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Another smoking L20b


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#1 loungin112

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Posted 10 December 2017 - 12:58 PM

Greetings...

 

I tried searching for this issue without any success.  My situation is a bit different than everything I have read, so I'm hoping the gurus here can give me direction.

 

I have an L20b (likely from a 200sx due to the dogleg that is with it) that went through an entire, overpriced and drama-filled, rebuild in 09/2016.  I wouldn't trust the builder with flushing a turd, so bringing the car/engine back to him is not an option.  With that said, there is virtually 0 miles on the rebuild since I have been working on other things to get the car ready to drive.  So, here is the problem:  after the first freeze (not really that cold though) of the year, I noticed a pool of antifreeze under the car.  I searched for the source and could only find a small pinhole in the exhaust collector which is where the antifreeze was coming from.  There was perhaps 1/2 to 3/4 cup worth on the floor.  I held my breath, started the car, and a bunch of moisture spurted out the back.  Then came the white smoke.  Not a lot (perhaps extended one foot out tail pipe) but is spitted a bunch of fluid.  There was some oil mixed in there too...i imagine from the new rings still settling.  The radiator emptied quickly.  

 

So, I tried retorquing the head bolts.  Same result upon startup.  The head gasket is the 1.5mm nismo with new head bolts, part # listed in the DQ.

 

I'm' stumped due to the newness of the headgasket, the mixing of oil/antifreeze, and the small amount of smoke but huge amount of moisture.

 

My next step is to recheck the intake/exhaust manifold bolts, but they look okay as of now.  Oh, and I forgot to mention that prior to the first freeze, the engine ran like a champ...smooth, a little rich, no pings/knocks, etc.  Some oil exiting the exhaust but no moisture or smoke.  

 

Thanks everyone.



#2 flatcat19

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Posted 10 December 2017 - 01:03 PM

Send head to machine shop to test for leaks.

Replace head gasket while doing so.

You'll probably find something obvious upon disassembly.

You can't hang if your nuts haven't dropped...it's physics


#3 loungin112

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Posted 10 December 2017 - 01:42 PM

I should add the following:

 

dual 38mm SU's

Stock Exhaust mani

U67 head

p68 pistons

AmeriCam

Mallory distributor

Stock radiator

 

Regarding the mechanic...seems to be a good mechanic but a crook.



#4 loungin112

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Posted 10 December 2017 - 01:43 PM

Send head to machine shop to test for leaks.

Replace head gasket while doing so.

You'll probably find something obvious upon disassembly.

 

Thanks...I guess it could be worse.  Thanks for the suggestion.



#5 datzenmike

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Posted 10 December 2017 - 02:01 PM

Dogleg does not guarantee engine is from an S10200sx....could also be from an A10. Could be from 620, 720, 610 or 710 also. After all these years things get traded around a lot to keep them on the road.

 

If you have the proper antifreeze/coolant you shouldn't worry about any freezing. You do have antifreeze in it?.

 

 

 

 

 If U67 head what intake did you use? and did you drill out the two holes in the head to allow coolant to flow into the intake runners?

 

 

A few things. You said you don't trust your mechanic/rebuilder?

 

Head is severely warped to have an external coolant leak on the manifold side.

Head to block alignment dowel(s) were lost/not used and head is on crooked and gasket not sealing properly.

Head/block surfaces not cleaned of old gasket properly, new gasket not sealing.

 

Intake exhaust gasket is not clamped properly and the two coolant runners in the intake manifold are leaking. 

 

The steamy exhaust is likely normal. All engines have steamy exhaust in the winter. If you have antifreeze in the coolant, smell the exhaust. If there is coolant present it will smell sweet. This could be the intake sucking in coolant at the gasket when running, leaking on floor when not.


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#6 racerx

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Posted 10 December 2017 - 02:16 PM

White smoke is normal during cold mornings. You can do a compression check.

#7 Stoffregen Motorsports

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Posted 10 December 2017 - 03:46 PM

Leaky intake/exhaust manifold gasket? Check the torque on those fasteners first, then remove the intake if it persists.

 

Did you install the intake? Did you surface the manifold with a Roloc disc on a 20000 rpm grinder? If so, that's bad and could be the cause.



#8 distributorguy

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Posted 11 December 2017 - 10:47 AM

The big question: where did the coolant leak from? How did the radiator empty so quickly?  

Napa sells a "Block Tester" that allows you to pressurize the cooling system to see where the coolant is going.  Good investment.



#9 loungin112

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Posted 12 December 2017 - 12:36 PM

Thanks for the insights and direction.

Mike, i agree, the trans could be from any of those models you noted....assumption on my part...the car was purchased from someone who didn't care about the car history. And, i don't know about drilling out the intake.

I'll start with trying to tighten the intake and exhaust manifolds...hopefully that is a cure. Otherwise, of comes the head for a pressure test.

Stoff...i do not think the head was cleaned up in the manner you noted. But then again, reference my earlier comments about the mechanic/rebuilder.

Distributorguy...thanks for the suggestion...i may need to add to the tool chest.

Question: if the head was installed without the alignment dowels, would such an issue result? Are the dowels a port or channel for coolant or simply an alignment mechanism?

#10 datzenmike

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Posted 12 December 2017 - 05:53 PM

Two of the head bolt holes in the block (on the left side) and the head have a wider hole. A small sleeve or dowel fits into the block holes and sticks up. When the head is aligned it drops down over the dowels

 

fel-es74007_w_ml.jpg


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