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-   -   timing gears (https://67-72chevytrucks.com/vboard/showthread.php?t=454857)

justinburnett 03-23-2011 07:25 PM

timing gears
 
So I'm putting my engine back together and I don't know where to line up the cam. THe hear on the crank doesn't just have a dot, it has a bunch of +4,-4 stuff. There are 3 keyway slots and it is in the +4 position so do I line the cam hear timing mark with the +4 then? Someone please confirm for me that I am right, and then tell me what it means. Thank you.
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Cramitthefrog 03-23-2011 07:52 PM

Re: timing gears
 
Those marks are for advancing or retarding the cam so many degrees, but there should also be marks to install it straight up.

justinburnett 03-23-2011 08:08 PM

Re: timing gears
 
I didn't pull it because I don't have a tool and the gear 's in great shape. If I leave it it +4 what happens? Is that going to hurt my low end torque to have the cam advanced?
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wyattglock 03-23-2011 08:09 PM

Re: timing gears
 
The marks on the cam and crank gear should line up. If you can see the +4, -4 marks on the crank gear there should be a mark roughly 120 degrees from each. I don't know what else has been done to your engine, but straight up is usually the best way unless you have a real hot cam and a good set of heads.
One question, what kind of timing set are you putting on? I just did an Edelbrock set and it had a circle at TDC, a square at +4, and a triangle -4.

justinburnett 03-23-2011 08:41 PM

Re: timing gears
 
I left it where it was. I can't find a press for the gear anywhere. I already had all the pistons in or I'd drag the crank down to a machine shop, unless I'm totally screwed if I don't, in which case I'll tear the whole thing apart now. I put in a new RV cam, if that matters.
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justinburnett 03-23-2011 08:42 PM

Re: timing gears
 
I don't know who made it. It was on there before.
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I could maybe use a balancer install tool and a piece of pipe to press it on, couldn't I? Maybe that would be a good idea. I don't know if I should have a short duration cam advanced. Thoughts, feelings, better ideas? I don't want to throw this in and have run crappy or have little power.

Tx Firefighter 03-23-2011 09:18 PM

Re: timing gears
 
To install it, put the crank gear in your wife's oven at about 400 degrees for half an hour or so. Using good thick gloves, slip it on real fast while still hot. No tools required (other than gloves and a stove).

justinburnett 03-23-2011 11:30 PM

Re: timing gears
 
I'll give that a try. I thought metal expanded when it was hot. Will let you guys know tomorrow.
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jrcaprai 03-24-2011 01:18 PM

Re: timing gears
 
Quote:

Originally Posted by justinburnett (Post 4573723)
I'll give that a try. I thought metal expanded when it was hot. Will let you guys know tomorrow.
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Exactly... is there a 0° mark ? the best method is a degree wheel such as
http://www.summitracing.com/parts/SUM-G1057/

Tx Firefighter 03-24-2011 02:32 PM

Re: timing gears
 
If you heat a gear it grows both inside and out. You can slide it on by hand until it cools. Then it fits with the proper interference fit. Trust me. I've done it a bunch of times.
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justinburnett 03-24-2011 04:00 PM

Re: timing gears
 
Gotta get it off first which is proving harder than I thought it would. I'll get it though.
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justinburnett 03-24-2011 05:33 PM

Re: timing gears
 
Made a ghetto gear puller out of some bar stock, nuts and bolts. Slid right off. Got it lined up on 0, pressed it on with a harmonic balancer tool and some pipe, couldn't use friend's oven cause the house was locked. All in all it worked good and I'm glad I did it.
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wyattglock 03-24-2011 05:49 PM

Re: timing gears
 
Now that you have done that, try and get your hands on a degree wheel. A good degree set will have a dial indicator. You can indicate off the rocker or the top of the valve and get your high point for top dead center. That will get you dialed in pretty good. Then make sure the engine is at TDC and install the distributor. Use a timing light and you should be able to get that thing running great in no time. I prefer the timing lights that have the advance dial on them.


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