & wicker basket crowd still complained. Next, Lotus introduced the 107 cam... more of the same (milder). If the E-cam was one step toward milder, then the 107 cam was two steps milder.
So, what do you prefer? More low-end torque and easier driveability? Or full-throttle, top-end performance?
C & D cams are biased more toward top end performance. They're at their best at full throttle above 4000 rpm. Not 'racey', but not mild-mannered either.
The 107 cam leans heavily toward the low-end torque part of the spectrum. Given time, it will eventually pull redline, but you have to wait for it. It's pretty much all done by 4500-5000 rpm, then it's pretty lazy the rest of the way to redline.
The E-cam is somewhere between the above two. It's specific target was low-end driveability and torque, but it didn't go as low as the 107 cam.
The 'street-hot' 104 cam targets top end performance. It doesn't really wake-up until 4500 rpm, then it will scream right past redline. It's up to you to lift off, because the engine will just keep going.
So, which personality do you want your car to have? Both/ All aren't options. Pick the appropriate cam, then install the correct MOP pulleys for the cam's used.
C & D Cams = 110 MOP = Red dot
E Cam = 102.5 MOP = Yellow dot.
104 & 107 Cams = 104 MOP = Green dot.
The stock C-cam and the later, street-hot 104 cam both have 272 duration. The difference is in the 104 lobe's very aggressive opening & closing ramps banging the valves open & closed, and the greater valve lift. Plus the stock C-cam runs milder 110 MOP pulleys, and the 104 cam runs hotter 104 MOP pulleys. "IF" you put the 104 MOP pulleys on the stock C-cam, it will have the same event-timing as the 104-cam, but not the aggressive lobes and lift. If you wished to autocross in a STOCK class, but want to 'sneak in' a little more top-end performance ("If you don't get caught, it's not cheatin"), then the 104 MOP pulleys on the stock C-cams would give you sort of a baby 104 cam set-up. It would produce more top-end power at the expense of low-end torque and driveability... just not as much as the 'street-hot' 104-cam would). Either plan on spending most of your time above 4500 rpm during an autocross run, or don't bother with the 104 MOP 'cheat'.
Running the 102.5 MOP, yellow-dot pulleys on the C-cam is 1.5 degrees further down that 'stockish-cheat' path. Even stronger top-end performance even higher up the rev range, and at greater expense to low end torque and driveability. If you prefer driving your Esprit with your foot on the floor, you might like the result. If you prefer taking your lady for a drive through the park, then you're probably not going to like it.
None of those combinations are going to bend valves... that's not the issue. The difference will be in the engine's personality (milquetoast, or bonkers) and performance (down low, or bouncing off redline) verses what you like. "Dissapointment is a function of expectations".
Choose.
*~*~*
I don't know which vender has a supply of all the pulley MOPs, but there are some parts suppliers who are selling incorrect pulleys. Some owners have received pulleys from Kent-Cams that have one MOP, but are marked as another. And some of the 'Lotus' vendors are getting their pulleys from Kent-Cams. You need to be careful.
Adjustable pulleys are an option... they are what you make them during installation. The problem is that they are much more complicated to set-up, and you need to KNOW what you're doing. It's easy to make mistakes, and bad mistakes can bend valves. If you don't know how to set-up adjustable pulleys, or don't have a knowledgeable fried who can look over your shoulder on your first attempt, then adjustables probably come with too much risk for a beginner.
So, first question first... what do you want your engine to be?
Low-end torque and easy driveability, or
top-end performance.
"Both" isn't an answer.
Later,
Tim
07/22/2022, 11:35AM, Ian Munro, <webdudeca@...> wrote:
toggle quoted message
Show quoted text
Folks,
I have recently rebuilt my engine following what I now believe to have been an oil delivery problem to my exhaust camshaft. I purchased a used cam carrier and a used camshaft to replace the failed ones but failed to notice my replacement camshaft was a "C" version while my original one was an "E" version. As you all likely know (and I have now learned) they use different pulleys which are keyed to provide different MOP degrees.
