123Rover50,s turbo install

**123rover50** · 25th August 2012, 06:40 PM

Originally Posted by DRanged

Spend the extra dollars on a new set of head bolts as well

Justin

The more I think of this the more I think you are right. I was not going to but how many times have they been reused.

I found another manual. NPR W4 1986- 1987
Isuzu Truck Of America IST-SVC-5136.

Their torque figures.

NA new 1st step 47 to 54.2 ft/lbs
2nd step 68.7 to 78

reuse 2nd step 79.5 - 86.8

Turbo 1st step 50
2nd step 65
3rd step 90deg to 120deg

With the old bolts I would do as Dougal said. With new bolts should I do the same or go for the turbo setup?

2nd step

**Dougal** · 25th August 2012, 07:20 PM

There are Isuzu methods are all a little different, but probably just rounding and conversion. This is from the US 4BD1T manual.

68Nm
85Nm
90 deg.

For 4BD1/6BD1 with the asbestos sandwich gaskets:
70Nm
90Nm
90deg.

With reused bolts:
70Nm
95Nm
115Nm.

I have reused my bolts many times and haven't had any issues. But I've also been using a different torque method which is hand-written in a book I have at home (where I currently aren't). IMO if the bolts inspect fine, then re-use them.

**123rover50** · 29th August 2012, 07:10 AM

Got th head off yesterday. Not blown as such but to my inexperienced eye it looks as if it may have been weeping for a while and the turbo just made it worse.
Any thoughts?

**c.h.i.e.f** · 29th August 2012, 11:48 AM

If anything I'd say the water corroded the gasket and it may have been enough to allow pressure to squeez through...Make sure the deck is spotless before installing everything

**123rover50** · 29th August 2012, 01:44 PM

Yes, there is pitting on some of the head bolts and around some of the holes in the block. Not near the cylinder though.
Still confused with head bolts. Why oil on NA and moly on turbo. Is it because turbo are angle torqued?
Our engines with turbo,s. Are they considered turbo or NA still.
This gasket is a sandwich with I suppose asbestos between the steel. I dont have the new one yet, will it be the same or all steel?

**Dougal** · 29th August 2012, 02:27 PM

Get thee a multi-layer-steel (MLS) head gasket and use the turbo bolting torques.
Your engine is turbo now.

**123rover50** · 31st August 2012, 01:40 PM

Here are pics of head and block
Do you think I should use Hylomar on the gasket to help with the pitting?

**123rover50** · 1st September 2012, 02:18 PM

New gaskets. Ended up with two. One Land Rover and one Isuzu. One didgit different in the part number.
Head bolts were a bit pitted too. Bought some more $50 the lot but have 12 point heads instead of 6.
Waiting on a 12mm 1.5 tap to clean out the threads.

**123rover50** · 5th September 2012, 05:12 PM

Degreased the head and block and gasket. Gave the latter a light squirt of Hylomar and bolted it up with new bolts with moly grease.
Went to 65 ft/lbs for the second stage.
Now turbo says go for 90 to 120 degrees.
I set the T.W. at the N.A. 2nd setting of 79 ft/lbs and this clicked at about 45 degrees.
OK do I leave it there or go for the turbo setting and crank on another 50 degrees or so?

**isuzurover** · 5th September 2012, 05:44 PM

Originally Posted by 123rover50

Degreased the head and block and gasket. Gave the latter a light squirt of Hylomar and bolted it up with new bolts with moly grease.
Went to 65 ft/lbs for the second stage.
Now turbo says go for 90 to 120 degrees.
I set the T.W. at the N.A. 2nd setting of 79 ft/lbs and this clicked at about 45 degrees.
OK do I leave it there or go for the turbo setting and crank on another 50 degrees or so?

Turbo settings.

Have a read of Bush65's posts about bolted joints. Much better to overtorque than under.

Thread: 123Rover50,s turbo install

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