Zetec Flywheel Protection?

I had the unfortunate occurrence of spinning off this past weekend and knocking off several teeth from my Zetec flywheel. The actual flywheel protrudes through the bottom of the floor pan is pretty much unprotected. I was thinking of putting a couple more of the skid blocks that are on the bellhousing in front of and behind the flywheel to protect the new one. Any thoughts on this idea?

The alternative would be to make sure all tracks do not have big drop offs at the edge of the pavement and curbs, but that is a task I don't think get too far.

Anything that protrudes downward from the main bottom plane of the car is subject to being ripped off or damaged. So if you're going to protect the flywheel, I think you need to have something that tapers gradually and has some major structure above it.

First thing to do is put a dial indicator on the flywheel, and see if it's still straight
Similar occurrences have been known to bend/break crank and/or block in a Kent engine

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Originally Posted by Charlie Schmidt

First thing to do is put a dial indicator on the new flywheel, and see if it's still straight
Similar occurrences have been known to bend/break crank and/or block in a Kent engine

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Added "new". The damaged one could, itself, be bent.

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Originally Posted by DaveW

Added "new". The damaged one could, itself, be bent.

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I snapped a Brand New Crankshaft and blew up a New QS engine when i damaged my flywheel in a FF after hitting the flywheel, you really need to check everything somehow better safe then sorry.

I think some FC guys run jabroc under the alum floor. Not sure if that is thick enough.

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Originally Posted by BeerBudgetRacing

I think some FC guys run jabroc under the alum floor. Not sure if that is thick enough.

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Food for thought...
I use 4-mm Jabroc under the middle of my undertray, mostly to keep from wearing through the fiberglass undertray. I also have steel structure in front of and even with the bottom of the bellhousing which is ~3/16" thick below the flywheel. So my flywheel is pretty well protected. I also have 1/8" steel sheet under my main chassis area for ballast (28 lb) and for aluminum floor protection. So the height of the bottom of the car is continuous from the front of the frame to the end of the undertray Jabroc.

I think something similar to what I have could be added to most cars, but would likely also result in some material below the main chassis bottom. And of course it would add some weight.

I made a crude one of these and used it for years - basically a plate that covers the flywheel protrusion, with a slot for it to pass through and then a plate welded over that and the welds ground smooth.

I also made it the proper thickness to replace the stacks of washers necessary between the bell, the frame, and the original skid.

I know it works because it cracked on several occasions and had to be re-welded. no flywheel damage though, not even any rubbing.

A friend made me this one to replace it. Thinner, and made of stainless. I put the original skid back in front of it and it all fit perfectly. Been on there for a couple of years now.

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Originally Posted by david oleary

I snapped a Brand New Crankshaft and blew up a New QS engine when i damaged my flywheel in a FF after hitting the flywheel, you really need to check everything somehow better safe then sorry.

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When I get the new flywheel, I'll mount it and do an axial runout check.

The old flywheel on the car had around 6 damaged teeth, not completely gone but definitely broken enough so the starter wouldn't engage. We did a visual on the old flywheel, turning it by rotating the rear tires, did not seem to have any noticeable axial runout, and I drove it in the two races that weekend without any issues.

We started the car by dragging it behind our golf cart. FYI, the car does not like to start that way. Took a long time to get it going on the second day when sitting overnight.

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Originally Posted by Rick Kirchner

I made a crude one of these and used it for years - basically a plate that covers the flywheel protrusion, with a slot for it to pass through and then a plate welded over that and the welds ground smooth.

A friend made me this one to replace it. Thinner, and made of stainless. I put the original skid back in front of it and it all fit perfectly. Been on there for a couple of years now.

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This is what I'm thinking of, tying it into some rivnuts inserted in the frame tubes around the flywheel opening. Tapered at the front, back, and sides and just high enough to protect the flywheel. Then remove the skid blocks on the bellhousing.

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Originally Posted by Lyngengr

This is what I'm thinking of, tying it into some rivnuts inserted in the frame tubes around the flywheel opening. Tapered at the front, back, and sides and just high enough to protect the flywheel. Then remove the skid blocks on the bellhousing.

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I'd leave the ones on the bellhousing and see if you can add more of them (using the same type of skid pad) in front of the flywheel. That way you aren't inventing something bespoke.

Possibly shim them with a tapered shim to get a little more height if needed.

of course the 97 and earlier and the 98 and up have different attachments between the bell and the floor. But, I'd avoid rivnuts. I'd think you could easily just rip them out, and the skid has to be thick enough to have flush fasteners (which will grind down, that's always a problem with my front skid where I frequently have to drill the flatheads off)

the nice thing about the stock 95 rear skid and the plates I've used is that they are held in by the lower bell to frame bolts. Those aren't going anywhere (as long as you secure them with safety wire that is.....)

The 97+ are fairly thick:
https://www.primusracingparts.com/Re...ent_p_134.html

I think sticking with a standard/interchangeable part is best.

This one is like I had on my 94. It was fairly even with the floor but by flywheel did not run proud of the floor.
https://www.primusracingparts.com/Re...ing_p_672.html

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Originally Posted by BeerBudgetRacing

The 97+ are fairly thick:
https://www.primusracingparts.com/Re...ent_p_134.html

I think sticking with a standard/interchangeable part is best.

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I've got those on the bellhousing now, didn't do anything to help.

Putting something around the flywheel opening to protect it from impact is pretty easy to make and attach to the frame rails. All sides will be tapered so that any contact slides over the surface, with just a thin slot for the flywheel opening.

I replaced the old flywheel last week, but prior to removing it, I did a runout check on the clutch surface and had 0.002 - 0.003 TIR. I did not measure the runout out by the teeth, but when I put the flywheel on my worktable, it laid flat with no obvious warping. The actual surface had 0.040 of material removed, the pressure plate had an obvious wear pattern, and the clutch cover fingers were worn down to about 1/3 of the thickness from the throwout bearing. The actual clutch disk looked pretty good, had a little over 0.100 inches in thickness.

I mounted the new flywheel on the crank, using new ARP bolts, torqued as per ARP spec (85 ft-lbf), then did another runout check. This time I got between 0.001 - 0.002 TIR, so everything looks good.