We just got done completely rebuild a 289 and now we have a bad vibrations when you raise the rpm. Its hooked up to a c-4 tranny. We thought the flywheel might of been installed wrong or whatever so we decided to have the tranny shop look at it and they said it was installed right. Its an older 289 with 28oz balancing and we had the entire motor balanced when it was machined. THe harmonic balancer is brand new and was giving to the machine shop for balancing but when i installed the harmonic balancer i had to beat on it because i forgot to clean off the paint residue so i took it back off then the next time it went on fine. could the beating change the balance to make it vibrate violently or could it possibly be an unbalanced flywheel?
I dont know... but im going to check when we get it back. the thing is the machine shop had the new harmonic balancer, the crank and the flexplate and they balanced them all together. so it might be from installation.
Correct me if I am wrong but I don't think the machine shop actually spins it to balance the stuff. there is a chance that you got the wrong flexplate or balancer and they didn't notice.
I know they spin the crank to balance it ive watched the guy do it a few times. were going to go buy a new harmonic balancer and if it doesnt fix it we can just return it and try something else. i dont think it could be anything else because we had the tranny rebuilt with a brand new flexplate and torque converter 2k miles ago(had old motor then) and had no problems what so ever . Then we broke a cam shaft bearing trying to do a mild cam so we said screw it and rebuilt the motor, we had everything done by a reputable machine shop with new parts. only thing left is the harmonic balancer UNLESS they screwed up the machine work which i highly doubt. I was thinking maybe giving it a few wacks might of knocked the weight over or loosened it up so it shifted after it was ran the first time.
Alright... I got a used oem balancer from a local shop to try out and it seemed to help the vibrations but not eliminate them. Ive been reading on some forums and ive heard that poly tranny mounts can cause vibration. Also, does a mild/kinda wild cam cause vibrations? Ive heard high lobe cams can do that. When i rev up a bit outside the car and hold it i cant feel any excessive vibrations when i put my hand on the motor, seems to run smooth. What do you guys think?
Is your firing order correct? It will still run with two wires crossed. Have somebody who didnt install the wires check them, so they will look at them with an open mind. Your firing order might have changed with the camshaft you put in, esp. if it was for a 5.0HO, or 5.8.
A cam should not cause vibrations, even lumpy ones for racing.
I dont think the poly tranny mount is your problem.
Did the machine shop give you back your orig. crank and flexplate?
Does your crank snout/spacer sleave have a counterweight on it(I am SBF ignorant)
I was going to say firing order. Depending on your camshaft it could be 15426378, which is the "early firing order" or that late model / 351 windsor firing order which is 13726548. Counterclockwise on the cap. The only sbf that I know uses a counterweight is the hipo289. Dont beat on the fawkin balancer either, they make a puller for it... That defintely didnt help your balance issue. whoops double post edit
Im 99 percent sure the firing order is correct and it doesnt feel like its vibrating because of a miss its def somthing not in balance. Its a late model 289 not a newer 5.0 and the cam is made for the motor so it shouldnt change the firing order. Now im thinking the machine shop messed up when they balanced the crank or they installed a piston backwards. If that isnt messed up then maybe the cam was cut wrong or not straight, the chance of that is slim and none unless crane cams has to history for making bad cams. more then likely the motor has to come back out again.
There is no late model 289, the camshafts are interchangeable from an early 289/ 302 firing order to the later style firing order. Installing pistons backwards on fords have been known to gain horsepower because of the offset pin, acts as a longer rod which has its benefits.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Pirate 4x4
18.7M posts
366.4K members
Since 2000
A forum community dedicated to custom off-road vehicle owners and enthusiasts. Come join the discussion about trail reports, builds, performance, modifications, classifieds, troubleshooting, fabrication, drivetrain, and more!