I have at least three options to sort this out. One is to obtain a replacement "E" camshaft and return everything to stock using my existing pulleys. Two is to purchase a "red dot" pulley for the "C" camshaft and operate the engine with a mix of camshafts (Tim advises this is workable.) Three is to purchase two "red dot" pulleys and convert the engine to full "C" camshaft spec (I actually already have two "C" camshafts.)
My question to the group is do any of you have any of these items (qty 1 "E" camshaft and/or qty 1 or 2 "red dot" pulleys) available for sale?
Thanks.
Ian Munro
JPS commemorative #32
|
Ian, Where are you? And, what pulleys do you have now? I may be able to help with some pulleys but I¡¯ll have to check and see what I have. Do you know for sure what pulleys you have now? Are they marked well enough to see the color of the dot? The E cams should have yellow dot 102.5 deg pulleys but those were only used on European cars and I thought that you were here in the states. There are adjustable pulleys out there for both pulley tooth profiles but they¡¯re expensive. The right way to install adjustable pulleys is to dial them in to your specific engine and set them to actual MOP for your engine which is a tedious process. That said, if you get a set of adjustables, I can set them for you to match any of the Lotus OEM pulleys or any MOP based on the Lotus OEM spec and Loctite the adjustments which will will get you as close as new factory pulleys would. ?I can also measure your current pulleys and verify what the are if your not sure. Do you know where the E cams came from?? Dave C
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On Jul 23, 2022, at 6:25 AM, Rich Flowers <richnpeg@...> wrote:
?Ian,
There may be another option...
As I also have an S4s with 910 engine which they make variable timing gears for, they might also make them for a 907 engine.? Tim E. would know.
--
Rich F
'79 JPS #040
'95 S4s ...SHF63000
|
Tim,
I have the major components from a JH engine that someone gave me years ago, including the cams. Without me having to dig these out, do you know what cams these would be, and will they help out Ian?
Bill
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] <> On Behalf Of Tim Engel Sent: Saturday, July 23, 2022 5:24 PM To: [email protected]Subject: Re: [S1S2euroS3LotusEspritOwners] Camshafts and/or Pulleys for sale Ian, I don't have either an E-cam or 110 pulleys for you, but... What is your preference for how the engine will run? Do you prefer higher performance at the top of the rev range, or milder manners/ easier driveability/ better low end torque? You can't have both stronger top-end power and better low-end torque. You must choose, and one comes at the expense of the other. If you're going to spend money to sort this out, then you should at least get what you want in the end. The pre-1974 Lotus cars (Coventy-Climax, Lotus-Ford Twin Cam... etc) were meant to be flogged, and their owners were boy-racers rat-racing through the countryside. I think they would have loved the early 907. But I think Lotus failed to realize that buyers for the Jensen-Healey, and for the new 4-seat Elite 'Executive Express' were not going to be members of the previous crowd. And Lotus got a lot of complaints from early owners about the 907 being too high-strung, having to be driven hard in order to perform, and not having enough torque at low rpm. In the 2nd & 3rd years of production, Lotus made some relatively minor carb changes aimed at taming the 907. But it wasn't until later that they actually made an internal change. The E-cam was Lotus first attempt to de-tune the 907. It helped, but the silk scarf & wicker basket crowd still complained. Next, Lotus introduced the 107 cam... more of the same (milder). If the E-cam was one step toward milder, then the 107 cam was two steps milder. So, what do you prefer? More low-end torque and easier driveability? Or full-throttle, top-end performance? C & D cams are biased more toward top end performance. They're at their best at full throttle above 4000 rpm. Not 'racey', but not mild-mannered either. The 107 cam leans heavily toward the low-end torque part of the spectrum. Given time, it will eventually pull redline, but you have to wait for it. It's pretty much all done by 4500-5000 rpm, then it's pretty