Tensioner replace and timing question

[sperberj]

Thanx Bob---tommorow I begin! Ireally appreciate this thread and all your help. Will post pix!

G'nite!

[Alan L]

You can do it in the car - you are just doing #1&4. The A/C should be OK. Take the top valve covers off and mount the dial gauge. I use a magnetic dial gauge holder - and bolt a steel plate (just bigger than the base of the block) to the cam cover studs. (You need to place it so the other rocker arms don't interfere/lift the plate) You will have a bit of stuffing around to get the gauge oriented right. Try and position the pointer tip of the gauge in line as much as possible with the travel of the rocker arm - so it is following directly the downward path of the rocker arm. You place the tip on top of the valve adjuster and try and avoid the adjuster slot - because it will often drop into the groove as it travels with the arm.
You then zero the dial with a turn or so pre load in the gauge - so it can record as it extends down. If that all makes sense. It will do 1+ a small bit of a revolution to get the correct timing.
But if you just want a quick check you can avoid all this via Andy's method. But if you go this track, you will be able to reset your valve timing anytime you want. Make sure the valve lash clearance is right before you do this if resetting from scratch.
Alan
Alan

[sperberj]

Hi All;

I ordered the Z bracket and the gauge from PP and spent the day prepping the engine to check. I installed the collars and they did not have that much room so I am assuming the chain has not stretched much. Teeth and innards all looked fine also. I cleaned up the engine and replaced a leaking oil line to the left side. Bolted up the tensioners and now wait for the parts.

Thanx again for all the help and I hope to have pix and data as soon as I get the parts. Again, I really appreciate this help and I also think this should go into the 101 projects book as a check for a tensioner install or upgrade --- this was really valuable data!

Thanx again!

Joe

[Chuck.H]

Originally Posted by sperberj

Those look useful so I will get them and also the dial indicator like Bob said. I just don't want to fool with the timing if I did not skip a tooth.

Actually, I would disagree and say you DO want to fool with the timing - it's very easy to reset to factory specs and that will put it back in time even with any stretched chains... I just did this w/o the Z blocks (rigged up my own dial indicator holders) and I can confirm it's super easy once you understand the process.

Chuck.H
'89 TurboLookTarga, 372k miles

[sperberj]

Hi All;
I will try all the suggestions but still waiting for the Z and dial gauge. I don't think my chains are very stretched as all the teeth look good and there is not a lot of gap in the tensioners to attach the collars. They barely are able to traverse the full travel without hitting the lip and I can get the supplied gauge to fit the gap. Anxiously awaiting the PP parts and again thanx!!!!!

[keynsham1]

If the chain stays on both sprockets, then I don't se why letting it go loose makes any difference to the cam timing as the two chain wheels will always return to the same plate with respect to each other when the chain is tightened again with the tensioner. As for the chain jumping a tooth, I don't believe that this is possible inside the crankcases as there is not enough clearance around the edge of the chain wheels on the intermediate shaft to allow this to happen. Also, having just reassembled my engine ad done the cam timing (last week) these chains do not just jump a tooth. It is hard enough to get them on to the chainwheels to begin with!

[sperberj]

Hi and thanx--that is what I thought also but then I started reading and worrying and thinking about a complete engine rebuild because I missed a tooth slip. 99.9% it did not slip but the .1% keeps me awake at night.

Also, I now have a reason to pull the valve covers and clean them up.

TODAY the parts came in-----and a major snowstorm also!

Thanx and keep ya posted!

Joe

[sperberj]

Got the gauge from Pelican and it looks and feels great. More importantly it is made in Germany and it is really nice to see a great product at a good price that is not made by a military or religious dictatorship by slave labor. You GO Pelican!!!!!

[Flat6pac]

If you have jumped time, you only need to pull the tensioner, with the dial guage in place, and slide the chain over the gear as you turn the cam in the necessary direction.
Remember the cam turns CCW to advance, clockwise to retard but the timing is already set until it jumped.
If youre out of time you wont be able to measure timing by rotating the crank because if you jumped time you ll run into valves.
Bruce

[sperberj]

I wondered about that earlier but there wasn't a reply on that one. I rotated through clockwise gently by hand and did not detect any resistance. I wasn't sure if a one tooth jump would be enough to cause a detectable contact with a valve. Are you saying that a one tooth jump will cause the contact to occur? Any data on this would really be appreciated!

