failed flexplate

I had starter issues and rewired with new 1 ot (0 gauge) put in a new starter that was cranking fine and starting the engine with no issues. My starter stayed engaged and chewed up the flexplate. I'm wondering now if the Scat flexplate had an issue. I never heard grinding before today, so I am not sure. Any thoughts? Anywhere I could have gone wrong?


Its bad timing really. It was using a ton of fuel. I thought gasket at first, but maybe a carb issue. I was about to do a compression test. I guess Ill do a leakdown test instead. I am afraid to invest more time in it, my wife is getting frustrated.

Did you measure the starter pinion to ring gear clearance? Have had to shim to get right more than once .

I have to confess I did not. I am not sure how to do it with that c4 bell housing and the limited space down there?

I added. 2 photos to the gallery...not sure how to post or link here. You can see where the starter pinion gear was/was not making contact....if I can get it uploaded correctly.

https://m.imgur.com/a/Hi8YrJd

This is an Ultima, but the 1st starter I tried was a db....and it had drag. I rewired, and it was still slow cranking. It started 1 time and failed. I didnt notice any flexplate damage when I changed to the Ultima, but I didnt rotate the flexplate arouund.

Any flexplate recommendations if I do move forward with it?

I probably have an oem unit back in Ohio, but prefer to stick with an sfi unit.

I was actually there today and forgot to look before I left

CSI plate is a good one

Someone located my old oem fp in Ohio....I'll try it 1st. Unless something warped it over the years it should work....it did before. I figure I better stick with what Is proven for now.

Thanks

Looks like more than a failed flexplate.....unless its scraping something.....doesnt sound like it is. I spun the engine around to tdc and felt a tight spot tonight . I rotated it by hand a few times, the tight spot is hit and miss. It is not every rotatio and notvevery other. It also is not the same spot each rotation. Bearing? I would expect more consistency?

Ill unhook the alt, loosen rockers, etc after the leak testing and go from there, but certainly looks like Ill be piecing the engine out at this point.

I am doubting my father would have forgotten that, but certainly will add it to my checklist. Thanks for the responses

Considering the starter issues I had, I feel like this tightness may have been there before, but I didn't happen to catch it.

It was tighter tonight...I unhooked the alt and everything freed up. Huge relief! On to thek next step

Well....more to follow. i was about to start the leakdown test and needed to rotate back to tdc. I needed a large breaker bar to move it. No metal in the oil filter, but definitely wasnt the alternator. Ill leak down tomortow, after I'll back of the rockers, unhook the totque converter....in a couple of weeks I can get the flexplate off. If none of those make a difference Ill dig in.

Depending on what I find, chances are Ill part it out and do a turbo2.3l.

Next week I will probably create a new post regarding current findings. I did the leak down test, everything was within 3% range top to bottom, very consistent. No air leaking.

The valve train is now backed off, I still have a tight spot. I do notice a slight creaking sound when I hit the tight spot. I can't tell if it is internal or not. It is not louder with the vc off or the dzzy out. I don't have an engine stethoscope.

I did insert a borescope. 6 cylinders are perfect. 1 has a very small horizontal line/scratch. It is almost certainly not enough to catch a fingernail on. It is near the top, probably around where the rings would be. The number 1 cylinder has some scoring on the intake manifold side of the engine. I am guessing had some fuel wash....but wondering what of the 2 is cause or effect. The scoring does not appear deep to me....but it is just a scope. I'll post images when I return next week. I am doubting these are related to the tight spot unless it just happened. I an wondering about a wrist pin.

Lastly, the random tight spot is in a range of about 45-60 degrees, but seems to hit tightest in the movement none of the pistons are tdc or bdc. I am suspecting that is not coincidence.

I know it needs to come apart, but on the off chance whatever failure happened is in early stages I hope for expertise so I don't miss something....and considering the oil it appears to be in early stages.

Is it possible that you've got a bent connecting rod, or maybe a spun bearing?

Wayne (SAWDOFF) Pearce

It was running fine, just gas smoke. No knocking, etc. I doubt a bent rod. I will get around to checking bearings. If it started to spin, it has not shed metal into the oil yet. The filter and oil were metal free. Not saying it isn't possible, I consider it possible. I would not even rule out the fp making contact somehow....


Edit fwiw... It was mostly fuel smoke. I couldn't rule out oil being mixed in, but I did not see indications of it either, and engine was cool. 10 minutes was the longest run.

I'm posting as much to follow up on myself.... I am going to do the stethoscope. I ordered one. I am hoping to pinpoint the sound before ripping it apart. Maybe I can maybe I cant't? At this point I just want to make sure I can figure out the where, and hopefully the why.

I have: starter issue and flexplate issue. Heavy fuel flow & smoke and cylinder damage. Also, the tighteness. It's almost certainly 2 sets of issues. If I can't narrow down cause and effect I'd be fearful of reassembly.

I think I see what caused the fp/starter issye now. I have a very slight gap between the motorplate and block. I torqued it down to spec when assembling, but the gap is in a dark spot and not easily visible. I am wondering if the midplate is slightly bound. It is a 1/16 gap at best, top drivers side. I think that would be enough to cause issues?

The smoke...exhaust reversion?

Exhaust reversion, bad valve timing, excessive fuel consumption, fuel wash, piston scores cylinder wall....the the tighteness forms and causes a flexplate failure, magnified by a slightly skewed transmission alighnment.

The tightness yet to be diagnosed, but looks like this is probably it. It would explain why nothing helped the carb.

Any thoughts in that regard?

Ignore the horizontal line, I realized it moves with the piston. It is just a reflection. This is the same spot different angles that catch the scoring best

I started loosening bolts last night. The tightness is from the fp....I am guessing it warped, assuming that slight crookedness on the bellhousing probably did it? At least it is not the crank/rods

. How concerned should I be over the cylinder wear on the pictures? I am thinking I should get it running 1st and after pull it for a freshning up?

I finally pulled the fp. The tightness and noise, it was rubbing the block/trans plate. Looks like it is warped, 1/4 seems to not sit flat. I never considered checking flatness. Live and learn. No more Scat fp's for me!