head gasket

this is the part number that the army order

and the part number is 8941458390

Quote:

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Originally Posted by DRanged

Thanks for the info mate. Mine seems to be very slowly pressurising at the moment but I will do some more tests. Sounds the same as yours though. I measure the intake pressure at the bend into the inlet manifold, where is your boost guage reading from???

Justin

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Same place, except I made my flange, its straight with silicon bend right angle:)

My ISUZU workshop manual says there are 3 DIFFERENT HEAD GASKET THICKNESSES!!!

You are supposed to measure the distance between the pistons and the block deck, and choose the head gasket according to the smallest measurement.

I can post the gasket markings/pns tonight if anyone wants them. My manual is for 4BD1 and 4BD1T, but doesn't mention any difference between na and t gaskets. AFAIK they are the same.

Don't use a composite head gasked, I have known several which have failed. The genuine ISUZU gasket looks like a bunch of thin stainless sheets sandwiched together.

Quote:

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Originally Posted by isuzurover

My ISUZU workshop manual says there are 3 DIFFERENT HEAD GASKET THICKNESSES!!!

You are supposed to measure the distance between the pistons and the block deck, and choose the head gasket according to the smallest measurement.

I can post the gasket markings/pns tonight if anyone wants them. My manual is for 4BD1 and 4BD1T, but doesn't mention any difference between na and t gaskets. AFAIK they are the same.

Don't use a composite head gasked, I have known several which have failed. The genuine ISUZU gasket looks like a bunch of thin stainless sheets sandwiched together.

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if you could post any numbers that would be great. Do you measure all the pistons at their TDC and take the smallest measurement??

Thanks justin

Quote:

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Originally Posted by DRanged

if you could post any numbers that would be great. Do you measure all the pistons at their TDC and take the smallest measurement??

Thanks justin

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Yep - that's what the manual says.

Will try and post this evening.

It'll only vary compression..........marginally

Be good if you could post details Ben:)

Quote:

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Originally Posted by rovercare

It'll only vary compression..........marginally

Be good if you could post details Ben:)

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Might be more to do with varying the valves marginally:p

Quote:

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Originally Posted by 100I

Might be more to do with varying the valves marginally:p

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WAAAAYYYYYY to much clearance for that to happen;)

The head bolts for the 4BD1-T are tightened differently to the 4BD1.

For 4BD1:

lubricate bolts with engine oil
1st step - tighten bolts to 6.5 to 7.5 kg-m (47.0 to 54.2 ft lbs)
2nd step - if new bolts, tighten to 9.5 to 10.5 kg-m (68.7 to 10.5 ft lbs)
- if re-used bolts, tighten to 11.0 to 12.0 kg-m (79.5 to 86.8 ft lbs)

For 4BD1-T:
lubricate bolts with molybdenum disulfide (MoS2) grease
1st step - tighten bolts to 7 kg-m (50.6 ft lbs)
2nd step - tighten to 9 kg-m (65.1 ft lbs)
3rd step - tighten a further 90 to 120 degrees rotation

If using more boost, I would recommend tightening to the 120 degrees rotation.

Edit: to convert kg to N (Newton) multiply kg by 9.81

OK, Page 6A-107 of the manual (N series, 1985 on).

You need to measure piston PROJECTION from the block deck - at the FRONT AND BACK of the engine (i.e. both sides of a line connecting the piston centres).

3 Grades of Gasket - A,B,C - A has 1 notch, B has 2, C has 3 (in the side of the gasket)

A= 1.55mm B=1.6mm C=1.65mm

Projection MUST be between 0.688-1.000 mm

Max. Piston Projection between 0.688-0.770 Use gasket A
Max. Piston Projection between 0.771-0.812 Use gasket B
Max. Piston Projection between 0.813-1.000 Use gasket C

Sorry but I don't have PN's.