lazy the rest of the way to redline. The E-cam is somewhere between the above two. It's specific target was low-end driveability and torque, but it didn't go as low as the 107 cam. The 'street-hot' 104 cam targets top end performance. It doesn't really wake-up until 4500 rpm, then it will scream right past redline. It's up to you to lift off, because the engine will just keep going. So, which personality do you want your car to have? Both/ All aren't options. Pick the appropriate cam, then install the correct MOP pulleys for the cam's used. C & D Cams = 110 MOP = Red dot E Cam = 102.5 MOP = Yellow dot. 104 & 107 Cams = 104 MOP = Green dot. The stock C-cam and the later, street-hot 104 cam both have 272 duration. The difference is in the 104 lobe's very aggressive opening & closing ramps banging the valves open & closed, and the greater valve lift. Plus the stock C-cam runs milder 110 MOP pulleys, and the 104 cam runs hotter 104 MOP pulleys. "IF" you put the 104 MOP pulleys on the stock C-cam, it will have the same event-timing as the 104-cam, but not the aggressive lobes and lift. If you wished to autocross in a STOCK class, but want to 'sneak in' a little more top-end performance ("If you don't get caught, it's not cheatin"), then the 104 MOP pulleys on the stock C-cams would give you sort of a baby 104 cam set-up. It would produce more top-end power at the expense of low-end torque and driveability... just not as much as the 'street-hot' 104-cam would). Either plan on spending most of your time above 4500 rpm during an autocross run, or don't bother with the 104 MOP 'cheat'. Running the 102.5 MOP, yellow-dot pulleys on the C-cam is 1.5 degrees further down that 'stockish-cheat' path. Even stronger top-end performance even higher up the rev range, and at greater expense to low end torque and driveability. If you prefer driving your Esprit with your foot on the floor, you might like the result. If you prefer taking your lady for a drive through the park, then you're probably not going to like it. None of those combinations are going to bend valves... that's not the issue. The difference will be in the engine's personality (milquetoast, or bonkers) and performance (down low, or bouncing off redline) verses what you like. "Dissapointment is a function of expectations". Choose. *~*~* I don't know which vender has a supply of all the pulley MOPs, but there are some parts suppliers who are selling incorrect pulleys. Some owners have received pulleys from Kent-Cams that have one MOP, but are marked as another. And some of the 'Lotus' vendors are getting their pulleys from Kent-Cams. You need to be careful. Adjustable pulleys are an option... they are what you make them during installation. The problem is that they are much more complicated to set-up, and you need to KNOW what you're doing. It's easy to make mistakes, and bad mistakes can bend valves. If you don't know how to set-up adjustable pulleys, or don't have a knowledgeable fried who can look over your shoulder on your first attempt, then adjustables probably come with too much risk for a beginner. So, first question first... what do you want your engine to be? Low-end torque and easy driveability, or top-end performance. "Both" isn't an answer. Later, Tim 07/22/2022, 11:35AM, Ian Munro, <webdudeca@...> wrote: Folks,
I have recently rebuilt my engine following what I now believe to have been an oil delivery problem to my exhaust camshaft. I purchased a used cam carrier and a used camshaft to replace the failed ones but failed to notice my replacement camshaft was a "C" version while my original one was an "E" version. As you all likely know (and I have now learned) they use different pulleys which are keyed to provide different MOP degrees.
I have at least three options to sort this out. One is to obtain a
replacement "E" camshaft and return everything to stock using my
existing pulleys. Two is to purchase a "red dot" pulley for the "C"
camshaft and operate the engine with a mix of camshafts (Tim advises
this is workable.) Three is to purchase two "red dot" pulleys and
convert the engine to full "C" camshaft spec (I actually already have
two "C" camshafts.)
My question to the group is do any of you have any of these items (qty 1 "E" camshaft and/or qty 1 or 2 "red dot" pulleys) available for sale?
Thanks.
