I've debated on contacting a company to make a gear drive set for our engines. This replaces the timing chain with 3 to 4 gears eliminating the "chain stretch" that is commen with our engines. Before approcing I wanted a list of all cars/engines this would fit to make it seem like they would fit a broad market, rather then just a handful of cars.

Anyway, I found out that most our engines use GM# 14102670. Same as s10, citation, few other gm rides.

It is NOT the same as the FWD cars, so I looked that up.. FWD cars use 14102671.

After looking this over....
It says that 1987 to 1990 FIREBIRDS use the FWD chain? But 82-86, and 91-95 use the RWD chain.


It also says that on the feiro 85-86 models use RWD, and 87-88 use FWD chain.

This is raising a big WTF to me.

Does anyone here have a FWD engine/chain sitting next to a RWD engine/chain to compare for me? Could this MFG possibly make it universal to fit FWD and RWD for a bigger market?

Also while posting this. Who would be interested in such a product? Price I am guessing to be between 75-150 bux.

 

The difference between the FWD and RWD chains is thickness. The RWD chain is thicker (accross the chain and sprockets) than the FWD variant. I don't remember exact difference, but it was between .100" and .125".

The chains can be swapped between FWD and RWD. Some FWD timing covers will need clearancing though, but I can only confirm this for the Cloyes double roller, which I believe is thicker than the RWD chain.

The Crank snouts are the same between RWD and FWD, and the Cam sprocket pattern is the same between RWD and genI and genII FWD. The genIII (3100/3400) uses a single large bolt for attachment.

So the fitment list you are looking for would be:

S-10 '82 to '94
F-body '82 (?) to '96
Cavalier '85 to '94
Sunbird '91 to '94
A-body '85 to '90 (I think that was the last year)
X-body '82 to '??
P-body '85 to '88
Firenza '87 to '89
Cimmaron '85 to '89 (I'm pretty sure the Firenza and Cimmaron were both available up to '89)
W-body '89 (?) to '93

I'm sure there are others, but that covers most of it.

I know there would be a few guys in the J-body comunnity that would be interested in a gear drive.

Myself, I won't run one, to many harmonics created, or passed from the crank to the cam, also too loud to hear anything else.

I'm more interested in a timing belt.

 

I was always under the assumention the chains on the fiero and firebird are the same.

However, if you go to gmpartsdirect and do a reverse search, they are not the same.

The gear drives, you can get silent or noisy. Your choice I want the noise Thanks for info on why the chains are different.

As for a list
RWD(or RWD chain):
Buick centry 86
Buick skylark 80-85
Astro 85
Camaro 82-95
Caprice 85-86
Cavalier 85-86
Celebrity 82-86
Citation 80-85
El Camino 85-86
Impala 85
Monte 85-86
S10 pickup/blazer 82-93
s15 " " 82-93
Cutlass Ciera 82-86
Cutlass Cruiser 85-86
Omega 80-84
6000 82-86
Fiero 85-86 (I thought tell 88)
Firebird 82-86,91-95 (as it states and my strange finding)
Phoenix 80-84


*breathes*

FWD (FWD chain)
Centry 87-89
Regal 88-93
Cimarron 85-88
APV 90-93
Beretta 87-93 (guess they dropped the v6 after 93?)
Cavalier 87-94
Celebrity 87-90
Corsica 87-93
Lumina 90-94
Lumina APV 90-95
Cutlass ciera 87-89
Cruiser 87-89
Supreme 89-93
Firenza 85-87
Silhouette 90-94
6000 87-91
Fiero 87-88
Firebird 87-90
GP 88-93 (think higer)
Sunbird 91-94
Transport 90-95

*sigh*

 

I'd be interested, seems like it's gonna be a pain to change the timing chain and I'd like to not have to do it ever again.

 

Note that there can also be a cam timing difference between the two chain setups.

RBob.

 

Regarding silent or noisy, what kind of noise do gears make?

 

Straight cut gears howl, can be heard for miles. Tapered (or angle cut) are quiet but create side or end thust.

RBob.

 

is it an annoying howl or like a turbo kinda howl?

 

They sound kinda like a supercharger kicked on 24/7.

Best I can explain is watch one of the first sceans (sp) on fast and furious one. Where they pull up to the sandwich shop and the blue car is making a noise. Its very similar to that.


Rbob, is the 2deg advance/retard not possible on a gear setup, just chain?

 

Comprable to a turbo kind of howl. If you drive the car frequently every day, it gets annoying sometimes.

 

Dale: The L-body (Beretta) changed to the genIII 660 in '94, hence why the chain won't fit '94+

I don't understand this timing difference between the two chains. If you install the cam straight up, with either chain they are straight up.

 

Is the gen 3 so far off that it couldnt be incorperated either?

 

Should be able to make it +- any amount (within reason). Cut three key ways in the crank gear, and place three different marks on it. One Cloyes chain for the SBC has 0 , +4, and -4 degrees.

All I mentioned is that there is a possibility that the chains may have different timing. Why would the same engine in the same car use two different chains from one year to the next? GM has been known to do this kind of stuff. For years the stock GM chain for the SBC was set to +6 degrees. Worked fine when used with GM cams, not so good with aftermarket cams.

Dale, is there a cam difference between those years that use a different chain? For some reason I don't think there is.

RBob.

 

Yes, very different. The genI/II use 3 6mm (IIRC) bolts to retain the cam gear to the cam.

The genIII uses one large bolt, approximatly a 13mm diameter thread, to retain the cam gear to the cam.

The difference between the gears is thickness of the chain. there is no change in cam timing.

 

Cloyes for the v6 has a +/- 2 I belive? Been a while since I had one.

As for cam difference, I dont think so for the bird. Doubt it on the fiero.

Raven, thanks for the info.

 

Since we're on the topic of timing chains and I've been having a hard time finding a replacement one with solid information behind it, can someone recomend a good timing chain for my '91 3.1? Preferably something made for performance application.

 

I'm using a FWD replacment in my hybrid. I thought I ordered the RWD part, but crossed the numbers.

BTW I laid down 218 HP and 270 ft/lbs when I was at the dyno last, through a T-5 and 7.5" rear using 3.73 gears. so you can make the call there.

 

Cloyes makes a double roller chain that is for our engines, and its make about 1 hour away from me

Above in this thread, or in another posted this week crane now makes 3 peformance chains.

 

At the tires correct? Whats that est out to at the fly?

 

Found out cloyes makes gear drives, and sells them to edlebrock. Searching on there site, I found this


Accu-Drive® Gear Drives are not recommended for use above 7,000 rpm or on computer-controlled vehicles with knock sensors.


So yes, this is now dead in the water. But I did find alot of info.

Double roller it is for me next time

 

Approx. 250 HP and 310 Ft/lbs.

 

Although for the 2.8 guys, we don't have knock sensors so we don't have to worry

I've got the Cloyes true dual roller chain/sprocket set in my car, I put it in at 186,000 miles. Can't use the stock tensioner anymore because the new sprockets hit it (the box has the directions in it- "remove stock tensioner").

Now I'm at 291,000 miles, so the chain is definately durable

 

I would be interested in a not so noisey one.

 

What're the odds of getting an idea of the slack you've got in it?