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HG failing again, A15 in my Midget

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RickB

RickB

Yoda
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Everything was great over the weekend, then this morning I start up the engine and have a big cloud of white smoke and the engine running rough.
Diminished power going uphill but no overheating.
I assume I've got another HG failure in the works, thinking I'll swap in an H72 head and send this one for a rebuild.

Can anyone recommend a good shop for Datsun head rebuilding in the greater Seattle area?
East side would be nice but I'll take anywhere in the Seattle area if they are good and won't rob me.
About what "should" it cost?
 
Just stop fooling with that nasty old head and send it to me, Rick. I'll even pay freight!:friendly_wink:


Kurt.
 
Not trying to make light of a tough situation...but sometimes in human organ transplants, the body ends up rejecting the organ. It sounds like your British car is rejecting its Japanese heart.
 
Kurt, exactly what are you sending me in exchange? :cool-new:

I'll clean up one of my heads - maybe the H72 and slap that on as a temporary.
What I should do is remove the valve covers on my two spare motors and see what heads are on them before I do anything else.
Before I try to drive home I'm going to get some "Miracle Head Gasket Sealer in a Bottle" from the local auto parts place and see if that helps at all.
Maybe I'll get two bottles.

The Japanese heart has been very very strong over the past 7+ years. It maybe needs to watch it's cholesterol and clean up it's arteries a bit though.
 
Rick, I ruined a head and block by trying to drive home! 1275 cast iron that was a little tougher than aluminum but I did try for most of 100 miles!
 
Eww not fun Kurt.
I'm going 13 miles and will take it very easy.
 
Compression results:

195
205
195
195
I found the plugs very fouled, replaced them and was back to "normal".
The head no doubt needs a valve job, new guides and seals.
Next time it acts like this I will pull the plugs, clean or replace.
 
Eastside Machine
Redmond.
Kurt knows his stuff.
425-869-5193 shop.

Dave
 
RickB said:
Next time it acts like this I will pull the plugs, clean or replace.
Click to expand...

Or, save the ones you took out, clean and gap them, put then in a ziplock baggie (twice) and store them in the boot with a plug wrench.
 
Yeah I may do that next time.
Oil fouled, not too rich - just oil.
 
Dave: Thanks for the compliment but I didn't know enough to not try driving home with a leaky head gasket!

Tom: I think Rick's A15 has done many miles!

Kurt.
 
nomad said:
Dave: Thanks for the compliment but I didn't know enough to not try driving home with a leaky head gasket!

Tom: I think Rick's A15 has done many miles!

Kurt.
Click to expand...

Yes, mine is a driver.
To my best recollection I've had it a bit over 7 years and have put on about 40K miles.
The motor was "well broken in" before I got it.
I added the oval port head and dual SU's.
Right now I'm pretty convinced I have a valve problem, not a ring problem.
Once I can get the springs off I'll confirm this and at least install new seals.
I know this won't solve worn out guides but may slow the flow of oil running through #2 cylinder.
That's my hope anyway.
 
Rick, your compression seem's pretty high though fairly even. Wondering if your engine has flat top pistons or dished? Mine are half dished and figured the compression at 9.5 to 1 but haven't done a gauge check on it.

Kurt.
 
Mine are dished, now I'm glad I haven't sprung for the flat tops.
Maybe it's the H89 - don't know how it affects compression unless there's less cc's in the tops.
When I first tested the compression a couple months ago I had about 145 all the way across.
However I had forgotten to open the throttle for that test.
This time I held the throttle open while testing and the compression increased by about 50 lbs.
See what reading the manual does, sometimes you get to doing things right.
At least it's pretty even across all 4 cylinders, so I've got a good HG anyway.
 
Could be just your gauge...if it doesn't rattle under acceleration I guess it's OK.

Kurt.
 
Also it's an A15 block with a head designed for an A14, don't know if that makes any difference.
Even numbers all the way across is what really matters, and of course having more than 100lbs in all of them is good.
I could test again with the throttle closed to see if I get the 145's again and then test with WOT and see if I get 195 lbs.
They guys on Ratsun don't seem to think the numbers are out of line.
 
I may have read and forgotten, pardon if that is so, but what cam do you have in that A15?
 
Not sure, I didn't install the cam and I haven't looked at it.
Is there any easy way to find out?
 
You can just measure the movement of a valve or a rocker from closed to fully open and then add in the clearance for gross lift then divide by 1.5 (rocker ration) to get net (lobe) lift. Then compare against the cam specs at the Datsun1200 wiki and see what comes close.
 
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