Technical Ford 260CI Flexplate

just a couple of points:
1. I just compared the overall dia of the OEM 160T to a new SFI 157 I have......both 13.250". The tooth
thickness appears thinner, but not measurable.

2. The OEM 160T was replaced 20yrs ago w/ another 157T SFI.........no issues w/ starter now
20 yrs later.

3. The 160T that I keep referring to shows 4 minor weights added and several holes countersunk
I don't doubt if Ford balanced the rotating assy to the nearest few grams, but countersinking
can't remove much weight. I think there is a good prospect that any 28.2 compatible flex plate
will help your vibration, but will not be "perfect".

 

Well, if I needed a another flex plate that would be alot easier.
157 tooth is more available than the 160 tooth. Only can find used for 160.
I have read though, that their are starter conflicts on 160 tooth vs 157 tooth.

 

I've measured both ring gears major dia to be 13.25". Inferring that the tooth spacing would be
0.005" wider with a 157T. My starter apparently hasn't cared about the 0.005" difference over past
20 yrs since using a SFI plate w/ a 157T. By the way a 164T doesn't utilize a different starter gear,
just a different mount location.

Any undamaged 28.2 plate may help your sensing vibration, however engine balancing entails the entire
rotating assembly (flexplate, flywheel, pressure plate, etc). My original Ford 160T has the major large weight and 4 x 3.6g minor weights welded at 100* and 140* offset from the major weight. The point is that you may have to be satisfied with a less than perfect improvement unless you want to tear it down
to balance everything.

 

I will know more today as to what has to be done.
I don't think my flex plate is going to be re-usable.
Possible it was hitting torque converter drain bolt.

 

Ok, got a call from trans guy today.

I have a 6 bolt bell housing, not a 5 bolt and a 157 tooth flex plate.
Seems who ever did some work on the trans or motor welded
a weight to the flex plate. Thus causing the shit storm in there.

He couldn't find a Ford # on the flex plate, no number at all.
Now I'm confused I thought a 260 motor had a 5 bolt bell housing and 289
had a 6 bolt. So if I order a 157 tooth for a 289 would I be good to go??

I got to get this ordered today, any help is again appreciated.

 

Early 289s also had 5-bolt bellhousings.

If you've got 6, it is a 289, after they went to 6, or, a 302.

Are there any casting numbers on the block?

There should be a letter C (alphabetical, for decades after WWII, 1960 are therefore C), followed by a number.

For example, C2 is 1962, D5 is 1975, and E0 would be 1980.

 

You need to find out exactly what engine what you have.
Later model 302s, 5.0s used a 50oz imbalance. This may be why some yahoo welded a weight on that flexplate.

Until you find out what the engine is, you are just throwing stuff against the wall to see what sticks.

 

I have the mechanic getting numbers off the block and bell housing.
I'll know more when he gets them to me.
I think for my sake if it's a 289 it would be better for future parts availability.
The guy my son bought it from said it was a 260.
I found the owner previous to him and he told me also it was a 260 with 289 heads.
What a cluster F%*K

 

Sounds like you've found the problem, once you have the numbers and get the correct flexplate for that engine. Sounds like its just a case of someone cobbling together stuff they had. It doesn't seem like that is also causing the lurching you described.

Sent from my SM-G973U using The H.A.M.B. mobile app

 

I am pretty sure the 260 does not have the same imbalance as the 289.
I'll see if I can dig this up in my reference books later.

 

The 260 and 289 used the same crank and balance factor, only the bore was different. I'm wondering if he got sold a 255 as a 260 which would need an aftermarket conversion flexplate due to a 50 oz balance factor...

 

If it is a 255, or 50oz later 5.0, then the block will have a provision for a push in dipstick on the drivers side above the oil pan rail. Might be hard to see, but you should be able to reach around there and see/feel a niche below the freeze(or whatever you want to call it) plug behind the engine mount boss on the block.

 

Didnt 260's have the breather coming out the timing cover also?

 

worst case scenario.....
A 50oz crank in a earlier 289/302 block, junkyard pot luck where the engine was assembled from stuff laying a round.
Numbers would mean nothing.

 

Kevin,
sorry my PM end is working. 221,260 289 same M1 crank and 28 oz imbalance. Presumably
you don't have a later (83) assembly.....what was block the casting #.
The pic of the welded weights looks strange. Here is an old article for info:
https://www.cartechbooks.com/techtips/rotating-assembly-parts-interchange-for-small-block-ford/

 

Many years ago a guy sold me a 260 out of a Falcon for $25, got it and started taking it apart found it was a 351.
Asked him later how he figured it was a 260......................well that's what it said on the fender was his answer.........................

