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did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 11, 2022 07:21AM

This engine knocked and it was logical to assume it was a rod but when I opened it up, everything looked like it didn't have a lot of miles on it. The journals all look good as do the bearings and lifters. You can see the play in the second two pics. Half of the thrust washer is still in the block but you have to look close. The block looks good but once i do a more thorough inspection, ill order a cam and lifters. They look good but the thrust action may be an issue with the wear. I cant imagine it was driven long with the cam knock and since there is some shown use, I think the cam had to have slowly walked out (its not loose on the shaft).

Does anyone recognize the paint marks on the cam? I dont recall seeing it on other teardowns but its been awhile. There is also matching paint on the crank.

Just sharing. Thoughts/opinions are welcome

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)

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Re: did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 11, 2022 07:22AM

.

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)

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Re: did the cam gear move or was it incorrectly installed?
Posted by: zarfnober ()
Date: August 11, 2022 07:44AM

Unless the makers of the cam gear have finally fixed it, check the new cam gear against a known good one for the timing Mark to be in the correct place. And I would definitely check the cam gear backlash against the crank gear throughout its entire rotation after checking that crank gear for damage.

Rocco

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Re: did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 11, 2022 09:14AM

For sure Rocco. This gear isnt good but the mark is so it will suffice at least for mark confirmation

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)

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Re: did the cam gear move or was it incorrectly installed?
Posted by: wittsend ()
Date: August 11, 2022 10:09AM

In the picture it looks like there is a deposit of aluminum on the corner of the key (red arrow). To me this would indicate that the cam was on far enough to leave the deposit as it moved forward. Was it installed far enough as to be proper? I'm inclined to think you may never know.

The broken thrust washer is also interesting. In my haste and naïve-ness I pressed a gear off supporting it at the washer. That said it took a bit of hydraulic force before it broke. So..., I'm wondering if the washer was cracked when the gear was installed and eventually broke? For the most part it would seem the washer would just rattle around intact if installed loose. Still that is a lot of walking forward for that gear. Are there any marks on the bellhousing from the excessive end play?

Whatever the cause I'd think the fail safe gear would be a step in avoiding this again.

------------------------------------------------------------------------------

***'61 Lakewood, a "Freebie" in hibernation for 27 years - In the process of applying CPR.***

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Re: did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 11, 2022 10:51AM

The bell is mark free and that alloy chunk is part of a gear tooth. This engine has little history. The turbo was the 1st to go in the late 70's so it was gutted and welded. Then one of the heads dropped a valve seat in the mid 80's. When this happened they pulled the turbo parts off and installed 110 heads and carbs. (Fortunately they saved everything.) When they put the heads on, it looks like a new cam was installed with some sort of a rebuild. Then the knock came (cam) This is when it was parked (late 80s) until I picked it up this year.

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)

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Re: did the cam gear move or was it incorrectly installed?
Posted by: RexJohnson ()
Date: August 11, 2022 12:17PM

I disassembled an engine several years ago that the cam gear came off like this. It rubbed up against the bellhousing and after awhile it caught ahold of the bellhousing seal. The seal was pulled into the gears and formed to the teeth. When this happened there was not enough room for the metal part of the seal so the crank broke just behind the #5 rod journal. The #5 and 6 rods were connected to the same part of the crank but somehow the rod from one would hit the bottom of the opposite piston. This caused the front part of the crank with #5 and 6 rods attached plus the flywheel assy. to wobble on the front main bearing. With this wobbling it broke the diff. thro out bearing shaft, bent the flywheel attaching plate and broke the small retainers behind the starter drive in the starter. The gear that came off was a Fail-Safe. Now I do not know if the gear was installed correctly or not but if you want the gear to stay on you need to put some set screws between the cam and the gear.

RJ tools
Salem,Oregon

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Re: did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 11, 2022 03:04PM

Yikes. I'd be driving in fear for awhile after that

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)

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Re: did the cam gear move or was it incorrectly installed?
Posted by: RexJohnson ()
Date: August 11, 2022 03:07PM

It was not my car, I just got to clean up the mess.

RJ tools
Salem,Oregon

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Re: did the cam gear move or was it incorrectly installed?
Posted by: playerpage ()
Date: August 11, 2022 09:59PM

Now I'm gonna be listening to my car extra close for...forever.

Eric C. Player
Fargo, North Dakota
MEMBER: CORSA National, Central Coast CORSA, South Coast CORSA, Vintage CORSA, Sfba CORSA, and Great Plains Corvair Club.
THEN: 1965 Monza 110, Canary Yellow - 1965 Corsa 180 Turbo, Red - 1966 Monza 110, Purple - 1967 Monza 140, Red - 1966 500 110, Black; nicknamed "Shadow" - 1965 Monza 110, Camaro Yellow; nicknamed "Silver"
NOW: 1966 Corsa 180 Turbo, Blue; nicknamed "Bluvair"
---------------------------------------
"He cautioned me not to take notes. It would not have helped if I had, as he would start a paragraph with, 'It is therefore obvious. . .'
and go on from there to matters which may have been obvious to him and God but to no one else."
-- Robert A. Heinlein, character of Daniel B. Davis, 'The Door Into Summer.'

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Re: did the cam gear move or was it incorrectly installed?
Posted by: vairmech ()
Date: August 12, 2022 05:02AM

That gear looks to be a stock GM cam gear, there is a PN on it. Some early aftermarket had some PN's cast in but not the GM number.
Yes, that gear moved but what came first? The gear moving or the washer breaking. I would have to look at the block very closely before I would consider using it again.
You only showed paint marks on the cam, is there a part number cast into the cam in between the lobes? Is there an etched number(s) on the gear end? Doesn't look like it.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: did the cam gear move or was it incorrectly installed?
Posted by: 110PG ()
Date: August 12, 2022 09:37AM

It's the correct 3872304 but no etched # on the gear end and the cam gear is a gm gear.

Joe
Western WI

66 Corsa Turbo CPE
69 Monza CPE (sons car)



Edited 1 time(s). Last edit at 08/12/2022 09:39AM by 110PG.

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Re: did the cam gear move or was it incorrectly installed?
Posted by: roger65180 ()
Date: August 12, 2022 12:43PM

if you would heat the gear and remove it you may be able to verify weather the gear was not installed all the way and that caused the washer to fail , if that is what happened the very end of the bore will be smaller than the other side . I have seen this before on a rebuilt engine , altho the washer hadnt failed the motor dropped a seat and it fractured destroying all 3 cylinders and pistons , on tear down the gear was almost an 1/8 in from all the way on ( any one need 3 0.030 jugs rods and pistons for a 102 hp theses are the good ones cheep )

Roger R
Madison Wi
62 ct pg turbo
65intercooled 180 4sp,autocrosser
62 Rampy

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