vibrating gyrating ford 302-- just annoying

Yeah pretty easy to see when its side by side like that.. mine is nearly identical to the bottom one.. with the exception of there isn't much of a curve to the weight on mine..

 

now is it possible for me to take a drill bit and drill out some of the weight on the opposite side to get it better in balance? im pretty much at the limit of washers on the bolts.. and I feel a little like that just isnt right.. but it works.. so im not knockin it. I definetly want to replace that.. im going to probably starting this week look for a good aod.. hopefully I can find one I don't have to put a lot of work into. sucks too.. I've got a genie shifter.. i'll need to do something about that.. and especially if I lower and push the engine back when put it back in.. there is such a large gap right now at the back due to the way the engine is mounted on stock perches.

 

We've always run B and M flexplates and have had great luck with them, plus, they are SFI certified. But there are a lot of good brands available from places like Summit.

Looks like you are on the right track.

Don

 

You would have to remove quite a lot of area on the opposite side to make the flexplate equivalent to a 50 oz-in since the flex plate sheet metal is only a fraction of the thickness of the counterweight.

I would just swap in the correct flex plate when you do the trans swap.

But there could be more complications- like was the engine balanced with the flexplate that is on it now? If so, when the "correct" flexplate is put on, then the engine will presumably be out of balance again.

 

"it was balanced"
So the flexplate is not the same one the balance shop had when they balanced the crank?
Or perhaps 'balanced" means the rods and pistons were just weight matched.

 

I really do not know if he used this exact one or not... when I picked it all up from napa it was in the box. now the napa in my town is 35 miles away from the other one where the machine shop is... I assume there is a possibility he just told the store to order a flex plate for the original 1984 f150.. and that is what they had for me.. who knows. but the one I have deffinetly does not have the cut out like the 50oz units do.. and I would assume that since adding weight to what obviously looks like a smaller oz plate, that I would need a 50 oz plate.. and that is what the front balancer is for..

 

Glad to hear that helped, sometimes it doesn't take much. You could make some elongated weights to fit under the studs for now, just don't add too much more. I wouldn't try to cut out or drill the other side with it in the car, could damage your convertor. Then you might end up on that proverbial creek without the paddle! LOL!! ; (

 

had the same problem with a Ford 3.8 V6, found that Ford had 3 different combinations of flywheels and harmonic balancers for the same year but different models. One of the reasons I stay away from Fords now

 

I'll add my little bit of thoughts on an AOD. It's a good trans, I was working at the dealership when they came out in '80. There were a few problems at first, but Ford got it straightened out quickly, pretty trouble free. I can't say that about Brand Xs unit, I sometimes wonder if you can really fix those things. I put an AOD in my '70 short bed. 300 six with a Offenhauser manifold and a "small" 4 barrel! With the original C-4 it was fairly peppy, no giant killer but it ran decent and the mileage was good. Found a trans and a good friend gave me a hand on some of the details when I overhauled it, but I was into it for about 300 bucks. Put it in my truck and frankly I was a little disappointed, maybe its in the convertor, but the truck did not run as good. Loved the O.D. part, that was neat, and I worked out a link for the T.V. lever. I drove it a lot, pulled my car trailer all the time. I put at least a 100 thou on that trans before I sold the truck. Maybe someone can give a different perspective, but I think a looser convertor would help. Mike.

 

I commend both you and Mike for your efforts, but this is what we engine builders call " chasing your tail " when balancing a crank. You just keep moving the imbalance around the RPM range, which is exactly what you said in your post. The vibration is now starting when at the RPM it used to end.

Again, you and Mike are not chasing your tails, just the physics of balancing is chasing it's tail LOL.

For different tracks in circle racing we often purposely use different balance " factors " to do what you are doing, moving the sweet spot around the RPM range for a different track or set up. It get's very complicated to say the least.

Now different manufacturers might or might not have the cut out opposite the weight, if they don't it will be a very long weight. The Ford F/P has the cut out, it cuts down manufacturing cost's when you are stamping 10 million F/Ps. Easier and cheaper to add a die to cutout the slot than to weld a much larger piece of C/W, see what I'm saying.

