Engine guru's please
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Posting Guru
Joined: Jan 2006
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From: Malvern, Ohio
Engine guru's please
Ok so im timing the race car, its a 305 chevy with vaccum advanced. When i time it into the specification it runs terrible, but when I adjust the distributor so it actually runs good its not even on any timing mark on the timing cover tab.
Could this be a stretched out timing chain? Its got some power...... for a 305 anyways.
Could the timing gear be off 1 tooth also or no?
Thanks for any input, its very appreciated and is benefiting me also.
Could this be a stretched out timing chain? Its got some power...... for a 305 anyways.
Could the timing gear be off 1 tooth also or no?
Thanks for any input, its very appreciated and is benefiting me also.
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From: 3rd Rock
Chevy harmonic balancers are two pieces, they have a rubber isolator between the inner hub and outer ring, they can rotate on it.
Especially if it is a 377/392 stroker…..
Especially if it is a 377/392 stroker…..
Last edited by IB Tim; Jun 27, 2007 at 05:07 PM.
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From: 3rd Rock
After finding TDC, using the positive stop method, & degree wheel, once cam is degreed go back to TDC, disassemble all paraphernalia for degreeing and place HB on it…..scribe a line with a straight edge, on the face of the HB from pointer down through the Key "WAY" slot...that way at any point in time you can use a flashlight and check to see (if you think it has slipped). If the two rings move at all ….you will see the scribed line...not lining up...easy check.
This works for Ford Chevy.... any HB that is two piece.
Or you can pin the ring in three equal places, with roll pins, install the roll pins and spot weld all three holes on the outer ring, just so you won’t shoot the pins out when it is turning.
This works for Ford Chevy.... any HB that is two piece.
Or you can pin the ring in three equal places, with roll pins, install the roll pins and spot weld all three holes on the outer ring, just so you won’t shoot the pins out when it is turning.
Last edited by IB Tim; Jun 28, 2007 at 05:48 AM.
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Joined: Aug 2002
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From: BC, Canada
Check to make sure there aren't 2 timing pointers. Some small block Chevs had the pointer at the side and others had it behind the water pump. You aim the timing light behind the water pump, from above.
Safe to assume you have the timing light pickup lead on #1 cylinder? That's the front one on the driver's side, not like a Ford where it's on the passenger's side.
Safe to assume you have the timing light pickup lead on #1 cylinder? That's the front one on the driver's side, not like a Ford where it's on the passenger's side.
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Posting Guru
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From: Malvern, Ohio
Yeah, theres only 1 timing tab behind the water pump. I never knew some chevys had 2 timing tabs.... maybe because thats a Chevy thing. Yeah I knew the #1 cylinder was on the drivers side like Chrysler & the other GMs prior to this thread, thanks though Raceguy. Anything else I should know?????
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Hotshot
Joined: Aug 2002
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From: BC, Canada
How old is the timing chain? Was it installed correctly if it's fairly new? On a Chev the marks on the timing gears aren't the same as on most other engines. The mark on the crank gear isn't straight in line with the keyway and that fools some people.
Otherwise I'd check what Admin said.
Otherwise I'd check what Admin said.
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Initial advance is set with the vacuum disconnected, usually about 8* on a chevy.
Using a timing light, set the initial advance, watch the timing light and speed up the engine. This is without connecting the vacuum line. The timing should advance due to the mechanical advance inside the distributor. You should get a good 12 plus degrees advance.
If it does not advance, the mechanical advance is stuck/not working.
If the mechanical advance is working, connect the vacuum line and repeat the process. The timing should advance to around 34/36* total. If it doesn't advance, the diaphragm in the pot is probably broken and the pot needs to be replaced. jd
Using a timing light, set the initial advance, watch the timing light and speed up the engine. This is without connecting the vacuum line. The timing should advance due to the mechanical advance inside the distributor. You should get a good 12 plus degrees advance.
If it does not advance, the mechanical advance is stuck/not working.
If the mechanical advance is working, connect the vacuum line and repeat the process. The timing should advance to around 34/36* total. If it doesn't advance, the diaphragm in the pot is probably broken and the pot needs to be replaced. jd