Ian Munro
JPS commemorative #32 -- This email has been checked for viruses by AVG.
|
Ian, I¡¯ll add a little more confusion to the fire¡ In line with what Tim said about using the C cam as a mild 104 cam, the 102.5 pulleys can be reversed and repositioned to produce 104.5 MOP. They¡¯re not marked for it but that can be fixed easy enough. That would be a little closer to his mild 104 cam option.
Dave C
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On Jul 23, 2022, at 4:24 PM, Tim Engel <TSEngel@...> wrote:
?Ian,
I don't have either an E-cam or 110 pulleys for you, but...
What is your preference for how the engine will run? Do you prefer higher performance at the top of the rev range, or milder manners/ easier driveability/ better low end torque? You can't have both stronger top-end power and better low-end torque. You must choose, and one comes at the expense of the other. If you're going to spend money to sort this out, then you should at least get what you want in the end.
The pre-1974 Lotus cars (Coventy-Climax, Lotus-Ford Twin Cam... etc) were meant to be flogged, and their owners were boy-racers rat-racing through the countryside. I think they would have loved the early 907. But I think Lotus failed to realize that buyers for the Jensen-Healey, and for the new 4-seat Elite 'Executive Express' were not going to be members of the previous crowd. And Lotus got a lot of complaints from early owners about the 907 being too high-strung, having to be driven hard in order to perform, and not having enough torque at low rpm.
In the 2nd & 3rd years of production, Lotus made some relatively minor carb changes aimed at taming the 907. But it wasn't until later that they actually made an internal change. The E-cam was Lotus first attempt to de-tune the 907. It helped, but the silk scarf & wicker basket crowd still complained. Next, Lotus introduced the 107 cam... more of the same (milder). If the E-cam was one step toward milder, then the 107 cam was two steps milder.
So, what do you prefer? More low-end torque and easier driveability? Or full-throttle, top-end performance?
C & D cams are biased more toward top end performance. They're at their best at full throttle above 4000 rpm. Not 'racey', but not mild-mannered either.
The 107 cam leans heavily toward the low-end torque part of the spectrum. Given time, it will eventually pull redline, but you have to wait for it. It's pretty much all done by 4500-5000 rpm, then it's pretty lazy the rest of the way to redline.
The E-cam is somewhere between the above two. It's specific target was low-end driveability and torque, but it didn't go as low as the 107 cam.
The 'street-hot' 104 cam targets top end performance. It doesn't really wake-up until 4500 rpm, then it will scream right past redline. It's up to you to lift off, because the engine will just keep going.
So, which personality do you want your car to have? Both/ All aren't options. Pick the appropriate cam, then install the correct MOP pulleys for the cam's used.
C & D Cams = 110 MOP = Red dot
E Cam = 102.5 MOP = Yellow dot.
104 & 107 Cams = 104 MOP = Green dot.
The stock C-cam and the later, street-hot 104 cam both have 272 duration. The difference is in the 104 lobe's very aggressive opening & closing ramps banging the valves open & closed, and the greater valve lift. Plus the stock C-cam runs milder 110 MOP pulleys, and the 104 cam runs hotter 104 MOP pulleys. "IF" you put the 104 MOP pulleys on the stock C-cam, it will have the same event-timing as the 104-cam, but not the aggressive lobes and lift. If you wished to autocross in a STOCK class, but want to 'sneak in' a little more top-end performance ("If you don't get caught, it's not cheatin"), then the 104 MOP pulleys on the stock C-cams would give you sort of a baby 104 cam set-up. It would produce more top-end power at the expense of low-end torque and driveability... just not as much as the 'street-hot' 104-cam would). Either plan on spending most of your time above 4500 rpm during an autocross run, or don't bother with the 104 MOP 'cheat'.
Running the 102.5 MOP, yellow-dot pulleys on the C-cam is 1.5 degrees further down that 'stockish-cheat' path. Even stronger top-end performance even higher up the rev range, and at greater expense to low end torque and driveability. If you prefer driving your Esprit with your foot on the floor, you might like the result. If you prefer taking your lady for a drive through the park, then you're probably not going to like it.
