aaddpp

I was getting ready to put the driver's side cam cover on this evening. As I was cleaning the threads on the 13 cam cover bolt holes, I noticed what seems to be slack in the driver's side cam chain. There are a few threads on RL that go into this, but its tough to gauge whether the slack I found is on par with these threads.

My photos below:

One photo shows the chain lying on the outer facing pad. In another photo, I am lifting the chain and you can see about a 1/4 to 3/8 of an inch of slack between the chain and pad. The top photos just a downward view of the tensioner setup.

When I checked the passenger chain and tensioner, there is no slack that I can find - slack is taken up by the piston / pad pushing outward.

Any thoughts on whether this is normal for the driver's side?

Thanks,
Dave

namasgt

I can see that you upgraded to the later style oil plugs, make sure some were not left out during assembly.
can you tell if the chain tensioner is not stuck compressed, check the oil line that feeds the tensioner see if all the sealing aluminum washers are there.
I would also check the oil valve seal on the head.

Edit: this is not normal for the drivers side, one problem could be that the tensioner lost pressure during the time your car has been sitting.

jeff spahn

doesnt the tensioner takes up that slack when pressurized?

Jim M.

When I did mine I had NO slack. Your chain tensioner blocks don't appear to have much wear, but something is wrong. Did you remove the chain tensioner? Could it be assembled incorrectly? How many miles on the engine/chain?

borland

That's probably normal. Depending on the crankshaft position, with the engine at rest, the upper cam can rock back slightly. In the process, slacking the chain.

With the engine running, the upper run of chain (driver side) between the two chain sprockets would be in constant tension, so it doesn't need a tensioner like on the bottom side. It's just the opposite on the passenger side.

Even if you can rock the chain sideways, its normal to expect some chain wear.

aaddpp

Yes, all of the old oil plugs were changed. I had one bad one on the passenger side so I opted to swap them all since the cams were open. As far as the other parts, in will have a closer look in the AM. Oil check valve I opened on both heads and cleaned, replaced o-ring and reassembled.

Not sure. Some of the threads spoke about this, but not sure there was consensus. To check oil flow, I spun the oil cam until I got oil in the heads - not sure if this would be sufficient to pressurize everything.

I have not removed the chain tensioner. As for incorrects assembly, it could be possible. Some of the work done to the car in the past was not up to spec.

Total miles on the car are about 70K

namasgt

What Borland is saying could be true, if you took the timing belt off and the cam moved CCW. Note that the drivers side chain tensioner is only pressing on the chain on the bottom section, the top part is solid. The passenger side, chain tensioner is pressing on the chain upward and the bottom part is stationary.

Now that you have changed the O-ring, make sure that the allen screw holding the ball, spring and cap assembly in place is tightened all the way flush with the head surface, it only takes 1 ft/lb of torque, so don't over tighten. Some have not screwed it down enough, causing the assembly to pop out from oil pressure and breaking the cam.

GregBBRD

This is probably normal. I'm going to guess that it has been a few days since this engine has run and the tensioner has simply run out of oil. The valve spring pressure on the cams is pushing one of the cams towards the other cam. The tensioner doesn't have any oil left and has collapsed. If you turn the engine some, the valve springs will push on the cams a different direction and the slack will disappear...and all be on the lower portion. The "spring" in the tensioner will push out and take up the slack. If you rotate the engine a few revolutions, you can watch the tensioner piston push out and retract, as the spring pressure on the cams pushes the cams in different directions. Once there is oil pressure, the tensioner will hold the chain tight.

Of course, there is always the chance that somehow the hydraulic part of the tensioner has failed...but this is very rare on "late style" tensioners. If you are really worried about it, remove the oil line and fabricate up a method to pump oil into the tensioner under pressure. You can use a regular oil squirt can with a tapered rubber piece fitted over the end. Push the taper into the oil hole and pump the tensioner full of oil, when the cams are such that the top of the chain is tight and the slack is on the bottom side (piston extended.) This should make the tensioner firm and not allow it to collapse. I have an old tensioner oil line that I cut in half, for this job. I simply attach a hose from the squirt can to this "half an oil line" (which I install onto the tensioners) and pump the tensioners full.

If you decide to do this, make sure that you "stuff" something down into the oil return passage in that section of the head, before you remove the oil line. Those aluminum crush washers like to "jump" down that oil passage and then travel all the way to the oil pan. I use half of one of those blue paper shop towels that come in a roll. They don't fall apart and leave lint in the engine. Don't forget to remove the "plug" when you are done.

blown 87

There is a way to check chains for wear, pm me with a number and I will call you to explain how, just a bit hard to write how to do it.

aaddpp

Greg thanks for the offer to walk me through the process of checking chain length. I will PM you shortly with my contact information.

Thank you Borland, Namasgt, and GregBBRD for the suggestions / explanations. I have gone back and used what you posted to have another look at the system. I should have added in my earlier post that the car has been on stands since June (got much busier than expected) , and I only just added oil back into the system last weekend.

Since I was only one step past putting the TB back on I decided to take a step back and pull the ballancer / belt, and spin the oil pump to get oil back into the system (i) to have a visual check that I did things correctly, (ii) to check the chain tensioners.

After getting oil to the heads, I put the belt back on - saw an issue which I will save for another thread - and spun the TB by hand. As Borland, Namasgt, and GregBBRD suggested turning the TB took up the slack on the drivers side cam chain. As was also suggested, it looks like the lower and upper cam shafts are turning a touch more and causing some slack to develop.

Bringing oil back to the system also is letting the tensioners function properly. I was able to see the driver side tensioner extend and take up slack on the lower side of the chain. One difference I noticed was that you can depress the passenger tensioner with some finger pressure, but that was not possible on the drivers side (this was after I watched it extend).

Would still like to confirm the chain is healthy, but it looks like everything else is working as it should.

Thanks so much for the help,
Dave

PS - NamasGT, when I put the cap on the check valve I tried to line it up with the original point the Allen screw contacted. Also I tried to test the cap by using a bolt and trying to pull to see if there was any play -- it seems solid.