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Full Version: CM871 Cam and Injector gear slip
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I have a 2009 ISX CM871 that I did an inframe overhaul. Reused camshafts and gears. After approximately 100 miles engine lost power and had thick smoke coming from exhaust. Towed back to shop and found camshafts out of time. Removed drive gears and could not see any evidence of loctite contamination from assembly. Retimed camshafts. Cleaned EVERYTHING. Gears, cam gears, bolts, and retainer plates. Used Loctite 680 and reassembled. Torqued retaining bolts per QSOL specs. On second test drive cam gears slipped again. What else can I try before replacing both cams and drive gears?
I have done a whole bunch of them.. never had one slip.

Matter of fact, the gears are an absolute b$itch to remove if done 100% correctly... nonetheless will slip.

Here is a video on how I do it...





So... if it was done exactly like this video shows.. you would be hard pressed for it to ever slip.

The only thing that would cause it to slip if installed exactly like that video shows, is if the cam(s)
were binding up .. I.E.> valves or rocker shafts not set right, etc.

What is the detent clearance?... and is it a certified OEM head?... or something else?.

Is it all OEM camshafts, rockers, etc.?... or something else?.

ref: http://rawze.com/forums/showthread.php?t...66#pid9466
I thought Loctite 609 is what is recommended vs Loctite 680?
(12-13-2023 )Rawze Wrote: [ -> ]I have done a whole bunch of them.. never had one slip.

Matter of fact, the gears are an absolute b$itch to remove if done 100% correctly... nonetheless will slip.

Here is a video on how I do it...





So... if it was done exactly like this video shows.. you would be hard pressed for it to ever slip.

The only thing that would cause it to slip if installed exactly like that video shows, is if the cam(s)
were binding up .. I.E.> valves or rocker shafts not set right, etc.

What is the detent clearance?... and is it a certified OEM head?... or something else?.

Is it all OEM camshafts, rockers, etc.?... or something else?.

ref: http://rawze.com/forums/showthread.php?t...66#pid9466

Head is aftermarket. Did everything in the video except replacing the retaining washers. I have the old style and was unaware they could not be reused. Ordering new ones today. Thanks!
(12-13-2023 )hhow55 Wrote: [ -> ]I thought Loctite 609 is what is recommended vs Loctite 680?

609 is recommended. Since the gears slipped before, I wanted to try something stronger. 609 has a shear strength of 3000 psi and 680 is 4000 psi.
(12-13-2023 )Rsansing Wrote: [ -> ]Head is aftermarket.

That could be the problem right there!!

The casting could be off by enough to make the cam bind up like hell against the rockers once everything is up to operating temp. If that's the problem your going to end up trashing your cams(if you didn't already)if you keep trying to run it.

Just because it looks like a new cylinder head and everything bolts on doesn't mean the specs and tolerance's are correct, and only God knows what material it's made out of. Even if your problem ends up being something else, I have to tell you I've never heard of an aftermarket head working out on an ISX......... not a single time.
(12-13-2023 )Rsansing Wrote: [ -> ]...
Used Loctite 680 and reassembled
...

THAT STATEMENT SLIPPED RIGHT PAST ME ..LOL

NO, you cannot use loc-tite 680. It is completely incorrect loctite and will not do any much good in that application.

Rawze Wrote:Your assumption or source of info is incorrect for that particular application. 609 is for fine micron, high polished, no clearance applications and 680 is for rougher steel with larger micron gaps in the fit. They are 2 quite different products. The 680 has a much higher expansion rate that is not suited for fine finish applications. The 680 will expand too much and possibly cause issues and/or the fine micron high polished surfaces to slip under separation.
(12-13-2023 )Rsansing Wrote: [ -> ]...
Head is aftermarket.
...

(the beer is talkin') ...
With that after-garbage head, it is only going to last about 2-3 years any ways.. so most of your efforts are for not any ways. Seen it so many times, that it ain't funny.

You watch and see.
I find that aftermarket heads are like recap tires..........Fail everytime!!
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