None of those combinations are going to bend valves... that's not the issue. The difference will be in the engine's personality (milquetoast, or bonkers) and performance (down low, or bouncing off redline) verses what you like. "Dissapointment is a function of expectations".
Choose.
*~*~*
I don't know which vender has a supply of all the pulley MOPs, but there are some parts suppliers who are selling incorrect pulleys. Some owners have received pulleys from Kent-Cams that have one MOP, but are marked as another. And some of the 'Lotus' vendors are getting their pulleys from Kent-Cams. You need to be careful.
Adjustable pulleys are an option... they are what you make them during installation. The problem is that they are much more complicated to set-up, and you need to KNOW what you're doing. It's easy to make mistakes, and bad mistakes can bend valves. If you don't know how to set-up adjustable pulleys, or don't have a knowledgeable fried who can look over your shoulder on your first attempt, then adjustables probably come with too much risk for a beginner.
So, first question first... what do you want your engine to be?
Low-end torque and easy driveability, or
top-end performance.
"Both" isn't an answer.
Later,
Tim
07/22/2022, 11:35AM, Ian Munro, <webdudeca@...> wrote:
Folks,
I have recently rebuilt my engine following what I now believe to have been an oil delivery problem to my exhaust camshaft. I purchased a used cam carrier and a used camshaft to replace the failed ones but failed to notice my replacement camshaft was a "C" version while my original one was an "E" version. As you all likely know (and I have now learned) they use different pulleys which are keyed to provide different MOP degrees.
I have at least three options to sort this out. One is to obtain a replacement "E" camshaft and return everything to stock using my existing pulleys. Two is to purchase a "red dot" pulley for the "C" camshaft and operate the engine with a mix of camshafts (Tim advises this is workable.) Three is to purchase two "red dot" pulleys and convert the engine to full "C" camshaft spec (I actually already have two "C" camshafts.)
My question to the group is do any of you have any of these items (qty 1 "E" camshaft and/or qty 1 or 2 "red dot" pulleys) available for sale?
Thanks.
Ian Munro
JPS commemorative #32
|
Bill,
The stock Jensen-Healeyl 907 used two C-cams. What vintage? Early engines were timed with 115 MOP pulleys for emissions. They were never used on any other 9XX, and later J-H followed the Lotus 907's development.
Later,
Tim
07/23/2022, 4:30PM, Bill Galbraith, <lotus@...> wrote:
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Tim,
I have the major components from a JH engine that someone gave me years ago, including the cams. Without me having to dig these out, do you know what cams these would be, and will they help out Ian?
Bill
|
Thanks Tim. Sounds like that won't help Ian out. Oh well, I tried.
Bill
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-----Original Message----- From: [email protected] <> On Behalf Of Tim Engel Sent: Saturday, July 23, 2022 6:51 PM To: [email protected]; Bill Galbraith <Lotus@...> Subject: Re: [S1S2euroS3LotusEspritOwners] Camshafts and/or Pulleys for sale Bill, The stock Jensen-Healeyl 907 used two C-cams. What vintage? Early engines were timed with 115 MOP pulleys for emissions. They were never used on any other 9XX, and later J-H followed the Lotus 907's development. Later, Tim 07/23/2022, 4:30PM, Bill Galbraith, <lotus@...> wrote: Tim,
I have the major components from a JH engine that someone gave me years ago, including the cams. Without me having to dig these out, do you know what cams these would be, and will they help out Ian?
Bill -- This email has been checked for viruses by AVG.
|
Bill,
I should have thrown out more info... I wasn't thinking. The 115 MOP and 110 MOP are on the same pulley.
There's a red dot/ blue dot dual MOP pulley. When the red dots are properly aligned, the blue dots are FOUR teeth down. Sound familiar?
In the same way, when the red dots are properly aligned, the 115 MOP timing marks are THREE teeth down. See teh attached JPEG.
If the IN next to the red dot is facing forward on the Intake pulley, then the EX mark will be facing forward next to the 115 timing mark.
