An odd bolt on the camshaft retaining flange

[Kenny_Z]

Has anyone ever run across this? The bolt on the retaining flange is an odd size. 10mm is too small and 11mm is too big. I also tried 3/8 and 7/16 to no avail.

http://uploads.m-cgi.com/kennyz/Delorean/Projects/engine47.jpg

As you can see I already rounded the corner when I tried with an 11mm. I'm about to take a cheap 10mm and use a grinder until it fits over the bolt unless anyone has any better ideas? Also, it's not a reverse threaded bolt is it?

[DMCMW Dave]

Has anyone ever run across this? The bolt on the retaining flange is an odd size. 10mm is too small and 11mm is too big. I also tried 3/8 and 7/16 to no avail.

As you can see I already rounded the corner when I tried with an 11mm. I'm about to take a cheap 10mm and use a grinder until it fits over the bolt unless anyone has any better ideas? Also, it's not a reverse threaded bolt is it?

I don't recall a problem with that one. Are you using Harbor Freight tools? The jaws will open up if the bolt is too tight.

[Kenny_Z]

I've tried my Craftsman set and others. It is just a very odd bolt. I'm wondering if it's something a previous owner did.

[DMC5180]

Kenny,

Where did you get the cam gear tool?

[DMCMW Dave]

Kenny,

Where did you get the cam gear tool?

From me. We have a couple of loaners.

[DMC5180]

From me. We have a couple of loaners.

Good to know [emoji6]


Dennis

[Ron]

Good needle-nose vice-grips or roll it out with a chisel/punch.

[DMCMW Dave]

For this process he only wants to loosen it. If he wrecks the bolt the timing cover needs to come off. Don't forget to take off the rear cam cover too.

[David T]

For this process he only wants to loosen it. If he wrecks the bolt the timing cover needs to come off. Don't forget to take off the rear cam cover too.

If the metric wrenches don't fit properly maybe it isn't metric.

[DMCMW Dave]

If the metric wrenches don't fit properly maybe it isn't metric.

Factory bolt is 11 mm or a slightly sloppier 7/16.

[PJ Grady Inc.]

11M is the correct size. Someone must have damaged the hex.
Rob

[Kenny_Z]

The rear cam cover was the first thing I removed. I read the note in the box with the sprocket retainer. That thing is awesome by the way. Thank you for having them made, Dave.

It's looking more and more like I'm going to have to remove the timing cover to get this thing off. I'm going to soak the bolt with penetrating spray for a couple of days and then try again. After that the timing cover is coming off.

[dn010]

Try heating up the surrounding area, might help loosen things up when you do get a wrench on it, especially if someone used Loctite.

[Ron]

For this process he only wants to loosen it. If he wrecks the bolt the timing cover needs to come off. Don't forget to take off the rear cam cover too.Ah, I take it he's working on a cam swap then....maybe a quality 15°-60° open-end wrench (they aren't cheap, but...).

[Kenny_Z]

After buying a couple of sets of very nice (read expensive) wrenches I found that a 7/16th box end worked. For those that may run into this in the future, it's a Craftsman set of small wrenches that are thinner than standard wrenches. I purchased the metric set at first and the 11mm did not fit. I bought the SAE set yesterday as a last ditch effort and the 7/16 worked. This morning the bolt was defeated and the flange was lifted. I can finally make some progress toward repairing this car.

Thank you for all the suggestions.

[PJ Grady Inc.]

Just for the record and FYI Kenny if you still have the bolt check the grade marking on the the head. I would expect it to have an 8.8 marking which would indicate a damaged 11m bolt. If it has bars as a grade marking then someone retaped it to an american thread which would make reusing the cam a risky proposition as the threads would be compromised.
Rob

[Kenny_Z]

I'll be sure to check it out once I get the head removed. I just loosened the bolt this morning before work but an outage kept me from getting home with any sort of light left to work. This bolt is only on the retaining flange, not the cam itself.

[PJ Grady Inc.]

I'll be sure to check it out once I get the head removed. I just loosened the bolt this morning before work but an outage kept me from getting home with any sort of light left to work. This bolt is only on the retaining flange, not the cam itself.

You're right I shot from the hip on that reply.The plate bolts to the head. With the timing cover off, or head removed, a 7m "Timesert" or "Helicoil" would be a quick and effective repair if needed.
Rob

[Kenny_Z]

Even more fun that just guaranteed that the timing cover has to come off. I put the hex wrench into the bolt that's supposed to back the cam off the sprocket. I turned it a bit and found it was not tight at all. I used two fingers to turn it. Then I realized the cam was not backing out. From what I can tell the head is snapped off.

I'm betting that little bit of bolt is not going to come out of the cam without a fight.

[PJ Grady Inc.]

Even more fun that just guaranteed that the timing cover has to come off. I put the hex wrench into the bolt that's supposed to back the cam off the sprocket. I turned it a bit and found it was not tight at all. I used two fingers to turn it. Then I realized the cam was not backing out. From what I can tell the head is snapped off.

I'm betting that little bit of bolt is not going to come out of the cam without a fight.

This ones a headscratcher because if that large M10 Allen bolt is broken then the only thing holding the gear onto the cam is the timing chain preload. What kind of PO could round off the cam holdown bolt and snap off a hardened M10 cam bolt. Certainly no one I'd care to meet. Paging Mr. Hamfist....paging Mr. Hamfist!
Rob

[Kenny_Z]

The thing is I've had that head off before. I didn't mess with the cam sprockets when I did so I have no idea if it has been broken that entire time or if it broke in the passed two years. There's enough thread on the piece of cam bolt that it could have been broken and I didn't know.