CLASS RACER FORUM - Even my luck is good somtimes. Cracked bedplate and mainweb

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Re: Even my luck is good somtimes. Cracked bedplate and main

Quote:

Originally Posted by Mike Taylor 3601 (Post 381840)

I was told the same thing years ago,about no counterweights causing problems.They were running chevettes here on dirt track, some of them were cutting counterweights off,I balanced several of them ,they never did run long.
I do know 4.750 stroke BBC will run faster w/ crank w/extra center counterweights,even though it's heavier, than crank w/o extra counterweight. All I can guess is that extra center counterweight must smooth out some of the harmonics and in doing so eliminates some twist/flex in crank,and picks up some power.
Some signs of harmonics are balancer and flywheel mounting areas will show signs walking,galded surfaces, also where main caps meet block,or in your case main bed, will show signs of walking ,main bed may crack like yours before it walks,because of it being held in line w/alignment dowels.
Something else come to mind is a engine that is lugged will break mains/main webbing,Art you have'nt been lugging down the neon so you don't go too quick have you?LOL

Mike Taylor 3601

Mike you might have something here. I've cracked 2 trigger wheels And had trouble with the bolts holding them to the balancer breaking. The first time it happened I blamed the balancer (actually myself for using a hammer to help install it). I put a plain aluminum pulley on it (no balancer) and it happened again. I found someone that wanted to buy the custom balancer so I sent it back to the manufacturer to see if it was repairable. Other than the bolt holes it was fine. So it didn't have anything to do with the previous problem.
The number 5 (last ) main bearing was badly beat up on the front half. And that was the one web with no cracks. One other thing that was not normal was the rod bearings (1 run)were showing some wear at the ends. I remember with the hemi's we had to cut the rod bearings when we used a full radius fillet crank. The neon cranks are not full radius but undercut. So it should not be needed to trim the bearings.
I don't have a clean neutral so when I lift it lugs down. But I don't think thats the problem.
A lot of these neon's are making more power than me and don't seem to have these problems.

Re: Even my luck is good somtimes. Cracked bedplate and main

Art ---sent u a PM but I remembered who it is---Steve & Danny Rhoades from Frameworks in Glendale AZ---Telephone 623-869-9277--- might be able to help you---FED387

Re: Even my luck is good somtimes. Cracked bedplate and main

Quote:

Originally Posted by SSDiv6 (Post 381854)

As regards to the bedplate straps not working, the failures I know that have taken place are on engines running turbos and exceeding 500hp. By the way, I am not implying your engine is not making enough power; I believe that if you use the turbo or SRT block with the straps with your current setup, it will increase the chances of survival.

Also, the reduction of the counterweights will affect the dynamics of the engine, especially on a 4 cylinder. Could you post a picture of the crank?

Another factor to consider is the engine mounting and the stiffness of the mounts. On a FWD, the acceleration and dynamics of the body and transaxle will have and effect on the block. By the way, do you have a filled block?

It would mean a new cylinder head to go to a late style block.
I have the crank up at my machinist right now. But all the counterweights are taken off except for the second one which was left for using the stock reluctor pickup (which I don't use anyway). It looked weird like it would be way out of balance, so I had them recheck the balance. And it checked fine. It is 8 pounds lighter than a stock crank.
Block is not filled. Motor mounts are hard but not solid.
In thinking, posting, and asking about this problem. I've come to the conclusion that I'm going to use a stock crank. The crank seems to be the one difference between my motor and many others that make more power and torque than me.
I hope the 8 pounds of spinning weight dosen't slow me down much.

Re: Even my luck is good somtimes. Cracked bedplate and main

The only thing that I could see causing the block to fail is detonation, which would explain your bearing issues and your crank trigger failures. How much timing are you running? Mike

Re: Even my luck is good somtimes. Cracked bedplate and main

Quote:

Originally Posted by Mike Roth (Post 382051)

The only thing that I could see causing the block to fail is detonation, which would explain your bearing issues and your crank trigger failures. How much timing are you running? Mike

Nothing up top shows any sign of detonation. I'm running the same timing that most N/A motors similar to mine are running.