 

Yeah, that's my fear. I've ran into a few, been guilty of it myself although I did it for good reasons. One advantage of the 50 oz crank is it's considerably lighter yet still strong, so the motor will rev easier.

 

If you pull the pan, look at the crankshaft first counterweight, it will have '1M' '2M' or '2ME'.
2ME/2MA cranks are the 50oz imbalance. A 255 will have hollow rod throws.
302(2M) cranks will have two nub counterweights on either side of the center main. 5.0(2ME/2MA) will not.

 

The trans guy said he would sort it out and let me know whats going on tomorrow.

 

I was unable to find my reference book, but this topic has been covered a couple times in the Fairlane Club of America forums (members only) and I copied this from one of the threads on the subject:

"There is an engine balance issue. The flex-plate for the 260 Fordomatic is counterbalanced 24.5 ounce-inches. The 289 requires 28.2 ounce-inches."

Believe it or not at your own pleasure.

 

I'd have to believe the difference must be in the torque convertor, as the 260 and 289/302 use the same manual flywheel.

 

It would have to be the torque converter for the aluminum Fordomatic as the 260 was not used with a C4. I suppose a Fordomatic flexplate could be used with a C4, but why? It seems that problem would work it's self out as I don't know if the Fordomatic flexplate is even compatible with a C4. Knowing Ford, I would say no. Then again knowing Ford, maybe yes.
Also we don't know if that info is accurate about the 24oz flexplate. It probably is but maybe not.

The question about the 260 is mute because it's been confirmed to be a 6 bolt engine....supposedly.

 

So the trans guy called today and confirmed it's a 1965 289CI and not a 255, 260 or a 302.
I told him that part numbers are not so reliable and he said he made sure.

Said he has he right flex plate for it and that someone welded on a weight and then used
a grinder to try and balance the flex plate, he thought at first it was rubbing on torque conveter.
Upon further inspection he noticed grinding marks from a grinder.

I mentioned to him that there could be the 28 or 50 ounce flexplate.
I told him to start the car before he shoves a fresh c4 back in it.

We will see what happens.
.

 

Kevin, hopefully you are on your way to a fix.
* Weren't your weights on the opposite side of converter? what was he thinking?
* not likely a 50 oz w/ block ID'd 1965 and 3 bolt damper.
* off the shelf 28.2 flexplate hopefully satisfies you, but since the rotating assy is not balanced together
as Ford or a fresh build would be done, it could still have some a harmonic. Street engines can tolerate
up to an ounce, most shops can accomplish down to 10g, 5g, or 2g if motor built for higher rpms

 

I have complete confidence is this shop, they communicate well.
Whoever welded the weight on the flex plate was trying to lose weight on it by grinding it.
I remember when checking crank pulley and damper it had the one on the left in pic.

We will see what happens, hopefully there is no more surprises.
He assured me it will be right when done.

 

You can run a 157-tooth flexplate, at 28.2oz, with a common 289 starter.

 

This is cracking me up now.
So I just wanted to confirm for myself that there was a 289 in my car.
I asked the mechanic to relay me the engine ID # (C30E-6015133828)

Looks to me likes its a 260 not a 289 after all.
What the F@%K! !
He has been going off of other part #s on the trans.
I told him they are not reliable. He said he would make sure
everything is proper and working the way it should before it leaves his shop.

Now I'm wondering how it can have a 6 bolt bell housing???

It could be 1 of these 3

C3OE – 1963, 221 Windsor small-block, 2-bolt mains, 5-bolt bellhousing, 2 freeze plugs

C3OE – 1963, 260 Windsor small-block, 2-bolt mains, 5-bolt bellhousing, 2 freeze plugs

C3OE – 1963, 289 Windsor small-block, 2-bolt mains, 5-bolt bellhousing, 2 freeze plugs

It's got to be a 5 bolt bell housing.

 

Kevin,
keep your sense of humor. A 157t 28.2 compatible flexplate should still be best bet.

 

I was anticipating a mis-ID of the engine.
So It's indeed 5 bolt small block from 1963.
I cant find my book but that Prefix could mean
1963 221
1963 260
1963 289
They all used that same prefix.
With a C4, the 28oz flexplate should do it and solve your flexplate problem.
Is he overhauling that transmission? What year is the transmission? It should be on the case, not the Bell, the case.

 

I'm good, no worries it will get fixed. Thanks man.

Actually I asked him to get me the ID after he was going of part #s on the transmission.
And as you said numbers mean nothing. I just told him to make sure he got a 28 oz 157 tooth flex plate.
I'll let you guys know as this keeps unfolding. I also thought the 289 didn't come out
until mid 1964.