scootchu

I wish I had only one problem with my car or maybe I was a little more accepting of it's quirks, but I started thinking about some things that I have issues with and one is an engine vibration at 2500 rpm. I have messed with the timing and it's not as bad, or less noticable, but I have too many things going on in my head to just focus on that.

I am looking for another T5 to swap out with the current one with the 2nd gear grind and I started to think, wow how come my pressure plate wasn't the three finger type? When I pulled the tranny I was surprised to find the multi-finger PP.

I was reading somewhere that only later model flywheels were drilled for multi finger pressure plates. I have a multi finger on there now. It' starts to get confusing as to if I even have the right flywheel on the engine. Who knows what the previous owners stuck on there. I found an auto starter on a manual tranny, a 65 bellhousing on a 68 block, with what is supposed to be a 25 spline toploader (actually a 28 spline) so nothing would surprise me.

Sooooooo what I am asking is could there be a multi fingered PP made that bolts to a 28oz flywheel on this Frankenstang?

Now I know why people like an "all original" car.

Also, just say it was a 50oz flywheel with a 28oz damper, I would have huge vibrations correct?

BTW I am pretty sure it's the engine. I run it in neutral and get the rhythmic "boat like" vibration at 2500rpm with the belts off the accessories. It's not huge, just there.

Like I said there's a laundry list of things I would love to fix, kinda like me... aching knees, stiff neck, etc...

OCHOHILL

Attitude adjustment. It's a restomod not a frankenstang. I have never done it but the incorrect balance should vibrate at any rpm. The clutch thing would take some research. If the PP was a late model performance clutch for a 289 flywheel then I don't see why it couldn't be a multi fingered (aren't they called diaphram?) clutch. I thought those were better thean the old school 3 prong kits. You may want to double check that the PP holes jive well with the flywheel. Perhaps a 50 oz style clutch was modified to fit. Tough to do, I think, but anythings possible.

2+2GT

I wish I had only one problem with my car or maybe I was a little more accepting of it's quirks, but I started thinking about some things that I have issues with and one is an engine vibration at 2500 rpm. I have messed with the timing and it's not as bad, or less noticable, but I have too many things going on in my head to just focus on that.

I am looking for another T5 to swap out with the current one with the 2nd gear grind and I started to think, wow how come my pressure plate wasn't the three finger type? When I pulled the tranny I was surprised to find the multi-finger PP.
There is a variety of diaphram-type PP's for early cars. I don't like them. I prefer the semi-centrifugal OE type, I use a direct copy of the C7ZZ 289HP/BOSS 302 clutch. Grips better as engine rpm increases.

I was reading somewhere that only later model flywheels were drilled for multi finger pressure plates. I have a multi finger on there now. It' starts to get confusing as to if I even have the right flywheel on the engine. Who knows what the previous owners stuck on there. I found an auto starter on a manual tranny, a 65 bellhousing on a 68 block, with what is supposed to be a 25 spline toploader (actually a 28 spline) so nothing would surprise me.
Having the wrong weight wheel would cause a severe vibration that would get worse as rpm increased.

Sooooooo what I am asking is could there be a multi fingered PP made that bolts to a 28oz flywheel on this Frankenstang?
Sure.

Now I know why people like an "all original" car.
I go as original as possible, even with T5 conversions.

Also, just say it was a 50oz flywheel with a 28oz damper, I would have huge vibrations correct?
Yup. Very huge.

BTW I am pretty sure it's the engine. I run it in neutral and get the rhythmic "boat like" vibration at 2500rpm with the belts off the accessories. It's not huge, just there.
Drive the car at the problem speed, then pop into neutral and coast. Does the vibration drop with the engine, or continue?

smittycm

You can use either the 3-long finger style or the diaghram style pressure plate with the T-5. They sell aftermarket 28 oz. flywheels drilled for the diaghram (5.0) style clutch. You could also possibly take your flywheel to a machine shop and have them redrill for the diaghram style, or take a later model flywheel and rebalance it for 28 oz. There are multiple possibilities in this case. Bottom line is you have a 157 tooth 28 oz flywheel drilled to accept the metric style PP. The diaghram style PP which you have on there now is the better one anyways. I would leave it alone.

As for your auto starter. That is the correct starter to use in an early model Mustang with the T-5 swap.

As for the vibrations. Yes, you would KNOW if it was an imbalance factor coming from the engine. It wouldn't be any sort of small vibration if it was a difference of 28 oz balancer with a 50 oz flywheel. That's not to say your vibration issues aren't engine related though. Put your car in neutral and rev the engine. Does it still vibrate, or does it only vibrate when in gear and rolling down the road? If it vibrates in neutral and at a stand still, then you've just isolated your vibration issue to the engine. If it's while rolling and in gear, then I would start by checking your tranny yoke for wear, as well as your u-joints for wear and looseness. From there I'd probably move to the tires to check the balance, etc. Do those tests and get back with us.

scootchu

If i drop the rpm's and coast it goes away.
It's not speed related. Was worse before I adjusted the timing and now the power seems to be overshadowing the vibration. It occurs at 2500 rpm and if you have ever been trolling in a sterndrive boat it is close to that harmonic vibration. It's cyclical.

I am finding that this is indeed a Frankencar. Parts that come close to fitting... yep they'll work. LOL

Thanks for clearing up the diaphragm PP issue too. After looking I do see that they are made for earlier flywheels.

On a side note:
I am looking at a 1352-249 T5 to swap out for the troubled T5 I have in my car right now. The 249 is supposed to be one of the better transmissions in the T5 group.

1969boss302

Have you had any clutch linkage issues since you have owned this car? I had a 68 Cougar that I swapped a 5.0 out of a late model (at that time) 84 Mustang GT wreck. After getting it on the road I would periodically bend the rod that connects the equalizer bar to the clutch fork. I replaced it 4 or 5 times before digging into to it to figure out the problem. In the end it was the diaphram clutch spring pressure causing it. I swapped out the diaphram clutch for a 3 finger OEM (for the car) unit and I never had another problem with it. I will be surprised if you haven't had an issue with yours, but as time goes by nothing shocks me about these cars anymore. Have you had the pressure plate off of the car? If the car was pieced together like you describe maybe there is some kind of extra washer or spacer contributing to a slight out of balance on the flywheel??

scootchu

No, not any real issues, but the return spring from the z-bar was missing and the throw out fork was cut to clear the headers or least that's how it appears.

I had the PP off the flywheel and it fit fine, no loose parts either. The clutch was replaced in late 2008 so it was all in good shape.

It's definitely rpm related. I may swap out the motor mounts just to cover that.

kalli

any chance the problem could be spigot bearing (whatever the little bearing is called that holds the input shaft of transmission), or bellhousing runout? did you use original bellhousing with adapter or latemodel bellhousing?

scootchu

I thought about that and changed the pilot bushing to a new pilot bearing, but it is the old bell housing with an adapter.

I picked up another T5 and this one is a 1352-249 which is supposed to be rated at 330 and have beefier internals and it came with the bell housing. I will give this one a shot. I have the removal and installation of these T5's down now with all this practice. LOL

kalli

i would imagine so :-) i know there's common problems with the adapter plate to get the trans to sit right (runout). the bolts that came with my plate were too long. they would hit the bellhousing so that the transmission would never sit straight in there. just a thought ... best of luck with it. it would be great to be able to run the engine without gearbox, (just with bellhosuing for the starter), so you can see if the vibrations are still there.