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Discussion Starter · #1 ·
I rebuilt my lower engine and the top is all new parts. I still have a bad vibration. I'm going to check my balancer today to confirm it's 50 oz. If it is I'm going to replace the short block. Any suggestions as to where to get one. I may just have mine professional rebuilt, but it had a large ridge in the cylinders I had to take out. 3 new torque converters and 2 transmissions and 2 driveshafts with no improvement. The vibration is 2000 to 2500 rpms in all gears. Thanks for any suggestions. Steve

[ August 24, 2007, 08:10 AM: Message edited by: Maddog in Michigan ]
 

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Trying to remember all the post about the original vibration problem. Sorry the trans flex plate did'nt cure it. Thought the balancer was already confirmed as being correct?
An original balancer it could have moved/rotated on the rubber insert to cause off balance.Wrong balancer most definetly will cause this. Do you know if it is the original that came on the motor? About the only reason to have a vibration caused internaly would be if when rebuilding 1 rod or 1 piston was changed. Other then a bent crank. Motor run ok? Has compression been check to verify no weak cylinders?
Exsactly what was done when rebuilding the engine,includeing parts used in the short block.
Was the motor original and complete when you got it,or pieced together from new or other engines.
No real way of knowing cost of rebuilt till disassembled and mic'ed. May or may not be less then remanufactored short block.
 

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Discussion Starter · #3 ·
I bought a disassembled donor. Parts were everywhere. The motor was partially disassembled. I was told it was out of a 87 mustang LX. It came with the auto transmission. The rear end was 2.73 which says to me the auto was not in the car. I thought autos came with 3.27. I have know idea what I have. The engine has a roller cam so I assumed it was an HO. I put an e-cam in it and it runs fine. Can the pistons be put in backwards. Because there were 4 valve cutouts I thought they could go in either way. All new high quality bearings, rings,etc. Thanks. Steve
 

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just another builder
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In searching your HB number in your other post I found a number of forums discussing the very same vibration problem that you seem to have...google E4TE A3A
maybe someone else figured it out
 

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Discussion Starter · #5 ·
The posts were confusing and seemed contradictory. I'm going to pull the pan and see if anything looks out of whack. Thanks. Steve
 

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Pistons need to go in a certain directin. They will have a "notch" on the tops. Can't say for sure if they will fit if put in backwards. Never tryed.
Balancer is the quickest and easyest thing to check first. Most likely cause also.
Not knowing if it's HO motor or not. Did you also try the "other" non HO fireing order? That could cause vibration.
 

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I have my old 302 shortblock with only 2300 miles on it-replaced it due to valve clearance issues with the new heads. I'll be glad to cut you a deal on it if you cant find your problem.
 

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Discussion Starter · #9 ·
Cobrastang,
Thanks, I'll let you know. I'm pulling the pan to look at the bottom. Woodward Dream Cruise is tomorrow and I'm bummed. Steve
 

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Originally posted by Hind Sight:
Did you also try the "other" non HO fireing order? That could cause vibration.
He said he put an E cam in it, so he needs the 351/HO firing order.

I haven't been following this, but maddog talks about the transmission, balancer and torque converter. What flywheel are you using? It also needs to be 50 oz.
 

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Discussion Starter · #11 ·
The flywheel came with the other parts and I assume came from the transmission that I received. I couldn't find any numbers on the flywheel where I could see. It is stamped AOD C5. Thanks Steve
 

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Besides the notch on the top of the piston, which should go forward, the rods should have been installed to the piston correctly. There is a bevel on the crank journal portion of the rod which should be towards the counterweights and the side without a bevel should be up against the other rod. So where the two touch, there should be no bevel, only on the two outsides. I doubt this would have anything to do with the vibration, but for lubrication, you want them installed this way and the notch forward ensures the valves don't hit the pistons. If you have them backwards, could the valves be floating at higher RPM and ticking the pistons, thus causing the vibration????

If you find the bevels to the center of the journals, this may be something to check. Unfortunately, it requires head removal. Someone else can maybe confirm or reject what I just said, but its my 2 cents worth.

Jerry
 

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Just to clarify, I realize there are 4 depressions on the pistons for valves, but there are large and small ones. You have to have them in the correct orientation or you could have a small notch where the large valve is and this is why the notch has to go forward, but rod installation needs to be correct to this as well.
 

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Discussion Starter · #14 ·
I checked the rod bearings and main bearings tonight. They all look good. The pistons had arrows on the underside and they all pointed forward, so that is good. I went to autozone and picked up a new balancer. Identical to mine. I took it back and the guy looked up some other part numbers and bam, E4TZ 6316A. Just what I was told it should be. $122.00. I was also told that the AOD Balancer is E4TZ 6316B. Can anyone confirm that. Thanks. Steve.
 

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So you are running an AOD in your cobra? The AOD mustangs used a different driveshaft that had a ring around them to control some sort of vibrations. Also as others have said you need to have the correct flexplate.
 

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Discussion Starter · #16 ·
Does anyone know if I need the E4TZ 6316B or A Balancer for my engine? Thanks. Steve
 

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Steve, you need the one that matches your flexplate. It can be 28oz, 50oz, 0oz, just needs to match. Now since your telling us you got everything in a pile with asst random parts from various vehicles, nobody can tell for sure but you. If your saying its a stock 89-93 mustang HO engine that had a AOD then it would be a 50oz balancer. The E4TZ6316A balancer was a 50oz balancer and used from 80-95 on 5.0 engines. The same number with E8 instead of E4 was used on 351W and was 28oz. Typically if just the last letter changes then its the same part just a newer rendition.

Here is a decent page showing various ford balancers http://www.ventureproducts.com/pictured%20dampers%20ford2.htm
 

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I've run several different trans' in mine,Lentech AOD being one of them. Never changed balancer and used same drive shaft
Marc A
 
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