just installed su now white smoke from exhaust

[dr.feltersnatch]

so its an l18 with u67 head. i swapped out weber 32/36 for dual flat top su (2 bolt sss). fire it up and i am getting a ton of white smoke from the exhaust, so water is getting in somewhere. i let it run for like a minute then shut it down, no oil in water and oil is still black. my concern is are the coolant ports all the same? could it be they dont quite line up? the intake flange is nice and flat and clean. or could it be somewhere else? like a misrouted hose or something. looks pretty straight forward so i doubt it.

[Laecaon]

odd, as the U67 doesnt have coolant ports to the intake mani...

 

Did you hook up the coolant line to the intake mani? I would disconnect that...

[I'm BLUE]

was the car running prior to weber to su swap or sitting ? (exhaust condensation)

 

do you have fresh fuel ?

 

any other work done at same time in addition to carb swap ?

 

if all checks out i would be looking into a blown hg diagnosis procedure.

[dr.feltersnatch]

yes it was running fine this afternoon with the webber. coolant lines are hooked up, just as they were before. that head may not have come from the factory with coolant ports but its got em now! i would have not hooked up the lines (major pain in the ass) but figured it would come out of the head ports so i had to.

[DISLEXICDIME]

sounds like your intake gasket is leaking in to one of the ports or your intake manifold is cracked

[dr.feltersnatch]

ya i will pull it back off tomorrow. those bottom center bolts are a motherfucker to get to. is there an effective wat to block off those ports other than just put a gasket over it, that has had a low success rate for me in the past.

[Laecaon]

I get to the bottom center bolts by using a ratcheting wrench.

 

But switching to SUs, I was able to use a straight extension on my ratchet/socket with the heat shield off.

[H5WAGON]

Tap and plug holes...

[dr.feltersnatch]

is there any reason to run coolant in the intake manifold?

[Laecaon]

Sure, but I never have...

 

I think mostly it keeps a minimum temp in the manifold, and helps from icing the carb(s). Course I could be completely wrong...

 

http://community.ratsun.net/topic/13116-coolant-ports-on-the-l-series-intakes/

[ggzilla]

Yes the coolant improves part-throttle power.

 

Make sure your aftermarket SU manifold.covers the water Ports fully. If it doesnt then tap the coolant holes and install blind plugs as per Datsun competition manual

[datzenmike]

If the intake air temperature is constant or confined to a narrower range the engine can be tuned for better performance, emissions and mileage. Coolant flow in the runners keeps the intake air at a more consistent temperature. It warms the air Shortly after cold winter starts and running and absorbs radiant heat from the exhaust manifold and 'cools' the intake air during the summer.

[wayno]

Did you use a good intake/exhaust gasket?

Did you reuse the old gasket?

Did you use one of them cheap black intake/exhaust gaskets?

 

I buy good gaskets, and use a very thin film of permatex gasket sealer around the coolant passage holes in the head/intake manifold, I actually reuse these gaskets once if they come apart without damage, and that is determined at that time, and if I see anything bad, I either replace the gasket, or use permatex on the whole thing the second use.

Take it apart and examine the gasket and manifold carefully.

[ggzilla]

180 degree coolant cant cool intake air.

 

But Mike is correct the constant temp allows constant tune. Also provided good.cold engine perf. And more efficient burning.

 

All in all its a good thing. Without it the carb should be re-jetted richer to maintain the same power. but will still run ok if you dont

[H5WAGON]

If not leaking water....are the carbs loosing oil?

 

Burning oil could cause white smoke..?

[D52E]

Did you accidentally spill coolant into the exhaust system? I've had a couple occasions where this has happened on other vehicles while changing intake manifolds or heads. Even a small amount can cause some white smoke after you rev it up a bit to get the exhaust temperature up and flow going. If that's the case it will burn off after a test drive.

 

Other than that, double check everything you did. Perhaps you can pressurize the cooling system to check for leak down to confirm if there really is an internal leak? this will require you to borrow a pressure tester tool with a gauge. Good luck.

 

 

[hobbes_the_cat]

"oil is still black."

 

Probably not the source of this particular problem, but not good. If the oil is black it needs to be changed. :(

 

This problem sounds like an intake manifold gasket issue to me. I have seen a few put in backwards that were leaking.

[dr.feltersnatch]

so i went out this morning and let it run for a few minutes and the smoke seems to be going away, must have just needed to be warmed up. i also go to checking things and the oil in the carbs appears to be atf. i read that will cause it to run lean. should i replace it with motor oil?

[dr.feltersnatch]

"oil is still black."

 

Probably not the source of this particular problem, but not good. If the oil is black it needs to be changed. :(

 

This problem sounds like an intake manifold gasket issue to me. I have seen a few put in backwards that were leaking.

ya its about due for an oil change. what i meant by that was its not milky like water in the oil.

[datzenmike]

180 degree coolant cant cool intake air.

 

Maybe not a lot but radiant heat from the exhaust pipes just an inch away just has to warm the intake above 180 on hot summer days. Under hood temps can get pretty high. SUs use a heat shield.

[ggzilla]

Yes, coolant keeps the intake manifold cooler than if you block the coolant ports. So the air still heats up but not as much.

[ggzilla]

If you have SUs then ATF is fine. If you have factory Hitachi, Datsun recommended 10W30, which should work well for stock engines.

 

Modified engines may need slightly leaner or richer tuning which is why people try various weight oil. As I understand this mainly affects acceleration mixture not running mixture

[Sealik]

If you have SUs then ATF is fine. If you have factory Hitachi, Datsun recommended 10W30, which should work well for stock engines.

 

Modified engines may need slightly leaner or richer tuning which is why people try various weight oil. As I understand this mainly affects acceleration mixture not running mixture

 

Yeah...I believe the heavier oil slows the 'piston'/dashpot from rising to quickly on acceleration...less air..<....more fuel....<...richer mixture

 

EDIT

 

..."Dampener Oil or Dampening or Damping Oil: Function of the damping oil is three-fold. First, to lubricate the precision fit and the never-ending movement of the dashpot. Second, to dampen rapid pulsing of the dashpot at low RPMs, and thirdly, to slow dashpot response when throttle opening is increased, effectively enrichening the air-fuel mixture (an accelerator pump effect)".....