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T5 clutch/flywheel - HELP!

8K views 35 replies 9 participants last post by  rbtconsultants 
#1 ·
So, disappointing day. We are getting ready to drop the new 347 into the 66. Got it off the engine stand on to the lift, and all we have left to do is to bolt the flywheel, clutch and bellhousing on (and the headers) and drop it in.

Here's the dilemma. The rotating assembly was balanced together by the vendor, including flywheel and balancer. When ordered I specified a 157 tooth flywheel and and i specified for a 10 1/2" clutch, but it looks like they screwed up. It is definitely 157 tooth, we counted them, but the clutch doesn't come close to fitting. No part number on the flywheel box. I am contacting them but who knows what the resolution will be or how long it might take, so I'm trying to assess my options.

I don't think I want to just replace the flywheel with an off the shelf since it won't be balanced with the assembly, correct? I'd have to get a new flywheel and pay a machine shop to match balance it with the incorrect one?

So, if I just wanted to keep this flywheel, do I have options? I think I do, but not 100% sure. Attached is a pic. You can see I started the bolts in the only holes that come close to fitting my bolts. Am I right that it looks like it's drilled for a 10" clutch? I'm not sure why the other holes are even there, I don't think they have threads in them. They all go all the way through. 3 appear to have a shoulder inside them, which I thought was to hold the alignment pins.

Can I get a 10" diaphragm clutch that will work with my '90 t5 bellhousing and t5 fork? Will this flywheel have any issues with my mini-starter I have now (I'm guessing not)? Do I need different bolts to mount the pressure plate to this flywheel ? (I'm thinking yes, the bolts I have for the 10 1/2" pressure plate seem to almost fit but not quite, won't finger thread in past the first turn or so. Metric thread vs. SAE?)

Sigh. Any thoughts will be VERY APPRECIATED.

Thanks,

Bob

 
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#3 · (Edited)
I don't think I want to just replace the flywheel with an off the shelf since it won't be balanced with the assembly, correct? I'd have to get a new flywheel and pay a machine shop to match balance it with the incorrect one?
Bob,
Your flywheel looks like it has the pattern for the early type clutch. Perhaps you recieved the wrong clutch. Your 347s crankshaft is most likely made to a Ford standard 28.2 in oz balance. You can buy off the shelf flywheels made to that spec that have the correct pattern for the late diaphram clutch, or dual pattern. If you end up with a new flywheel you do not need to have it 'custom balanced' but you do want to have it checked to verify its balance.

Paul
 
#4 ·
Paul - thanks. I didn't "receive" the wrong clutch, I have a 10 1/2" clutch for a 90 mustang I expected to bolt up. It didn't come with the rotating assembly.

So you also think It looks like this is a flywheel for the "early type" clutch, i.e. 10" clutch?

My question is, can I buy a diaphragm clutch that would fit this flywheel and work with my 1990 t5 bellhousing and fork?

This flywheel was balanced with the rotating assembly, it has obvious balancing holes drilled in it on the back, but I don't know if it came from the factory that way or it was drilled that way when it was balanced at the rotating assembly vendor. So it may not be "custom balanced" but it was balanced as part of the whole rotating assembly and is not "off the shelf".

Bob
 
#7 ·
Yes he is. The later model roller cam motors use metric bolts, 3 dowels and a different PP pattern. If a 5/16 bolt doesn't thread in, you have a metric style with the M8 bolts. You will need to get a 80's style PP. You will also need to get the 3 dowels as well.

Fr my Gt40P I bought a PRW billet flywheel because it uses a bolt on weight and it's drilled for both early 5/16 and metric 8M. I can use any sbf PP.
 
#8 ·
I apologize. I seem to be having trouble communicating my problem/question. I have a pressure plate for a 90 mustang t5 10 1/2" clutch.

It does not fit this flywheel, which is a 157 tooth flywheel with an unknown (to me) bolt pattern.

I'm trying to determine what kind of flywheel I have and whether there is a clutch I can purchase that will work with this flywheel and my 1990 t5 bellhousing and fork.

If there is such a clutch, what kind of clutch would that be? I.e. model year or manufacturer/part number.

Thanks,

Bob
 
#11 ·
Bob,
No need to apologize. You were quite clear. Perhaps this will help:
http://www.bcbroncos.com/ford starters.pdf

Scroll down to page 7 (last page). You need a flywheel that has the 'evenly spaced' pattern (type 2) or one with both patterns for your 1990 Mustang 10.5 diaphram pressure plate. As mentioned the holes will be threaded for M8 bolts. To match you stroker crank the flywheel will need to be 28.2 oz balance.

