TD42 head gasket .........what size ?

Submitted: Thursday, Mar 13, 2003 at 15:03
ThreadID: 3830 Views:7709 Replies:5 FollowUps:6
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Hi All,
I have asked Nissan dealer to get a head gasket for my GQ TD42 93.
They ask me what size do I want as they showed three different thickness (1.15, 1.2, 1.25) and quote $92.8 each
I was quite hesitate to choose as I have no idea which one will suit.
Then, a senior manager suggested me to get the thickest one 1.25 considering the age of my car.

At the end I didn't choose as I was still not yet confirmed.
Why does old car need a thicker gasket comparing to younger car? Why don't they just use same thickness of all gasket ?

Anyone can help?
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Reply By: Truckster - Thursday, Mar 13, 2003 at 16:59

Thursday, Mar 13, 2003 at 16:59
The older the motor the thicker you want..

Thicker lowers the compression slightly, which helps crank pressure etc on an older motor.
AnswerID: 15098

Follow Up By: kezza - Thursday, Mar 13, 2003 at 23:08

Thursday, Mar 13, 2003 at 23:08
Are you sure truckster???

When this rig is back together and not running right are you gonna pay for another head job to get it right??

I know you just had to say something but to make an unqualified statement like that will really undermine your credibility with the groupies!!

I suggest iamgq finds out if the head has been shaved and does a lot more homework before selecting a gasket let alone whatever else is getting done to the donk.

We dont want to alter the the compression ratio do we??


FollowupID: 9187

Follow Up By: Truckster - Thursday, Mar 13, 2003 at 23:29

Thursday, Mar 13, 2003 at 23:29
if he is just putting a gasket on to his old unrebuilt engine with 250,000klms on it, then its gonna be worn a fair wack aint it.

Unless you get a micrometer onto the gasket you are going to change the compression arent you... you are only given 3 sizes to play with...

If you want more compression adn want to wear out the engine, then go with the thin one....

to me its just common sense.
FollowupID: 9195

Follow Up By: kezza - Friday, Mar 14, 2003 at 19:21

Friday, Mar 14, 2003 at 19:21
glad u dont fix anything of mine,with that sort of common sense truckster

FollowupID: 9250

Follow Up By: Truckster - Friday, Mar 14, 2003 at 23:06

Friday, Mar 14, 2003 at 23:06
Why what doesnt make sense?

Old motor needs all the help it can get, so dont up the compression for no reason. You up the compression you risk blowin seals and undue stress.

If its a rebuilt motor, then u would go with measuring it up, and do it that way.
FollowupID: 9262

Follow Up By: kezza - Saturday, Mar 15, 2003 at 01:30

Saturday, Mar 15, 2003 at 01:30
obviously the different size gaskets are for varying changes to head size due to head machining. There is no need to drop compression on a diesel just because its old. Usually if the head is off a diesel its being rebuilt anyway - a change in compression is not gonna make the motor die any sooner or later- if its that close to 'death' - why not rebuild it ?????????????????
Sorry truckster I know you are not a mechanics bootlace but there are no 'seals' you need to worry about when looking at the compression in the cylinders - only the rings and beleive me when they are shot - he'll replace them
just stick to topics you know some thing about and dont confuse people.

I really didnt want to say any more about this but it seems that you need to have an opinion on things wether you know jack about it or not - not good for your credibility.

I believe you chase up some good info at times and help people heaps but to quote an old cliche " a mans gotta know his limitations"

Honestly I can see your heart is in the right place but sometimes you just loose all credibility by shooting off your "keyboard".

with due respect


FollowupID: 9270

Follow Up By: kezza - Saturday, Mar 15, 2003 at 01:56

Saturday, Mar 15, 2003 at 01:56
As an aside you will at least be impressed to know that on the subject of tyres - which I know you and I have differed on at times in the past.

A good friend and I are trialling the goodyear MTR alongside the BFG Mud terrain so as to give a totally unbiased ( yes I know thats very rare these days) comparison between the 2.

The MTRs will be fitted to a 4.2 TD GU Patrol next week and I will objectivly report as we find out how the 2 compare.

The GQ with the BFG MTs will be doing the simpson, strezleckie and birdsville tracks soon (may)
I might add that the "only" reason that the MTRs are being used on the GU are that you have convinced me that they are worth a look and I am a compulsive reseacher and really like to know what are the ideal products in the market place.Also I have since spoken to at least 2 happy MTR users that feel that they are performing well offroad and on wet bitumen.

However. I still feel that a lot of people who take on an all terrain tyre in the misconception that they will perform safely in the wet need to look at this new generation of "soft compound" offroad tyre.

I will not be offering opinions based on what 'others' have said but on what I actually see and experience with these tyres (yes I know thats rare too)

By the way I can get them (mtr's) for $275 each (for 16' rims)

more to come on this


FollowupID: 9273

Reply By: sensei - Friday, Mar 14, 2003 at 00:54

Friday, Mar 14, 2003 at 00:54
You will need to measure the head thinkness to be sure it has not been shaved before hand.
With the head upside down measure where the head gasket would normally seat and down to the valves with a depth mic. You may also need to measure the depth from the top of the block to the top of the piston at TDC. With both of these measurements you should be able to match head gasket thinkness from the manual. You dont really want to alter the compression ratio to much one way or the other. When a thicker gasket is used it would normally mean that the head has been shaved to keep the ratio STD or as close as you can.
A good WS manual or someone with a WS manual would be in order i think just to make sure you get it right first time.
AnswerID: 15163

Reply By: crfan - Friday, Mar 14, 2003 at 15:51

Friday, Mar 14, 2003 at 15:51
You should fit the same thickness gasket that came off it if you have the old gasket there should be some sort of mark or notch to tell the differance between them.
The Head Exchange has a web site you could email them and find out how to tell and they will be able to supply the gasket as well,
AnswerID: 15196

Reply By: Member - Robert- Saturday, Mar 15, 2003 at 01:42

Saturday, Mar 15, 2003 at 01:42
the different size gaskets are for how far the pistions are abovethe block so you have to messure all the pistons above the block 1 to 6 then go to the nissan dealer and tell him how far the pistons where above the block nissan then can supply you the right gasket

AnswerID: 15241

Reply By: Ken - Saturday, Mar 15, 2003 at 11:42

Saturday, Mar 15, 2003 at 11:42
Thanks for all you guys' feedback !
Going to bring my old one and get the same size. Really appreciate to all of yours opinions and quick responses.
AnswerID: 15254

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