I wish I had better news for you, but I don't. If the crank was drilled/weight added and balanced with a wrong F/P, just replacing the F/P probably won't fix the problem without spinning up the crank again. I will just hope for your sake it does. My experience is that you will just chase your tail around the RPM range of imbalance. I hope for your sake I'm wrong, TR

 

With out reading through 5 damned pages, let me say; if the motor was in fact balanced and then you changed something (I beleive you said the balancer) then the thing that you changed id WRONG! Try putting the old part back on.

 

yup.. put on a new balancer.. no change.. negative or positive.. I do have a 50 oz Dorman replacement balancer... while who knows what will happen when replacing the flex plate.. just looking on the internet and whats said here.. all the 50 oz plates look nothing like my plate. they either have a similar size weight and a large hole ore a really large weight.. I have neither. assuming that since adding weight to my plate I can only assume that I need the 50 oz.. The only thing I know is that the current flex plate was for the original motor.. 1984 f150 302 that I took him ... thats what the box part # was for... I kept the 1984 V belt pulleys.. front accessories.. and timing cover. This plate was a part that was given to me by NAPA as I did not have a flexplate with the original motor. maybe they made a mistake or assumed it was 50 oz and it isn't.. I don't know. but, my plan of action is to get a 50 oz flex plate and give it a try.

 

I just looked at napa online... they have 2 plates .. looks like
this one is what I have..


and this one is what I need or needed.


only 2 they have listed for SBF in 84 ...

 

I believe the top one shown is for the 84 351/W 28oz. and the other is for the 84 302 50oz.

 

they had 5.0 listed for it.. the lower one did not have any information attached to it... but the first one did have both 351 and 5.0 listed for several years up to the 90s

 

Again, if the crankshaft was spun on the balancer with the wrong F/P, changing the F/P is NOT going to change where the weight was removed or added from the cranks counterweights to correct the imbalance. You will just be imbalanced some where else.

All you or anyone has to do is go and watch him spin a crank. Take a hunk of modeling clay and stick it on the crank or the F/P somewhere and spin it again, you will be severely out of balance. Now remove the clay and put it somewhere else, out of balance again.

" chasing your tail ", real engine builders know this.

I understand if you don't care for me, and that's fine but LORD knows I'm trying to help, TR

 

BTW, the modeling clay is not a joke. This is what we use when you are balancing a $6000-$8000 only 1 in the world one off crankshaft. You don't start drilling and welding and installing Tungsten until you are absolutely sure of the results. The modeling clay does this perfectly.

 

Ok maybe make of car unrelated..My same type of vibration issue was with a Dodge 440 and 727 trans set up..

turned out to be the wrong torque converter, just throwing it out there

but yes it was a drive line out of balance situation

 

A long time a go I swapped a 1968 302 to replace a 300 six. The 300 six flywheel (manual trans) bolted up to the 302 just fine. I had exactly the same shaking you described. Exactly, as if you and I had written the same description.
Found out the 300 flywheel was neutral balanced and the 302 used 28 oz. imbalanced fly wheel.
I got a 302 flywheel and swapped it out, the vibration/ shaking went away, smooth as silk.
I too think you have the wrong flex plate / imbalance weight.

 

im sure I have a conglomeration of different things.. I have learned my lesson on buying things and piece milling it together... buying a running driving drive line with all the bits in place is definitely a good road map to follow next time. Traditions.. I really appreciate the info.. no dislikein going on here. I will see if I can find someone around arkansas that can do a balance.. and see what they charge to do so. Im not against it. I just would of guessed it being a stock crank with a stock 50 oz hbalancer that a stock 50 oz flex plate would be a good starting point... but like I said earlier I really have not been around this side of the engine world much so I can see that maybe if he machined something out it would need additional balancing... but I figured that since he gave me a stock plate that would of been what he wanted me to run... just looks like the local boys handed me the wrong plate... I think there is a guy in Little Rock that does balancing.. and I know that JD wooley in Cabot or Searcy can do it but he has like a 1 year waiting list. He is considered one of the best around here.. and I took him a 390 I had.. he was swamped over when I was doing this one. If you know of anyone I'll give em a call.