Good luck
Paul
 
#9 ·
331 and 347 kits are balanced to the older 28 oz unbalance. To be honest I don't know what flywheels the later Mustangs guys use for their 331/347 swaps. They could very well be a special 28 oz balance with the metric bolt pattern. But in your case the 28 oz balance of your 347 as you know is the same as the old 289 you pulled. The shop could have used a common 289/302 with 28 oz balance. It will work with a regular 289/302 pressure plate with your T5 transmission and bellhousing. You just need to use the T5 throw out bearing and I think you'll be fine. On the GT40P I just put in my 66, I used a Ford Motorsport Cobra cutch kit that my brother gave me years and years ago. I have a Toploader 4 speed. Do you have a older 289 pressure plate to see if it fits the 347?
 
#10 · (Edited)
OK, time to straighten this out again.

The 65-73 289/302 10" clutch and the 65-70 10.5" 289/302 clutch use the the same attaching bolt pattern.

This is the 289 157T wheel, with 10" clutch:



This is a 289HP 157T wheel:



Here's the BOSS 302 164T wheel. Note it has the same bolt pattern as the 289, because it used the same clutch as the 289HP:



Anyway, it looks to me you have the correct flywheel, which means you must have the wrong clutch. But, you haven't showed us your clutch. Please do.
 
#13 ·
Ok - I now understand that there are two types of bolt patterns that will fit a 10.5" clutch. The clutch I have is for an evenly spaced bolt pattern that has m8 bolts.

For this flywheel I need a clutch has a bolt pattern with 3 groups of two bolts. I will need 5/16 bolts.

So, I have to buy a new clutch. That's fine.

What clutch would I buy? What model/year cars would I use to lookup a diaphragm clutch with that "3 groups of 2 bolts" pattern?

Thank you for all the help and patience.

Bob
 
#15 ·
At this point I'm convinced I could get a 10" diaphragm clutch that would fit the bolt pattern on this flywheel.

I'm now trying to figure out if I can get a 10.5" diaphragm clutch that would fit. If so, what would I get? How would I look one up.

Is a 10" fine? It's not a drag car.

Thanks,

Bob
 
#19 · (Edited)
Why a diaphragm clutch? Ford uses them because they are cheaper, not because they are better. Of course, there are such clutches that work fine, but I'd feel a lot better about this if you'd tell us the attaching bolt circle diameter on your flywheel.

And we still haven't seen your clutch, or leaned the part number on that.
 
#21 ·
Also, we have a hydraulic clutch do I thought for sure that required a diaphragm clutch with preload on the throwout bearing.

Is that incorrect?

Bob
 
#22 · (Edited)
I'll check that diameter shortly when I get down to the garage. Don't I require a diaphragm clutch with the t5 bellhousing and fork?
No. A stone-stock 1966 289HP/BOSS 302 pressure plate will almost certainly fit your flywheel. See below.

And why would you want to use a Fox-body release lever (fork) in a 1966 Mustang?

It looks like it is very difficult to locate a 10.5" diaphragm pressure plate with that "3 groups of two" bolt pattern. They appear to be uncommon and expensive.
Well, any 1966 clutch will not be thick on the floor at your local parts store. No matter what car.

On the other hand, 10" are common. Maybe I'll just get one of them.
No, 10" 1966 clutches are not common.


This is the clutch I have in my 66.
https://www.summitracing.com/parts/ram-92502/overview/make/ford

I have superimposed the 289HP image at 50% over your flywheel. Allowing for my inexact alignment, it looks like a dead-on match between them, which means the flywheel supplier gave you the perfect wheel for your 1966 car.


 

Attachments

#23 ·
So, to put a bow on this. Thanks all for the thoughts.

The car currently has a 1990 t5, with a 1990 t5 bellhousing and clutch fork, and a hydraulic clutch slave cylinder. The 289 we pulled out has a flywheel for a 1990 10.5 diaphragm clutch. I assume I need a diaphragm clutch with this configuration.

I ordered a 347 rotating assembly with a flywheel for a 10.5 inch clutch. I did not order anything for a 66 mustang. I could have reused the flywheel we already have but chose to have the vendor supply a new flywheel that was balanced with the rotating assembly.

