Cracking flex plate consensus........Cheapo TQ converters?

[Shadow]

Wondering what the consensus is for the cracked and failed flex plates in the auto sector of our community?

I've done very few auto builds and have only come across the cracked flex plates in high mileage vehicles. Never experienced a flex plate going out in a matter of days..........until now, Maybe?

Those who I have spoken to so far seem to point to the TQ converter as the main culprit;

Poorly machined center hub that does not fit snug in the crank.

Flex plate mounting pads that are Not all the same thickness, so plate wobbles when placed on top of them.

Flex plate mounting pads that are the wrong depth, so factory bolts bottom out on converter.

ect ect.

Thoughts?

[MILKCARTON]

This just happened to me in my Shadow, I figured it was the 1.62 short time paired with the 190,000 mile converter/flex plate. I have yet to take it apart but suspect it is cracked around crank bolts. I was going to try buying two new ones and remove the ring gear from one and stack them.... any ideas?

[A.J.]

All I run is autos. I've never cracked a flex plate. I've used stock converters, to $90 cheapo converters, to Hughes and Suncoast custom converters. I even had to drill new torque converter mounting holes in a 31TH flex plate (I built a jig using another f.p. to get the holes centered) to use the larger 10.5" converter Suncoast built for me and put 360 whp/460 wtq though that flex plate with no problems.

I've seen cracked flex plates on 3.3/3.8 V6's though.

I've heard/read torque converter alignment is the problem. I have no first hand evidence to back this up.

[glhs875]

This just happened to me in my Shadow, I figured it was the 1.62 short time paired with the 190,000 mile converter/flex plate. I have yet to take it apart but suspect it is cracked around crank bolts. I was going to try buying two new ones and remove the ring gear from one and stack them.... any ideas?

Are you using the factory smaller diameter round support ring on the flexplate or just bolting up the flexplate by itself to the crank?

[MILKCARTON]

Are you using the factory smaller diameter round support ring on the flexplate or just bolting up the flexplate by itself to the crank?

I have always used the support ring

[Reaper1]

Funny that I *just* was talking to a retired transmission engineer buddy of mine the other day and this subject came up.

I said to check the run-out on the hub. It seems crap or barely in tolerance type converters can cause this issue in very little time.

[tryingbe]

Off a 2.2L turbo TC.

[Vigo]

This was the first big problem i ever had with a TM and caused me to take apart my engine at the age of 16. Mine was not as obvious as ^ that but the main problem was back then i didn't know enough. I learned that lesson hard enough that im now pretty good at diagnosing them. I remember spending about $120 freshening the engine (rings/bearings/gaskets) and the flexplate only costing $19.

I dont know for a fact but i suspect that a sloppy converter snout allowing the converter to be tightened up slightly off-center, and converter pads of different heights are the most likely theories. I've never had a repeat failure on a flexplate but i've never followed a flexplate replacement by repeating the same mileage that was on the original flexplate, so i dont know if the ones i've replaced 'fixed' the problem or simply punted it another 100,000 miles. Although that's pretty damn fixed in my book..

[wheming]

Does anyone have a sound clip of what a cracked flexplate sounds like?
I suspect Slug might have one but it only makes noise under specific conditions.

[tryingbe]

Idle makes loud knocking noise. Moving at speed the noise goes away.

[bakes]

I had a flex plate break multiple times on a nitrous feed big block 4x4 raced truck went through 2 flex plates before finding a ballooned TC.

[wheming]

Idle makes loud knocking noise. Moving at speed the noise goes away.

That doesn't sound the same for me.
Here is my old thread.
http://www.turbo-mopar.com/forums/sh....php?p=1015859
Still has not been resolved.

Since i had installed the engine in Slug, and the shortblock in MeanMini, it is possible i damaged the flexplate in Slug during the install. When i had Brian go through the van, he foundvthe flexplate bent. Possible that i did it during install, or that it was already bent.

