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By mercman-49 - 14 Years Ago
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I would like to find out if a 239 flywheel will work on a 292.Ihave a 292 with a 11 inch bolt pattern,i;m wanting to use a 10 inch clutch.I have a flywheel from a 239 but all the bolt holes are the same size,I don't know about the balance,thanks Darrell Gipson,Mobile,AL
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By paul2748 - 14 Years Ago
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As far as I know, all YBlock flywheels were zero balance
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By mercman-49 - 14 Years Ago
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I have been in my shop 3 hrs tring to line up bolt holes in flywheel and crankshaft;it looks as if someone redrilled one hole in crankshaft,it dont have a bevel around edge of hole.Thanks Darrell
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By MoonShadow - 14 Years Ago
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It will only go one way. You can usually see an impression from the back of the previous crank to help line it up. Start with on hole and rotate it through the others. It should work. Chuck in NH
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By mercman-49 - 14 Years Ago
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I tried lining up the two flywheels and one hole off is the best it gets.I lined up the flywheels and ran 1/4 drill bit through the pressure plate bolt holes for a mark,will drill and tap tomorrow.If it was easy anybody could do it. Darrell
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By Hoosier Hurricane - 14 Years Ago
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If you were trying to line up the flywheels with each other back to back, you won't get all the holes to line up. Also, keep in mind the clutch bolt holes are not necessarily indexed with the flywheel mounting holes.
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By Ted - 14 Years Ago
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239 and 292 flywheels interchange at the crankshaft. There is an offset threaded bolt hole in the flywheel flange which allows the flywheel to only be installed one way. You may have to rotate the flywheel to each hole combination until all the bolt holes align with each other. All Y-Block flywheels are neutral (zero) balanced at the factory making them interchangeable without balance issues.
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By Rono - 14 Years Ago
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Ted; I have a two-part question here; First, I have two flywheels I'm considering using on this stroked and blown motor I'm trying to put together; A schiefer Aluminum one and a steel one. All things being equal, which one would you use? The plan right now is to use a Centerforce 11" clutch and pressure plate and T-5 tranny. Secondly, if all flywheels are zero balanced at the factory, why does everyone want you to provide one when balancing a rotating assembly? Is it really not necessary? Thanks, Rono
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By charliemccraney - 14 Years Ago
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Reasons for balancing a flywheel that is balanced from the factory:
After thousands of miles of wear and tear have been put on a flywheel, it tends to get out of balance.
Resurfacing can throw it out of balance.
New flywheels should be checked especially if it is for a performance build. Even the greatest companies can mess up sometimes so don't assume it's right. Usually balancing the rotating assembly includes balancing the flywheel so give it to the machinist. If it doesn't need balancing, it didn't cost you any more and now you know. If you're using a flywheel with unknown history, or one that has been resurfaced, absolutely get it balanced.
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By Ted - 14 Years Ago
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Rono (2/21/2011)
Ted; I have a two-part question here; First, I have two flywheels I'm considering using on this stroked and blown motor I'm trying to put together; A schiefer Aluminum one and a steel one. All things being equal, which one would you use? The plan right now is to use a Centerforce 11" clutch and pressure plate and T-5 tranny.For a lot of stop and go driving, a heavier flywheel allows the engine to take off easier without a severe rpm drop or what would be perceived as a ‘bog’ off the line. For road racing where there’s not a lot of taking off from a dead stop, then the aluminum flywheel allows the engine to rev quicker once the clutch is engaged. For a street driver, my own preference is a flywheel weight that is equal to at least 1% of the car weight. A 3200 lb car would need at least a 32 lb flywheel. My truck has a 60 lb flywheel which allows the clutch to be engaged without any serious riding of the clutch in which to get the load moving.Rono (2/21/2011)
Secondly, if all flywheels are zero balanced at the factory, why does everyone want you to provide one when balancing a rotating assembly? Is it really not necessary?Charlie has done a good job in explaining why you rebalance a flywheel that’s already been neutral balanced in the past. I’ll add that if a piece rotates, then at least checking for imbalance is recommended and especially where the balance history is unknown. Besides the fact that the flywheels are not perfectly balanced from the factory, anytime a flywheel is resurfaced additional imbalance can be imparted into the flywheel. Additionally, if the crankshaft flywheel centering flange is not perfectly centered (this can happen when the crankshaft is reground), then that can also throw off the weight on the flywheel. Hence the need to at least check the flywheel on the crankshaft after the crankshaft has been brought to its desired state of balance. And then there’s the pressure plate which adds another group of nuances into the balancing equation. That’s another paragraph for later.
