ReinerFink

I hit a snag tonight -- was about to remove the goo from the chain housing (sprockets, ramps, etc and the housings themselves) when I decided first to rotate to TDC for cylinder #1 just so I know where things are before I start taking things apart.

Well, I get almost exactly 270 degree rotation on the crank before I hit a wall. Then I can rotate it back the other way 270 before I hit a wall again.

All of the plugs are out, and I don't want to force anything. I can see the intake valves opening and closing for cyl #1 and #3 during the 3/4 turn I do get on the crank. Hmm..

Any ideas why I seem to hit a wall trying to just turn things over by hand??

-reiner

trophy

Hey Reiner...

Are you cam chains loose? Ie are the still on the cams wheels on the cams? If they are not they can bind up as you rotate the engine and stop it rotating.

ReinerFink

The chains are still on the cam sprockets. I have not undone anything (except temporarily the left side tensioner to remove the shield that is bolted on top).

I could just start pulling it apart, but I its weird that it won't turn in this state since it was apparently running fine before this all started.

-reiner

Mike J

Updated - read the thread, you are at the disassembly phase. Interesting, not sure what you have stripped off the engine, but it sounds like binding. If you have not changed the timing, then it should not be contact of the pistons to the valves.

- is the transmission off the engine? clutch is free and clear of the engine stand?
- timing still in place for both banks? Are the tensioners still in place, or are the ramps loose (that might cause the chain to bind).

If you suspect valve to piston contact, remove the rockers and see if the engine turns over freely. Not sure how this would happen if you have not changed the timing.

You also mentioned getting an updated washer on the cam gear - I thought you had the older style sprockets that use a pin to hold the position (the best way!).

Cheers,

Mike

ReinerFink

The trans and clutch are all off.

Both tensioners are in, but I can see the ramps move up and down when I turn the crank the 3/4 turn it will go.

I am guessing the chain is just binding because there is no pressure on the ramps.

p.s. I do have the old style pin in the cam sprocket...

-reiner

trophy

Was it running before the strip down?

Do you have any pics you can post of the chain housings and the flywheel end of the engine.

ReinerFink

Here are picts of the left/right chain and fw end:





Sorry for the low quality...

-reiner

ReinerFink

In those picts I do have the tensioners removed. Though I would try taking them out to see if it made a difference.

I am going to have a friend come over and put pressure on the ramps with a screwdriver through the tensioner hole while I slowly crank it over to see if that makes a difference.

Also, car was running before the engine drop. I don't see how the timing could have changed at all at this point.

-reiner

Mike J

You are going to need to make up a tool to tension the ramps anyways to time the engine, so why dont you do that and tension both ramps, take the slack out of the chains (or do it with your friend). I think you are on the right track, its likely the right hand chain binding if I go with the pictures, they look pretty close.

Its always interesting to check the timing on an engine before its taken apart anyways. Are you going to time it the old fashioned way, or do you have access to the factory tools?

Cheers,

Mike

e3photo

The chain on the right side looks like it is binding.



Emerald

NP993

Just tear it down. It was running fine before you pulled it. The binding is surely because you removed the tensioners. Just inspect the layshaft gears and timing chains once you have it apart to make sure there's no damage.

ReinerFink

Yep, I'm leaning that way. Next hurdle - obtaining a 10 mm socket that is thin enough to fit onto the chain guide M6 bolts

trophy

For a rebuild of heads including a full new set of RS Valves etc you are looking at around $3100, this however is variable because the retail of the valves etc moves around.

This is not saying that the difference between 2500 and 3100 is the cost of the RS valves. Most of the time when Steve redoes heads he ends up having to replace the exhaust valves anyway, He can chime in on the frequency. So sometimes the incremental cost only ends up being the cost of the new Intake valves and the difference between stock and RS exhaust valves...

I reserve the right to be corrected by Steve W.....

trophy

A snap-on 12 point 10mm works a treat, or a nut driver.

+1, If she was a runner, just tear into it.....

ReinerFink

I think a large part of the additional machining cost is enlarging the piston intake pockets to clear the 51.5mm RS valves... but I also defer to Steve.

-reiner