tuning an alky motor

[fast75vega]

ok... one of our vega's has 434ci sbc running on alky. we think its running rich cause it never gets over 160 deg. and the oil gets real milky after just one weekend of running. we want to install the sensor in the exhausts but not sure how to got about it or what to look for while tuning it.


any help as to what you think as far as the engine temp/ milky oil problem or how to do the sensors would be great :wink:

[maxpower671]

how about a complete rundown of your car and application..

[fast75vega]

its a 1/4 mile drag car

434ci sbc pro top heads...it has a 4/7 swap 675 lift cam.......950 holly carb (i think it has 151 jets all the way around)

the engine temp just doesnt get hot....the highest it gets is just under 160 on a hot day

what is the best way to go about tuning it?

[hammertime]

Does it gain any temp going down the track ?

any idea where the idle mixture screws are at ?

[fast75vega]

Does it gain any temp going down the track ?

any idea where the idle mixture screws are at ?

it never goes over 160 even after a run :(

[fast75vega]

car runs 9.50's and very consistent....... the car runs cold and seems really rich.......plus doing alot of oil changes cause how milky it gets. i know it will run cooler and use more fuel but i dont know if the milky oil is normal or if not getting up near the 200 deg temp is hurting anything?

[maxpower671]

car runs 9.50's and very consistent....... the car runs cold and seems really rich.......plus doing alot of oil changes cause how milky it gets. i know it will run cooler and use more fuel but i dont know if the milky oil is normal or if not getting up near the 200 deg temp is hurting anything?

try leaning it a little at a time...when your consistency goes away you're too lean...you may build a little heat during the pass..

your oil is getting milky because you are too rich, and/or you are not getting enough heat in the engine... do you have header evacuation or a vacuum pump?

with mechanical injection, fuel can be bypassed to lean engine out and build heat, with a carb not sure what would be the best way? :?:

[fast75vega]

no vac. system. we even turn the fan and water pump of trying to build heat and the damn temp stays put(we tried different temp gages too to rule out a bad reading) i heard that you can tune by exhaust temp ... is this true and how is it done? what temp should the exhaust be at then ?

[hammertime]

Does it gain any temp going down the track ?

any idea where the idle mixture screws are at ?

it never goes over 160 even after a run :(

so if you hit the starting line @ 160 it stays at 160 when your back at the trailer ?

How about the idle mixture screws in the metering block, they will have a lot to do with it at idle building temp.

How big of a radiator do you run ?

[fast75vega]

Does it gain any temp going down the track ?

any idea where the idle mixture screws are at ?

it never goes over 160 even after a run :(

so if you hit the starting line @ 160 it stays at 160 when your back at the trailer ?

How about the idle mixture screws in the metering block, they will have a lot to do with it at idle building temp. the radiator is like 2ft x 2ft x 3"

How big of a radiator do you run ?

yeah.... it will be around 160 after a run and as we get back too the trailer. it will be around 145 at the line as far as the screws go... im not sure off the top of my head

[shawnp]

So you stage at 145 and get back to the trialer at 160?

A good alky set up will gain no more than 10 degrees down track. We hit the water 160-165. Stage at 170 and the car never goes over 180.

Whose carb is this? Have you contacted them to get an idea of where to start with your jetting?

[SABOT7]

I think a lot of your issue with the milky oil is not running an evac system and is more like the result of condensation rather than alcohol. We run a 377 SBC on an rear engine dragster, 820 cfm Rupperts Carb with 166 jets square. we leave the line at 160 and are back at the trailer at about 170 to 175. We only use the water pump and fan to keep temp below 160 in the lanes before staging. We run an electric evac system that is really cost effective (about $220) and it keeps the majority of the milk out of the oil. To help keep condensation from building during a race and between week ends, we run the car at an idle when we get back to the trailer and bring the temp up to about 180 or 185. During the week when the car is stored in the trailer, we leave the breathers out of the valve covers.

[supernova65]

You should always run your water pump. If you don't you could develop hot spots from the water not circulating and melt something.
Also if your not running your water pump, you are not getting true temp readings, just the temp of where the water sits stagnant under your sensor.
Control heat with your fan and a leanout valve.