Thread: *Urgent* need help identifying chain, 7/8th or 15/16?

I'm assembling my built transmission, with a new 300m input shaft and a used (supposedly less than 500 miles) 2.93 single chain set. Upon assembly, the chain appears stretched.. I can press on it and it touches the bottom of the case.

It looks a little different than some of the 7/8 chain sets I've seen pictures of, so I am wondering if this is a 15/16" chain? The measurement shows it to be more the size of 15/16th, at 0.9325" in a caliper.

This is for my turbo GTP.. Does anyone know where I can get a replacement chain and which one this is? Was hoping to install this trans next weekend.

See pics: sc92bird's Library | Photobucket

Thanks,

Jeramie

if you can ball it up or fold the chain around backwards it is a "15/16th" style, if it is straight and will not fold over it is a "7/8th"

That is a 15/16's.

Like everyone said...15/16...and you're really gonna want to run the 7/8" instead.

I have pics of a caliper on a 15/16" if you need it. It's also the only chain I've seen snapped. Adding further..the gearset is not the same between the 15/16 and the 7/8 chaings. Pitch (I think it's called) is slightly off. Clearly ...as you know the chain touching is too stretched to use. ATSG book says you should have 1/8" or more to the case.

You're lucky...15/16" chains usually don't stretch. They just break.

Originally Posted by GTPpower

You're lucky...15/16" chains usually don't stretch. They just break.

This

Thanks for the confirmation guys, I just ordered a 7/8th 2.93 chain set from Dave @ TEP. I was tempted to wait for zzp's new chain, but I just want to get the car back together at this point. Its just a rockered GTP with an intercooled 58mm turbo, so not insane like some of the other turbo builds around here. Might run mid 12's.

I would have thought a thicker chain would wear better and be stronger. So are they made different? Is that why the 15/16 can be balled up?

I would have thought a thicker chain would wear better and be stronger. So are they made different? Is that why the 15/16 can be balled up?

I think the roller vs rocker design is where the weakness is. This chain was pretty stretched with only 500 miles, but it also had several track passes on it from a VSx cammed GTP on a 100 shot of nitrous on slicks.. That car dynoed 440whp, so the 15/16th chain is not adequate for that power level. I hope to be around 400whp with my setup on E85 and more boost, so I figured if the 7/8th is a little stronger it would be better for me.

If anyone is interested in my 15/16 single chain setup (2.93) ratio with a brand new chain, send me a PM. I bought a brand new chain before deciding to go 7/8th. The gears are tapped and the reluctor wheel is screwed on and red lock-tited down so it will never fly off. This setup would work for lesser hp supercharged guys, and I'll let it go pretty cheap. PM for details.

Some of us can kill that "never coming off" w/o trying hard.

Love my 1" chain

Originally Posted by ls1camino

Love my 1" chain

Do they make a 1". Somewhere I read they didn't make them or they quit. So, just like my question on the 15/16 - 7/8, I would have thought the more width the stronger the chain. I guess unless they cut back to lighten to cut down on rotating mass. If I read some post here right, I guess how the 15/16 is constructed actually make them weak. So if there is a 1" chain, what is it's pros and cons compared to the 15/16,7/8?

Originally Posted by penright

Do they make a 1". Somewhere I read they didn't make them or they quit. So, just like my question on the 15/16 - 7/8, I would have thought the more width the stronger the chain. I guess unless they cut back to lighten to cut down on rotating mass. If I read some post here right, I guess how the 15/16 is constructed actually make them weak. So if there is a 1" chain, what is it's pros and cons compared to the 15/16,7/8?

1" is the best you can get. It was made by GM for their racing division. They pop up for sale every once in awhile for the average cost of $2000. I've never heard of one failing.

5/16" chains snap.

7/8" chains stretch after awhile.

The lack of a good chain is the main reason you don't see more turbo 3800s. Some are content replacing their 7/8" chain every 10k miles and others are content on replacing their stock trans with another stock trans when they finally catch traction and pop something.

For example:
ClubGP Message Forum troubleshooting

Here's a pic of my 1" chain:

In talking to Dave at TEP, he referred to the 15/16 as a mismeasured older 7/8. Anthony and some others can probably comment on it more, I believe the way the chains are put together is different, which keeps them from folding on themselves etc and makes them stronger.

Also..on the 1" there are two different versions. There's the 800hp set and the 1200hp set. The Ecotec guys started snapping the first version.

I also heard ZZP's new 1" chain that is due for release in August is still a HyVo rocker chain. Basically a 7/8" chain with 2 extra links, the material is no different.This leads me to believe that, combined with only being offered in a 3.29 ratio may not be as durable as it sounds. Surely better than the 7/8" but by how much? I'll let someone else be the guinnie pig, and maybe after I stretch my 7/8" give the ZZP one a shot if its doing well in other people's cars.

Some of us can kill that "never coming off" w/o trying hard.

Hey, if you can't beat someone at the track, you can at least fling a reluctor wheel at them..

But seriously, what is the do all end all solution to not tossing your reluctor wheel at your opponent like a chinese star?

The answer is ...don't drive like me.

In under 2000 miles I was able to stretch the 7/8"