[Mk2] [Turbo] Best headgasket

[badgerbob]

Ongoing with my forged engine build... Looking into what other peoples preferences are to choice of head gasket, engine will be running 9.0:1 cr pistons alongside a water meth kit.

Power output will be approx 400-450 at the wheels

So far Iv seen....

TRD gasket
Cometic gasket
HKS gasket and a few more...

For those running similar power or are in the know how, could anyone aid some advice to the best choice?

Many thanks

[pistol pete]

toyota metal standard rev3 gasket...

its what was recommended to me by peter gidden, and pretty sure he uses it in all his big builds...

[badgerbob]

To be honest i was hoping someone would say that as the standard gasket is quite literally half the price lol, what sort of power are you running pete if you dont mind me asking and how many miles have you covered since?

Cheers

[Gary ST165]

....also consider the Toyota Caldina GT-T ST215 multilayer steel headgasket = generation 4 of the 3SGTE







http://www.gt4dc.co.uk/forum/viewtopic. ... 5&start=15


Cheaper and slightly thicker (1.23mm when compressed) >>> than the ST205 /SW20 rev3 gasket (1.14mm)

Last time i checked these were RRP £41.42 + VAT





hth

[badgerbob]

As stupid as this may sound but would that fit without modification?

[Gary ST165]

Judge for yourself


ST215



vs.

OEM = SW20 rev3 / ST205
TTE = SW20 rev1&2 / ST185




ST205 / SW20 rev3 Cylinderhead




Perhaps one of the clubs more experienced engine builders will be able to tell if the alignment of gasket waterways and oil ways present any issues regarding coolant or oil flow between block and head. I can't see any...

[bobhatton]

Ongoing with my forged engine build... Looking into what other peoples preferences are to choice of head gasket, engine will be running 9.0:1 cr pistons alongside a water meth kit.

Power output will be approx 400-450 at the wheels

So far Iv seen....

TRD gasket
Cometic gasket
HKS gasket and a few more...

For those running similar power or are in the know how, could anyone aid some advice to the best choice?

Many thanks

What piston to head clearance have you designed for?
How far down the bores are the pistons, or do they come up above the block face.

So much more to it than just what make to use.

I take it you will be using racing fuel to get that power with that compression ratio.

[badgerbob]

Pistons are the same spec as these...

http://www.wiseco.com/PDFs/Wiseco-Toyot ... tonKit.pdf

I wont be using race fuel due to its availability but as mentioned il be incorporating a meth/water system to stop any det within the engine, Having read several projects over the years its quite amazing the overall effect it has on reducing cylinder temps. I know this limits me on boost pressure but with the correct set up Il hope to achieve roughly the quoted figures at approx 1.5 bar (wont be going higher than this for obvious reasons).

wether the piston will rise above the block I admittedly assumed that there would be enough clearance not too, I cant find anywhere with dimensions to work from to compare figures??? Untill Im at the point of rebuilding it Im not sure how else to accuratey measure though i agree that will need to be taken into consideration

essentially is there a way to calculate the above so i could order a headgasket the right thickness which can compensate for both compression and clearance?
I appreciate the help and open to any suggestions

[ashley]

The more I find out about modern race engines the less I buy the conventional thinking that more boost means you must lower the compression ratio. The latest engines I've seen are 11.5:1 and running 2 bar for endurance racing (mapped to 2.5bar), and no- they are not melting their exhaust manifolds.

But- they do have direct injection, maybe that's the key.

As for head gaskets, as Bob says- you need to understand what clearance you need between the head and the block. FWIW I've got an HKS gasket on mine, but only cos there was one on the shelf in my engine builder's workshop.

You can measure the volume of the cylinder head combustion chamber, and likewise the volume of the piston face at TDC- that will let you calculate your CR, but tbh it's not ideal to use a super thick gasket to drop your CR too much...I'd stick with what you have.

If you haven't decked your block, or skimmed too much of the head then the Wiseco pistons will go straight in without clearance issues. And if you haven't removed too much material from your cylinder head combustion chamber then you're resulting compression ratio will probably be in the region of 8.8:1 (based on two of my builds I was 8.7:1 with a worked head and 9:1 Wiseco's).

With that in mind you could go for a slightly thicker gasket to drop it slightly, or just shop on price...

