Too much reference angle with FAST?

[carbuff]

Hi guys,

I'm having a problem after just rebuilding the motor that doesn't make a lot of sense to me. I'm getting a LOT of exhaust popping now, and I don't know why...

The engine is the same other than some new bearings and rings. I've made some slight adjustments to the FAST program to try and help the problem but so far I'm not having any luck.

My question is this. Is it possible to have the distributor reference angle too big? I'm currently set at 58 degrees. This is on a SBC with an MSD Billet distributor and an MSD 6AL driving it. I can adjust it back down, but before I do I was wondering if anyone thinks that is a problem? I wouldn't think so, but....

The other possible problems I can think of are a stuck injector, or the rockers being misadjusted. I have checked the rockers several times, so that's not it. And the injectors have very little use, but certain it's worth checking...

Anyway, if anyone know about the ref angle I would appreciate it. Thanx!

Bryan

 

[TurboTR]

Check the timing with a light!!

TurboTR

 

[carbuff]

I have... I edit my timing table whenever I set the timing so that I have a fixed value across all entries. I also zero out the timing trim for idle so it's not messing with the timing.

So, right now, I have the entire table set to 20 degrees with 0 degrees timing trim. I adjust the distributor to get it close to 20 degrees on the timing tab, then use the reference angle to get it exactly. In this case, that's 58 degrees reference angle to show exactly 20 degrees on the timing tab with the light.

Bryan

 

[TurboTR]

Sounds like you're good to go then! I think the ref angle you have is fine, shouldn't cause any run problems. We ran similar on a sequential Honda recently with no observed problems from that ref angle range. What does the sw limit us to, like 6x deg?

TurboTR

 

[Chuck Leeper]

20*??

Bryan, is this a blower car?? How long did the engine sit while being rebuilt? If it was a while, then the gas in the injectors could be scammer and causing a funky pulse width...

 

[carbuff]

Chuck,

The engine was just rebuild last week. The pistons went in the holes on Thursday, and the motor was fired for the first time on Friday. The motor was running fine before tearing it down. The only reason I did so was because of oil smoke during decel.

As for the timing, that's ONLY during the period when I'm setting the timing. Once I have the base set, I adjust it to a curve more like you would expect for an SBC. It's still conservative though, at about 32-34 degrees max right now until I get everything worked out.

TurboTR,

I don't know what the SW limit is... Glad to know that you have run a similar angle with good success though. Thanx!

Bryan

 

[Craig Smith]

TurboTR will likely fly to Michigan to kick my @$$ for saying this, but it is possible that with a 58 degree reference angle, you have a huge rotor phase problem. I would try to roll that number back to about 50 and see if it helps. If it seems to help you may want to think about a Cap Adapt thingie from MSD and a phasable rotor.

 

[TurboTR]

Good point. I forget sometimes about distributors And I was even the one harping about rotor phase to you guys on the phone a few weeks ago, lol ;-) Old age kicking in big time...

TurboTR

 

[carbuff]

Follow-up...

Ok, I thought I would let you guys know I found the problem, and I'm feeling pretty stupid for it... :-(

Apparantly I must have dropped a couple of my spark plugs when I pulled them out, and I didn't think to regap them before reinstalling. Of course, one was completely closed, and another was at about 10-15 thousandths. Ugh. That would certainly explain things...

So, there was no problem with the reference angle that I know of. And probably no problem with my program either. Sigh... Just glad I found it!

Bryan

 

[TurboTR]

Doh! But how IS your rotor phase anyway, lol?

TurboTR