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By mercman-49 - 14 Years Ago
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I found the problem was one bolt hole in the crankshaft had been drilled out one size,and two holes in the flywheel had been drilled out,I finely got all the holes to line up except one, i drilled it out one size larger and bolted it up.Thanks to every one for info.I got the 292 for a song ,it was rebuilt 20 or so years ago and never fired.The cam and crank was timed dot to dot ,it changed hands three times before I got it.Thanks again Darrell
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By YBLOCKEREDH - 9 Years Ago
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I am installing a used resurfaced flywheel to my 312. Purchased clutch pressure plate ARP bolts and 5 speed conversion kit from JM. What nice parts he sends!!!
My issue is I went to install the flywheel, aligned all the holes hand started the bolts which started great but quickly started to bind 3/4 in....stopped removed all bolts and discovered the unthreaded shoulder of the ARP bolt would not pass all the way into the hole. Flipped the flywheel over and went in perfect, I assume the holes are tapper drilled ....Backwards? Yes the machine shop re-surfaced the correct side...LOL. Has anyone run into this before? shall I just widen the hole deep enough to accept the last 3/16 of the bolt?
Gary
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By charliemccraney - 9 Years Ago
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The flywheel is drilled such that it will only go on one way. If it went on perfectly backwards, then backwards probably is not backwards.
The flywheel is dished where the bolts go. When it is installed correctly, you will see the dish. If you see only a big smooth disc when mounted to the crank, that is backwards.
What was the condition of that flywheel before it was resurfaced?
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By YBLOCKEREDH - 9 Years Ago
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Thanks Charlie,
It was very good condition. I watched the resurface performed, the flywheel was not warped and probably never surfaced. I received the flywheel from a gentleman who had it in dry storage many years. The dish is facing out, the ring gear is great. I referenced the bolts fitting flush entering from the back as an example. When entered from the front the shoulders of the bolts will not enter all the way flush with the back of the bolt head remaining 3/16" from contacting the flywheel, the holes are to small for the shoulder of the bolt. It is as if the holes where drilled from the back at factory with a taper or cone shape.
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By charliemccraney - 9 Years Ago
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The holes aren't tapered. Do you have original bolts to compare the new ones with?
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By Ted - 9 Years Ago
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YBLOCKEREDH (12/23/2016)
I am installing a used resurfaced flywheel to my 312. Purchased clutch pressure plate ARP bolts and 5 speed conversion kit from JM. What nice parts he sends!!! My issue is I went to install the flywheel, aligned all the holes hand started the bolts which started great but quickly started to bind 3/4 in....stopped removed all bolts and discovered the unthreaded shoulder of the ARP bolt would not pass all the way into the hole. Flipped the flywheel over and went in perfect, I assume the holes are tapper drilled ....Backwards? Yes the machine shop re-surfaced the correct side...LOL. Has anyone run into this before? shall I just widen the hole deep enough to accept the last 3/16 of the bolt? Gary
If the shoulder of the bolt is a problem fitting into the hole, then the flywheel bolt holes likely just need to be cleaned up with a drill bit or file to eliminate deformation of the hole where the bolt(s) start in. This is type of deformation is sometimes called brinelling and is caused by previous tightening of bolts at those holes.
Once you get past this, then a secondary issue can come up. ARP bolts have a radius under their heads. If not using a washer that has a chamfer on one side to accommodate the radius under the bolt head, then you may need to put a chamfer on the starting edge of the flywheel bolt holes to fit that pronounced radius under the bolt heads.
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By YBLOCKEREDH - 9 Years Ago
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Thank you Ted and Charlie, that looks like exactly what has happened, I will sneak up on them with a file. The bolts do not have a radius under head and should be good to go. Thanks for the help!!!
Gary
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