My engine has a vibration that is bothering me. Obviously any vibration should bother me. I've ruled out my headers touching the frame and remember 4 years ago when I put my Moroso 6qt pan on I didn't clearance to modify it at all when I put it on. My block is obviously clearanced but I want to know if any of you have used the same moroso pan and what if anything you had to do to it or what you had to do to ANY pan you used. My rotating assembly is the 1pc rear seal Eagle kit, 5.7" (I'm pretty sure) H-beam rods and -16cc JE Pistons. I know for a fact I'm not using short skirt pistons or the 6.0 rods. I thought the pan had enough clearance but trying to track this thing down. There isn't any metal on metal smacking that I hear but maybe its just enough of a hit to cause the vibration? What else could cause a vibration in an ENTIRELY new drive line, drive train, etc while driving and in neutral??

 

i dont see how an oil pan could cause a vibration.

does it do it when sitting still in park or neutral and rev it? or just when the car is moving?
isnt the pan clearance for 3.8" stroke? i have hte same pan on my 408 and it only needs some small mods that i cant even see to make it work.

 

Probably a stupid question but did you balance the rotating assemble with the balancer, flywheel and pressure plate? Is the pressure plate indexed to the flywheel? What your describing sounds like a balance issue. Not something hitting the oil pan.

 

The engine does have a vibration while in neutral and parked, revving.

Comp, not a dumb question. The kit came balanced in terms of the pistons, rods, and crank from Eagle. I didn't have the flywheel, clutch etc at the time. I don't recall seeing any registration / key for the flywheel. I'm using a Forenza steel crank and ASPEC stage 3 clutch setup. I'm sure I'm chewing the hell outta my main bearings now aren't I??

Another thought I just had is maybe my engine builded muffed up way back when and didn't use the right balancer? My eagle kit is internal balance, my flywheel is supposed to be neutral. My balancer should be neutral as well right?

I plan on tearing the engine apart this winter to switch blocks (my current block is ceramic filled up to the first freeze plugs).

 

Now for the bad news.

The balancing the kit come with is a "rough balance". The vibration you have it that the motor is not truly balanced correctly. When a motor is correctly balanced you take one piston, rod, wrist pin, bearing, ring, and set it up so all eight are the same. Then you take that rotating mass and balance it to the crank. Once the crank is balanced (usually requiring heave metal with most of the stroker kits) you now stick the balancer on the crank and add the flywheel and recheck it again. I have seen lots of "neutral balanced" motors that require to machining the flywheel to get it truly neutral. Again, once your at neutral now you add the pressure plate and make sure it stays neutral. A lot of work but that is how it is done correctly.

 

Probably a balancing issue but as far as the pan goes. I Had to cut the damn baffle out of my stock 350 pan cause the rod bolts were catching it just about everywhere. I could almost guarantee that this is not your problem though because, at least with mine, if I wold have started it that way, I would have had a huge problem right away and probably about 5 quarts of oil on the ground!

 

Comp, I've had worse news. So I guess I'll be tearing my engine apart for real this winter. Also sounds like I'll be needing new bearings 8( I only have about 3-4 hundred miles on the engine right now so hopefully I haven't ruined anything.

 

Did it just start vibrating, or has it done it since it was built?

 

MN246, pretty much done it since I started it. I talked to Eagle and my engine builder. For their internally balanced sets they don't need the flywheel or pressure plate for the balance. I do have the sheet that shows all the weights of my rods, pistons, etc still and see the weights are VERY close to one another.
I'm going to check my dampner and make sure its not an external when it should be a neutral balance. I may even have to drop my tranny to check the flywheel but I remember calling Forenza to ask if they had a neutral balance flywheel and that wa the one I ordered. This is all off 4 year old memory as that's when I had my shortblock put together.

 

Have you checked out your ignition system to make sure it's not missing on one of the cylinders? The easiest way that I know of to do that is to use an infrared temp gun to check the block and see if one of the cylinders is cooler than the others.

