Aside from a manufacturing defect, the only things that will cause a cracked flex plate are improper torque on the plate bolts at the crank and torque converter and the most common cause of transmission to engine misalignment. Scat crankshafts fp454sfi flexplate for big block chevrolet. I saw this very failure on a new forklift using the same style torque converter flex plate setup where the bushing wear was missed and the new flex plate broke again in the same amount of hours, we then found. I used a sharpie to mark them as i went around so i would know which ones were tightened. The flexplate can crack or warp due to an out of balance engine or torque converter. The tci superquality flexplates are thicker than stock plates to withstand the stresses of todays high rpm engines and highstall torque converters. Click here to see all chevrolet vehicles destination freight charges. Try loosening the tc bolts to allow the tc to move back slightly and evenly using the bilts to pull it back towards flex plate to allow it to self centralise. Someone drilled 3 holes inboard of the 6 to mount the converter, they are so close to the outer holes they intersect. A cracked flex plate will usually cause a squeaky sound like a belt but shorter and sharper and changes when in gear or park and under load. I tried to start the car again and it struggled, got it to turn over abit but sound like metal was grinding but did not start. Cant pinpoint the source of the noise im thinking either the flexplate or torque converter its a 2000 5. Weve had a few forum members get broken flex plates in the last few years.
Technical chevy torque converter flex plate crank vibration. Those factors ensure that when the engine starts and the driver puts it in drive, the cracked flexplates movement will create a noise. Attached is a video of the startup and idle of the flexplate disconnected from the torque converter. Broken or loose bolts on the crankshaft end of the flexplate, or on the torque converter side, missalign the flexplate, causing a high side of the plate to strike or rub against internal components. A cracked flexplate can allow relative movement between the converter and crank flange, as well. When they crack near the crank flange, they sound rodknockish. I borrowed an inspection camera to check around the flexplate and hopefully will give me better results.
The cause is the torque converter putting too much stress on the flex plate due to not being located correctly breaking the flex plate. The same things that cause the flexplate to crack can also cause transmission problems. Excessive crankshaft flange runout or end plate can also cause flexplate cracking. Steve, it would be very hard to carefully check out the end play without removing the engine, macs engine has 30k on it which means nothing cuz end play differencial can happen in a very short amount. This item scat crankshafts fp 454 sfi flexplate for big block chevrolet. All 396, 402, and 427ci engines are internally balanced and all 454ci and larger. Broken flex plates can not be repaired, they must be replaced. Furthermore, if not properly diagnosed it will occur again and often damage to the transmission may follow. It bolts to the end of the crankshaft and the transmissions torque converter bolts to it. I have a cracked flex plate im told i might need a flex plate. This is a external balanced plate that will work with 454 502 engines.
A good possibility it is flex plate, your description of the card clicking and sounds like a rod bearing are generally good indications of flex plate cracked broken,with that much noise you ought to be able to see the damage by removing the inspection plate on the trans and rotate the crank by hand turn a full 360 deg to verify. I have also seen the alignment dowels go missing between the bell housing and the engine block. What causes a flywheel to crack numerous times justanswer. I just thought id post a short video of what a cracked flexplate on a 6. The teeth around the edges can also break off, causing your starter to not engage the flexplate. We should all complement clint on how clean he keeps his bilge. Broken or loose bolts on the crankshaft end of the flexplate, or on the torque converter side, missalign the flexplate, causing a high side of the plate to strike or. A serious crack can cause a mild vibration when driving, so can a faulty torque converter. Sfi big block chevy 454 flexplate bbc external balance. They will accept the same flywheel flex plate as the early small block engines. I need to change the flex plate on my 2001 2500hd is there a heavy duty plate to replace the original. A flex plate should never break under normal circumstances so, either the dealer who replaced the. Now the car is back in for a broken flexplate, and they are not going to cover it. All other big block displacements used a 2pc rear main seal, internal or 0 balance, and 168 tooth ring gear.
