Inliners International Forums General Discussion Engines 292 Cam gear

I am rebuilding a 292 for a customer that came in with a BAD rod knock. I tore it down and no bad bearings. What happened was the cam slipped about a quarter inch out of the cam gear and the head of one of the #2 rod bolts was hitting on the cam lobe causing the knock. Anybody have any ideas to prevent this from happening again? I don't think there is enough room inside the timing cover to drill the cam and put a bolt and washer. It doesn't look like it would clear.
A few years ago the 250 I had in my Dodge developed a really weird knock. I put in a 292 and never really figured out the problem. I looked at it yesterday and--same problem.
Is this a common Chevy six problem? I hope someone has a solution. Thanks, Joe

Had this happen on my first 235 in high school. Fixed it like you describe by drilling and tapping the end of the camshaft. As for not having enough room for a bolt head, thats what hammers are for. Heat up the spot with a propane torch and smack it with the hammer.

ROTFLMAO!!!

A true American fix!



I bet it comes with a warranty!

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(O)2(O)5(O)0(O)S(O)I(O)X
PHAT250Six
Git in! Sit Down! Shut Up! Hang On!
And when in doubt... STICK YER FOOT IN IT!
250 L6 in a '69 Camaro


[This message has been edited by PHAT250Six (edited 06-15-2003).]

First off one reason this happened is That If the cam gear is alum It was not Installed the right way. It sounds as if some one just pressed it on with out first Heating the gear. But anyway Here Is you fix If you do not what to make any Mods to the timing cover. Where the gear and the cam meet (meaning at the seam line) Drill and tap for a 1/4 pipe plug This will hold the gear to the cam so it will not walk off the end again. Only draw back in doing it this way Is That if for any Reason You need to replace the gear again It will be very Hard to drill and tap that same spot again With out having to drill & tap for a bigger pipe plug. PES sells a bolt & washer to install in the end of the cam. But to me that is a pretty Thick settup. (about a 1/4 in washer) What I have is a very thin bolt and washer That I got yrs ago And only had to make a small dimple in the timing cover.So you not even realy know i had to do that. I have Now since found the right Bolts And I'm still working on Matching this washer. But If you don't want to make Mods Like I said before then just 1/4 drill & Tap. Hope this Helps.
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NovaMan/Twisted6/Larry

I'll second Larry's advice for the retainer method, if you need to use it. BUT:

The most likely reason the cam gear slipped in the first place is the gear was replaced once already WITHOUT the crank gear also being replaced. I've seen that a couple of times where a new cam was been installed with a new gear. They used an aluminum gear when the original was a fiber unit. The backlash for fiber and aluminum setups is enough different that it won't work for long. The aluminum gear hub gets pounded out because there isn't enough clearance between the gear teeth.

Always use a matched set when replacing these things. Don't cut corners by trying to get by with only one gear. If the cam slips out of the press-fit gear, the timing can retard about 15 degrees. If the crank bobs don't hit, it'll slip again, possibly knocking out the coreplug in the back of the motor for a major oil leak.

The owners were operating the engines at sustained high RPM climbing hills, which was making for maximum heat and oil pressure. That combination caused maximum thrust from the distributor drive (oil pump) to pull the cam right out of the gear.

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David
newbie #4153

Thanks, guys. Twisted, I will try your method.It sounds like a great idea.I guess I am ignorant. I thought the gears were supposed to be pressed on. I didn't know you were supposed to heat them.
I don't know if someone used a matched set or not. This is apparently a rebuilt block that has been put in at some time. It was bored and the crank turned. It is just an old ranch pickup, so it hasn't been hot rodded, but has pulled a horse trailer a lot.
Thanks for the help. Joe