If the EX next to the red dot is facing forward on the Exhaust pulley, then the IN mark will be facing forward next to the 115 timing mark.
To switch from 115 to 110 (or vice versa), it's necessary to remove the pulley, flip it over, then time using the other MOP's timing mark.
Besides, it's been 52 years since the J-H was introduced. Who knows what some interim owner might have installed on the cams.
Later,
Tim
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On 07/23/2022 6:46 PM Bill Galbraith <lotus@...> wrote:
Thanks Tim. Sounds like that won't help Ian out. Oh well, I tried.
Bill
|
Dave,
Thanks for the note.? My car is located in Canada BUT it is a
domestic spec series 2.? Thus it came with Dellortos and "E" cams
and yellow dot pulleys from the factory.
Adjustable pulleys COULD be an option for me but I am wondering if
that means pulling the engine again to properly "degree" things??
Maybe not the end of the world but my preference would be not to
go through all that again.
To me the "simplest solution" would be to find an "E" camshaft and
return the engine to stock but I have not been seeing any of those
offered for sale.? It would be great if you (or someone out there)
had one for sale.
I appreciate your offer of an adjustable pulley "set" to a
suitable MOP.? I will keep that option in mind if no other
solution can be found.
Tim,
Thanks for your thoughts on my options.? Your explanations are
always so clear and helpful.? The ONLY issue I have with your
questions (you advised me to choose - exactly right of course) is
that I have very limited experience with what these changes mean
in the real world.?
I have had this car on the track in the past but not for some
years and I have no plans to do so again. I did take the car for a
four-hour run this pas week.? It was the first time I have run the
car any significant distance with the mis-matched cams ("E" on the
intake and "C" with yellow dot pulley on exhaust).? The car ran
okay but I definitely noticed far less punch at the mid to
high-end of the rev range than I recall from the stock setup.? I
would like to fix that.? Where my lack of experience comes in is
that I don't really know what the effect would be (in real-world
terms) to convert to "C" cam setup.? I know I will need higher RPM
to launch from a stop (as an example) but how much and will that
spoil my driving experience??? Maybe I need to find an example of
a stock Jensen Healey to take for a spin?
Based on my current level of knowledge and your guidance I am
thinking my preference would be to return the engine to stock
(with two "E" cams) with the second best option being to put the
"C" cam on the intake and "E" cam on the exhaust.? To do that I
would need a confirmed red dot pulley.? I think my least preferred
option would be to find two red dot pulleys and run "C" cams on
both intake and exhaust.? (Note: I actually do have two "C"
camshafts available.)? I am quite certain I do not want to go with
the 104 cam setup since that sounds too boy-racer for me.
Ian.
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My 2nd hand opinions, recalling what a close pal with S1 had to say on cams assuming the car, purchased back around '81, has the C type. With the stock wheels assembled at 110 MOP the car would wind out pulling hard past 7K, this with 45DCOE's, DBE 4-2-1 exhaust manifold, and higher CR pistons. After time my buddy felt it could benefit from the change to 104 MOP so he switched to green dot wheels, also converting to HTD belt train for the sake of better reliability. What he reported was that the 907 had shifted power usefully lower in the range, telling me the car felt like upshifting before 7K rather than hauling on upward as before. This is consistent with established valve timing doctrine identifying intake closing as the prime determinant of where power band occurs and would indicate that a change to 104 MOP affords better low - mid range grunt, all else remaining equal, as compared to 110 MOP. The E cam profile may well be the weak sister of the family, likely inferior to the 107 overall. With great respect for Tim's experience I cautiously propose that perhaps the 107 cam has been less well understood to this point owing to dogma on the all-conquering reputation of the 104 MOP wheels. Engine sim work I've mucked with at length indicates 107 cam on 110 MOP wheel to be superior to the C cam on either 104 or 110.
Cheers
Steve
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Ian,
Just one more thing to ponder.
