3b to 3bt, head gasket not sealed (1 Viewer)

[bj70bc]

I have a post on this in the diesel section but wanted to ask a more general audience about head gaskets not sealing and what might be the cause.
I put a turbo on so I did all the head related preventative maintenance
The coolant overflow bottle is bubbling and water temps are trying to overheat upon driving.
The new head was decked, precups set at 0 protrusion, clean surfaces, MLS head gasket was used, multi stage torquing procedure from the center out,
maybe i used too much oil on the head bolts?
maybe should have used the copper gasket spray?
maybe somehow damaged the head gasket on install?
Any thoughts?

 

[Behemoth60]

I trust the head was checked for cracks. The 3B head has two weaknesses.... if they overheat, the casting between the intake and exhaust valves can crack. The water passages are poorly designed for extracting heat, making them prone to overheating in Turbo'd applications. The aftermarket so-called 'High Nickel' Heads, in addition to having a bit better metallurgy, also improved the coolant passages for better heat extraction. The stock heads also have pretty rough intake and exhaust port castings, and I believe they benefit greatly from a good port polishing to improve air flow and resulting heat extraction out the exhaust rather than heat soaking the head through the rough exhaust ports. The factory sized ports in the pre-cups are also itty bitty compared to the mass of air that needs to flow in and out of those teeny holes, which we are effectively doubling when running a turbo at 14 psi, and all that air needs gets heated as it compresses to get through that tiny pre-cub hole. I also advise opening up those pre-cup holes a bit.
The one thing you didn't mention was whether the block was decked? Maybe it was not flat?
I would re-check the torque on all the head bolts, and then maybe over-torque them some... maybe 15-20% more torque than the manual calls for.
If that doesn't work, I would remove the head for another look-see, and another head gasket. I've never heard of it... but it's theoretically possible you got a defective MLS gasket, I suppose.
It's also possible you've got a stretched head bolt. Most people (me included) just re-use our head bolts. Maybe find some new head bolts. Has anyone ever figured out if there is an ARP stud kit that will work on the 3B? I am not sure of that.

^^^^
All the reasons I never recommend turbo'd 3B's to anyone anymore.

 

[bj70bc]

Thanks,
yes, it got a new head, and the head was decked but the block was left alone, the precups were slightly ported and polished.
im starting to consider doing an exhaust gas test to see if the bubbles in the overflow are from boiling or combustion pressure, maybe a bad rad cap.....

 

[lacalvette]

Is the engine had this trouble before removing the head?
To me, sound like a seating issue. Bubbling in coolant, exhaust gaz reach the coolant system…
If you remove the head, look for corrosion on the bloc, they have that spot with number(piston size??) in it which is not cover by the gasket (like it allow you to see the number)
On some engine these hole are very close to coolant passage and comb. Chamber, not that much on 3B but still.
I think the previous gasket type could allow some imperfections but the MLS can’t.
Like said above, these head develops cracks between valve (overheat, cycle), cracks can go as far as coolant..

 

[bj70bc]

The head gasket was only done to access the precups and to upgrade it to a mls one for the turbo.
Ill have a look for that on the block when i tear into it again.
the head was new and decked so it was pretty nice but the block was well cleaned and left as was, ill give it another level of cleaning this time i guess.
I think ill spray it with the copper gasket spay this time as well to perhaps help with some block surface imperfections.

I really hope that does the trick though.

If anyone has any tips for mls head gasket install and dealing with the block surface I'm all ears.

 

[bj70bc]

Just an update....
think i have the issue figured...
i originally bought a teiken HG, turns out the pos is 1.39mm instead of 1.5mm as the toyota one is supposed to be so when torqued down the head is most likely contacting the cylinder sleeve protrusion (fire ring) and not allowing full HG crush in the neighborhood of 0.2 mm....
Live and learn, its my own fault for not buying the toyota one...
on the upside i can tear the head down in record time and know the engine much better........
hopefully the new oem gasket seals up this time