Temprature Increase...JETTING????
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Temprature Increase...JETTING????
Is it common for engine temp to rise as much as 10-15* with just a jet change??? In a Holley 4160, I went from a 74 to a 72 on the primary and she's now running 10* hotter (210*) Idel mix is fine, As is timming.
Thanks guys
Eddie
Thanks guys
Eddie
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Your correct run something to lean temp goes up along with possible
burned pistons, sounds like even with the 74s you might have been
on the ragged edge better put the 74s back in might try 76s see if temp goes down lower then it ever was, retarded timing causes heat but you said your timing was good.
burned pistons, sounds like even with the 74s you might have been
on the ragged edge better put the 74s back in might try 76s see if temp goes down lower then it ever was, retarded timing causes heat but you said your timing was good.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Hi Eddie! Lean will run hot. Better off a little rich. Need to get a base A/F ratio and go from there. A chassis dyno tune is your best bet as you can get an idle ratio, primary ratio, cruise ratio, wide open throttle ratio....... but you already know that.
Tough to find a dyno shop anymore with a good Holley guy. All the modern tuning is laptop or burn a new chip.You might want to back your timing down a little. 36 degrees seems to be what everybody shoots for but the modern combustion chambers are more efficiant and for example the fast burn heads run 32 degrees total timing, all in by 3000 RPM. Your AFR 210's might like a little less timing. Leave the smaller jets in there, Dial it back 2 degrees, take it for a ride, and check temperature.
Tough to find a dyno shop anymore with a good Holley guy. All the modern tuning is laptop or burn a new chip.You might want to back your timing down a little. 36 degrees seems to be what everybody shoots for but the modern combustion chambers are more efficiant and for example the fast burn heads run 32 degrees total timing, all in by 3000 RPM. Your AFR 210's might like a little less timing. Leave the smaller jets in there, Dial it back 2 degrees, take it for a ride, and check temperature.
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,943
Likes: 3
From: Wildwood IL
Wuzz-up Kevin?
I'll try dialing it back 2*to see. Didn't think 2 jet sizes would effect temp that much. Plugs were sooty with the 74's, so that's why I changed em to 72. Been raining almost every weekend so I'm not missing any road time.
P.S. Got the job @ Grainger....
Eddie
I'll try dialing it back 2*to see. Didn't think 2 jet sizes would effect temp that much. Plugs were sooty with the 74's, so that's why I changed em to 72. Been raining almost every weekend so I'm not missing any road time.
P.S. Got the job @ Grainger....
Eddie
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
A small jet change will make a noticable difference in temp if your real close to optimal. Bet a little less timing and that 72 jet will get you closer to where you want to be.
Your on the right track. Make 1 small change, evaluate and make the next small change. You will get that thing dialed in. Still owe me a ride.
Last edited by 63mako; Jun 22, 2008 at 06:38 PM.
