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Clutch cover bolts
Charlie_Zetec - 17/3/13 at 12:57 PM

Afternoon all,

Trying to finish fitting my clutch to the flywheel on my zetec engine. After the fiasco of the clutch issue with the Burton lightened and balanced flywheel, got myself the right Pinto clutch and set about piecing the lot together. But, stupidly, Burton sold me the wrong bolts to attach the clutch cover plate to the flywheel. They told me the bolts were M8 fine x 14mm or M8 fine x 16mm 8.8 grade. But I've checked and they're actually a 5/16 x 18tpi x 14mm.

Does anyone know where I can get some of these bolts (preferable with the built-in washer under the bolt head)? Local Ford stealership can't get hold of any apparently, and the only option is externally with minimum order of 20; at £2.47 + VAT each this route isn't really feasible.

Please help!

zetec-phill - 17/3/13 at 01:06 PM

U2U sent

Paul Turner - 17/3/13 at 02:07 PM

quote:
Originally posted by Charlie_Zetec
Afternoon all,

Trying to finish fitting my clutch to the flywheel on my zetec engine. After the fiasco of the clutch issue with the Burton lightened and balanced flywheel, got myself the right Pinto clutch and set about piecing the lot together. But, stupidly, Burton sold me the wrong bolts to attach the clutch cover plate to the flywheel. They told me the bolts were M8 fine x 14mm or M8 fine x 16mm 8.8 grade. But I've checked and they're actually a 5/16 x 18tpi x 14mm.

Does anyone know where I can get some of these bolts (preferable with the built-in washer under the bolt head)? Local Ford stealership can't get hold of any apparently, and the only option is externally with minimum order of 20; at £2.47 + VAT each this route isn't really feasible.

Please help!


Burton have not sold you the wrong bolts. The Burton flywheel uses standard Zetec metric flywheel bolts to mount the pinto cover, got that on mine. If you use imperial ones you will probably damage the flywheel.

Before you do anything speak to Burton.

Charlie_Zetec - 17/3/13 at 02:18 PM

Hi Paul,

I've tried my old zetec clutch cover bolts and the new M8's I picked up from Burton on Saturday - they won't even get 1 full turn in! But I have tried a 5/16 bolt and stud, both of which fit the thread nicely. I've carefully checked internal and external threads with tap/die/pitch guage and i'm 110% positive the threads are 5/16. I'm now wondering if it's been made to spec for someone else, and sold to me by mistake?!?

Gonna have to make the call tomorrow and see what they say, which probably means taking the flywheel off the engine and back to them for inspection.... And the purchase of 6 new flywheel to crankshaft bolts!

britishtrident - 17/3/13 at 02:23 PM

18 tpi on 5/16" is UNC --- I have never seen UNC threads used to hold on a clutch cover.

Because it is more prone to vibration induced slackening in automotive use 5/16" UNC is only normally restricted to non-rotating parts usually on ends of studs screwed into casting.

If they are unified inch sizes (nb not Imperial) they will more likely be 5/16" dia 1/2" long UNF which is 24tpi

Are you sure they aren't Metric M8 x1.0 or M8x1.25 M8x1.0 is easily confused visually similar in appearance to 5/16" 24tpi

britishtrident - 17/3/13 at 02:33 PM

I have just checked a standard CVH flywheel bolt it is 8mm x 1.25 13mm length Flange head, the bolt was pre-coated with thread lock.

Check all the bolts are the same weight before fitting.

Charlie_Zetec - 17/3/13 at 04:05 PM

quote:
Originally posted by britishtrident
I have just checked a standard CVH flywheel bolt it is 8mm x 1.25 13mm length Flange head, the bolt was pre-coated with thread lock.

Check all the bolts are the same weight before fitting.


Yup, same as the old ones I've got here that I took off originally. Definitely not the same thread as the flywheel. Tried an M8x1 and M8x1.25 and they just don't go.

Tha me for the tip about UNC - checked against pitch guage and I've definitely got 5/16-18 that fits in the flywheel.

Doubt there's much more I can do today about it, just wait and see the outcome of my call tomorrow....

Charlie_Zetec - 18/3/13 at 10:35 AM

quote:
Originally posted by Paul Turner
Burton have not sold you the wrong bolts. The Burton flywheel uses standard Zetec metric flywheel bolts to mount the pinto cover, got that on mine. If you use imperial ones you will probably damage the flywheel.

