timing chain project?


I've been perusing the board lately and for some reason I keep running into timing chain horror stories (ie: gears with missing teeth, etc.)

So, I figure that I should think about changing mine. The problem is, as we all know, that you can't just do one thing when you're doing a "mod" or repair.

I figure that since I'm already in there I want to do everything I can, short of a full rebuild, of course.

So, here's what I'm thinking... New timing chain, new water pump, oil booster plate or higher performance oil pump assembly, new neoprene front seal, new rear main (since I'll have to pull the oil pan), and possibly a Biggie oil filter adapter.

Am I missing anything??? Any other suggestions? Any particular brand of chain or for that matter any of the other parts? Or any vendors you can recommend? (I have a huge list of vendors, but I'm always looking for the best deal around)

I need some experienced advice...
I would not mess with the oil booster plate, pump, or rear main UNLESS there are any issues with those parts right now and the water pump does not even need to be removed from the front cover. Biggie oil filter adapter is not really messing with parts and is an upgrade that many say is a good upgrade - will find out for myself very soon. The seal in the cover is easy enough to do when it is apart.

Maybe a new belt and check of the cam sensor.

Massive clean job before work starts will make it all go much better.

I have about 300K on my front cover and oil pump so I decided it was time to replace it when I did a cam change some time ago - the Silver Seal cover sucks - sorry I messed with it as the 300K part still spec'ed out just fine.

If ya got to play with it, this would be a great time to learn the difference between the cam you have and something different :)
youll need
timing cover gasket set , comes with front seal
oil pan gasket (rubber or cork )
oil pickup tube w/screen
rear main seal (if its not leaking bad dont touch it) its easy enough to drop the pan down later if a leak should get worse ,
rtv -smeared at the parting lines of the cap and front cover
thread sealer (or permatex ) -for the bolts that go into the block since they are in water passages
loctite -for cam gear bolts and oil pickup tube bolts , also good for pan bolts
cam button roller type ,
permatex #2 non hardening - i like to smear paper gaskets with it when coolant is involved , also good for bolt threads
coolant -2 gallons (you could get away with RMI-25 and distilled water in so. cali, I run RMI 25 and water during racing season )
oil- 5qts
cam sensor setting tool from caspers (or his new cap)

other stuff since your pulling it apart
the small S bypass hose from back of cover to manifold,
upper and lower rad hose unless yours are new
assorted water hose clamps
if youve got a stock mounted I/C ,good time to clean it inside and out and maybe upgrade the hoses/clamps if you havent already.
good time to go to a 160 therm or replace it if its been there a while.

on the timing cover
dont mess with the oil pump unless you have issues right now
just check to be sure that there isnt any slop in the drive gear shaft (the end that connects up with the cam sensor ) ,slop would indicate a worn timing cover case
check the surface where the old cam button rubs (spring type)
if its worn a groove or a peak its not necessary to replace the cover , just make sure the surface is flat (no pont in the center) for the the new roller type cam button , if its recessed a little thats ok but if its peaked in the center grind it flat ,

on the original cover the seal goes in from behind , if yours was never off the car it mays still have the rope which is held in with a steel retainer ring , tap that ring out with a drift from the front side and discard that ring , from the back side tap the new 1 peice oil seal into the cover

make sure you torque the cam gear bolts and use some loctite on threads

once you get the cover back against the block and before you put all the bolts in make sure the cam button is still in the cam and didnt fall under the car

if your new chain is not a stock type dont reuse the tensioner !

before putting the cam sensor back check shaft for slop or up down play and if its side to side time for a new one, if its just up down it (it should have some play about the thickness of a dime ), if its too much it can be shimmed . also replace the roll pin in the gear , mine had up down slop and the pin had cracked in two and dodged a bullet catching it when i did the chain . since replaced with a new GM one part # PC-16 (in standard motors box) for around 50bucks , kirbans still has some of those pc-16s if you dont want to search around for it .

lastly 220ft lbs on the balancer bolt

torque specs are available online for all fasteners
I did the same on my 105K. The stock gears and chain were in great shape.

Don't change the rear main unless it's leaking. Mine didn't leak, changed it, now it leaks... :mad:
Jerryl said:
VERY NICE write-up! Bet it is all from memory. :eek:

amazing how much junk is stuffed in the attic ,
but dont ask me where i put my keys or the name of that guy i met yesterday . :D
A stock steel replacement timing gear with tensioner will work fine for most all applications down to a mid-10 sec car. No need for a double roller which will chew up the tensioner.
Not when you don't install the tensioner! Most, if not all double-rollers are made to be used WITHOUT tensioners, correct!?
GM Timing Chain part#12537202. GM Bearing type cam button part # 25532588. In case your cam sprocket needs replacing part # 25523115, crank sprocket part # 25519954........ :D
I was wondering about the double roller chain as well. I wanted to upgrade any parts that can be.

So, is the concensus that I should use OE parts or should I go for the gusto and use the heavy duty stuff?

I'm not a drag racer type but I'd like to end up with somewhere in the 11 second neighborhood eventually. It's just nice to have gobs of power on tap for the unsuspecting fools that try to challenge the Buick :eek:

Therefore, I endeavor to make everything as strong as possible.

BTW, thanks for all the input. I need all the help I can get...
Double roller not needed unless using roller cam. I prefer GM replacement chain but to each his own. I'm using a new GM stock chain with my new build currently. HTH. Paul.
How many miles are on it?
I know someone running low 12s and 180K on the stock timing chain that has used synthetic oil and never detonated it, its still working fine.

Good advice above :), but wait till it breaks before you tear it apart.
If it slips, it might bend pushrods if the heads have been decked.
Thats the worst horror story ive heard about if the nylon gear breaks.
I have read the thread. It was prompted me, along with a few other threads, to think about doing mine.

My 86 was purchased with a broken odo and speedo. Carfax and DMV records put me as the thrid owner but prior registrations terms indicated unknown miles. It stopped recording at about 70k and that was years ago.

Based upon a general average calculation I estimated that the car was at the 180 mark instead of the 86k that it currently reads. However, the car was a basket case and I'm sure it was rarely driven because of all of the problems that it had. Bad brake system, bad trans, bad cat, etc...

Anyway, I've since replaced just about everything I can short of opening up the block and I figured that I'd try the chain and a few minor things as opposed to doing a major renovation such as QWK... :biggrin:

The "boss" will let me do something that needs repair, but isn't too keen on the whole "I gotta upgrade everything" concept. Therefore, I was just interested in checking to see if the gears were bad but I figured that if I was going to check that I might as well just replace or at least have all of the parts on hand just in case.

Currently the car is in perfect running condition. Scanmaster numbers are on the money and I just want to be on the safe side...
I was thinking about the valve springs (not sure what spring rate? 80, 100, 120?) but then I was afraid it might affect some other component such as the Cam. Am I mistaken?