Flex Plate Bolts Hit TC
 

I wish I would have inspected this a year ago when I pulled my engine for the first time. My torque converter was hitting my flex plate bolts. I rebuilt my engine and am ready to re install and get it running. I took the TC off to check and see how to address the clearance of the Flex plate bolts when I noticed a lot of large metal shavings in the TC and around the input shaft. What could be going bad from this added pressure to the trans? Bad pump? Is this something I can maybe fix myself? Theres probably no way of flushing out the TC so ill need a new one? The trans was running fine when i pulled the engine but I feel horrible about running a new engine behind a blown tranny especial in the current state of the trans community.
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Did you set the converter gap when you installed the converter?

If not, the converter was probably not engaging deep enough in to the front pump.

I bought a trans specialties convertor years ago that hit like that. I called them and they said in larger units the bop was different. Swapped it out.

When I noticed a lot of large metal shavings in the TC and around the input shaft.

First thing that has to be done now is Transmission, Transmission lines, tranny cooler and torque converter all have to be cleaned. In other words, Transmission has to come apart and be inspected and rebuilt. There are clearances that have to be checked when installing a converter. 1/8" to 3/16" gap between converter and flexplate with converter fully seated in transmission. Pilot on converter has to be checked for engagement. Flexplate bolts checked for interference. Another step over looked is spinning the converter before bolting to flexplate to check for binding in crank.

" a blown tranny especial in the current state of trans community " !!!
Forgive me, I had to say it.

OK, the transmission needs to come apart. Shiny stuff in the fluid is not good. T400s are pretty easy. Loose it good, tight bad.

With the amount of dish that's in the face of that converter where the bolt head marks are it looks like you had the flex plate bolted on the Crank the wrong way , or where you using flywheel bolts to hold the flexplate to the Crank ?

A competent converter rebuild place can cut it open, clean it out, and reweld it. You probably just need to put a grade-8 washer between the converter and the flexplate. Make sure the pilot has sufficient engagement in the crankshaft and the converter has sufficient engagement in the pump. Plenty of good install procedures out there. One should have come with your converter.

It's not that simple as putting a washer between flexplate and converter. Distance has to be measured.

The fix IS that simple. Or it usually is. I know it needs measured. That's why I suggested an installation procedure. I also said the verify engagements. That's usually done by measuring.

I came across a situation like that before. No matter what I did something wasn't right. I started off by using low profile flex plate bolts. Finally pulled the converter and sent it to Midwest to have it corrected (most shops didn't want to touch it because it "wasn't their product"). The guy told me the "geometry" was off, he corrected it and sent it back. Everything fit perfectly after the geometry was fixed.

I spilled some trans fluid lol and I have the transmission off to a guy to be checked out. Let me re-state that this is my first time since buying the car 5 years ago I have taken this engine/trans apart. I measured the amount that those flex plate bolts were crushed and it measures at about .100" So my flex plate was bent around those Flex plate bolts for at least 5 years. Pretty nuts its lasted that long. I'm wondering if this could be a possible cause of my cracked crankshaft.

Anyone ever use an FTI transmission? I see summit has some in stock with an ultrabell on them. Does an ultrabell for a TH400 have the BOP holes in it? Thats what it looks like. Im looking for other options if my trans is going to be an expensive fix and I need this car running and driving in a couple weeks.

https://www.summitracing.com/parts/fti-th400-4ub

They make short head bolts for that stock ones are big.

I run an FTI Glide, zero issues. Their work is good and customer service is top notch.

Yes, the Ultrabell is drilled for both bolt patterns

Does anyone run a Coan 20320-2 converter in their Ponchos? How do you like it? This is what they recommended and im wondering if its overkill.


http://www.coanracing.com/coa-20320-...per-sprag.html

Don't know enough about your combo. It does bother me when companies call their 258 mm converter a 10" converter. A true 10" uses a more expensive core and has been around for fifty years. The 258 mm is a newer core that is being developed to replace the 10" due to the 10" inch core supply drying up.

They can both be made to work and Coan offers a quality product.

having the same problem with a new Coan converter here. Both factory and ARP flexplate bolts hit the converter. Cant shim it as it is already within specs. so get to send it back and wait for whatever fix it might get

Any chance you could post a few pics of the front and back of the converter? I ordered a 9" inch from them and had the same issue your having and I had to send it back to be revised. It cost me shipping for their mistake. Wasn't happy about that. They had to change the back cover. Thanks.