[h20490]

Ive gone for a 1.5mm Cometic on a rev 2 block with a known head rebuild before I just re did it. so far so good running a bltiz access ecu

[badgerbob]

The more I find out about modern race engines the less I buy the conventional thinking that more boost means you must lower the compression ratio. The latest engines I've seen are 11.5:1 and running 2 bar for endurance racing (mapped to 2.5bar), and no- they are not melting their exhaust manifolds.

But- they do have direct injection, maybe that's the key.

As for head gaskets, as Bob says- you need to understand what clearance you need between the head and the block. FWIW I've got an HKS gasket on mine, but only cos there was one on the shelf in my engine builder's workshop.

You can measure the volume of the cylinder head combustion chamber, and likewise the volume of the piston face at TDC- that will let you calculate your CR, but tbh it's not ideal to use a super thick gasket to drop your CR too much...I'd stick with what you have.

If you haven't decked your block, or skimmed too much of the head then the Wiseco pistons will go straight in without clearance issues. And if you haven't removed too much material from your cylinder head combustion chamber then you're resulting compression ratio will probably be in the region of 8.8:1 (based on two of my builds I was 8.7:1 with a worked head and 9:1 Wiseco's).

With that in mind you could go for a slightly thicker gasket to drop it slightly, or just shop on price...

Cheers for the detailed response buddy much appreciated , The donor engine I have stripped came as a running low mileage engine with no faults and 170psi across all 4 cylinders so I'm hoping no machine work will be needed on the head or block. Albeit this could all change when i get round to giving it a closer inspection but for the time being I'm planning on it being OK for that reason I'm assuming the clearance should be OK and the pistons will drop in with no issues as you suggest

Thinking my best option will be to hang fire on ordering the gasket until I have it all assembled, then as you say measure accurately all the above discussed and go from there, Most likely (provided I have the clearance) I'll stick to the standard thickness OEM gasket and proceed with my intended CR seeing as its provided in the engine gasket kit.

By no means am i trying to build a low budget engine but having heard great things about peter Giddens builds and aware of the fact at times you pay for Brande names. I cant see his knowledge on gasket choice and experience being wrong. cheers for the shout Pete.

Are there any other peeps out there running high power on the stock rev 3 tubby gasket?

And also cheers to others for putting in their input and experience, much appreciated

[bobhatton]

The more I find out about modern race engines the less I buy the conventional thinking that more boost means you must lower the compression ratio. The latest engines I've seen are 11.5:1 and running 2 bar for endurance racing (mapped to 2.5bar), and no- they are not melting their exhaust manifolds.

But- they do have direct injection, maybe that's the key.

Yes that is why they can run at 11.5:1 or even higher, you cannot have detonation with no fuel. Being race engines they may well not be run on road fuel.

[bobhatton]

Cheers for the detailed response buddy much appreciated , The donor engine I have stripped came as a running low mileage engine with no faults and 170psi across all 4 cylinders so I'm hoping no machine work will be needed on the head or block. Albeit this could all change when i get round to giving it a closer inspection but for the time being I'm planning on it being OK for that reason I'm assuming the clearance should be OK and the pistons will drop in with no issues as you suggest

Thinking my best option will be to hang fire on ordering the gasket until I have it all assembled, then as you say measure accurately all the above discussed and go from there, Most likely (provided I have the clearance) I'll stick to the standard thickness OEM gasket and proceed with my intended CR seeing as its provided in the engine gasket kit.

By no means am i trying to build a low budget engine but having heard great things about peter Giddens builds and aware of the fact at times you pay for Brande names. I cant see his knowledge on gasket choice and experience being wrong. cheers for the shout Pete.

Are there any other peeps out there running high power on the stock rev 3 tubby gasket?

And also cheers to others for putting in their input and experience, much appreciated

There is so much more to this than just bolting a box of part together.

As you say wait and get the gasket after one of your trial builds and measurement.

[badgerbob]

Cheers for the detailed response buddy much appreciated , The donor engine I have stripped came as a running low mileage engine with no faults and 170psi across all 4 cylinders so I'm hoping no machine work will be needed on the head or block. Albeit this could all change when i get round to giving it a closer inspection but for the time being I'm planning on it being OK for that reason I'm assuming the clearance should be OK and the pistons will drop in with no issues as you suggest

Thinking my best option will be to hang fire on ordering the gasket until I have it all assembled, then as you say measure accurately all the above discussed and go from there, Most likely (provided I have the clearance) I'll stick to the standard thickness OEM gasket and proceed with my intended CR seeing as its provided in the engine gasket kit.

