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Saturday Night Racer >> RACE TECH >> DART IRON EAGLE HEADS 180/49cc
http://www.latemodelracer.com/cgi-bin/yabb2/YaBB.pl?num=1227506983

Message started by rbrduck71 on 11/23/08 at 10:09pm

Title: DART IRON EAGLE HEADS 180/49cc
Post by rbrduck71 on 11/23/08 at 10:09pm

bought a set, on the intake side of intake valve there is oil after running motor (SBC) 20hrs and heads are on the bench look down the runner and theres oil on top of all 8 intake valves, put new guide seals from dart 32$ and six passes down 300ft track still oil, WHAT GIVES????? never had this much trouble with wore out stock parts! any help i can get would be geat THANKS! THE DUCK

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by Andrew on 11/24/08 at 6:17am

If there is a mismatch with the angle of the head and intake surface you could be sucking oil at the intake gasket. Happened to me, and it's a b*tch to diagnose and confirm.

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by TALON75 on 11/24/08 at 10:17am

if the heads have been milled at all the intake needs to be cut to match .

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by rbrduck71 on 11/25/08 at 8:41am

brand new F@&#ing heads, i looked over the intake gasket real good didnt see any trace of oil, how did you figure this out on your set? Heads havent been milled, had the heads long enough that dart wont do anything for me. THANKS for the help guys.

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by Bap33 on 11/25/08 at 4:44pm

you might be sucking the oil down the stem when you shut down at high RPM. Here's how I cam up with that.
Running down the track you are at high Revs when you shut down, and the following stuff is all going on.
1) The valve covers are full of oil after a 12 second long hard high Rev run.
2) The crank case is under pressure from blow-by and heat expansion.
3) The valves are "wiggling" with each stroke at those high Revs. Even good ones wiggle if they are pushed by a rocker.
4) When the throttle is cut at high RPM there is a vaccuum created in the intake area. This means each intake valve's stem is under the effects of a bit of vaccuum when it gets opened. The piston is headed down and the valve is headed down and the vaccuum is looking for air.

So, maybe the oil is setting on the stems when you shut down at high Revs and gets pulled down the stems from the high vaccuum created at that point of shut-down. Might go away if you put a positive crank ventilator that gets tugged from the exhaust. That would create a vaccuum in the valve cover/crank case area that would continue even after shut down because the exhaust is still moving a volume of air that should overcome any high rev vaccuum in the intake.

If it was a seal or guide issue there would be smoke and oil use.

Anyways, I thought I'd toss out an idea. Good luck

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by jp80 on 11/25/08 at 9:09pm

Is it smoking? If you're getting oil on the valve and only on the valve .. it's the guide or valve guide seal. If the piston is soaking wet and black then it might be intake manifold. That's my 2 cents. Of course it could also be not enogh drain down from the heads to the pan, this would fill your valve cover and make it tough for the seal to work... my .02 cents

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by bigmikes on 11/25/08 at 10:02pm

had the same problem and had to have a complete valve job, its sad that they send new heads out this way

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by rbrduck71 on 11/26/08 at 1:35pm

if u go to www.avenalsanddrags.com, photos, NOV.2008, then look for 2 pics of #6302 and you will see the haze of smoke, my dumb ass used a high volumne oil pump so i will be getting rid of that while i have the heads off. By the way this is only a 7000rpm motor

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by rbrduck71 on 12/11/08 at 7:42pm

guess im screwed

Title: Re: DART IRON EAGLE HEADS 180/49cc
Post by rbrduck71 on 12/14/08 at 12:55pm

BUMMER