Where is advance on Indmar's HEI distributor?

The ignition control module has a built in "logic." This logic references off of the pick up coil and rpm. This "logic" has a built in timing curve of about 21deg. plus the 10deg. gives you a total advance of 31deg. When at 3000rpm, you should have about 28deg. showing at the crank. I have seen cases where the module has gone bad and not delivered the proper timing. This can happen when the shunt wire is hooked up to positive current to long. Hope this helps, keep us posted. Brian Raymond

The ignition control module has a built in "logic." This logic references off of the pick up coil and rpm. This "logic" has a built in timing curve of about 21deg. plus the 10deg. gives you a total advance of 31deg. When at 3000rpm, you should have about 28deg. showing at the crank. I have seen cases where the module has gone bad and not delivered the proper timing. This can happen when the shunt wire is hooked up to positive current to long. Hope this helps, keep us posted. Brian Raymond

The ignition control module has a built in "logic." It gets its references from the pick up coil and from the rpm signal. The module has a programmed timing curve of up to 21deg. When adding the 10deg. from the motor, you end up with a total of 31deg. of total advance. When at 3000 rpm, with a timing light on the balancer, and the shunt not hooked up, you should show about 28deg. I have seen modules go bad and keep it at 10deg. no matter what rpm. This can be caused by leaving the shunt wire connected to a 12v source for long periods of time. Hope this helps, keep us posted. Brian Raymond

[Brian Raymond]

The ignition control module has a built in "logic" that gets its references from the pick up coil and a rpm signal. The module has a programmed timing curve of about 21deg. The 10deg. from the motor shoud give you around 31deg. of total advance. When the motor is at 3000rpm, with the shunt wire not hooked up and the timing light on the balancer, you should get about 28deg. I have seen modules default internally and not let the motor advance past base time. This can be caused by leaving the shunt wire connected to a 12v source for long periods. Hope this helps, keep us posted. Brian Raymond

[Rusten]

Hi Brian,
Thank you for the information. On a separate note, have you noticed the strange issue on this forum lately where "phantom" style posts are appearing with no author?

Regarding my troubleshooting -- here is the latest after a weekend of testing new suggestions (if only I could find an Indmar mechanic, life would be so much better).

On Geezer's suggestion, I checked the distributor gear -- no problem there. The only strange thing I noticed is that it didn't look like brass -- I was under the impression all distributor gears must be brass when used with roller cams. The original Delco module, no matter what I did, was stuck in base-timing. Brian - it had never been connected to 12v for a long period of time, but it's good to know one can fail without the other -- sounds like it may be the module.

I dissassembled the engine and removed the timing cover to check the cam v. crank location and they were dot-to-dot (8 hours wasted with that disassemble/reassembly).

In short, everything seems to be "degreed" correctly; however, the engine runs far better at 35-40 degrees of advance than it does at 10 degrees, and I'm just talking about idle! I've double checked this with two timing lights (one expensive digital, one conventional) and I've done it by degreeing the harmonic balancer, they all agree.

Despite the ignition not showing advance, this appears to be an entirely separate issue (the spark timing v. balancer position can't lie no matter what is going on to cause problems, right?) And I'm out of ideas again.

Is there any diagnostic book that can give me ideas as to what to check / why my engine would require so much advance timing to run? Someone also mentioned that it could be the pickup in my distributor, could this be at all relevant?

Thank you in advance,
Rusten

[Keaton]

Pickup coils are either good or bad. If they are bad then it wont run at all. With the kind of system then Brian explained it would just about have to be the module but you should double check with Brain as Im not familiar with this style of ignition. A module shouldn't be that expensive. Its worth a shot to put one on and see if it fixed it.

Cars require inputs to know how the engine is running like for example. Engine load via vacuum, rpm, throttle position to control timing if its an ESC system. I think its different because boats don't have to meet EPA regulations that cars do so they can get away with this kind of ignition system. Basically that explains some of your questions about car parts tranfering over to boat applications. The anwer is no. I was reading some of your other post about the engine being from automotive application. I would advise that if you do get this problem resolve try and stay within the boat application parts. I don't have anyway to prove it but I wouldn't be surprised if the cam is different in then the motor that was origanal. I do know that the freeze plugs are going to be different so keep an eye on them or you'll be doing this again. Keep in mind there is two in the back of the engine.

[Rusten]

Hi Keaton,
Fortunatley the freeze plugs in the engine are brass. I switched the cam with the original, and although the lobe height was identical, the opening was quite a bit longer. I concur in the cams being significantly different, not to mention the marine application uses a roller cam. This forced me to replace all related components -- push-rods and everything. It hasn't made a performance difference, but you can definitely hear the difference in sound.

But at this point, I have an engine that is 100% marine. Because I utilized all Indmar parts (from the intake manifold, to the balancer -- everything) and because the cam and all related parts have now been switched, this is the marine engine. The distributor and module we're discussing is the original that ships with Indmar as well.

Based on what I've found, you're correct about the emissions being the issue relating to not requiring MAP sensors and so forth; I've read that factually on several ignition websites, etc.

I'm just hoping to determine what could cause the engine to want so much advance. This can't be the module alone, I don't believe, since the timing light proves it.

-Rusten

[Rusten]

Brian-
It occured to me while mentioning the differences relating to Indmar's 350 Vortec marine cam v. standard 350 Vortect, that the cam may also be set advanced in the engine. Perhaps this is why after replacing the cam (going to the Indmar cam instead of the stock Vortec cam) I increased the RPM's a bit, but didn't get the full RPM's.

Have you or anyone else on the forum taken a look at the cam positioning or read a spec that shows whether the Indmar cams are degreed?

Thank you!

[Keaton]

Did you put a indmar timing chain and sprockets on when you changed the cam shaft. That would eliminate the posibility of the cam degreeing. I think you on the right track. I think you have a problem with the corrolation between the crank and cam therefore having to advance the timing because the cam is advanced. You can make sure that the cam is degreed right with a degree wheel. That way you can make sure the valve are opening and closing at the right time. You would have to get the specs from Inmar and that could be a task. LOL. Even working for a dealer getting that info could be tough. But like I was saying if you use the Inmar timing set then it should already be degreed and will take out the guess work. If all that checks out then Im stumped. Its starting to be one of those problems where you just have to be there and work on it.

[Catdog1]

When degreeing a cam set-up with a degree wheel, doesn't one actually change the relative positions of the gear alignment marks?