Timing Chain Tensioner Check

[Pawel66]

I would like to request help in determining if my chain tensioner works properly. I read about it and I thought I knew what to do, but when I looked inside the engine - it is not that simple... for me, that is.

Two points to check: does the tensioner work and is it extended all the way or not.

1. When looked at the chain after removing the valve cover (car was not used for several weeks) - the chain seemed tense. I do not think there was chain noise I had heard before.
2. When I started trying to press/feel the tensioner sprocket arm, it became lose. I felt only the spring load. The oil is still there, in the basin.

So I do not know where I am. What shall I do next?

1. I should try to pump the tensioner - how do I do that? Press and pull the sprocket arem slowly at its sprocket end?
2. How do I determine if the tensioner is fully extended? I guess I need to take out the oil from the basin to see it. How much should it be extended so that I can say it is fully extended? As much out as the sleeve is long?

I know that when putting it all back together I should prime/pump the tensioner - again, back to point 1. I know it is trivial topic for a lot of you, but please shed some light on it for me.

[clunker]

As I understand it to prime the tensioner pump:
- fill the oil basin
- press down with a large screwdriver (or anything really) on the sprocket arm
- the sprocket arm will then pivot against the chain tensioner piston pressure
- press down slowly and some some bubbles should/may come up in oil basin as you prime the pump
- release and repeat pressing again, each time the pressure will get harder
- it is primed when you cannot use reasonable pressure to pivot the sprocket arm to depress the tensioner piston.
If the tensioner will not prime, ie piston stays easy to depress, or does not hold the pressure over time (check after few minutes) then the tensioner is faulty.

[Pawel66]

Ok, many thanks for your kind help! I will try.
And the piston is max out - just roughly it is out about as far as its sleeve is long?

[clunker]

That does not seem right / maybe just unclear. Can you post a pic?

[Pawel66]

Ok, thank you, will do - I just need to get there, I do not have the car here.

Thank you for your help!

[Pawel66]

Let me use the pics from the forum. This is more or less what I see. I think it is the hole of the piston. So I thought to determine if the piston goes max out it should more or less move out as far as its length. And its length is similar to its housing (sleeve) length. Not sure ow to determine if it is fully out.

Maybe when it stops going out and the sprocket arm is still lose?

Sorry for my ignorance...

[Benz Dr.]

Is your timing chain tight after you prime your tensioner? If your tensioner is primed and won't move easily, yet your chain is loose, you can figure on several different possibilities.

worn chain
worn gears
decked block/head
all or any of the above

If you have a new chain and gears yet your chain is still loose you can try adding a cam shim .015'' thick under each cam bearing which will raise your cam and take up some slack in your chain. It may require two shims under each bearing but one usually works.

[Pawel66]

Dan, thank you - I will be looking across these options and causes.

I think I have a bit worn chain. I had the head planed, but I do not know how much, top or bottom. I do not have repair size camshaft bearings nor the shims you talk about. I have somewhat worn gears.

I do not want to pull out engine again or remove head again at this stage. So I was thinking what I can fix and it seems that I could:
- check and fix the tensioner if need be
- replace the chain
- replace the camshaft gear (the crankshaft gear I guess is a tough one)
- do the shims

I hope it gets me half way there.

[Pawel66]

Dan, I am sorry, I have a request. I know I saw you posted the picture of the famous cam bearing shims, but I cannot find them now. I want to send the pictures to have the shims made - cannot find them....

Could you post the pictures again?

[Benz Dr.]

No need to remove the head. You can remove the cam shaft with bearings, then place the cam shims under the bearings, then you can reinstall the cam shaft and bearings.  Cam shims are available - I usually keep a couple of sets in stock but I can get more if I run out. If both sides of your head was planed then you will need cam shims for sure.  If you don't use them and run out of adjustment on your ball studs it will likely take out your valve guides due to rocker geometry problems. I can't state enough how important rocker position and geometry is on our engines. You can literally ruin a set of valve guides in a few minutes of running on a fresh cylinder head before you even drive your car.

I would also get a new cam gear and chain.

[tel76]

Hello Pawel66,
I have a spare camshaft shim I could send it to you so that you could have some made, I would want it returned.

[Pawel66]

Dan, I am happy to hear I am in line with what you are suggesting. This is after reading yours and other's posts including those about rocker geometry and ruining the guides.

I took out the camshaft and bearings and sent to camshaft shop to make a new camshaft and make sure the bearings fit and are new and clean. I will replace chain and I will replace sprocket on camshaft, do not plan on replacement of crankshaft sprocket if chain will have enough tension.

I have a set of thrust washers 3.5mm and 4.5mm, which should help on rockers alignment. I understand that rockers should press on thrust washers straight down, not at an angle different than square - this is what I understood from the forum.

What I am missing is the shims. Thank you for your kind offers Douglas and Dan, but I am pretty sure that the shop who have cam bearings can make them for me - all I need is a picture to get an idea of what I am talking about.

So maybe you could post a picture?

[Benz Dr.]

What you probably need is 4 camshaft shims. I could send some to you but I have no idea how long it would take for them to get to you.

[Pawel66]

Dan, could you be so kind and post picture?

I saw the pictures on forum, but cannot find them now. If I have pictures, I will have them made.

Thanks for help!!!

[Benz Dr.]

( laughing to myself ) I'm not a picture poster - don't know how to do it.............. They're  small enough and flat so they could be sent by mail.

[Pawel66]

I see! I remember they are one flat piece of metal sheet each, reflecting the shape of the bearing redestal foot, correct? I think I remember they may have open holes for screws so that you can slide them from the side under the bearing pedestal foot. Do I rememeber correctly?

[Tyler S]

Pawell, I dont think they had slotted holes but be sure the front most shim has a hole for the oil galley that feeds the camshaft oiler. The rear also needs to be notched for the oil return on the back of the head. Yes they are the shape of the bottom of the camshaft bearing tower.

[Benz Dr.]

You remember correctly. 

[Pawel66]

Ok, thank you, I will tell about those two holes/notches - hope they are reflected in the shape of the bearing pedestals and if not, I will cut out/file them before assembly.

Ufff...

Trust me, I am not a youngster - posting pics is easy! 

[Pawel66]

Still waiting for the camshaft and shims.

Checked the tensioner in the meantime: I figured how to pump it! So it works - it gets stiffer so it is hard to press. It does not stay like this for long - after half an hour I had to pump it again, but this time it was just two-three movements to make it stiff again.

I suppose this is how it is supposed to be - I do not think, as there are no sealing elements, the pressure will stay there for long anyway.

[Benz Dr.]

There's a blue pill available that could be helpful in this situation. 

[Pawel66]

Well, this tensioner is 47 years old...