Even my luck is good somtimes. Cracked bedplate and mainweb
 

I usually have to manufacture any good luck. But I've had a drop in oil pressure for most of this season. I've changed oil brands, rod bearings, even changed the oil pump, and the gauge. With no change.
I used to have 35 pounds at idle hot, now it dropped to 20 hot. 80 pounds cold, now 60 pounds cold.
I pulled the motor to look at the main bearings. Pulled off the bed plate, and had one bearing stay on the crank (#5). Looked at it and it was worn thru to the copper on the front half of the bearing. I proceed to look at the other bearings and they seem okay. As I push them out and clean and number them. I notice a ridge across the back of the bearing paralel with the crank. I look and sure enough I find a crack in the bedplate main webbing. Upon further inspection I find 2 other cracks in the bedplate main webbing. And a crack in the block main webbing on number 3 (right across the oil feed obviously the cause of the low pressure).
I haven't inspected the crank yet, but it doesn't look bad.
I'm so glad I found this before it puked all over the race track. And I blamed a connecting rod or something else for the catastropy
My question is has any one else had this happen? I'm trying to figure why?

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

Art,

What engine?
Sorry to hear the news.

Sean

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

2.4 liter 4 cylinder Chrysler.
It was actually good news. I'll have to replace the block. But if I had kept running it I'm sure it would have scrapped the whole motor.

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

Crank checked out perfect.
Now I have to guess what caused the block failure.

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

Just a bad casting not made to do what we do to them.

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

How well is the engine balanced ?

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

Art,

Do you have the EDZ casting engine block?
If you do, that is the standard production block used on the Minivans and regular cars.

The SRT and Turbo cars have the EDV and EDT casting numbers.
Although they say all the blocks are the same, I believe the SRT and turbo blocks to be stronger.

Another option is to use the DCR billet bedplate reinforcement.

http://dcrsrt.com/index.php?_a=product&product_id=162

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

I run an early block 99 (caravan/stratus). The oil drainback vent is different on the 2001 and up blocks.
I've talked to several people about the bedplate straps. They all seem to think they are worthless at best. They would be easy to make. You have to machine material off the bedplate to use them. I know of a couple of high HP cars that have broken blocks with them installed.
The balance was checked twice I bought the crank used it was supposed to be balanced but I had it redone (it checked out fine) Plus they just put it on the balance machine this morning.
I have been told that cutting the counterweights off, sometimes leads to bad harmonics

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

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

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

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?

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

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
 

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
 

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