Advice on Timing Chain Replacement

[rpoletis]

Hello Everyone,

My name is Rich and it has been 2 years since I last posted anything to this website. Being in the military, I usually rotate in and out and my GN goes into lay-up while I am deployed. Now that I am back, I need to change my 87 GN's timing chain (it has 110,000 miles, it is definitely ready). FYI my vehicle is bone stock and I just cruise around town with it on weekends. It never sees any hard use.

I have the information on how to change it (from this website), but I am having a little problem on what kind (OEM or after market). When I look at Summit Racing, I did not see many items for Buick vehicles. When I talked to the dealer about a kit with all of the required parts, he did not seem too knowledgeable, and he was fumbling through the computer on what I need.

Therefore, I am asking the experts on the web site about timing chains. Do I go after Market or should I stay with OEM equipment from the dealer? Are there kits available out there? I think I should replace the oil and water pumps (because of the cars mileage). Is there anything else I am missing or need to be watch out for? Any advice would be greatly appreciated

[GNXDad]

I am no expert, but either oem or a reputable aftermarket is fine. I would not change the oil or water pump unless your having problems with them. just my 2 cents. I am sure as the forum grows or the gurus chime in you will get a wealth of more info. than you can handle.

[Keller]

Summit carries many things they don't list that just aren't popular. Like Buick parts. If its not for an SBC, its usually not worth listing in the catalog. They may not even stock it. But they can get it.

The stock chain works fine. Just be sure to add in a new tensioner and the GM cam button that our cars never got. The double rollers were popular serveral years ago, but led to some problems. It was never clear whether to use the tensioner or not. I believe its not needed with the double rollers. I know of at least one person who's double roller ripped off the tensioner, munched it up, and ended up requiring him to tear things down and look for all the pieces.

IMHO, if you aren't looking to build a monster motor, stick with what already treated you well so far. Stock chains seem to work ok with stock or mild motors. I'd be interested in hearing how yours looks after you tear things down.

[pfredricks]

"...the GM cam button that our cars never got."

Are you refering to the missing nob on the timing cover or the spring loaded button that fits in the front end of the cam shaft?

[Keller]

The latter.

[gofstbuick]

The tensioner is not required for a double roller chain. If you use a tensioner with the double roller timing chain, the chain will eat the nylon tensioner, and the nylon particles will deteriorate to a cloth type material (suspend in the engine oil) and completely or partially plug the oil pickup tube. I have since switched to a single row timing chain with steel timing gears. I purchased a cloyes timing set with steel gears. If you're really interested in using a DR, I'll sell you my used Edelbrock true roller DR timing set, but as described above, don't use the tensioner. You should follow the advice of changing the tensioner and replacement of the cam button (preferably a needle bearing type).
If you're not having problems with the water pump, I would leave it alone.
Regarding the oil pump, the oil pump housing is aluminum and the gears wear the surface. This is the thrust surface of the oil pump and may affect oil pressure. I would suggest the use of a oil pump rebuild kit. It is equipped with a new steel thrust surface (some have termed this as a booster plate). You can set the clearances between the booster plate and the gears. The factory service manual has very precise specifications regarding oil pump clearances. You can also open the oil passages up on the oil pump housing. There are also high volume kits. I would stay away from high volume kits. It put too much volume against the cam bearings. I had a lenghty conversation with Jim Belle (Kenny Belle) and he said to renew the thrust surface (with a booster plate), but no longer recommends the HV kit. The reasons was the volume placed on the cam bearings and may eventually lead to front cam bearing failure. You take this how you want, but my stock oil system produces 15psi at idle and 45psi@2400 rpm (spec is 37psi@2400rpm) and is sufficient for me. If you open the oil galleys and oiling passages in the engine, then you may be able to support a high volume system, but you'll be better off with a booster plate for a stock oiling system. Additionally, the gears from a stock turbo timing cover are said to be matched better than a normally aspirated engine, so if you install a booster plate, retain the stock gears.

[rpoletis]

Everyone,

Thanks for the info on the Timing Chain Replacement. I am leaning toward the POSTON kit (replacement for the stock chain). Overall, I am going to stay away from the double roller system. The plan is to start ordering all the parts next week, and begin the work in early October. Hopefully, everything will go smooth and I will have no issues. I will keep you posted, especially if the cam sprocket looks real nasty.

Thanks Agan

Rich