my old 302 had a moderate vibration i blamed on the flexplate i installed so my converter would fit because i dont remember a vibration before then. now i have installed a built 1974 302 with a 28 oz. flexplate & 28 oz. fluid damper and now the vibration is worse. its really bad from 2000 to 3500 rpm in park and smooths out above that. Could my converter be out of balance that much ? Its bad enough that i dont want to run or drive it. Please help!!!
some ideas... Is the engine the definent source for the vibration? does it vibrate while in park (revving up to the RPMs you mentioned)? A lot of customers that I have had said they had a vibration, and it turned out to be a missfire or multiple cylinder missfires during certain RPMS, could that be a possiblity? let us know what you find.
is this the same flexplate as before. and the vibration started when you changed flexplate? if so i'd try a different flexplate and see if that's it.
OK, First you say that you have a newly built engine. When you built the engine did you have it ballanced with the flexplate and ballencer that you are using now? If you did not have the engine ballanced and you did some oversizing on the bore and different pistons, rings, barrings, rods, etc..... the vibration could be comming from anywhere. and as was said before----- it could be a misfire problam stemming from miss adjusted valves, bad wires, bad cap, coil breaking down under load. Many things could cause the vibration. Give us something to work with. What machine work did you have done to your engine, what work did you have done to your heads, do you have adjustable rocker arms or sholdered studs, do you have a bigger cam installed in the engine, what type of valve springs are you using? Give me some really good info on the engine build and I hope I can help you with it. This is what I do for a living, let me have some good info and I can give you places to look and some fixes for some of your problams. Don
engine was bored .040, crank turned .010 on rods and mains.heads are all stock except roller rockers and new springs. has a new sfi flexplate and fluid damper -28.2 oz. i thought maybe my old balancer or flywheel might be the problem, but i also installed the new converter at the same time, so i bought a new damper and flexplate, still vibrates bad. engine is not misfiring, all new msd ignition, engine has not been balanced, but to vibrate as bad as it does, i dont think any balnce job would. i have been a mechanic for 21 years, and have never run into a problem on a ford like this.
did you reuse your motor mounts from the previous engine? also, did you reuse the torque converter from the previous engine that was vibrating, because it sounds like you did? could have been bad from the factory.
new motor mounts, same torque converter. vibration is so bad that it will vibrate the tools off the fender covers as well as a full quart of motor oil off of the roof.
Have you checked your crank to see if it has any play? Thats what was wrong with mine even after the rebuild. Everything speced fine when putting it together. But after just a few minutes of driving it started vibrating again, ate the crap out of the new bearings and crank, and you could move the crank up and down by hand, it was terrible. Im thinking it was the line bore. I nor my father have ever seen one that bad. Just something to check.
hate to say it but id pull the torque converter and try a loaner one, if im understanding correctly that its the same one that vibrated on the other engine. try everything else you can first though, all the usual compression checks and such. i also had a friend with a chebby that busted the new bolts on one of his connecting rods because they were faulty. it left the rod up in the cylinder so it just ran reeeeel rough but no knock or anything.
Hey i had a similar problem. I have a question, does it run rough as in a back fire or poping when u give it some gas.
OK, From what I can see you have narrowed it down to two things. 1- The torque converter was bad out of the box (Have had more than a couple new parts bad from the factory) 2- The guy that turned your crank had a bad set up on the grinder and induced an error into the crank when it was cut. There is quite a long prosess to set one up and if you miss one step the crank wont turn right. Who knows he may have had to answer the phone, take a pee break, or whatever. We are all human and miss things once in a while. ( now you are giggling to yourself thinking about that one thing you missed that made you feel really stupid, I know I am) As a matter of fact just yesterday one of the guys in the shop did a brake check on a truck along with some other stuff on the front end and when he put the tires back on he forgot to put the rear drums back on before he put the tires back on. Boy was he red in the face. One other thing you might try is when you get the tranny off get a C-4 or manual bell bousing and bolt it bare to the engine to mount a starter and fire up the engine without a converter on it. This will give you more of where you need to look, and maybe save you another trans pull. If it is the engine it will vibrate, and if the vibration goes away then you have a bad converter. As was said before, I would switch the torque converter with a known good one and if the problem is still there I would look at the crank for the problem. Good luck Don
