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Tomei Head Gasket Questions

JustinP

By JustinP,
in Engines & Forced Induction

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JustinP Mentor

JustinP

Posted
Posted

A couple of quick questions :)

1) Is the RB25DET (R33) Tomei head gasket OK to use on an R34 Neo engine?

2) Is is definitely OK to use a 87mm bore head gasket on a 86.5mm bore engine? I guess this will drop the compression ration slightly.

3) Does the Tomei head gasket come with a oil restrictor, and what size is it?

Thank you!!!!

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The Dan Grand Master

The Dan

Posted
Posted

1. Yes

2. Definitely ok

3. I have never ever seen a restrictor come with a gasket and I have bought dozens. But the Tomei Oil Gallery Orifice is 1.5mm as stated above. Refer to the forced induction section for restrictor sizing depending on application and pump being used

Beer Baron Grand Master

Beer Baron

Posted
Posted

1. Yes

2. Definitely ok

3. I have never ever seen a restrictor come with a gasket and I have bought dozens. But the Tomei Oil Gallery Orifice is 1.5mm as stated above. Refer to the forced induction section for restrictor sizing depending on application and pump being used

1, I concur.

2. yes, doctor, I concur.

3. yet again, I concur. the restrictor orifice only comes in the tomei full gasket kits (ie the ones that come with MLS head gasket, exhaust gaskets, inlet gaskets etc. they include the oil feed restrictor. but if you just buy a head gasket on it's own, all you get is head gasket. need to buy a restrictor separately.

JustinP Mentor

JustinP

Posted
  • Author
Posted

Thanks to everyone for the quick replies :)

I will source the restrictor separately.

1, I concur.

2. yes, doctor, I concur.

3. yet again, I concur. the restrictor orifice only comes in the tomei full gasket kits (ie the ones that come with MLS head gasket, exhaust gaskets, inlet gaskets etc. they include the oil feed restrictor. but if you just buy a head gasket on it's own, all you get is head gasket. need to buy a restrictor separately.

JustinP Mentor

JustinP

Posted
  • Author
Posted

Arrgh one more question....

I presume the Tomei 1.5mm oil restrictors for the RB26DETT will also suit a RB25DET Neo??

Thanks :whistling:

Thanks to everyone for the quick replies :)

I will source the restrictor separately.

SargeRX8 Grand Master

SargeRX8

Posted
Posted

I'm just asking a noob question but why do you need the restrictor? Is this due to the head gasket change or something else? I thought you change the restrictor if you upgrade oil pump to maintain same flow in oil around the engine... Also noticed many different thicknesses for headgaskets. Does increasing the headgasket size increase bore capacity by that little tiny bit thus requiring a tweak up of the tune?

I'm not nit picking, I genuinely don't know.

Beer Baron Grand Master

Beer Baron

Posted
Posted

the oil feed restrictors are a good idea even with stock oil pumps. especially if your engine is going to see a lot of sustained high RPM use. as kiwi said even a stock oil pump running and long periods of high rpm will flood the head with oil.

as far as thicker head gaskets go they don't increase the bore diameter. they do slightly increase chamber volume which reduces squish and reduces compression ratio. you need to ensure you know what you're doing when chosing head gasket thickness so you get the characteristics you want.

Ramius83 Collaborator

Ramius83

Posted
Posted (edited)

I have actually just bought two Tomei 87mm bore 1.2mm thick RB26 head gaskets and both came with the Tomei 1.5m oil restrictor in the bag. Both head gaskets were bought about 6 months apart and came from two different vendors.

Edited by Ramius83
JustinP Mentor

JustinP

Posted
  • Author
Posted

Damnit!!! I just bought the head gasket and the restrictors separately.... And wasted $21 in the process... Nooooooo!! :)

I have actually just bought two Tomei 87mm bore 1.2mm thick RB26 head gaskets and both came with the Tomei 1.5m oil restrictor in the bag. Both head gaskets were bought about 6 months apart and came from two different vendors.

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