You should consider calling PTC they can help. Coan is not the company it once was.

I remember that. If I recall correctly they wanted you to pay for their converter not fitting properly but then came to their senses. Did you get an explanation why it didn't fit initially?

here are the pics. I rotated the converter against the back of the flexplate so i can see where the bolts were hitting

I just talked with a guy at Coan again and it sounds like what is happening is most converters are made with BBC in mind. Those take a 7/16" bolt with a super short head. The pontiacs have a 1/2" bolt with a thick head. So he pretty much told me that I needed to step up to the billet front cover with a deep dish for an extra $400. No way im doing that. It looks like Fly-wheel bolts for a pontiac have a thin head but they have a shoulder on them. Im wondering if that might be an option. OR Mopar flexplate bolts are 1/2-20 and have a short head. But the thread length is only .500"

That really is infuriating that Coan wont own up to their mistakes. I looked at flywheel bolts also. But as you said, shoulders are too long including the ones made by Mr Gasket.

You could use a low profile button head screw. That would sit lower than a factory BBC bolt.

IMO if one sells a torque converter advertised to fit a Pontiac, then says it doesn't fit because it's not a Chevy the torque converter isn't really for a Pontiac.... It's seems Coan has moved back in time fifty years. Their torque converters used to fit Pontiacs without issues. I've used and sold more than a hundred of them.

Perhaps you could add a mid plate, even if you just used it as a spacer and didn’t mount it to the frame, and then space the converter accordingly to maintain the proper depth in the transmission.

https://www.ebay.com/itm/23491336073...BoC8mUQAvD_BwE

This deserves another LOLZ

How much were your bolts contacting by? Were you using the 5/16 or so sized thick head?

I would say the contact is around 1/16". And yes i was using the bolts with head about 5/16" thick (stock bolts). I found ARP bolts have a slightly thicker head but have a smaller diameter head, which helps in my case.

Hi Paul. No never did explain why it didn't fit. Rep told me they had no issue with these back covers on Pontiacs. They changed it at their cost and it cost me the shipping both ways.

Thank you for posting pics. That's the same back cover I had issues with that they changed. Here are the pics before they changed the cover on the back. I will never deal with Coan again.

Not to tell you what to do, but He wanted the cost to change mine also, and I said no way I'm paying for your mistake. We went back and forth and he finally agreed to change it at their cost. I was still pissed at freight cost. He would also not refund my money when I said I'm returning it. He said it's a custom converter so no refund. You can use me as a reference if you want. I'll provide you with my order number to show what the cost was. Let me know.

Pics of new cover. I included the numbers on the converter you can share with them. Coan

Sounds like Coan is a no go these days. What a terrible experience.
Lane-PTC. Great guy, knows Pontiacs.
I am just about done fitting a Alston .100 thick mid plate in a stock A body frame right now. That might take care of these problems with those Coan converters.
The mid plate is not very big by the time you are done chopping it up to fit. needs trimmed for whatever headers you are using.

If it's a "custom" converter that means it's made for a specific application. If it doesn't fit that application that means the vendor failed. Most likely if you paid with a credit card and filed a dispute they would be given the option to correct their error or refund the money.... That's probably why they caved and fixed Chuck's converter.

They seem to be aware of the issue using their product in a Pontiac. They should go back to their old ways, rather than make excuses and keep raising prices.

But that's just not how America works now

Trans specialties told me they have a different front section for BOP engines. The shelf convertors are Chevrolet based. I had this same issue but saw it when I was installing the trans. The box the correct one came in had BOP written on it.

I installed this new Coan converter to day and it fit perfect. The play from the converter to the flexplate is around .134
My ARP bolts from flexplate do not hit converter.

Have you received any other info from Coan on repair?

What a concept.... So we know for sure they still have the ability to make a converter that fits a Pontiac.

I hope the new converter exceeds your expectations.

Thanks Paul. Ya the converter went in perfectly. I somehow think it's a bit on the big side from what I'd like to see. It's a 245 mm converter.

I'm hoping it flashes to around 5500. My current one flashes to 5000 which seems to cause the engine to be lazy off the line.



https://www.coanracing.com/coa-20440...per-sprag.html

Did you get the ARP bolts in? Did it give you clearance?