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Author Topic:   Ignition timing
cmiller51
Member
posted July 16, 2003 09:15 AM
This question was raised some time ago and I just need a reminder. Using Vortec heads, 10:1 compression, what would a good starting point be for ignition timing. I am running at 36 degrees now with Darts. I could also use a suggestion on a spark plug number, also.


dirtbuster
Member
posted July 16, 2003 09:40 AM
34-36...
AC r43lts i beleive is the stock plug


sdhnc29
Member
posted July 16, 2003 02:27 PM
32-34 degree's . These are fast burn chambers and require much less timing than your Darts . I'd start at 32 degree's if you don't have access to a chassis or engine dyno . We use the Autolite AR3933 in the later castings that have provisions for a gasket type seat for the plug .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


RACEINMUD
Member
posted July 16, 2003 06:47 PM
Ok, I have a 350 with dished and 305 heads. I've been running 41 deg and motor was good. Running hot and was told to back it down. Put at 36 and the motor was a dog and still hot 250+. What will running that much timing do(harm)to the motor? Putting in new rad& fan for the cooling prob. Thanks! Mud


sdhnc29
Member
posted July 16, 2003 09:33 PM
I would double check your timing tab and make sure that zero is actually zero , and your timing is where you think it is . 9 times out of 10 if a guy is getting away with running as much timing as you are , then his engine is extremely rich . If you've been up to 250 degree's , odds are that you have at least wounded a head gasket also .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


RACEINMUD
Member
posted July 17, 2003 09:39 AM
Steve, how do I ck to make sure tab is correct? No oil in water or water in oil, so head gaskets seem fine. Is there somthing else to ck? Thanks! Mud


towmandan
Member
posted July 17, 2003 10:01 PM
If head gasket blows between cylinders or from compression to water you wont exchange any fluids.....BUT YOU WILL RUN HOT!!!!.....Towman


sdhnc29
Member
posted July 17, 2003 10:22 PM
The simplest way to check for exact TDC if your engine is together would be with a piston stop . You can take an old spark plug , knock the porcelain out of it , and tap it for a 3/8 bolt . Use a long enough bolt so you can use a nut to lock the bolt in place . Once you insert the piston stop in the head , turn the engine over by hand until you are close to what you think is TDC . Run your bolt down until it touches the piston . Rotate the engine by hand until you are just off the piston stop , and turn the bolt maybe 1/2 to 1 more turn and use your lock nut to keep it in place . Next you will rotate the engine by hand the opposite direction until you come up and the piston touches your stop . Mark your timing tab in correspondence with your zero mark on your damper . Next you will turn the engine back the other direction until you touch your piston stop again . Mark your timing tab once again in correspondence with the zero mark on your damper . Exact TDC on your timing tab will be found half way in between the two marks that you made on your timing tab . This is all taking into consideration that your damper is a good one , and the outer ring has not rotated .

You don't have to have water in the oil , or oil in the water to have a head gasket leaking . They might not be blown , but they could be seeping .

I would also want to have a look at your distributor , especially if it's a HEI . Make sure the advance is welded , and the breaker plate has not come loose .

Let me know if you find the problem .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


cmiller51
Member
posted July 18, 2003 04:33 PM
The spark plug AR3933 won't work with my heads. They have the tapered seat. Another suggestion?


sdhnc29
Member
posted July 19, 2003 12:00 PM
The plugs we used in the tapered seat head were Champion S53C , S55C , and S59C . The 53 being the coldest and the 59 being the warmest .

Steve

------------------
Hendren Racing Engines
Rutherfordton , NC
(828)286-0780


RACEINMUD
Member
posted July 23, 2003 11:06 AM
Not sure here, Does anyone have a picture of a welded HEI. Only have one and don't want to mess up. I'm thinking Steve is correct, when I try and time eng., the mark is never consistant. Thanks, Mud


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