I have a 95 LT1 car that I am replacing the engine with a LS1. I want to use my LT1 A4 tranny and converter so will it bolt right up to a LS1 flex plate?

thanks

 

someone has done this I hope!

 

The LS1 Flexplate HAS NO weights on it (Balancing is internal to the engine). If the flex plate that you have has any weights on it, it will not work. Moreover, it is unlikely that the bolt pattern on the Flexplate will mate with the engine.

You will most likely need an LS1 Flexplate that you will have to drill to match your B29 Converter or whatever converter you happen to be using.

Sam

 

Why not just get the correct LS1 converter and flexplate??????

 

Because a LS1 converter will not work in a LT1 tranny .

 

I have a LS1 flexplate. So I can use my LT1 tranny and converter bolted up to the LS1 engine and flexplate? I just need to drill for the holes ? The clearance between the flexplate and converter should be the same?

 

The crank pilot on your older torque converter is 1.600" in Diameter. The pilot hole in the LS1 engine is 1.700"

Fortunately the mismatch is in your favor. You simply need to make a small spacer that adapts one to the other.

The spacer would have an OD of 1.699" (-.004, +0) and and ID of 1.601" (-0.000 + 0.004).

If you have a lathe, it will take about 10 minutes to machine it. I will be making one tomorrow, in fact. I am doing exactly the same thing, until I modify my transmission to drive the correct torque converter.

I am told that to do this, I will need to replace the input shaft and the stator support in the pump.

If you want, once I finish the part, I can post the complete dimensions - but its a pretty trivial piece.

In fact, I have been driving my car using the old converter, the problem is vibration because the pilot on the torque converter is too small. I didn't notice it until today (someone (jason) on this site pointed out the discrepency).

Sam

 

Awesome. What would it take for you to make two ?

 

Ttt!!!!!

 

Made a mistake on sizes. Turns out that both the old converter and the new converter are 1.700 inch. Don't know how I could have made such a mistake.

Anyway, this complicates the sleeve. I did make one, but it was a bear - requiring two machining attempts. The piece I made is out of 6061-T6. I don't particularly like this piece in aluminum, but it did work to line things up well. The piece feels no stress in operation and is not involved in power transfer. Aluminum against steel has the problem of galling when first mating the TC with the pilot hole. It should at least be anodized (not that I anodized mine). Ideally, it would be made of steel. I just didn't have any two inch mild steel rod stock handy.

The same thing can be accomplished with a spacer but this has some downsides as well. For one thing, a spacer would be involved in the power transfer. It extends the bolts out further and subjects them to quite a bit of sheer stress. On such a small diameter and with as much as 400 ft-pounds of force being applied on 2" radius, this solution would worry me. The chance of breaking a bolt eventually is significant. I would want an extremely hard bolt if I chose this solution and even then... An alignment pin would also be required to center the spacer. Not a great solution but it is a solution.

How far off is your project? I am going to rebuild my transmission in the future to accept the right torque converter. I can send you the piece when I am done with it. Or, if you really want to get your own now, send me a PM. I will draw my sleeve solution with dimensions for anyone else who may want it as soon as I can get to it.

Sam

 

Why not go to the dealer and get the crank spacer for the 4l80-e for about $20.00

 

Thanks but I had no luck at the dealership. Do you know the part # ?

 

Try #12563532

 

Thank you! I will need to drill the LS1 flew plate correct? Or do they make a special one for this

 

found some useful info. look at the bottom for part #s
http://www.hpsalvage.com/st.htm


It does show a flywheel part #. I wonder if this will fit the LS1 engine?