best idle setting

[fryedaddy]

i have a 428 with a .244 at .050 flat tappet cam, bbm heads,11 to 1 comp, c6 with 3600-3800 stall.it hits a good lick at 850-900 rpm but has only 30 psi oil pressure hot at 850 rpm.if i bump it up to 1000-1100 rpm at idle it has 50 psi oil pressure and still sounds aggressive at 1100.with the stall either works ok.where would some of you guys set the idle.

[machoneman]

And what's wrong with 30 psi at idle? Nothing.....

[Stangman]

I agree I idle between 850-900 in gear hot about 24 psi

[fryedaddy]

it might be closer to 25 after a good drive. i was talking about in park or neutral not in gear. but by the responses it looks like i asked a dumb question.sorry

[cjshaker]

It's not a dumb question, so no need to apologize. I'd tend to set it as low as the engine feels comfortable with while in gear. Not sure how much rpm drop you get when you put it in gear (guessing not much with that stall), but as long as I could see 20 lbs of pressure or better, and the engine didn't feel sluggish, I'd feel fine with it at 850-900 in park. Especially since the pressure comes up right away. To me, hearing an engine that idles high just sounds like it's masking an idle tuning problem, provided it doesn't have some big monster cam in it.

[fryedaddy]

thanks.it sounds like popping corn at 850-900 in park.it dont drop hardly any when i put it in gear.i guess i should leave it alone.i didnt know if it would live longer and happier if i raised the idle.

[RustyCrankshaft]

25 or 30 psi at idle is plenty of oil even for a flat tappet. It won't live any longer idling higher I don't think, just whatever makes the engine happy.

Not that I'd recommend it intentionally, but the 460 in my 73 F350 dump truck might have 5 psi at idle and doesn't make much more than 30psi anywhere above that and it's been that way for years. No idea what clearances or oil pump it was built with, but since it's been like that for so long I suspect someone set it up pretty loose.

I don't think it's ideal and tend to like to try and set the clearances (and by default oil pressures) for the application, but the old rule of 10psi/1000rpm I've found will keep something from killing itself.

[Falcon67]

As above - no problem with hot oil pressure around 30 at idle.  No problem either with 55~60 at 7000. 

[Stangman]

I agree with Doug there are no dumb questions.

[plovett]

I think it is better to err on the high side when it come to idle speed.  A little too high will cause no problems.  A little too low could.  Not likely, but it could.


I have a fairly big cam in my 428.  I set the idle so it is about 900 rpm stone cold. When it is completely hot on a hot day the idle is 1200-1300 when in park or neutral.  Who cares?  I think it is better for the engine to run at a little higher rpm.

JMO,

paulie

[fryedaddy]

I think it is better to err on the high side when it come to idle speed.  A little too high will cause no problems.  A little too low could.  Not likely, but it could.


I have a fairly big cam in my 428.  I set the idle so it is about 900 rpm stone cold. When it is completely hot on a hot day the idle is 1200-1300 when in park or neutral.  Who cares?  I think it is better for the engine to run at a little higher rpm.

JMO,

paulie

WOW  just the opposite answer.that is why i asked the question in the first place.i know my oil pressure almost doubles from 850-1100.i understand 25 might be enough,but why not 50.thats why i asked.

[plovett]

Well, I also don't think 30 psi oil pressure at idle is bad.  I have an "aggressive" solid flat tappet cam and the higher idle speed (more than the oil pressure) keeps it alive.

JMO,

paulie

[fryedaddy]

Well, I also don't think 30 psi oil pressure at idle is bad.  I have an "aggressive" solid flat tappet cam and the higher idle speed (more than the oil pressure) keeps it alive.

JMO,

paulie

what size solid cam are you running if you dont mind me asking.im thinking about going solid.

[plovett]

Well, I also don't think 30 psi oil pressure at idle is bad.  I have an "aggressive" solid flat tappet cam and the higher idle speed (more than the oil pressure) keeps it alive.

JMO,

paulie

what size solid cam are you running if you dont mind me asking.im thinking about going solid.

It's 252/260 @ 0.050".  The advertised duration is 279/287 so it has pretty fast ramps.  My spring pressure is about 405 lbs open.  I could be wrong, but I think a higher idle speed helps keep it from wiping out.  I think the oil volume reaching the cam and lifters is more important than the pressure at the gauge.  I think so?

[fryedaddy]

im going to get Brent to match me up with a solid flat tappet cam. anything bigger than my .244 hyd from what i have read on here,i would be better off to go solid if i want to go bigger + run more Rs