[Flat6pac]

Yes, one tooth jump will cause a hit, either on intake or exhaust valve.
Bruce

[sperberj]

Interesting, because if that is true, all one would have to do is gently turn the crank by hand and see if the engine has strong resistance. I turned the engine through and only felt some compression resistance. I will use the checks that the guys have said but I think you are correct that anyone could very easily tell by simply gently turning through the crank 8 times to determine a valve hitting. Am I correct in this?

Really appreciate it!

[sperberj]

OH, also---I was worried that you could shift a tooth and the valves would e clear until higher rpms were achieved and then------catastrophe!

[Flat6pac]

No, you will bind if you have jumped.
Bruce

[sperberj]

Thats also great news -- the risk of really serious damage is so great that this thread has data that should be very useful to anyone rebuilding or updating their tensioners. Thanx again to everyone for this information.

[sperberj]

Hi All; Snow has let up so it was a good time to get you pix! Here they are and I seem to be short of clearance on the collars. Good or bad? And what to do?
Thanx

Joe

[sperberj]

Hi Guys; I checked the collars against the specs that everyone on the PP was stating, basically a gap of between 3 to 5 mm. I think at most I was getting 1mm so I decided to pull the collars and then wait about 10,ooo miles till the chains loosen a bit. Pretty good though that there are 97,000 miles on the engine and it is still pretty tight. Just going to check the cam timing on both banks and the button it up. Cleaned and polished the timing covers and valve covers and they are waiting for clear coat. Will keep ya posted!

[sperberj]

Here are the components that were polished up nicely for install. I am going to clear coat them with 3x 2 pack. The aluminum is porous so I wanted to make it easier to clean.

[sperberj]

Hi All; It was a 60 degree day on the East Coast and I completed the polish and paint on the valve covers and cam chain cover. I polished them with a 1500 grit sandpaper and then buffed with rubbing compound followed by Mothers. Then I broke the seal on the new Eastwood 2 pack clear and coated them to seal the Aluminum. It really looks good. I followed all the methods talked about using a Z fixture and micrometer. It indicated that I did not skip a toot. Then I turned the engine through at least 10 times gently to detect any binding. This all seemed fine also. Then I grit my teeth and turned the key! It fired right up (minus muffler) and I let her run about 2 minutes. Everything seemed fine and no cam chain rattle at the moment. I will provide pix tomorrow! Here are the important lessons learned from this process:

1. This forum is amazing and invaluable!
2. Mark all locations of the cams and the settings before you start.
3. Take pictures.
4. Tie up the cam chains on both sides of the tensioners as the tensioners will allow a lot of slack when removed.
5. Tie them up tight.
6. You can tell if the tensioners are bad immediately after you remove them by squeezing and if you can compress beyond 1/8 inch with your fingers, they have gone bad.
7. They rebuild pretty easy but lots of little bits and pieces that can go missing.
8. Re-install of the tensioners is a bit tricky but eventually there is a way!
9. If any doubt about the timing, the methods defined in this thread are great and a simple fail safe seems to be to turn the engine through gently to determine if any binding. If there is no binding between pistons and valves then you are good to go.

This thread is real great for understanding these issues! Thanx again for all the great help!

Joe

[sperberj]

Couple more things that I found:

1. You don't have to pull the distributor. I did the entire job with the distro in place. At least ya don't have to worry about that losing timing.
2. I had a rising and falling idle that I never could get completely fixed. After the tensioners were rebuilt this was reduced by a lot. I think that many of the idle issues that I have read about may be related to loose cam chains.....maybe.
3. I couldn't use the collars because the chain was not stretched enough but will have to relook at that in the future.
4. Its a great opportunity to get the engine looking good because this is a pretty messy job with lots of oil drips.

Pix coming and thanks again for all the help as I could not have done this without the experts in this thread!

Joe