 

How bad is the vibration and does it increase with RPM? Is it worse at a particular RPM or under any other circumstance? I think it's very unlikely an "out of balance" rotating assembly (with neutral balance flexplate/flywheel) would cause a vibration bad enough to cause concern.

 

Most Eagle kits come balanced fairly close. I have been told Older Eagle cranks were externally balanced and later ones come internally balanced. External balance would use 400 front balancer and internal would use 350-305 balancer. Flywheel would be the same for a one piece style crank.

 

I'll have to get ahold of an infared temp gun to take a peek. Other than that I've pulled all my plugs and nothing looks outta wack there. I ran without my blower setup, no change. I can't stress / explain enough that my ENTIRE car minus the interior and hood are NEW with only about 3-4 hundred miles on it between last October and this year. I'm going to do a compression test for haha's. I'm going under my car tonight to take a look at the back of my balancer if I can to see if its got any counterweight at all. The only thing after that is I'm going to track down the paperwork/invoice for my flywheel and clutch setup to make sure the flywheel part # is for a neutral balance.

One other thought too, how bad would a header tube on the k-member cause a vibration? I mean this vibration isn't teeth rattling but its enough when I have the shifter in neutral it'll cause the shifter to vibrate left/right where I can see it. It's there from idle and up, scary on the highway but I think thats also because either a flat spot in my tires from sitting for 4+years and maybe a thrown wheel weight.

 

You stated you had a one piece rear main seal crankshaft. The flywheels are the same. A two piece rear main seal flywheel will not bolt up.

 

Bassett, well thanks for letting me know that. Keeps me from having to look there.

 

Here's a pic I took way back when I was putting the rest of the engine together. Forgive my ingnorance but what would an external balance dampner versus an internal/neutral dampner look like? The one in the pic is the one I have on my car now.
I also had a shot with my flywheel although you can't see much and I'm thinking the flywheel isn't the issue.

 

Found some old photos and looks like the holes on the front that balance all on one side of a 400 unit. All other units have holes all the way around.

 

My 383 balancer has holes all the way around. It does have two other holes though that are both above the other one about 1/4 inch apart

 

So I did not see anything from the backside of the balancer when I crawled under last night. Can you tell by appearance in my photos if its an neutral balance dampner or external? Another question, the stock 91 L98 350's were internally balanced as well right? I should be able to troubleshoot the dampner using one of those.

 

looked neutral to me when I get to work I'll scan a photo out of a book I have and e mail it to you.

 

Eureka (I HOPE). I went through four and a half inches of reciepts, paperwork, stuff that came with all the parts I've put on my car during this project. I found one of the invoices (have about 6) from my engine builder. He put on a Pioneer SB Chevy - 6.25”, late model, weighted DA3071 harmonic balancer. The part number and description was on the invoice. SO, I'll be buying a neutral balance dampner tonight to install soon. Question is how much damage do you think might have been done to bearings / etc with about 300-400 miles on this motor??

 

does the weight come off?

the flywheel i bought, though it was a neutral balance piece, came with a balancing plate bolted to it, just in case you needed to balance it with a rotating assembly.

I couldn't tell you how much damaged, maybe none. Nothing is knocking is it?

 

All, I just did some more research. Pioneer Automotive (brand of balancer) doesn't have an electronic (online) catalog. There are a few places I've found that list my dampner as "weighted" and a few that say neutral / internal. The one site I saw that say's it'll fit my setup is Summit. I looked again and I don't see any sort of bolt on weight or anything on the back side of the balancer. SO, now I'm confused and will have to call Pioneer Automotive direct tomorrow to get it straight from the horses mouth. Only other thing I can think of or see is that my over axle pipe for my mufflex (4" OD) is hitting my track bar. Other than that, nothing else is touching. A primary on my driver side header is about 3/32's away from my K-member and that's about it.

 

DA3071 shows to be a neutral balancer. A DA400 is a balancer for a 400. notice the holes drilled one side. Do you know for sure that your crank was made for a 400 balancer? I dont think you have hurt your engine yet.
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Engine torque should raze the driver side header away from the k member.