Big Dave

Last night when I went to install the ignition rotors, one of the bolts wouldn't go in because the hole was partially obscured by the cam gear. Although I set the gear timing to 0*, it was now reading on the left-most hole of PorKen's cam timing tool.

I've now discovered after re-setting the timing three times, although the cam bolt is torqued to spec (~65Nm), whenever I rotate the crank 360* to re-check the timing, the cam gear slips from 0* all the way until the cam gear hits the woodruff key.

Bottom line - the cam bolt is not holding the camshaft tight enough to prevent it from slipping against the cam gear.

Has anyone experienced this? What's the best solution? I don't want to overtorque the cam bolt so much that I cause a bigger problem.

Just in case anyone asks, yes, I am using the large washer with the cam bolt (the one that is counterheld when tightening/loosening).

Big Dave

Here's the bolt that's allowing the cam gear to slip.

I have 2 spare cam gears...maybe try one of those?

PorKen

Seems silly, but... did you remove the 32V'r adjustment spacer?

Bill Ball

Unless you have the wrong bolt or washer, that is real hard to explain. It may be torqued to 65Nm, but it must have bottomed out. Is there something inside the bolt hole in the cam?

UKKid35

Very strange. Bear in mind that there are also several reports of Part 2 failing causing devastation - and I know you don't want to go back there...

toofast928

How does part 2 fail? By cracking?

H2

Yes, it's not uncommon.

Harvey

Big Dave

Yes, I removed the spacer.

Big Dave

I have the correct bolt and washer. In fact, I have a spare bolt and washer - it slipped even with the spare. I don't see how it could be bottoming out. I can turn the bolt by hand until it snugs up to the gear.


I'll have to take a look at it tonight. I don't have a spare for this piece, so hopefully it's OK.

I'm wondering now whether it would make sense to roughen the surfaces of the washer and cam gear so that they stick together better. I'm going to try one of my spare gears first, assuming all other parts appear normal.

The repair is on hold until this is solved.

AO

Is it possible that there's something in the cam that is causing the bolt to bottom out before achieving torque?

Big Dave

I suppose anything is possible. Does anyone know how much longer the hole is than the bolt? I can try putting a dot of paint on the end of the bolt and see if it gets marred when the bolt is torqued. I'd think that the hole should be a few mm deeper than the bolt, so the paint shouldn't touch anything. Just a random thought. Frustrating.

I guess a better idea would be to stick a thin screwdriver into the hole, measure how far it goes in, and then compare it to how far it goes into the camshaft I had to replace.

WallyP

Or just screw the bolt in without the washer until it bottoms, then compare the washer thickness to the space left...

Big Dave

Assuming it's not bottoming out, do you have any idea why it might be slipping? Have you ever heard of this before?

Thanks for responding, Wally...I was hoping you'd read this thread.

Big Dave

I've now got a dial caliper that can measure the depth between the current and old camshafts.

If it's bottoming out, is there a reason why I couldn't just shorten the bolt by a few mm? Would it change the torque requirements?

Imo000

Try this:

Take the cam gear off and tread the bolt it as far as it goes, then measure the distance that’s left. If this is close or near the same as the gear thickness then the bolt it bottoming out. This could be from either the hole is not deep enough or the bolt is too long, maybe there is, as Andrew suggested, something in the hole. If the hole is too shallow, it could be manufacturing defect or maybe the bolt is too long, again a manufacturing defect. Then there is the possibility that the gear is too thin, the washer is too thin or the adapter is machined wrong at the factory. In any case it would be as easy as just grinding the bolt down a couple millimetres.

I don’t believe roughing up the washer will solve this problem. The real problem is the lack of clamping force between the head of the bolt and the face of the gear.