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Discussion Starter #1
I posted a month or so ago regarding the BAD engine vibration I had at 2k RPM and above. Well I finally have had time to look into it.

I have a 383, and tremec TKO with a Lakewood and Centerforce Dual Friction Clutch. While in Neutral I can increase my RPM 's to about 2000 and the car vibrates really bad and continues as I increase RPM.

So last night I pulled the Trans, Bellhousing - what a PITA, and clutch. My symptoms now are a vibration around 1k (slight),2k(same as before), and smoothes out above there. I did notice that one of the mounting bolts for the Pressure Plate was not tight which could have been my other vibration.

I did not have the 1k before and that puzzles me as to why it has appeared.

I am using a stock type dampner and a 14" flywheel with a 10.5" clutch.

Thoughts?


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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi

[This message has been edited by kdorsett (edited 09-07-2002).]
 

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I also have a 383 that vibrates, mine has a Muncie with a Lakewood bell housing. My vibration was at 3300 rpm. Last weekend I changed the rear trans mount from stock rubber to Polyurethane, now it vibrates at 2200 rpm and at 3300rpm!!!! The vibation at 2200 rpm is much stronger than at 3300rpm. Both vibrations occur when parked in the driveway, so it's not a drive line problem.
Any ideas?
 

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Discussion Starter #4
mc, what do you mean by checking the crankshaft?

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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Gee I was gonna say something and forgot what it was.....
Wish I could delete this post.

-dnult

[This message has been edited by dnult (edited 09-06-2002).]
 

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I changed the trans mount back to a (new) rubber mount, what a difference. The vibration at 2200 is gone and the vibration at 3300 is much less!!! I am wondering if I should put fresh front motor mounts in?
 

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Discussion Starter #7
Yesterday, I pulled the motor since I already had trans pulled out. I bought the stroker kit well over a year ago off the net, and I am now questioning whether the assembly was balanced or not. So I am taking the crank,pistons et al to get balanced tomorrow.

QUESTION - When I reassemble, should I install new bearings or reuse the ones there? I have very little running time on the engine - 20 miles or so. Or should I just be safe and install new ones.

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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Is your 383 internally balanced or externally balanced? Perhaps you have the wrong flywheel. That may be the source of your vibration. If you take the rotating assembly to get balanced, don't forget to take your damper and flywheel.

Good luck.
 

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Very good point Bravewink.
kdorsett, did the engine some with the balancer and flywheel? If not you need to make sure you have the right balancer/dampner and flywheel. If you added the flywheel and dampner yourself, did you get them for a 350 or a 400? If you call the place you bought the engine from and ask if it is internally balanced or externally balanced they should be able to help you (it depends on what type of crank they used). Most of the earier kits used 400 balancing (external), many kits still do. If you put a 350 flywheel and dampner on an externally balanced engine you will have vibrations and the bearings won't live long. Check into that before you tear your engine down to find out you only have the wrong balancer and flywheel. This will save you some $$$ and time. Good luck

Royce
 

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Discussion Starter #10
Thanks for the replies guys!

I have a 400 balancer and flywheel for the assembly, Since I already have the block stripped back down I am going to my machinist to have him check, confirm the balance. I can no longer find the individual I purchased te kit from, so I prefer to be safe.

Should have back next week and fitted back in next weekend.

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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I hadn't thought about this until recently. It might not be a bad idea to install a flex plate instead of a flywheel as a test with the tranny disconnected. That might identify an out of balance flywheel. Hopefully you won't need it, but might help others with a problem similar to yours.

-dnult
 

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What does PITA stand for?
 

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Discussion Starter #13
Pain In The A$$!! TOO many Bolts. A couple I could not even get a socket on.

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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Discussion Starter #14
Picked up my rotating assembly today and glad I took it in. The machinist told me the balance was, as he put it, in La La land. So now for the re-assembly. Couple of questions though.
I have seen on a few post that some of you running poly engine mounts and that you were thinking of putting a stock rubber unit on the passenger side to reduce vibrations. Any particular reason for the passenger side? Is it because of easy access? While I have the motor out should I put one on?

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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I can't answer the question about the passenger motor mount, but would make a recommendation NOT to change anything else intially, to see what the difference is from the balance of the engine alone. If you change two things at once, you won't know what the real cause of the problem was.

I am, however, interested in the poly motor mount deal. I have heard of people swapping to poly mounts and have been totally satisfied, and in this post I hear some contrary opinions. I have the poly mounts on my 69, and have been chasing a vibration issue too. Was also thinking about pulling the engine to check balancing, but haven't gotten there yet. PLease post your results! And good luck.

Mark

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69 SS, ZZ430 Look-alike, Tremec TKO, Hotchkis Suspension
 

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I would have to agree with Mean 69. Don't change too many things at once when chasing a problem. If you do, you don't really know the cause of the problem. I would say that you have already found it though.

As for the Poly engine mounts, I have them on my car. It has a 400 small block in it that has had the rotating assembly balanced. I have no complaints. It is smooth as silk. I have heard several people complain about them, saying that they significantly increased engine vibration in the car. It may just depend on your particular engine combination and how well in tune (How smooth it runs) that it is. There is a factory interlocking rubber mount that some people on this board are running with engines as stout, or stouter than mine, without problems. If I had it to do over again, I would probably have installed them. It may have been smoother still.
 

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Discussion Starter #17
Mark and Cameron thanks for pointing that out, I was just trying to kill two birds with one stone. Wasn't thinking as to doing too many changes at once. I should have everything back in this weekend, I'll post my results when I do.

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 

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1) Definitely use new bearings. For the price there is no reason to take the risk. I used 2 sets when I blueprinted and assembled my motor. I miked both sets and confirmed the clearances would be the same, used the 1st set for all the pre-asembly work and swapped in the second, pristine set for final assembly. Maybe excessively anal, but that's the way I am and I have enough invested in the motor that I wasn't going to take any chances. Besides, I could see some small dust scratches developing in the 1st set.

2) The passenger side mount takes the compression load when the motor is under power. Using a rubber mount will help dampen any vibrations coming from the motor which should be minimal after a good balance job. However, this is old technology in our motors and they will never be vibration-free. The driver side mount is being stretched under power so there isn't as much tendency for the vibrations to transfer thru. BTW - I still run the original rubber mounts on my stout 400 and Ive had no problems at all.

Scott
 

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I put solid engine mounts on my 67 after breaking three stock mounts on the left side.
The fan hit the radiator shroud so hard it broke the shroud.

If the engine balance is good, the vibration levels should be hardly noticeable with solid mounts or polly.

I would re-use the bearings unless they look bad. New bearings would have to be Miked again for clearances.
David

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Check my web page for First Gen Camaro suspension info:
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67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer
 

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Discussion Starter #20
UPDATE - I started her up tonight. First indications show that the vibrations are gone. I took her up to about 4 grand and she was smooth, all without setting timing. Tomorrow night I Will set timing and see what happens from there.

Thanks to all for your replies and informative
suggestions.

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Kevin

68 Camaro SS - 383, Edlebrock Performer RPM, Trick Flow 23 degree heads, edlebrock 750cfm carb, dynomax headers, Tremec TKO, 3.73 Posi
 
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