Steve,
Sorry, I'm a little late to the game, but life has gotten in the way.
The blob of silicone sealant (RTV) in the bottom of the bore in the front of the cam is supposed to be there. Dig it out during servicing, and you'll expose the end of an Allen drive plug that's threaded into/ torque-tightened into a small threaded bore. The front end of the cam has a larger threaded bore for the bolt that retains the cam pulley. Remove that bolt and you'll exposed a glob of silicone sealant... dig it out clean. With the silicone gone, you have exposed an M8 (?) Allen drive plug. Use an Allen wrench to remove the plug.
The camshaft is "gun-drilled" full length... and out the back. At the bak end, there's a thrust washer that is retained by one bolt through it's center and into the cam. The "gun-drilled" bore is tapped at the very back end of receive that bolt and retain the thrust washer. Apply a Thread Sealant to the threads in the bore an on the bolt prior to assembly, then torque-tighten. Allow the sealant 24 hours to cure before attempting to start the engine.
Thread SEALANT is not the same as Threadlocker. Use a Thread "SEALANT"!
At the front of the cam, remove the bolt that retains the cm pulley. Look down into the threaded hole, and you'll see a glob of silicone sealant (RTV) in the bottom of the hole. Dig it out to expose an M8 (?) Allen Drive plug. Use an Allen wrench to remove the plug.
During re-assembly, clean the bore & plug threads to bare metal clean. Then use a Q-Tip to apply Thread "Sealant" to the threads in the bores, and also smear sealant on the bolt's threads & plug's threads. Assemble and torque tighten. Allow the sealant to cure 24 hours before proceeding.
At the back of the cam you're done... no silicone sealant glob required.
At the front of the cam, use Q-Tip or flux brush to coat a glob of silicone sealant over the exposed end of the plug's exposed end, and lightly fill the bottom/ end of the bore in the front of the cam. Allow the silicone sealant to cure for 24 hours.
Now you can proceed with installing the cam pulley, washer and retaining bolt. Apply anti-seize into the pulley's bore and onto the cam's front shank... the bit that slides into the cam's bore. Followed by the washer, bolt and torque-tightening.
At the front of the cam, "IF" pressurized oil gets past the Allend drive plug, and past the glob of silicone sealant, then it's very likely that it will also be able to wick past/ thru the threads of the bolt that retains the cam pulley. "IF" that happens, and oil gets out onto the pulley, there will be a spray of oil flung all across the front of the engine bay, in the plane of the timing belt/ csm pulley. You do NOT want that. She sealed plug and glob of silicone sealant is a "Belt & Suspenders" dual approach to sealing the front of the cam.
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Oil is pumped up thru the block to the head. It crosses thru the head gasket into a short vertical oil passage in the head... that then stops. Another oil passage is drilled from the front of the head, back until it intersects the short passage. The front of the bore is sealed via an Allen drive plug with Thread Sealant on the threads... no silicone.
From under the head, and oil passage is drilled up, thru the horizontal oil passage, and up toward the top of the head. The bottom of that bore (under the head) is sealed with another Allen drive plug and Thread Sealant... no silicone.
A final oil passage is drilled all the way across the front of the head, starting from the left side, just forward of the exhaust manifold. You'll see a bolt's hex head. On some applications, it's just a bare hex head doing nothing else other than plugging the drilled hole. On other applications, Lotus used that bolt to retain something. In either case, it plugs the drilled hole.
Remove the bolt and you'll see a glob of silicone sealant similar to what's in the front end of the camshafts. Dig out the silicone to expose another Allen drive plug. Remove the plug and clean the threads to bare metal clean.
Assembly is not similar to the cams. Thread Sealant, 24 hour cure, and silicone sealant, 24 hour cure. But now it can (in some applications) be different. There's a washer under the bolt's hex head. Under the washer there "may" be a counterbore with a rubber O-ring inside... surrounding the bolt's shank. One more thing to seal during assembly. Apply a little sealant to the O-ring and in the counterbore, then put it all together. IF your application doesn't have a counterbore under the bolt's washer, don't try to force in an O-ring.
IF that left-side bolt/plug leaks, it can make a heck of a mess down the left side of the engine block. Wind/ slip-stream can also blow any leaking oil back onto the hot exhaust manifold, creating a cloud of oil-stinky smoke. Seal it well,
Again, sorry about the late reply, but there's stuff going on in my life that's causing a distraction. Take it when you can get it.
Regards,
Tim Engel
01/12/2025, 11:41AM, dave78esprit, <armsdc@...> wrote:
The crude clop of RTV is pretty common. There is a grub screw installed with RTV in the front of the cam to seal the opening. The cam shaft is drilled through for oil and then sealed with that screw. You have the rear thrust washer bolt removed how about the actual thrust washer? Is it out or still stuck on the end of the cam? The cam shaft pushes out of the front and the only retention is that thrust washer and bolt. If the washer is sticking to the back of the cam use a longer bolt screwed into the back of the cam through the thrust washer to push the cam shaft forward. The thrust washer will be held back by the housing.
Dave C
01/12/2025, 1:26PM, wigl <wigl@...> wrote:
I am in the process of removing cams from Turbo/HC cam housings and perplexed at why the 1st is stubbornly refusing to budge. The cog wheel and snubber are removed and the thrust plate retaining bolt at the opposite end as well. These components have been out of service for years and the cam does not turn all that freely. No idea what was done in the PO's hands though there's a crude glop of RTV at the forward end of the cam. Insights?
Steve
Bill Galbraith
