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914World.com _ 914World Garage _ my exhaust is HOT!

Posted by: nebreitling Apr 12 2005, 04:16 PM

this is the new 2056 w/ 44 idfs, 9.6:1 comp, euro race header

problem: exhaust pipes and cylinder heads *seem* too hot, particularly on the passenger's side. oil is not too hot. i don't have a pyrometer.

i'm using my old '75 2.0 distributor w/ the vacuum advance disabled -- it has like 8 or 10 degrees of mech advance. can't afford a mallory right now. timed to 27 degrees, but the engine seems to want a little less advance when idling around 1800 (still setting up the carbs)

(any one have a 205aa or an 050 to sell?)

still working the carbs out, but they're not *bad*. if anything, a bit rich.

have all engine tin EXCEPT the driver's side cooling flap. the passenger's side flap is expoxied DOWN, such that air is forced through the oil cooler. I've seen numerous carbed cars with this set up.

i took the muffler off and the exhaust blows SIGNIFICANTLY stronger through just the 4-1 collecter. this seemed to cool the pipes off a bit, but it still seems a little hot. compressed air flows through the muffler okay, so i reattached it (don't believe it is plugged up).

i know i'm pissing in the dark here, but any suggestions that you guys could offer would be apreciatted.


beerchug.gif n


p.s. the good news is,,,, i DROVE it. still needs more tuning,,, but WOW! it pulls.

Posted by: Demick Apr 12 2005, 04:38 PM

I'm just wondering what makes you think they are too hot? Exhaust and heads should be much too hot to touch. So if you don't have a way of measuring how hot, what makes you think they are too hot?

Posted by: Aaron Cox Apr 12 2005, 04:44 PM

have a wide band 02 you can borrow?

are you lean?
too much advance? (pinging under load)

im pissin in the dark with you.... dry.gif

Posted by: nebreitling Apr 12 2005, 04:48 PM

QUOTE (Demick @ Apr 12 2005, 02:38 PM)
I'm just wondering what makes you think they are too hot? Exhaust and heads should be much too hot to touch. So if you don't have a way of measuring how hot, what makes you think they are too hot?

good point -- they're putting off a fair bit more heat than my old engine did. that's my only baseline here.


don't have an O2 gauge. want to buy an LM1, need to hold off until the finances recover. tuning by the seat of the pant for now.

Posted by: Aaron Cox Apr 12 2005, 04:49 PM

i would love to buy one of those quad EGT / CHT's from westach.... wub.gif

Posted by: SLITS Apr 12 2005, 05:29 PM

Exhaust temp on a good engine is 1400 (rich) - 1600 (lean) degrees.

Since a gasoline engine is, in reality, a heat engine and you have pumped it up, you will produce more heat...period.

Much of the heat is lost down the exhaust system. Expect it to run hotter while sitting idle...once you are moving, the surrounding flowing air will cool them a bit.

Since you are at the "center of learning", go to the Engineering Dept and see if they have some heat stickers that read in a range of 250 - 400 degrees. Stick 'em' on and see how hot they are running. TMR, above 350 is not really good.

And A-aron Admins, go to your local airplane parts supplier, they'll have EGTs all over the place. Chino Airport and in Ontario are located two aircraft surplus suppliers (or at least they were).

Posted by: Mueller Apr 12 2005, 05:33 PM

QUOTE (nebreitling @ Apr 12 2005, 03:48 PM)
QUOTE (Demick @ Apr 12 2005, 02:38 PM)
I'm just wondering what makes you think they are too hot?  Exhaust and heads should be much too hot to touch.  So if you don't have a way of measuring how hot, what makes you think they are too hot?

good point -- they're putting off a fair bit more heat than my old engine did. that's my only baseline here.


don't have an O2 gauge. want to buy an LM1, need to hold off until the finances recover. tuning by the seat of the pant for now.

can you drive the car to Napa or Antioch??
Our LM-1 (James, McMark and mine) is currently up in Napa, Mark might drive it down to Antioch this week(end)

I know nothing about carbs (plenty in theroy, no real world experiance), so maybe Mark can help???

Posted by: trekkor Apr 12 2005, 05:46 PM

1800 rpms is too high to set your idle mixture.

You should have the linkage disconnected and running at 900-1000rpm.
Are you using a sync tool?

KT


p.s. Mark's not a carb guy either...Said something about hating carbs. At least everytime I see him cool_shades.gif

Posted by: nebreitling Apr 12 2005, 05:57 PM

QUOTE (trekkor @ Apr 12 2005, 03:46 PM)
1800 rpms is too high to set your idle mixture.

You should have the linkage disconnected and running at 900-1000rpm.
Are you using a sync tool?

KT


p.s. Mark's not a carb guy either...Said something about hating carbs. At least everytime I see him cool_shades.gif

yeah, i realize that. still getting things set up.

it collects heat when idling. when it moves it seems to cool fine.

it would be HUGE to borrow you guys' LM-1. i'm gonna check my schedule and maybe tow up there. would bring copious amounts of beer, of course.

Posted by: nebreitling Apr 12 2005, 06:00 PM

QUOTE (SLITS @ Apr 12 2005, 03:29 PM)
Since you are at the "center of learning", go to the Engineering Dept and see if they have some heat stickers that read in a range of 250 - 400 degrees. Stick 'em' on and see how hot they are running. TMR, above 350 is not really good.

REALLY good idea, thank you. i'll ask around

Posted by: Racer Chris Apr 12 2005, 06:28 PM

QUOTE (SLITS @ Apr 12 2005, 07:29 PM)
Exhaust temp on a good engine is 1400 (rich) - 1600 (lean) degrees.

Even 1400 is lean! Temps at WOT are the only important ones as far as detonation is concerned.

Posted by: TimT Apr 12 2005, 06:40 PM

Yes
QUOTE
Even 1400 is lean!
the EGT curve is bell shaped the EGTs will rise as you to a point, then decrease..ie less fuel for the fire.

I like to trot this out every once in awhile

http://www.avweb.com/news/columns/182084-1.html

Lots of good info.. and the rest of the articles are very informative also.

Some people say that these articles only apply to Aircraft, I dont buy that..

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