base timing quetion
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From: maui
base timing quetion
im trying to set the base timing on my 390 that i just put back together and instead of the 8-10 degrees for base timing im on 25-30.if i move it to 10 it dies.i have the vacuum disconected and plugged ,i tried to do everything by the books,or by the instruction manuals of each part,but somewhere i messed up.
when i installed the new camshaft comp cam xe262h and new timing chain rollermaster with +2,+4,+6,+8 degrees slots,i had to use the +8 degree slot to get the correct # when degreeing the cam,and the numbers matched perfectly.
is there any relation between that +8 degree on the timing chain and the base timing #s on the damper?what about the camshaft,comp cams say the degree their cams 4 degrees advance,does that add up to ?
when i installed the new camshaft comp cam xe262h and new timing chain rollermaster with +2,+4,+6,+8 degrees slots,i had to use the +8 degree slot to get the correct # when degreeing the cam,and the numbers matched perfectly.
is there any relation between that +8 degree on the timing chain and the base timing #s on the damper?what about the camshaft,comp cams say the degree their cams 4 degrees advance,does that add up to ?
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Joined: Mar 2004
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From: Union, Washington
im trying to set the base timing on my 390 that i just put back together and instead of the 8-10 degrees for base timing im on 25-30.if i move it to 10 it dies.i have the vacuum disconected and plugged ,i tried to do everything by the books,or by the instruction manuals of each part,but somewhere i messed up.
when i installed the new camshaft comp cam 262xe and new timing chain rollermaster with +2,+4,+6,+8 degrees slots,i had to use the +8 degree slot to get the correct # when degreeing the cam,and the numbers matched perfectly.
is there any relation between that +8 degree on the timing chain and the base timing #s on the damper?what about the camshaft,comp cams say the degree their cams 4 degrees advance,does that add up to ?
when i installed the new camshaft comp cam 262xe and new timing chain rollermaster with +2,+4,+6,+8 degrees slots,i had to use the +8 degree slot to get the correct # when degreeing the cam,and the numbers matched perfectly.
is there any relation between that +8 degree on the timing chain and the base timing #s on the damper?what about the camshaft,comp cams say the degree their cams 4 degrees advance,does that add up to ?
Ignition timing is the relation between TDC and when the #1 cylinder gets it's spark. If the engine will not run at °8 BTDC your cam timing may well be the issue. Has your damper been checked for slippage?
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From: maui
first installed the timing chain in 0 degree,then following the "comp cams" cam degreeing instructions i checked it and the numbers where way of,then i tried +4 and the # were closer and then i tried +8 and all the numbers matched like the cam card said.so i thought that was ok.
i just checked #1 piston at TDC while rotating the engine from the damper bolt and it reads o degree, does that mean its ok?how can i checke for a slipping damper?
i just checked #1 piston at TDC while rotating the engine from the damper bolt and it reads o degree, does that mean its ok?how can i checke for a slipping damper?
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From: maui
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Sounds like a call to Comp Cams is in order. A cam MIGHT be a few degrees off, but 8 sounds like a lot.
However, there are plenty of other reasons not enough spark advance would kill the idle. How's the vacuum when it idles correctly?
However, there are plenty of other reasons not enough spark advance would kill the idle. How's the vacuum when it idles correctly?
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From: maui
vacuum is around 13 -14 at 750,but idle is kind of bouncy.
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From: maui
yeap now is idling at 8 degrees! sweet! but i still have low vacuum at around 12-13.i did not degree the cam ,but that didn't work before so...
on the right side on the engine i heard a slight noise,when i check the rockers there were two o three that were softer than the other ones.i did tight them to zero lash then 1/2 turn .then i try less pressure so i did 1/4 turn,but still the same.so if a few lifter fill softer does that mean they are empty of oil?they were the two in the front of the engine and one closer to the middle cylinders.
the lifters are new,maybe i didn't fill the with oil?i did sunk them in a can of oil though.
on the right side on the engine i heard a slight noise,when i check the rockers there were two o three that were softer than the other ones.i did tight them to zero lash then 1/2 turn .then i try less pressure so i did 1/4 turn,but still the same.so if a few lifter fill softer does that mean they are empty of oil?they were the two in the front of the engine and one closer to the middle cylinders.
the lifters are new,maybe i didn't fill the with oil?i did sunk them in a can of oil though.
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From: maui
now i have it idling at 8 degrees btdc.but my vacuum gauge reads only 12,and the idle quality is not that good.at the same time i have a noise on the left bank,it sounds like a vacuum/pressure leak.if i move the distributor advancing it, the idle quality is much better and that weird noise disappear and the vacuum goes to 17(where i want it to be),but when i read the damper ,I'm close to 40 degrees.so that's probably not good.
so one of my questions is :the 8 degrees btdc is a mandatory number or can i go higher,and check for detonation noise.
and if what could be the noise if the timing is too much retarded?
so one of my questions is :the 8 degrees btdc is a mandatory number or can i go higher,and check for detonation noise.
and if what could be the noise if the timing is too much retarded?