If you don't use the same cam and MOP timing on both intake and exhaust, then keep in mind that the INTAKE has more impact on the engine's personality. The exhaust isn't un-important, but it doesn't have as much influence over how the engine performs or behaves.
If you put a C-cam on the intake, and an E-cam on the exhaust, the result will feel/ drive more like a C-cam engine than an E-cam engine. But it's not all or nothing... it's somewhere in the middle, but leaning toward the intake's personality.
It sounds to me like you would prefer E-cam/ E-cam, but you're considering compromising with C-Cam Int/ E-cam Exh. "IF" you're going to run the mixed combination, then I'd recommend E-Cam Intake/ C-cam Exhaust. The end result won't be either one perfectly, but it will lean more toward the E-cam personality, which I perceive as your #1 preference.
Regards,
Tim Engel
07/24/2022, 10:02AM, Ian Munroe, webdudeca, <webdudeca@...> wrote:
(Snip)...
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Based on my current level of knowledge and your guidance I am thinking my preference would be to return the engine to stock (with two "E" cams) with the second best option being to put the "C" cam on the intake and "E" cam on the exhaust. To do that I would need a confirmed red dot pulley. I think my least preferred option would be to find two red dot pulleys and run "C" cams on both intake and exhaust. (Note: I actually do have two "C" camshafts available.) I am quite certain I do not want to go with the 104 cam setup since that sounds too boy-racer for me.
Ian.
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Tim,
I guess the obvious way forward then (assuming I can find a suitable red dot pulley) is to simply install the new pulley on the exhaust camshaft and see what that feels like.? That seems a harder task than I expected.? There are J-H pulleys listed out there but the vendors cannot confirm they are red dots so I am hesitating given your cautionary notes on the various versions that are out there.
Thanks again for your wisdom on this.
Ian.
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Ian,
Timing dots (drill points) filled with paint was a Lotus thing, and the Jensen-Healey didn't use it. They used a line/groove cut radially across the pulley rim for a timing mark, and engraved the MOP number on the pulley center-web, near the timing mark. No paint color. Asking them what COLOR MOP the pulley is will just get you a blank stare in return.
Jensen-Healey's all used C-cams. The MOPs were:
115 MOP Up through engine number 4030.
110 MOP from engine number 4030 onward.
In North America only, from engine number 10480 onward.
100 MOP on the Intake
110 MOP on the Exhaust.
By this time (1976), the J-H and Lotus 49-State versions of the 907 were the same, and the late Lotus Federal 907 also used this same 100 IN / 110 EX cam timing. It doesn't matter where you get the parts... you do not want this timing! It guts/ neuters the 907, and this config (along with the lean fuel mixture and lame ignition timing) is the source of the unkind "Gutless Wonder" saying. Not all 907s were gutless... only this last, Federal emissions 100/110 version.
Early 100 Blue dot pulleys were a true 100 MOP, but it didn't last long.
.The later 100 Blue dot/ 110 Red dot "DUAL MOP" pulleys 'cheated' the Blue dot to 97 MOP in order for it to fit on the same pulley with the 110 Red dot.
The 115 (no color),
110 Red, and
100 Blue/110 Red dual MOP pulleys
all contain 110 MOP on the pulley. If it's not marked (as on the 115) You just need to know where to find it... but it's there. IF you find one of them from a Jensen-Healey vendor, I can show you where the 110 MOP red dot is... or should be.
But when you speak with a J-H vendor, inquire about an MOP... not a dot color.
Layered on top of all of that is the question of MOP accuracy. Is the MOP pulley you find really the MOP that is marked on it. If you have the means to accurately measure the keyway location in the bore, some pulleys are clearly not the MOP that is marked on them. Oh fun...
Regards,
Tim Engel
07/25/2022, 7:19AM, webdudeca <webdudeca@...> wrote:
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Tim,
I guess the obvious way forward then (assuming I can find a suitable red dot pulley) is to simply install the new pulley on the exhaust camshaft and see what that feels like. That seems a harder task than I expected. There are J-H pulleys listed out there but the vendors cannot confirm they are red dots so I am hesitating given your cautionary notes on the various versions that are out there.