Before you do anything speak to Burton.



Well it turns out that Burton HAVE sold me the wrong bolts after all. I've checked with them this morning, as they had one of their flywheels in stock, and apparently they do take 5/16 UNC bolt.

They've told me to come in and they'll change the wrong ones over (nice 45 min trip each way for me), but I'm not convinced the ones they list are correct either!

THESE are the ones that should go in - but at 3/4" long I think they're going to be far too deep. The standard ones (as checked by me and also kindly reminded by BritishTrident) are only 13mm long.

Why do I get the feeling this is going to end up going horrificly wrong?!?

Paul Turner - 18/3/13 at 11:43 AM

quote:
Originally posted by Charlie_Zetec
quote:
Originally posted by Paul Turner
Burton have not sold you the wrong bolts. The Burton flywheel uses standard Zetec metric flywheel bolts to mount the pinto cover, got that on mine. If you use imperial ones you will probably damage the flywheel.

Before you do anything speak to Burton.



Well it turns out that Burton HAVE sold me the wrong bolts after all. I've checked with them this morning, as they had one of their flywheels in stock, and apparently they do take 5/16 UNC bolt.

They've told me to come in and they'll change the wrong ones over (nice 45 min trip each way for me), but I'm not convinced the ones they list are correct either!

THESE are the ones that should go in - but at 3/4" long I think they're going to be far too deep. The standard ones (as checked by me and also kindly reminded by BritishTrident) are only 13mm long.

Why do I get the feeling this is going to end up going horrificly wrong?!?


All very strange. Mine has been on the car since 2001 and when supplied came with a Pinto type clutch (actually a Sierra DOHC clutch) and all the fittings, when supplied the clutch was fitted to the flywheel for transport. Its been off a few times and I have always used the standard Zetec type clutch bolts with the built in washer. There has never been any problems fitting it.

All I can suggest is at some point Burton have changed the bolt spec to imperial but why they would have done that is beyond me. EVERY fastener on a Zetec is metric so why confuse customers by fixing the clutch with imperial bolts.

Charlie_Zetec - 18/3/13 at 11:46 AM

That's exactly what I thought. The only other imperial thread on the engine (I believe, and am open to being corrected), is the inlet/exhaust studs.

I'm gonna go there in a minute and see what I can try and salvage from the whole thing....

Paul Turner - 18/3/13 at 12:06 PM

quote:
Originally posted by Charlie_Zetec

That's exactly what I thought. The only other imperial thread on the engine (I believe, and am open to being corrected), is the inlet/exhaust studs.



The studs that fix the inlet and exhaust manifolds are 110% metric. Start screwing imperial bolts into those and you will be in for an expensive helicoil fix or worse.

Just to repeat EVERY fastener on a Zetec is metric.

[Edited on 18/3/13 by Paul Turner]

Charlie_Zetec - 18/3/13 at 04:50 PM

Well, I've come back with some new bolts, with at least the correct thread. But as previously suggested, at 3/4" they are too long.

Advice from staff at Burton was to just "cut them down to length". I've normally not got an issue doing this to bolts, especially when I'm going to threadlock and torque them right up. But part of me thought on the journey home "What happens if I cut the bolts down and one of them fails?"

So I've now e-mailed them to ask for confirmation that their advice of me cutting them down would not invalidate any warranty or claim with the sale of these items, due to modification of an off-the-shelf item they have sold me.

Am I being too picky? Or right in wanting to cover myself should the worst happen? Never had a H/T bolt sheer on me yet, but there's a first time for everything....

pigiron - 2/3/14 at 08:58 AM

I fell upon this thread looking for information as I had the exact same problem.

I can confirm that the clutch cover set screws are indeed 5/16 UNC.

I notice it is a year since the original post which has given Burton plenty of time to add the information to the product listing, after all it would boost the sale by a few more quid.

I rang Burtons and they were unable to offer a spec over the phone, they said they did not have such information at the point of sale. The guy promised to call me back but the call never materialised.

I agree that a coarse thread is not ideal on a high speed rotating item, I have been a fitter for 43 years and have never come across it before.

[Edited on 3/3/14 by pigiron]