Same effect with light springs on mechanical advance that are adding timing at and below idle speed. Easy to check with a timing light. What are your cam specs and what is your timing at idle?
RPM drop and electric fans!
- Thread starter FDNY340
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goldduster318
Overzealous Car Modifier
20' a 6 ga wire is good for about 30A total:
https://www.qualitypowerauto.com/Wi...ZjHhnEjMd32DJ1YUpnsctiyAoQuD7C6dWCfxEeGUiulrK
Cut that to 6' and it's good for about 120A. This would be especially critical IF the alternator has to push the current to the battery first and then it comes back.
Unless you really need to I'd just put the battery back under the hood.
https://www.qualitypowerauto.com/Wi...ZjHhnEjMd32DJ1YUpnsctiyAoQuD7C6dWCfxEeGUiulrK
Cut that to 6' and it's good for about 120A. This would be especially critical IF the alternator has to push the current to the battery first and then it comes back.
Unless you really need to I'd just put the battery back under the hood.
You need to run the fan power to the alternator. That just might solve this.
MSD Distributer out of the box I believe comes with heavy springs standard. I dont want change too many things at once. Trying to do this methodically. Timing at Idle right now is 14. Gonna add some to get it to 21ish but gotta change the bushing to fix the advance curve.
It certainly wouldn't hurt!
Actually going under my dash and taking this picture I realize they are powered through alternator. Alternator line goes to the American Auto Wire bus bar where it is fused and then powers that lug. The fans and accessories are powered from that lug. @RustyRatRod
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That looks purdy nice. I think I'd still pull the fan power wire out of that and go directly to the alternator stud.
Right on. Can verify by seeing if problem goes away when fans are disconnected. Also measure voltage at idle. Sould be over 14v just after start up. If it goes down to near 12.5v, alternator is not handling it.
You could just advance it for a quick Idle test to see if that helps and set it back if it doesn't help. If it does help then go to the trouble of redoing the curve. Don't forget to check the idle mixture.
If the Lunati cam has a lumpy idle [ do you have specs? ], engine will want a LOT more than 14* of timing at idle. Could be 25-40*, depending on cam. What will that do? It will produce more HP at idle. The extra hp will help carry the load that the fans impose on the electrical system & there will be less rpm drop going into gear. The idle mixture [ screws ] should also be adjusted with the trans in gear, NOT in neutral.
The correct procedure to get the best idle timing is this: car idling, in gear, loosen dist clamp. Slowly turn dist CCW to advance the timing. Rpm will increase, idle will get smoother. keep going until you get the highest rpm. Now check what the timing is. That is what your engine needs for best idle.
Note the 50* comment, below.
The correct procedure to get the best idle timing is this: car idling, in gear, loosen dist clamp. Slowly turn dist CCW to advance the timing. Rpm will increase, idle will get smoother. keep going until you get the highest rpm. Now check what the timing is. That is what your engine needs for best idle.
Note the 50* comment, below.
Thanks @Bewy
Cam Specs.
If that much advance is needed, would it be easier to just lock out the distributor. I just picked up a new MSD 6digital plus which can retard timing for start.
Lunati 40200734 Lunati Voodoo Camshafts | Summit Racing
With 1.6 Rockers
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goldduster318
Overzealous Car Modifier
I have a 227/231 duration at 0.050, .530 lift on a 9.8:1 340 and my car runs 22 up front because that's what it likes best. Starts just fine.
I would still want a timing curve. It probably won't like idling at 34-40 deg.
I would still want a timing curve. It probably won't like idling at 34-40 deg.
SRT_DSTRHOLC
"There is never enough horsepower...."
well this has turned into something, eh?
Yep..... but so far Im learning a ton. Spent a lot of time looking at old threads that turn into a bitchfest. The amount of knowledge some of these guys have is amazing. Just a sponge trying to soak up all the good stuff.
Totally agree. It really won’t like starting at that much advance.
My personal experience has been that more than a few of the starters out there will not enjoy a hot start once you’ve gone much past 22° advance at idle.
My truck idles just fine for long periods with 36 total. At idle. I have the vacuum can on manifold vacuum and it pulls in the extra from about 22 without the can. Runs very well. It starts fine of course, because the vacuum can doesn't pull anything in until the engine is running.
Some will start fine at 30 plus idle timing...when cold. But get that pup good and hot on a hot summer day and they'll protest.
Exactly. Cold start is easy, drive to the gas station when it’s it’s 110° and shut down and the hot restart is no bueno.
Might not matter for a race car, but I drive my car like a daily so it has to restart hot.
My general experience was more than 22° started to be an issue, but not all of those were nice expensive starters either.
You got that chit right. And the start fail is always at the least convenient times! lol
Here we are again, too much cam for the desired situation.
Trying to compensate for the mismatch by adding timing. Now that is bringing on new problems of its own.
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Trying to compensate for the mismatch by adding timing. Now that is bringing on new problems of its own.
☆☆☆☆☆
George you don't know what my desired situation is. You didn't ask, you just make sarcastic comments and offer no real input. Don't feel obligated to chime in.....
Have a great day
He said his box has a start retard.
Yes, seems like they always fail when your trying to start them. lol
Have you tried disconnecting the fans yet? That would certainly tell the story, imo.
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