Is there anything specific about 302 cranks? I have a 1980 302 that has been "redone". The crank that was in the motor was swapped for a crank from another motor,either a 289 or 302, probably newer model, not for sure. Everything else was redone with original parts from that motor. I have a vibration if I rev the motor now. Seems to be an rpm thing but there is no tack on it so I can't tell what rpm it starts.

New bearings, new everything else. The crank is the only thing changed. If I idle it with it in neutral and the clutch pushed in and kick it it vibrates to beat the band.

Anyone have any ideas? This has been a long time ordeal and I'm ready for it to be over. I've been able to drive the truck about 2 weeks all summer long and I'm already having withdrawal symptoms.

I've been going to let everyone know how this thing turned out when it was over... only it's not over yet.

Thanks
garyr

 

whoops, you probably have wrong fflywheel for the crank you are using. 1980 was changeover year for balancing these engines.
i had similar issue in 85 truck using flywheel from 85 on 78 302. changed them out and no more problem! it is a strange vibration.

 

Call the Ford tech hotline at 810-468-1356 and they should be able to tell you about flywheels etc.

 

Billy is half right. The changeover was '82 when Ford went with the 50oz. imbalance . '81 and under had a 28 oz. imbalance. If you have an '80 engine with an '82 or above crank you need to swap the balancer and flywheel/flexplate.

 

lvstang, thanks for update on years of balance change. it gets complicated when mixing parts, and most books and parts guys have different or no answers to help out!
it sucks when you put something together and discover a problem like this.

 

Thanks guys for all the input. This has definitely
been a learning experience. Most auto parts books
and even books at junkyards don't have the information you guys have. Billyb hit the nail on the head. My '64 F-100 has been sitting in a garage for most of the summer now. The first motor
we tried to put in this truck was a 1990 5.0. An extremely good motor out of a wreck. It had an automatic behind it. Took all the injection stuff off it and made it carbureted. Needless to say it didn't work with my 3-speed. I really wanted to keep the original 3 speed. One local yard had a tranny with clutch and flywheel but they wanted more for that stuff than I had in the motor.
So we went with the motor that was in the truck and began to rebuild it. Heads, bottom end, rings, you know the story. The crank was used out of another 302 but we weren't sure what year it was but then "the books" said nothing changed until around '86 so we figured everything was okay. After calling and then driving to talk to "Mr. Mustang", one of the local Ford dealerships,a yard
(mostly Ford guys) and a couple of guys around here that race Mustangs (all this takes time when you have to work all day) we have lost much hair and learned considerable about Ford motors after 1980.
We have one more 302 that we know is not mix and match that will go in this week one day to see if the vibration goes away.
Thanks again for the info.Guess I should have ask this before I got into this so much.
Garyr

 

One of the easier ways of knowing(even though they don't state why) is when looking through the Jeggs and Summit catalogs. The balancers for SBF's will state for '81 and below and '82 and above. The main changes for '86 was the advent of the port EFI motors. Of course '85 brought us the first roller cam blocks. There was also a change in the 70's some where from 3 bolt pulleys to 4 bolt. Let's not forget the different firing orders on H.O. vs. non-H.O. motors. Now do you see why the mentally challenged people like Chevies so much!!!!LOL!!

 

 

Hi can I just interject I am running a 1980 302.

It came with a 50oz harmonic balancer, so I got a 50oz flywheel to match, I have read in several places the change over was 80/81. I don't have much of a vibration, it does feel a bit like a missfire sometimes and a rough feel through the gear shifter (5speed) which I thought was a miss fire ;o).

I have replaced the rear crankcase oil seal and it is leaking again after only 200mile.. do you think the imbalance could be the cause?

Or with having matching 50oz harmonic and flywheel it should be ok even if it should be 28oz?
Any advice would be mucho appreciated.

 

The changeover was definately between '81 and '82 and if you have an '80 302 with a 50 oz. imbalance balancer and flywhell, Ford didn't do it. The external balance has to match the INTERNAL IMBALANCE, so you can't use a 50 oz balancer on a 28oz. imbalance crank. Unless the cranck has been changed out to a later year ( as the O.P.'s has), you are both in the same boat with each others parts. That is most likely the source of the problems you mention.

 

I got to ask... why didn't this motor work with your 3 speed?
It seems to me you are doing a whole bunch of work changing these motors when all you should really need to do is bolt the correct flywheel on to match your tranny.

 

Note that the thread last posted in Nov 2000 prior to Holmsey.

Seems like a recent trend, new users posting new questions on old threads.....