Chasv8z Posted June 28, 2003 Share Posted June 28, 2003 We'll I Put the exhaust on the car and started it up again and notice a vibration in the engine. Idle is good but when I give it some gas I feel it. Kinda fells like the harmonic dampner or in the fly wheel. The kit I used came balanced (a 383 stroker kit) but I changed the balancer to a street dampner for clearance. I did use a external balance dampner. Any suggestions. Quote Link to comment Share on other sites More sharing options...
dmyntti Posted June 28, 2003 Share Posted June 28, 2003 Are you sure you needed an externally balanced style harmonic balancer? Many aftermarket 383 cranks are internally balanced. Was the dampner you removed externally balanced type? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted June 28, 2003 Share Posted June 28, 2003 Are you sure you needed an externally balanced style harmonic balancer? Many aftermarket 383 cranks are internally balanced. Was the dampner you removed externally balanced type? Oh I disagree there....the VAST majority of 383 kits are externally balanced. The internally balanced kits are pretty pricey. Did you have the new damper balanced to the same balance as the old one? If not, that's likely your problem. Also, check that your exhaust isn't touching somewhere on the body (or close enought to touch when the engine twists. That can sometimes sound and feel like the same problem. Tim Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted June 28, 2003 Share Posted June 28, 2003 DITTO? Did you have the new damper balanced to the same balance as the old one? If not, that's likely your problem. Also, check that your exhaust isn't touching somewhere on the body (or close enought to touch when the engine twists. That can sometimes sound and feel like the same problem. anytime you have an enggine built all the rotateing parts should be BALLANCED AS A SET, and THE MOST COMON PROBLEM,Ive found is flexplates and dampers that don,t match or are ballanced incorrectly, yeah NOT what you wanted to hear, Im sure Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted June 28, 2003 Author Share Posted June 28, 2003 Ok here is what I got. A complete 383 stroker kit balanced. pistons, rods, crank, fly wheel, harmonic balancer all balanced as a kit. I changed the balancer so it would not hit my steering rack. I bought a street dampner for a 400 externally balanced. Should I have tried to make the other balancer work by using a spacer like in the jtr book? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted June 28, 2003 Share Posted June 28, 2003 personally Id take BOTH dampers to a ballance shop and have them match the ballance on the new damper to the old damper that was ballanced with the crank Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted June 28, 2003 Author Share Posted June 28, 2003 Thanks for you advice grumpyvette and others I will take them both to the machine shop monday. Quote Link to comment Share on other sites More sharing options...
RPMS Posted July 2, 2003 Share Posted July 2, 2003 Okay, now I'm a bit confused. I thought I had it all figured out, but now I see that I don't. My engine is a 1996 Chevy 350 with a fresh BONE STOCK rebuild. I bought an inexpensive flexplate out of Jeg's, and I still need to buy a damper. How can I make sure the flexplate is the right one, and how do I make sure I buy the right damper? *sigh*. I thought American engines were supposed to be simple! Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 2, 2003 Author Share Posted July 2, 2003 Ok called the machine shop and he said they could not balance one to the other so I will try to install the one that come with the kit. I will have to lower my rack but I was looking at that and it looks like it will drop the rack and mounts together because the rack is mounted to the cross member I have the spacers that go under the frame as per jtr but just don't see how they will work yet. Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 2, 2003 Author Share Posted July 2, 2003 RPMS--- I don't see where you will have the same problem I am having if it is just a stock 350 call jegs and let them know what you have and what you bought and they should be able to help you. Quote Link to comment Share on other sites More sharing options...
peej410 Posted July 4, 2003 Share Posted July 4, 2003 why dont you just pull the rack off put the dampner that came with the kit on and if the motor runs right then worry about modifying your setup... although youll need an alignment most likely id think this would be the simplest way to test both dampners Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 4, 2003 Author Share Posted July 4, 2003 In progress of doing that right now should know tomorrow thanks for the sugestion will update as I know something. I have the spacers that are in the jtr book for putting under the front cross member and the body rails but on the 78 280z the rack is bolted to the top of the cross member along with the motor mounts so I don't see how it will lower the rack without lowering the engine too. Quote Link to comment Share on other sites More sharing options...
Datsun660z Posted July 4, 2003 Share Posted July 4, 2003 In progress of doing that right now should know tomorrow thanks for the sugestion will update as I know something. I have the spacers that are in the jtr book for putting under the front cross member and the body rails but on the 78 280z the rack is bolted to the top of the cross member along with the motor mounts so I don't see how it will lower the rack without lowering the engine too. They won't, They are made to lower the engine to give you more hood clearance. Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 5, 2003 Author Share Posted July 5, 2003 What if I use the spacers under the frame rails and put some spacers under the motor mount brackets will that work. Quote Link to comment Share on other sites More sharing options...
peej410 Posted July 5, 2003 Share Posted July 5, 2003 i personaly would move the rack... the design that im using although a little more cluttered than jtr or msa allows me to mount the engine to my framerails and move my entire subframe anywhere i wish... wouldnt moving the rack down help decrease bumpsteer if your car is lowered?? Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 5, 2003 Author Share Posted July 5, 2003 My car is not lowered yet so bumpsteer is not an issue. I am going to use spacers under the frame rails where the cross member mounts to the frame and add some spacers to the motor mounts to raise the motor back up I then should have enough space between my rack and balancer that I can use the one that come with the kit. Will update soon.... Quote Link to comment Share on other sites More sharing options...
peej410 Posted July 5, 2003 Share Posted July 5, 2003 how much hood clearance?? or is that not an issue? Quote Link to comment Share on other sites More sharing options...
Chasv8z Posted July 6, 2003 Author Share Posted July 6, 2003 UPDATE--- Put the spacers under the crossmember (don't know if that is going to cause bumpsteer or not) the jtr book say's these provide clearance between the steering rack and the harmonic balancer not true on the 78 where the steering rack is mounted to the cross member it drops the whole thing. Then made some spacers to go under the motor mounts to lift the engine back up. Put the harmonic balancer on that come with the kit and fired it up NO VIBRATION man does that make me happy just drop the radiator a little to keep it from hitting the hood and adjusting the trans cable and that should be it for the moment at least I will be able to drive it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.