Thanks again for your wisdom on this.
Ian.
|
SJ Sportscars has some Competition cam pulleys that have 5 keyways for different timing variations. With 5 keyways and the ability to run the pulley on 2 sides you have 10 different timing options for every pulley tooth. With each tooth being 18 degrees of crank timing, that should give you 1.8deg steps for timing, however I don't know how they divided it up. I would have done it in 1.8 MOP steps but the may be built with smaller increments around some specific timing, I cant find anybody who knows. I just ordered one to experiment with. The catch is they are completely unmarked. I¡¯ll measure it and see what timing options are available on it and report back. The good news it these pulleys are pretty cheap. Like $69ea instead of over $300 for an adjustable. If one of the settings will work then it is an easy matter for me to mark it for that setting so it is easier to use for a specific application. I¡¯ll have an answer in a couple of weeks.
Dave C
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On Jul 25, 2022, at 11:08 AM, Tim Engel <TSEngel@...> wrote:
?Ian,
Timing dots (drill points) filled with paint was a Lotus thing, and the Jensen-Healey didn't use it. They used a line/groove cut radially across the pulley rim for a timing mark, and engraved the MOP number on the pulley center-web, near the timing mark. No paint color. Asking them what COLOR MOP the pulley is will just get you a blank stare in return.
Jensen-Healey's all used C-cams. The MOPs were:
115 MOP Up through engine number 4030.
110 MOP from engine number 4030 onward.
In North America only, from engine number 10480 onward.
100 MOP on the Intake
110 MOP on the Exhaust.
By this time (1976), the J-H and Lotus 49-State versions of the 907 were the same, and the late Lotus Federal 907 also used this same 100 IN / 110 EX cam timing. It doesn't matter where you get the parts... you do not want this timing! It guts/ neuters the 907, and this config (along with the lean fuel mixture and lame ignition timing) is the source of the unkind "Gutless Wonder" saying. Not all 907s were gutless... only this last, Federal emissions 100/110 version.
Early 100 Blue dot pulleys were a true 100 MOP, but it didn't last long.
.The later 100 Blue dot/ 110 Red dot "DUAL MOP" pulleys 'cheated' the Blue dot to 97 MOP in order for it to fit on the same pulley with the 110 Red dot.
The 115 (no color),
110 Red, and
100 Blue/110 Red dual MOP pulleys
all contain 110 MOP on the pulley. If it's not marked (as on the 115) You just need to know where to find it... but it's there. IF you find one of them from a Jensen-Healey vendor, I can show you where the 110 MOP red dot is... or should be.
But when you speak with a J-H vendor, inquire about an MOP... not a dot color.
Layered on top of all of that is the question of MOP accuracy. Is the MOP pulley you find really the MOP that is marked on it. If you have the means to accurately measure the keyway location in the bore, some pulleys are clearly not the MOP that is marked on them. Oh fun...
Regards,
Tim Engel
07/25/2022, 7:19AM, webdudeca <webdudeca@...> wrote:
Tim,
I guess the obvious way forward then (assuming I can find a suitable red dot pulley) is to simply install the new pulley on the exhaust camshaft and see what that feels like. That seems a harder task than I expected. There are J-H pulleys listed out there but the vendors cannot confirm they are red dots so I am hesitating given your cautionary notes on the various versions that are out there.
Thanks again for your wisdom on this.
Ian.
|
Dave,
I would be very interested in reading the results of your
investigation.? At $70.00 each this could solve a bunch of issues
some of us are having without breaking the bank.
Ian.
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Ian,
Lotusbits in the UK lists a used E-cam for ?50. However, the parts listed on their website are examples, and being listed doesn't mean thay have it in stock. They're not good at returning email messages, so call and talk with them.
Scroll down on the following page to the E-cam listing:
Regards,
Tim Engel
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Bill Galbraith
