[zippy]

So, Those who were following my Scat crank thrust to small thread. I got crank back from machine shop who messed up first place. Gave him a change to fix his mistakes. So, instead, he hands me a bill for $888!!!! After some heated discussions, he knocks $300 off... Upon returning home, I am unloading I notice my SFI flexplate has been ground. 3 large holes. I am pretty sure THIS same shop got me the Fluid damper and SFI flexplate when they got the crank as well. He did the rotating assy. Now, I looked online, and see 2 different flex plates. 1 internal, 1 external Mine, has 4 untoughed holes, like the External. But now 3 new holes opposite. BUT, it also has 1 broken tooth. I was thinking of just filling tooth with my TIG and reshaping it. Easy task really. I have the tools. BUT, now for replacememt later... I plan on doing a 5spd swap. Engine was supposed to be internal. So one can swap plate to flywheel easy. Now, I am not so sure.

Ill post some pics in next reply

[zippy]

Here's some pics

Middle finger pointing to a new hole, and thumb pointing to 3 large new holes. 4 stock holes to the left.

IIRC, it was similar to this plate. https://www.summitracing.com/parts/p...0/make/pontiac

[25stevem]

Holy crap!
I can’t believe that shop!
At this point in hindsight you would have been better off paying for a complete rotating assy from like Butler or KRE because even with today’s high shipping cost it would have cheaper and all balanced up.

[zippy]

Originally Posted by 25stevem

Holy crap!
I can’t believe that shop!
At this point in hindsight you would have been better off paying for a complete rotating assy from like Butler or KRE because even with today’s high shipping cost it would have cheaper and all balanced up.

Not really, remember I'm in Canada, so Canadian ducks and shipping prob be $500 alone now.....

SO, I am here now. Question is, where to go from here? Just rebuild the tooth with my TIG? Or get a new flex and take to DIFFERENT shop to balance? I assume they could balance just plate to plate? Or atleast tell me if this plate IS now internal balanced? I see a heck of a lot of weight taken off front and back lobes of crank. It's a forged crank as well.

[KEN CROCIE]

Does the flexplate fit the crank?

[zippy]

Originally Posted by KEN CROCIE

Does the flexplate fit the crank?

Yes. But now it's been modified for balance, and has a missing tooth. Are internal and external mounting for flexplates different?

[68WarDog]

Originally Posted by zippy

So, Those who were following my Scat crank thrust to small thread. I got crank back from machine shop who messed up first place. Gave him a change to fix his mistakes. So, instead, he hands me a bill for $888!!!! After some heated discussions, he knocks $300 off... Upon returning home, I am unloading I notice my SFI flexplate has been ground. 3 large holes. I am pretty sure THIS same shop got me the Fluid damper and SFI flexplate when they got the crank as well. He did the rotating assy. Now, I looked online, and see 2 different flex plates. 1 internal, 1 external Mine, has 4 untoughed holes, like the External. But now 3 new holes opposite. BUT, it also has 1 broken tooth. I was thinking of just filling tooth with my TIG and reshaping it. Easy task really. I have the tools. BUT, now for replacememt later... I plan on doing a 5spd swap. Engine was supposed to be internal. So one can swap plate to flywheel easy. Now, I am not so sure.

Ill post some pics in next reply

You mentioned using a Fluid Damper. Was it included in the balance assembly AFTER modification for the Pontiac crank pulley? Or do the newer ones come with holes already properly aligned? Mine is about 20 years old.

[zippy]

Well. I think this tooth should hold. But it's future replacement I'm wondering.

[zippy]

Originally Posted by 68WarDog

You mentioned using a Fluid Damper. Was it included in the balance assembly AFTER modification for the Pontiac crank pulley? Or do the newer ones come with holes already properly aligned? Mine is about 20 years old.

I never modify the damper. I drilled new holes in pulley to match damper.

[68WarDog]

Originally Posted by zippy

I never modify the damper. I drilled new holes in pulley to match damper.

You're correct. I had it backwards.

[zippy]

So, further my research on what 'machine shop' got me in 2016, The crank IS internally balanced. BUT, he sourced what looks like an Externaly balanced Flexplate. One with 4 holes. BUT, engine was 'supposedly' balanced when he built bottom end. I am 100% the extra holes were not there in the plate. Now they are. But, the crank was drilled in usual balance locations. Guess now, my next step is take the flexplate to another machine shop just to see IF it is been made to Internal balance or not. Pretty sure my tooth repair will hold. TIG is a great tool

[78w72]

how the heck did the machine shop break a tooth off?? they should be buying you a new flex plate & waiving any related labor charge. they should also be able to tell you what they did to the flex plate with those extra holes... & why.

[zippy]

Starter loosened off and broke the tooth, That wasn't shop. They never noticed until AFTER they did all them holes etc

[78w72]

ok wasnt sure how the tooth was damaged.

[racegto65]

Originally Posted by zippy

So, further my research on what 'machine shop' got me in 2016, The crank IS internally balanced. BUT, he sourced what looks like an Externaly balanced Flexplate. One with 4 holes. BUT, engine was 'supposedly' balanced when he built bottom end. I am 100% the extra holes were not there in the plate. Now they are. But, the crank was drilled in usual balance locations. Guess now, my next step is take the flexplate to another machine shop just to see IF it is been made to Internal balance or not. Pretty sure my tooth repair will hold. TIG is a great tool

Looking at the picture with your hand it looks like the 3 large holes were done during balance which tells me it was an external flex plate on a internal crank. I have balanced hundreds of cranks for all brands and never remove weight from the flexplate/flywheel because it makes it almost impossible to match and replace if needed. At this point I would never trust the plate or the balance job and replace it and have the crank respun to check. The first shop should have given you a balance card to duplicate the bob weight.

[25stevem]

And unfortunately two of those 3 new holes are right where the center section is welded to the ring gear so now the fkexplate is balanced but a good amount weaker!

[KEN CROCIE]

I asked about crank fitment because the flexplate didn't look like a Pontiac. Too many holes, I guess, threw me off.
The 4 holes , I believe, are the factory "offset" balance holes. The three larger holes appear to counter balance the 4 holes, making the flexplate "zero " balanced..
Pretty much the same conclusion you came to at #11 But you have to trust the machine shop that the balance was performed. Drilling the large holes to zero the flexplate would not be unusual.

[zippy]

Well. Saga continues. I made a rig to spin my flexplate to 2000rpm. Zero vibes. So it has been made neutral. That is good. Shop isn't responding to my emails. But, upon turning the trusts down. He nicked the journal in the middle. It's about 2thou deep. But in line with the oil hole and oil groove in the bearings. So it won't do harm. But eff me. Such shoddy work. He used to be good I hear. Not now.

[25stevem]

In that second photo why am I seeing evidence of circular polish marks against the then ones that run around the journal like they should?

[mgarblik]

Anyway you can post some wider shots of that damaged area? Very hard to see what I am looking at. Is that the #4 thrust bearing journal? Looks very strange to me in the tight shot. The damage you highlighted looks bad and they obviously went after it to "try " and clean it up with hand sand paper or an aggressive Scotch Brite pad. You can see the random scratch marks across the journal that would never be there if it was polished with a proper belt polisher in a lathe or better yet a micro-polishing belt. It's a bit of a mess overall. You may want to place new main bearings in the block, torque everything up with just engine oil and then rotate the crank a bunch of revolutions. If you see witness marks in the bearings, that crank needs to be addressed by a professional machinist to make it function correctly.