billybob6110

how do I lockout my timing so it don't advance past 36*? I read somewhere to weld it fully advanced and time it to 36*?? im confused by that

Vader

What kind of distributor?

sofakingdom

iTrader: (1)

Why do you think this would be a good idea?

Why do you think the timing is "advance past 36°"?

Why would it make any difference if it "advance past 36°", if that's WHAT THE ENGINE WANTS?

What's really going on? IOW, don't fixate about how to kill the alligators, when you're really trying to drain the swamp, and the only reason for even doing that is really because you're trying to build a road through it. Concentrate on how to solve the REAL problem at its core, not in getting bogged down in piddly details on how to hack something.

AlkyIROC

A locked out distributor has no advance. If the distributor is locked out, it's adjusted to full advance and stays there. At full advance, there's too much advance to get an engine started so some sort of start retard is required which will retard the timing enough to get the engine started then allow the distributor to go back to full advance once the engine is running. Locked out distributors are a common in a race only situation. For normal street driving, you need advance.

Now if you only need to have the advance go to a maximum of 36* then it needs to be recurved, not locked out. Recurving a large cap HEI distributor is easy. The weights and cams determine how much mechanical advance the distributor will go to. Springs determine how fast it advances. Mix and match the parts to get the desired result. One large weight and one small weight or one light spring and one heavy spring is fine. The small cap HEI has no weights and springs inside. The timing curve is controlled by the ECM and it would need a reprogramming.

If you know the base timing, you can determine how much mechanical advance is in the distributor. Stock timing marks won't help. You either need timing tape on the balancer, a balancer with degree marks on it or an advance timing light. Once you know how much advance is in the distributor, total minus base timing, you can start playing with the weights and cams to see how much it changes. Change the springs so that it's at full advance by 3000 rpm.

Now if you do need a fully locked out distributor for racing, with the weights closed, you can tack weld them in place and they'll never move. Disconnect or remove the vacuum advance. Once the engine is started, adjust the timing to your desired 36* and lock down the distributor. The timing will never move as the rpm range changes except for timing chain slop. As I already mentioned, trying to start an engine with the timing locked out at 36* will be very difficult especially with a cold engine.

An aftermarket distributor like one from MSD allows the timing to be easily be locked out by using a set screw.

The timing in my race car is locked out to 37*. My ignition system has a programmable start retard up to 20*. I think I have it retarding the timing around 10-12* to get it started but with the amount of duration in my camshaft, that's pretty close to where my base timing should be. Once the ignition sees more than 500 rpm, the start retard is turned off the engine runs at 37* of timing all the time.

novaderrik

use a timing light to set the distributor so that it hits the desired mechanical advance when it is fully advanced- this means revving the engine and watching the mark move... i love my dial back timing light, makes it easy, but you can use a regular light if you have marks for it or have a timing tape on the balancer...

AlkyIROC

That's good for setting your total advance but it will screw up your initial base timing. Best base timing depends on cam duration. If he currently has his base timing set at 12* and his full advance is currently 40* and he wants to drop it back to 36*, his base timing will be 8* which may be too low for the cam grind. To keep the 12* base and drop the total down to 36*, he needs to take 4* out of the mechanical advance. Rotating the distributor does not change how much mechanical advance it has in it. All that does is changes the initial and total points.

Still need the poster to say if he actually needs locked out timing at full advance or if the distributor just needs to be recurved to limit the advance.