[chuckies76ta]

Hi: Bought a new Coan Converter for our TH400 and did a trail fit and the converter is hitting the flex plate ARP head bolts. So, I bought a set of ARP bolts with a smaller head on the bolt and converter is still hitting the flex plate bolts. Did some measuring and I only have 3/16" room between the converter and the flex plate for the bolt heads. My ARP bolt heads are 1/4" thick.
The back of the converter is built with a bulge that interferes with the flex plate head bolts.
The black converter is the questionable one. You can see the witness mark on the converter from the bolt heads. The blue one is my current converter for comparison. It has a 1/2" of room for the bolt heads. They both are 1" from the feet of converter to the face of the bell housing which is good.

Anyone else ever run into this issue and what was the cure?


Thanks

[ponjohn]

My redneck convertor or continental did the same thing. I had to use OEM flexplate to crank bolts.

[joes455]

I thought i was the only one still using a redneck converter

[chuckies76ta]

Thank guys. I tried a smaller ARP Head bolt. Still hits. Seems like converter was made for a mid plate. Sending back to vendor for credit. They want more dollars to change the back plate plus shipping.

[ponjohn]

I tried the smaller ARP bolt as well - did not work.

[chiefbigb]

I seem to remember running into this on my daughter's 67 with a trans specialities convertor. When I told them it was for a Pontiac they sent me a different convertor that worked.

[chuckies76ta]

Ya, sent back today for a new back cover. Can't return cause it's a custom converter.. So, I pony up the dollars for the new cover.

[PAUL K]

Originally Posted by chuckies76ta

Ya, sent back today for a new back cover. Can't return cause it's a custom converter.. So, I pony up the dollars for the new cover.

Did you buy this new from Coan for your car? Sorry if I missed it but thought you did.

[chuckies76ta]

Originally Posted by PAUL K

Did you buy this new from Coan for your car? Sorry if I missed it but thought you did.

Yes, Purchased new for my wife's 68 Firebird.

[PAUL K]

Originally Posted by chuckies76ta

Yes, Purchased new for my wife's 68 Firebird.

Does your wife's car have a mid-plate?

[chuckies76ta]

No it doesn’t. It seems like it was built for a mid plate. They said that would cure my issue with the converter but I don’t want to use a mid plate.

[PAUL K]

Originally Posted by chuckies76ta

No it doesn’t. It seems like it was built for a mid plate. They said that would cure my issue with the converter but I don’t want to use a mid plate.

I'm not sure I'm understanding, but I'm a bit curious.... You bought this converter new from Coan for a specific application. The converter doesn't fit the intended application, so they want to charge you to make it fit??

[chuckies76ta]

Yes. Consensus on his part is they have built lots of these for th400 combos with no issue. I’m running an IA2 block and Reid case. Everything measures fine on my end. He said like $150 to replace back cover. Is what it is. They have your money. Don’t want a pissing match with them. It’s a custom converter and can’t be returned.

[PAUL K]

Originally Posted by chuckies76ta

Yes. Consensus on his part is they have built lots of these for th400 combos with no issue. I’m running an IA2 block and Reid case. Everything measures fine on my end. He said like $150 to replace back cover. Is what it is. They have your money. Don’t want a pissing match with them. It’s a custom converter and can’t be returned.

Thanks, that is what I thought was going on. I used to use a lot of Coan converters. With a few exceptions I've stopped using them because of crap like this. The last straw was when they missed the stall speed on a high horsepower engine in a heavy car. They said it was my fault because I must not of given them accurate information.... I only filled out their spec sheet and supplied an accurate dyno sheet. With that attitude, large increases in parts prices and their charge to re-stall a converter went from $150 to $450 has moved them low on my "go to" list. They do make a specific 8" converter that is bad azz for our Pontiacs however.

Good luck with the converter I'm sure it will all be worthwhile once it's together and running well.

[chuckies76ta]

Thanks Paul for the info. I’m not to happy about it, but sometimes gotta pic your battles. What kills us here in Canada is the shipping. I do like US made products though, before offshore. But will save that for another thread.
Ya their customer service kinda suck as far as I’m concerned. What was said to me when ordering the converter, “We been doing this for a long time “. Customer service to me is alway Top of list.

[PAUL K]

Originally Posted by chuckies76ta

Thanks Paul for the info. I’m not to happy about it, but sometimes gotta pic your battles. What kills us here in Canada is the shipping. I do like US made products though, before offshore. But will save that for another thread.
Ya their customer service kinda suck as far as I’m concerned. What was said to me when ordering the converter, “We been doing this for a long time “. Customer service to me is alway Top of list.

You don't have much choice. Next time take a look at PTC.

[Scott Stoneburg]

How close is it? I have always ran a thick washer between the flex plate and the converter.

[chuckies76ta]

Originally Posted by PAUL K

You don't have much choice. Next time take a look at PTC.

Yes, and that's who I was told to go with in the first place. I sent an email to Coan and they jumped on it right away. And I went for it. I heard and read lot of positive info about PTC. Thanks Paul.

[chuckies76ta]

Originally Posted by Scott Stoneburg

How close is it? I have always ran a thick washer between the flex plate and the converter.

Well here is my understanding about install a converter. It's not a matter of just install a thick washer. The consensus is that there be a minimum distance of 1/8" to 3/16" between converter pads and flexplate mounting. My last converter was within this spec and required no washers. If more than 3/16" they want it shimmed within spec. if less than 1/8" that is too tight and the converter pads would need to be milled. They want the converter to be able to move in the pump housing of the transmission. Hence the reason they call it a flex plate.

I know you know all this Scott, Just putting it out there in case my thinking is fubared. lol
The only other way to make space it to run a mid plate, but then you have to make sure the hub is it the crank snout properly. My converter hit the head bolts on the flex plate before I could bolt it up.

[chuckies76ta]

Just a update: Turns out that Coan will pay for the back plate change after some discussion with the sale rep. They also are paying for the shipping return. I'm probably not gonna run this unit this year as my existing converter is back in after a flash change. We did test run the car a week ago and the track was not prepped properly so we had traction issues off the line.