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Discussion Starter · #1 ·
So I am in the process of assembling my motor, in advance of purchasing the kit (which may be literally any day now).

Background:
351w stroker
FMS billet steel flywheel (M-6375-D302B)
McLeod Street Extreme clutch (75307)
ARP pressure plate bolts (150-2201: 5/16-18 x 1/2)

When installing the pressure plate to the flywheel, I am finding that the pressure plate does not snug down flush to the face of the flywheel (see pic). TBH, I am not sure if it is supposed to. The spec for the bolts appears to be 25 ft-lbs, and to get it to the point in the pic is more than 25. The clutch kit instructions are exceedingly lacking in detail. As I torque down the pressure plate bolts, I can feel the clutch binding (a good thing), but I am worried that if the bolts bottom out that I may risk damaging the flywheel if I continue to torque them. Will 25 ft-lbs be the right amount to drag the clutch, and I should expect to see some gap between the pressure plate housing and the face of the flywheel?? Are my bolts too long?

Any advice or guidance is appreciated

362817
 

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Start with the simple stuff. Make sure the holes in the flywheel are not blind holes, should go all the way through. Make sure the bolts with no clutch will thread in all the way.
Make sure your clutch lining is oriented correctly. There is an engine side on the clutch lining disk.
When installing the complete assembly, tighten the clutch bolts evenly around the clutch. NO gap between clutch pressure plate frame and flywheel.
I know all this is basic, but we have to start some where.
The pressure plate will definitely clamp the disk tightly. This will be the same clamping force while the car is being driven.
Do the clutch instructions specify 25 ft lbs on the bolts?
More info, will help diagnose.
 

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And, I don't see any alignment pins. I think that hole in the bottom of the picture is for those pins. Without them, you tend to get a vibration.
 

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Discussion Starter · #4 ·
Start with the simple stuff. Make sure the holes in the flywheel are not blind holes, should go all the way through. Make sure the bolts with no clutch will thread in all the way.
Make sure your clutch lining is oriented correctly. There is an engine side on the clutch lining disk.
When installing the complete assembly, tighten the clutch bolts evenly around the clutch. NO gap between clutch pressure plate frame and flywheel.
I know all this is basic, but we have to start some where.
The pressure plate will definitely clamp the disk tightly. This will be the same clamping force while the car is being driven.
Do the clutch instructions specify 25 ft lbs on the bolts?
More info, will help diagnose.
  • The holes do go all the way through. I had assumed they didn't, but I pulled one and shined a flashlight between the separator plate and the flywheel to verify.
  • The clutch is in the proper direction (doubled checked during install/alignment.
  • When I get out to the garage later, I will be more thorough in ensuring balanced tightening.
  • I also have an email into tech support to McLeod to verify the torque specs.

Thanks for the thoughts
 

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Discussion Starter · #5 ·
And, I don't see any alignment pins. I think that hole in the bottom of the picture is for those pins. Without them, you tend to get a vibration.
Alignment dowels are definitely installed (still have some ringing in one ear). The pic is pretty closely zoomed in and the alignment hole/pin didn't make the frame
 

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Discussion Starter · #6 ·
OK, I think I have it figured out. Took a phone call to FMS tech support to get the final answer.

The ARP bolt kit is 5/18-16 thread pitch. They are intended for 3-finger pressure plates, and used without alignment dowels. A diaphragm pressure plate is supposed to use M8x1.25 threaded bolts and alignment dowels. The FMS SFI flywheel is drilled for both, which is why there are 15 holes in the flywheel. The bolt patterns are different, ensuring the proper bolts are in the proper holes. Until a guy like me gets em mixed up.

Going to run to the hardware store and get some M8x1.25s to verify. If I can score some grade 5 or better, I will just install those.
 

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Discussion Starter · #7 ·
Following up. If this is common knowledge, my apologies. Hopefully someone out there will learn from my experience.

Spoke with FMS tech support and McLeod tech support, and I have confirmed that the SAE thread pitch is only for the 3-finger style pressure plate with the narrower pair of alignment holes. The diaphragm style uses the metric pressure plate bolts and requires dowels and the wider pair of alignment holes. Stock flywheels may not have all 15 holes, but the aftermarket SFI flywheel from Ford typically will. See the image below.

The FMS website for the flywheel even states this is a note "Diaphragm clutch uses metric bolts and dowel pins. Requires metric pressure plate bolts N602549-S51M and alignment dowel pins D1FZ-6397-B or Ford Racing kit M-6397-A302". Problem is, N602549-S51M is hard to find and the FMS tech rep said he didn't even have the specs for them. M-6397-A302 is a bit easier to find (it includes the dowel pins) and the specs are listed on Summit. I managed to find some stainless M8x1.25x20mm at the local big box store and it all worked out.

Now, if you are using an 11" clutch, there is a separate part number for those bolts and dowels (M-6397-A46), but I don't know the difference.

362825
 
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