By no means am i trying to build a low budget engine but having heard great things about peter Giddens builds and aware of the fact at times you pay for Brande names. I cant see his knowledge on gasket choice and experience being wrong. cheers for the shout Pete.

Are there any other peeps out there running high power on the stock rev 3 tubby gasket?

And also cheers to others for putting in their input and experience, much appreciated

There is so much more to this than just bolting a box of part together.

As you say wait and get the gasket after one of your trial builds and measurement.

Indeed buddy, May have slightly overlooked it

After researching most part of last night I came up with the following dimensions that i should expect to have come rebuild time:

Bore of cylinder = 86mm
Stroke of cylinder = 86mm
Compression height = 35.05
Dome volume = -6cc (dish)
Combustion chamber volume 49.5cc
Rev 3 gasket thickness = 1.14mm (thanks Gary)
Rev 3 gasket bore = 87mm
Piston deck clearance = 0mm

Going from the above the final compression ratio from that set-up should be 9.021544114708627:1 .....or 9.0:1 as I was expecting

soooo.....

Using the same data as above and selecting a thicker gasket to compensate the higher compression, I would require a gasket thickness of approx 1.8mm

Putting this into the equation

1.8mm equals a CR of 8.546132806709904:1 .....or 8.5:1 basically standard compression levels.


Now assuming the above is correct would that thickness of gasket (1.8mm) have any cons in strength compared to the standard thickness?

I.e would it be less reliable?

Personally for such a small difference and working with gaskets everyday I cant see an issue...But the industry i work in uses very different types of gasket and for a different purpose, which pretty much voids my experience

Input and help more than welcome

[badgerbob]

P.s will using a thicker gasket have any dramatic effect on the cam timing? That isn't so much an issue as the build is planned with vernier pulleys but would be nice to know in advance

[ashley]

Rev 3 gasket thickness = 1.14mm (thanks Gary)


I would require a gasket thickness of approx 1.8mm

Is the standard gasket 1.14mm once you have torqued down the head, or before you fit it?

My initial feeling is that 1.8mm is a big step to use a gasket to make up- how thick would it need to be before instal to squash down to 1.8mm?

Would the increased gap affect squish? I don't know- but those are the sort of questions I would be asking

[ashley]

Sounds like your calc's are pretty much spot on, have a read of this:

http://www.mr2oc.com/showthread.php?t=366753&page=1

[badgerbob]

Rev 3 gasket thickness = 1.14mm (thanks Gary)


I would require a gasket thickness of approx 1.8mm

Is the standard gasket 1.14mm once you have torqued down the head, or before you fit it?

My initial feeling is that 1.8mm is a big step to use a gasket to make up- how thick would it need to be before instal to squash down to 1.8mm?

Would the increased gap affect squish? I don't know- but those are the sort of questions I would be asking

Il have a standard headgasket included in the complete engine gasket kit< ill measure up that and compare the difference pre squish and after squish , I know that the compressed thickness should be 1.14 so I should be able to take that into account


In regards the calc's, I'm awaiting the admin to accept my registration so I can check that link, shouldnt be too long but cheers again

[badgerbob]

Just had a chance to check out that link found this a bit interesting which was a link listed on that thread to where pistons could be bought

Wiseco Forged Pistons - $499.99
(Comes with Rings, Pins, and Locks - Skirt Coating comes Standard)

Part Numbers:
K615M86 // 3sgte // Bore: 86.00mm (Standard Bore) // Compression: 9.0:1
K615M865 // 3sgte // Bore: 86.50mm (+.020" Overbore) // Compression: 9.0:1
K615M87 // 3sgte // Bore: 87.00mm (+.040" Overbore) // Compression 9.0:1
(compression rated assuming an aftermarket 1mm [.040"] headgasket thickness, compression is 8.5:1 with a standard headgasket thickness)

Soooo, throws another bunch os panners in the works A good link though cheers bud, nice to know i wasnt too far wrong . Proof of the pudding will be when i measure everything accurately

[ashley]