torque convertor gap

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Nov 15, 2016
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My Car
1972 Mustang Coupe 302 Auto RHD
Just getting the engine and trans together and in light of my previous problems with clearances I'm concerned my torque convertor gap is too tight

Installed torque converter onto trans correctly with 3 clicks to engage everything

Installed trans to engine then tightened bell housing bolts

Upon checking torque converter gap it looked too small, difficult to get feeler gauges in there so measure how much the stud pulled forward with the vernier calipers and it was .060". The convertor could have moved forward perhaps but the fact that it does have a gap and is not binding doesn't indicate this

Some say 1/8(.125) to 3/16 but others say .060"(1/16) - .187 thou so I'm concerned my gap could be too tight

Interested if anyone else has come across a tight gap and what is really acceptable

I read one thread on another forum where they tried 4 or 5 C4 flexplates until they got an acceptable gap so guessing the offset on my aftermarket flexplate could be wrong?

Have installed the engine/trans anyway but won't be starting it up until confident there won't be any issues and I really don't feel like pulling it all apart again!

 
Just getting the engine and trans together and in light of my previous problems with clearances I'm concerned my torque convertor gap is too tight

Installed torque converter onto trans correctly with 3 clicks to engage everything

Installed trans to engine then tightened bell housing bolts

Upon checking torque converter gap it looked too small, difficult to get feeler gauges in there so measure how much the stud pulled forward with the vernier calipers and it was .060". The convertor could have moved forward perhaps but the fact that it does have a gap and is not binding doesn't indicate this

Some say 1/8(.125) to 3/16 but others say .060"(1/16) - .187 thou so I'm concerned my gap could be too tight

Interested if anyone else has come across a tight gap and what is really acceptable

I read one thread on another forum where they tried 4 or 5 C4 flexplates until they got an acceptable gap so guessing the offset on my aftermarket flexplate could be wrong?

Have installed the engine/trans anyway but won't be starting it up until confident there won't be any issues and I really don't feel like pulling it all apart again!

Yes, brings back some not to fond memories...

 
Last edited by a moderator:
What kind of torque converter do you have?  Also, how thick is your spacer plate between the engine block and bell housing?

If it is a stock converter .060” is probably too tight.

If you have a performance converter that is beefier and less prone to “ballooning” .060 might be okay.  I’d make contact with whomever you bought the converter from and ask them what they think.

 
Last edited by a moderator:
What kind of torque converter do you have?  Also, how thick is your spacer plate between the engine block and bell housing?

If it is a stock converter .060” is probably too tight.

If you have a performance converter that is beefier and less prone to “ballooning” .060 might be okay.  I’d make contact with whomever you bought the converter from and ask them what they think.
I have a Hughes Pro Street 3000 stall with Aeroflow flexplate and OEM sandwich plate

Hughes say 1/8 to 3/16 so to be safe I will make a spacer to match the block pattern which will bring the trans back another 1/16 or more

Some people have use a second sandwich plate but I don't want to remove the trans again so will just slide a spacer into the gap and cut the dowel holes at half moon

Will probably have to make a spacer for the starter as it will move closer to the ring gear

Not taking any chances this time

 
TCI says 1/8" to 3/16" (scroll down to the fourth question)

https://www.tciauto.com/auto-trans-faq

Also read the fifth one.
Have read that one among many others and some say 1/16 to 3/16

One builder reckons he has done dozens of hi-po engines with only about 0.020 gap without problems

I still won't be taking any chances so will go the spacer route

 
Spoke to my transmission builder today regarding the gap and he reckons .060" will be okay

Reckons it would only be a problem on a high HP boosted engine or some GM applications needing 1/8"

Regardless I'm not taking any chances and will shim the transmission back .080 giving me slightly over 1/8" gap

Seems that with nearly everything aftermarket there will be clearance issues and I suspect the flexplate

 
Not that I think it's needed, but you can save yourself a bunch of work by using a Comp Engineering mid mount plate, which is from .090" steel and trim off what you don't need.

https://summitracing.com/parts/cee-4035/overview/make/ford
Thanks for the tip and I also thought of just cutting up another sandwich plate but both the wait and expense aren't worth it

Fortunately at my work we have some .080 plate and a plasma cutter so I will make a template from my spare cylinder block tonight

 
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