I haven't broken one yet that i know of, but they are easily damaged when installing if the torque converter isn't slid all the way in when bolting up the trans.

[Shadow]

This just happened to me in my Shadow, I figured it was the 1.62 short time paired with the 190,000 mile converter/flex plate. I have yet to take it apart but suspect it is cracked around crank bolts. I was going to try buying two new ones and remove the ring gear from one and stack them.... any ideas?

I've heard of people stacking two and welding the centers together, or at least they said they were going to. Never actually saw any eveidence that anyone has done it.

All I run is autos. I've never cracked a flex plate. I've used stock converters, to $90 cheapo converters, to Hughes and Suncoast custom converters. I even had to drill new torque converter mounting holes in a 31TH flex plate (I built a jig using another f.p. to get the holes centered) to use the larger 10.5" converter Suncoast built for me and put 360 whp/460 wtq though that flex plate with no problems.

I've seen cracked flex plates on 3.3/3.8 V6's though.

I've heard/read torque converter alignment is the problem. I have no first hand evidence to back this up.

Come to think of it, it may have been a V6 that I'm remembering. Removed the trans and took the flex plate off without undoing the bolts!

So what is everyone running for flex plates? I seem to remember a thread on P/T cruiser turbo flex plate being the one to use, but I may be confusing SRT-4 2.4l stuff into this.

[Warren Stramer]

The ATP brand flex plate I bought is .015 thicker than the factory piece. Good welding on it too. And have it balanced!

ATP part number Z-194

[MILKCARTON]

The ATP brand flex plate I bought is .015 thicker than the factory piece. Good welding on it too. And have it balanced!

ATP part number Z-194

Great Info, thanx

[Shadow]

The ATP brand flex plate I bought is .015 thicker than the factory piece. Good welding on it too. And have it balanced!

ATP part number Z-194

Awesome!

[contraption22]

The ATP brand flex plate I bought is .015 thicker than the factory piece. Good welding on it too. And have it balanced!

ATP part number Z-194

I'll echo this for the 2.4 flexplates. The ATP seemed beefier than stock.

[A.J.]

So what is everyone running for flex plates? I seem to remember a thread on P/T cruiser turbo flex plate being the one to use, but I may be confusing SRT-4 2.4l stuff into this.

It depends on if the PT uses a 9.5" or a 10.5" converter because the bolt patterns are different. The SRT-4 Neons ALL came manual so no flex plates are going to be listed for the model.

And have it balanced!

When I drilled, welded, and ground off old welds on my 2.4 flex plate to accept the 10.5" converter it was suggested that I have it balanced. I called around to a bunch of shops in the Phoenix area and nobody could do it. So I just put it in and haven't had any problems. Where would one go to get a flex plate balanced because I had a hard time finding somebody.

[lightbulb010]

First post on TM. My STOCK flexplate(87' a670) cracked only after repeated engine removal and destroyed my 3spd pump. New flexplate from advance worked for me. Get rid of your old worn out junk and get a new flexplate. How hard is it to drill holes these days?(from a manufacturing standpoint) A torque converter is another story. If you have enough power you will tear it(torque converter) up and cause other issues anyway. This thread is about cracking flexplates , however. I have this to say. I have only used the cheapest flexplate from advance in 2012-2013 and it is rock solid. I've broken many other trans parts since installing it. This same flexplate is even going on my new motor FWIW.

[Warren Stramer]

When I drilled, welded, and ground off old welds on my 2.4 flex plate to accept the 10.5" converter it was suggested that I have it balanced. I called around to a bunch of shops in the Phoenix area and nobody could do it. So I just put it in and haven't had any problems. Where would one go to get a flex plate balanced because I had a hard time finding somebody.

Any shop with a crank balancer can do it IF they want to. We mount them in a expandable mandrel on a shaft. The shaft just lays in the balancer bearings. Most balancers are made to accommodate many size shafts. Could even balance a small turbo compressor wheel.