Cam interrupter write-up

[alec_b]

Can someone let me know who did the JB-weld writeup for the cam interrupter? Another member from the w-body forums is having an issue with his L27'd olds and I gave him the writeup as a reference. Another member is writing some kind of "e-book" and would like to use the write-up and give credit to the author.

Thanks guys!

[harofreak00]

Can you post up a link of what you gave him?

[J Wikoff]

Padgett wrote it, and put it on his own page.

http://bellsouthpwp.net/p/a/padgett46/cammag.htm

From:

viewtopic.php?f=19&t=14829&p=155316&hil ... tt#p155316

[alec_b]

Ok, that's what I told him. Gave him Padgett's name. I didn't know if it needed to be more specific than that.

[1fatcat]

LOL! Has there been any follow up on how long this repair actually lasted? The term, "Mechanic in a can" comes to mind here.

[Jrs3800]

So far the guys that have done this have had no further issues..

I did not do this tho and prefer not to... I replaced the chain as a set and bought a new interrupter from GM...

But for the guys that have done the JB weld method, it seems to have worked..

[RJolly87]

Agreed, we have not heard of any further issues when they are JB Welded back in, but bear in mind, there is a degree of risk also. Varying from alignment issues, to dropping stuff. Usually, when this kind of thing happens, the engine could stand to get a new timing chain anyway, and it gives you an excuse to freshen up a few things while you are in there. It really depends on what your circumstances are, but there is no shame in this "Mechanic in a can" <or would it be tube...?>

[1fatcat]

Usually, when this type of repair is attempted, you don't hear about the failed results. I know it would work for a few hundred/thousand miles, but lets hear some feed back from the guys who actually tried it. Lets hear from someone who tried it and is strill running the car with that repair. I doubt anyone can chime in with more than 10,000 miles on that repair. 20,000 tops.
Plain and simple, this repair exist of "gluing an internal engine part that rotates at 3,000+ RPM living in an environment that is being bathed in 200*F engine oil."

[willwren]

It works quite well. Even though the L67 isn't prone to the initial failure like the LG3 and LN3, when I replaced my timing set on the Zilla 3 years ago, I applied some JB Weld just for safety, knowing I'd have it apart soon enough for an inspect. The Zilla gets torn down every winter.

I'm on year 3 now, and the JB Weld doesn't have any evidence of any cracks in it to date. While I don't drive it daily, and not as many miles annually as most cars here, when I do drive it, I beat the living tar out of it. The epoxy shows no signs of failure. I'm confident that if the metal clips failed or weren't installed properly, the JB Weld would have been sufficient. If it did fail at 20k, simply gluing another in would be far easier for most members on this forum than removing the timing cover and doing it 'right'.

I'd be curious to see the factory blueprints for the cam gear and compare it between the pre-series 1 and the Series 1/2. I'd bet the hole itself changed in dimension, because I'm pretty sure the magnet (interrupter) didn't.

Years ago, I JB Welded my depth finder back together on the transom of my ski boat. It was at the lower plan of the hull, subjected to 50-60 mph speeds in water for 4 seasons until I sold the boat, and it never let go.

[1fatcat]

If you want, I will put some miles on the Zilla to confirm the longevity of this repair.

[willwren]

You might not get the chance. It likes to eat timing sets, and I may have to replace it again before the next race season. The next timing set will be induction-hardened to a higher spec than OEM (I have the oem specs and prints for both the S1 and S2). The Zilla likes to use the cam key as a tool to rip the living guts out of the center of the cam gear. Higher-strength valvesprings, no matter how carefully selected, do have a negative effect farther downstream.

I was surprised myself about JB Weld in this application, but if you think about it, the forces exerted on the gear/magnet are purely rotational, and the way JB Weld is formulated, it gets it's strength from small fibers of aluminum in the resin, not too far off the principal of fiberglass. It's pretty strong stuff. I've machined it, drilled and tapped it, and repaired odd things with it. Some stuff it's just not suited for. This seems to work well though. There's no better way to convince yourself than to try it, even if it isn't an existing known problem in your application. Padgett has probably done more for the LG3 and LN3 owner's car longevity than any other living person on this planet, and this repair was carefully documented and tested by him.

[1fatcat]

I have used it and agree that it is VERY strong stuff! I just never would have thought it would hold up in 200*F oil? It doesn't specify that on the package.

[Jrs3800]

I think some of those guys were using Long Cure good for 700F iirc.. The quick set is good for 300F isn't it?

as long as the JB weld is at full cure it should hold up to oil... several got quite a bit out of the JB weld fix...

But I'll say it again, My preference is to go in and do the chain, tensioner and gaskets along with the interrupter...