 

Hold on, don't despair and start spending a bunch of money on balancing again. Just put on the "correct" flex plate and see if the problem is fixed, before dismantling the engine and sending the parts off for rebalancing.

I wouldn't give up on assembling engines (especially Fords) due to this experience, conversely you will be quite knowledgeable about them now!

The machine shop may well have grabbed its own proper 50 oz-in flywheel to balance the engine, and not used the "wrong" one that you got from the parts store.

Catalogue listings often have mistakes, especially in situations like this where there is a changeover close to the year in question, that affects only some of the engine family. Or someone might have swapped flexplates and returned the piece in the box to the parts store.

A friend changed the engine in his T-bird and the 83 5.0 he used was still the early balance, despite all the listings. This was a Canadian vehicle, which possibly could also make a difference.

 

I put a few Ford motors together, but dont know a thing about balancing. It seems to me that the guy doing the balancing wouldnt be able to balance it with the wrong weight flywheel. Or when he got done it would be balanced. How could it vibrate when its running but not on the balance machine? Just asking....

 

I've never balanced a rotating assembly, I just pick them up.
With that said, this guys set up clearly isn't balanced now. How could it have been balanced with a 28 oz imbalance plate? Would not it have been balanced ? Albeit incorrectly but balanced ? Let's say MR engine balancer had a 50oz plate and balanced- install 28 and its gonna be out. No? Let's say Mr engine balancer had 28oz plate and balanced - should still be balanced now no? Let's say Mr engine bakancer had 28 oz plate on and says "hey WTF ! Wrong plate "

What's more likely to have happened that created the current situation?

 

this is something that hopefully has an answer that will be saved to help others.

 

Just guessing, but I almost wonder if the guy balanced it with his 50oz flexplate, and just had the store get you a new one... which ended up as a 28oz. I haven't balanced anything - I'm no expert - but I've seen it done and understand the mechanicals of it. That said.. I don't believe you could easily balance it with the wrong flexplate?
Anyway... when I worked at the speed shop here in town, I had a couple customers with the exact same problem, and it was because they had the wrong flywheel,flexplate, or balancer. Your picture shows it's wrong for the rest of the parts you've got... so I'd buy a 50oz and go from there.

 

Might check this picture also: http://www.kmjent.com/cart/ford-sfi-flexplate-164-tooth-50-oz-302-5.0l-c4-aod.html

 

If the new flex plate doesn't work, here's what I think may have happened. When the crank was balanced, someone got word it was an old block and balanced it for it and not the newer weights. If the new flexplate fixes is, fine. I wouldn't trust that machinist though.

 

are all the mounts (trans and motor) good? been checked ?

 

Mr. Traditions, you know what you are talking about, I used to help a good friend balance a few motors, it's sort of a black art! I agree with you about those H/V oil pumps, rarely are they needed. I figured he could try the weight change on the flex plate, but if the shop that did the work did screw up, (I'm not trashing them), the crank might be junk at this point. A machinist I used in the '70s screwed up a couple of times; and at that point I started buying mikes and double checking everything. The guy I use now is VERY thorough, and conscientious, and he has one heck of a back log! How is the weather down there? Mike.

 

Thanks for the help guys.. mike, though it may be temporary... I took the truck out for a spin last night and holy cow... its almost smooth as butter.. not perfect yet.. but hey I appreciate the help.. amazing that in the few years ive had this motor and talked to several guys about it.. no one could ever put their finger on what was the issue. I haven't driven this truck a whole bunch since most of its life has been either apart or in the shop.. I really don't even think I've got but a few thousand if that many miles on it.. I don't have a Odometer yet.. as you can see in the video. but just driven around town. so Im hoping no real damage is done or at least minimal damage.. Thanks again for all the help.. and I'll keep you updated when I make the transition later.