Toyota I6 cylinder head questions

[user-9613590]

0,05 mm clearance on intake and 0,07 on exhaust.Any more and you working with WAG (just unbelievelable how sloppy the WV/Audi/Seat can be and still driveable!)
With real bronze quides I would tighten them to 0,03/0,05.
The original cast iron quides are fine;do not mess with them unless you have some real data that there is problem.Probably not.

[Kevin Johnson]

http://www.97supraturbo.com/1997%20Serv ... Engine.pdf Page EM 37. So, after comparing the 7M, 7MGTE, and 2JZGTE factory specs you now know they used the same clearance specs for NA and forced induction over two generations of engines. You will be wanting very specific reasons why you should deviate from those specs for your engine.

Good luck.

Bumping my own thread here again.


Ran over the FSM and found a "spec"

This combo will see 9500+ rpm and 1000+hp. Hoping the factory number is adequate.

Standard on intake is .025-.060
Standard on exh is .030-.065

Max on intake is .08
max on exh is .10

These values are metric (mm)

So from from a mechanical standpoint there is quite a range. I just dont know what to tell him to put me at.


(Ps. I promise im not padding my weak post count)

[ProPower engines]

On some of the serious turbo honda stuff I use .001" max on the intake and .0015 on the exhaust.
Inconell valves do not seem to grow as much as regular stainless but that said a honed valve guide will out last anything else so for what you are doing I would not accept a reamed guide as they always get bigger faster and seem to wear out.
And keep the valve seat width to .040" on the exhaust and .030-.035 on the intakes and the seats will last longer.

Sizes suggested in INCH measurements not milimeters

I agree with Pro Power, except I run them a little looser on the serious turbo 6mm stem stuff. .0012" intake, .0017" exhaust, especially if nitrous is involved. Definitely hone them to size. Most quality bronze guides come undersize so you can set the clearance yourself.

I would stay tighter on the intake just because the valve never see;s much heat and will not grow like an exhaust does.
I use .0008 to.001 on .341 stems in iron heads for circle track stuff with no issues on the intakes.The guide will get larger as the engine builds heat but with all the air cooling the valve I don't think it would be a problem.
My big issue with these little engines is seat and valve face concentricity. It the intake leaks that's real bad with a turbo thus the tighter guide sizing

But valve quality and stem straightness really show up when honing to fit valves for the 1st time I got some supposedly fresh ready to go World Windsor heads yesterday that some shop called honed guides so be ware that a baby flex hone run through the guides is not what they call a "honed guide job".

[RL]

The brand of the valves matter.

If they are a well known US brand you won't have a problem, but if they are an unknown brand - like from China - be careful because some of those manufactures use high expansion stainless, so you will need more clearance.

Your 6mm stuff won't expand as much as the 11/32 stuff we get, but we have to give the exh nearly 0.003" and run without seals just to stop them seizing.

You have a bucket and shim arrangement, so there is no thrust loads, and that means you can run looser without much detriment so long as the seals seal - not a problem with new seals -.

[Cubic_Cleveland]

I would stay tighter on the intake just because the valve never see;s much heat and will not grow like an exhaust does.
I use .0008 to.001 on .341 stems in iron heads for circle track stuff with no issues on the intakes.The guide will get larger as the engine builds heat but with all the air cooling the valve I don't think it would be a problem.
My big issue with these little engines is seat and valve face concentricity. It the intake leaks that's real bad with a turbo thus the tighter guide sizing

Always good to learn what other people are using for clearance and their results. Thanks.

But valve quality and stem straightness really show up when honing to fit valves for the 1st time I got some supposedly fresh ready to go World Windsor heads yesterday that some shop called honed guides so be ware that a baby flex hone run through the guides is not what they call a "honed guide job".

Agree 100%. It's always good for a laugh what some unscrupulous shops do and the stories they come up with. Too bad when a customer shows up at your shop hoping it can be fixed for cheap because they spent so much the first time.

[ProPower engines]

I would stay tighter on the intake just because the valve never see;s much heat and will not grow like an exhaust does.
I use .0008 to.001 on .341 stems in iron heads for circle track stuff with no issues on the intakes.The guide will get larger as the engine builds heat but with all the air cooling the valve I don't think it would be a problem.
My big issue with these little engines is seat and valve face concentricity. It the intake leaks that's real bad with a turbo thus the tighter guide sizing

Always good to learn what other people are using for clearance and their results. Thanks.

But valve quality and stem straightness really show up when honing to fit valves for the 1st time I got some supposedly fresh ready to go World Windsor heads yesterday that some shop called honed guides so be ware that a baby flex hone run through the guides is not what they call a "honed guide job".

Agree 100%. It's always good for a laugh what some unscrupulous shops do and the stories they come up with. Too bad when a customer shows up at your shop hoping it can be fixed for cheap because they spent so much the first time.

Beware that is only with valves that have .0002 or less runout on the stem and when using this tight of clearance the driver and crew must be aware that the engines must be brought up to temp before any hard use is seen.
Don't qualify stone cold in other words the temp must come up to give the exhaust guides a chance to grow bigger before denting the firewall with the right foot

[wyrmrider]

"Beware that is only with valves that have .0002 or less runout on the stem"

another reason to od hone the stems

[T-flow]

Have worked with several Race Teams and shops doing these 2jz's. If OP wants to get to his goal(pretty easy 1000hp), I hope the shop he is using is more competent than the machine shop. Good Luck

[SWR]

My point was that if you use the stock shop manual you will end up too tight with YOUR application

Not always. Have seen the other side of 800 hp on stock guide clearances, stock bore clearance, stock bearing clearances.... E85, 2JZ-GTE, 7500 rpm Pro drift use.. Lasted several seasons. Until idiots started playing with small wastegates...