I cracked two flexplates on a 350 olds i drove balls out all the time, until i threw away the torque converter and got a good one. Hughes performance hp3994 sfi rated hd flexplate with external balance for big block chevy. Slight misalignment may only cause a single flexplate to break in the life of the vehicle. Usual failure mode is the crankcase bolts or the torque converter bolts work loose, allowing the parts to start moving in different directions, the clicking sound you heard. Cost for parts and labor 2004 gmc sierra 2500 hd i have a cracked flex plate im told i might need a flex plate, torque converter and possibly a front pump bearing. Chevrolet performance offers ls, lt, and lsx series engine block flywheels, flexplates, and other components for your engine build or project car. And like gearcruncher said, the flex plate does have a spacershim and maybe they didnt install it. Im sure there are some 454 experts lurking here that will chime in. Turns out the flexplate bolts were right up against the starter plate. A vital part of an automobile engine equipped with automatic transmission, a flexplate consists of a piece of thick sheet metal that bolts to the crankshaft and. You really should check the end play on the crank using a dial indicator should measure 0. Atp z111 automatic transmission flywheel flexplate, flexplates. Broken flexplate, again the chrysler minivan fan club forums.
If you notice clunking or grinding noises while your engine is idle, in park, or neutral, check your flexplate. Symptoms of a cracked flexplate general discussion. Order your parts online or pick them up instore at your local advance auto parts. Too much end play could have something to do with your broken flex plate. Cracked flexplate how can i tell the chrysler minivan. Buick, cadillac, canam, checker, chrysler, citroen, daewoo, daihatsu, delorean. Now on the 454 there is a backing plate behind the flywheel bolted to the bellhousing. Loud knocking sound from torque converter or flywheel. More severe misalignment can break a flexplate in 15,000 to 30,000 miles.
A cracked flex plate is almost always a sign of other problems. Theres also a chance they didnt gradually torque the bolts that hold the flex plate to the torque converter and maybe its not balanced. This may occur in worn engines or engine that have been poorly rebuilt. The problem turned out to be a cracked flex plate which. There should be 2 dowels, one on each side, to align the bellhousing of the transmission with the engine block. Mine was cracked all the way around the center mounting holes shop the new. Dude, looking at your questions for the past 2 weeks, you should give up trying to fix your own vehicle. Cracked flexplates arent as rare on these vans as they are on other cars. So i put it up on ramps and got under it to look and its cracked again. The original plate was in the car for a long time before transmission was replaced, and the problem has occurred since then. The teeth around the edges can also break off, causing.
The flexplate has cracked twice in the past 6 months. If they are missing, or there is only one there, that will get the converter out of alignment with. A warped flexplate can make metaltometal contact with the inspection plate cover, or the starter drive mechanism, and can also make a knocking. The pads that bolt to the torque converter step out towards the torque converter. I went from an externally balanced 454 to a internally balanced stroker 489 which. When i inspected the old flex plate it was just starting to crack in a few spots. Selecting the correct flywheel or flexplate manual. Check the mounting dowel holes carefully for damage or wear as they are. On the flex plate shown below, this makes the counterweight face the engine. And when the engine turned over the flexplate bolts would shave a bit of the starter plate away.
Its possible the rear exhaust manifold or even the crossover pipe cracked and developed a leak. One more thing to check would be the side thrust of the crankshaft. Stamped from a extra thick 532 cold rolled steel plate for extra strength. The bolt pattern on the flexplate and crankshaft will only allow installation of the flexplate in one direction. Prw 1845400 sfirated external 168 teeth balance chromoly steel flexplate for chevy 454 197090, early. I hear of others replacing them and they cracking again. Long story short, will a broken or cracked flexplate.
Also does anyone know the bolt size and thread of the bell housing bolts, i want to try and put some long studs in and slide my trans. The rotating assembly with flexplate converter may be thrusting forward. Power loss at high speeds, the flexplate like most engine parts endures a considerable amount of strain and stress. I have a 1989 chaparral villian iii with mercruiser 7. There will be four bolts attaching the flex plate to the torque converter and if you get a socket on the main crank bolt you can turn the engine by hand to get at all four. The engine is a reman and has less than 50000 on it.
But check the torque of all the flex plate to torque converter mounting bolts before doing anything else. How to know if a flexplate is warped it still runs. If they loosened up it will make the same sound as a cracked plate at idle. M said he really doesnt know why the flex plate is cracking, but it would be very unlikely that two different engines would have defects that would cause cracking. I have the transmission out and a new starter plate. The flex plate has 6 converter holes in a larger bolt circle than the 3 the converter is using it also has 6 lugs. When you crack them out where the converter bolts are, they have a very tinny, almost ringing sound under load, and the cracks are very hard to see.
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