I could still reuse the flywheel that is on the 289, with the 1990 10.5" clutch I have. However I'm concerned it is not balanced with the rotating assembly.

So, if I want to use this new flywheel that was supplied and balanced with the rotating assembly I need to buy a new clutch that will work with this flywheel and my t5 hydraulic clutch setup, since the bolt pattern on this new flywheel is not compatible with my 1990 10.5" diaphragm clutch.

If appears there are lots of choices for a 10" diaphragm clutch that will fit this flywheel. I will likely get one of them.

Thanks,

Bob
 
#24 · (Edited)
Yep. The hydraulic clutch setup would not have been my first choice.

There is no 1990 Fox-body clutch that will attach to your present flywheel.

Since you have already completed the linkage setup, and purchased a 1990 Fox-body clutch, the simplest solution would be to replace your 1966 Mustang flywheel with the 1990 Fox-body flywheel. It will have to be rebalanced to match your engine.

The good news is you can simply give them the wheel that's on the engine now, and the Fox-body wheel, and have them balance it to match.
 
#27 ·
22GT, couldn't he just try a 66 PP anyway? I've found the local AutoZone have had a lot of parts in stock at the local store. If nothing else he could pick up a PP wether a 3 finger or diaphragm to see if it fits. I'm assuming Bob already has a metric 5.0 PP and compare dimensions.

Redneck, I found that out to be true as well. The cost to redrilled and resurface, you might as well buy a new one. In my case with my roller motor I already had a Cobra clutch kit and a T5 flywheel. The flywheel looked a little iffy, so I decided to buy a new one. A stock cast iron Chinese wheel is going to be about $90. For the price of a good set of work boots I upgraded to a billet wheel not only for safety reasons but the one I bought is SFI rated, has every SBF PP pattern, SAE and metric with dowels as well as having a bolt on weight. I can use the wheel on virtually any type of SBF. SAE, metric, 0, 28 or 50 oz balance. Plus this is the brand almost every Engine Masters contestant uses.
 
#28 · (Edited)
It probably would. He'd have to be very careful with release bearing selection, though, the OD of the face on the 66 bearing is larger than that of the 90 release bearing, I have seen people mix these and end up with the release bearing jammed in the fingers.

Personally, I prefer the OE semi-centrifugal clutch, the weights incorporated in the design of the fingers increase clutch pressure as rpm increases. Diaphragm clutches don't.

To each his own, of course, I would have recommended a completely stock 289HP clutch assembly and linkage. The 66 stuff would of course bolt right into a 66 Mustang, so for all intents, especially maintenance, you can specify correct parts for that year car. With Drakes roller pedal kit, it would probably have been easier and smoother than either hydraulic or cable.
 
#31 ·
Centerforce diaphragm pressure plates have centrifugal weights that supposedly increase the clamp load as the RPM goes up.

I also prefer the Long style pressure plates over the diaphragm type, but it seems that just about all you can get now days is the diaphragm, except for specialty type clutches.
 
#29 ·
Thanks 22GT - sigh. So now I'm concerned about purchasing a 10" clutch if I have to worry about the throwout bearing with the t5 fork.

The z-bar linkage is really a non-starter. We have a hydroboost power brake booster installed and a borgeson power steering box so fitting the hydraulic master cylinder in up at the firewall was a squeeze in itself.

Sounds like I need to just get the right 1990 flywheel and get it balanced. I guess I'll see what the vendor says tomorrow when they open about whether they will do anything to make this right. I really don't want to buy a new flywheel and pay to have it match balanced.

I suppose I could pull the flywheel off the 289 and have that match-balanced but I was planning on leaving it on as part of a sale of the 289 to someone, but maybe that makes no sense anyway unless the buyer is going to use it for at conversion.

So, I guess I'll figure it out tomorrow after I talk to the vendor.

Thanks,

Bob
 
#30 ·
unless I misunderstood, the concern is with the throwout bearing getting stuck in the fingers of the pressureplate not the fork. Match the throwout bearing with the pressurplate and you should be good.
 
#36 ·
Thanks for thoughts. I was able to confirm with the vendor that the flywheel that we got with the 347 was not drilled as part of rotating assembly balancing, so I can replace it with the flywheel we had on the 289 and use the fox 10.5" clutch. So that's what we are going to do.


Thanks,

Bob
 
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