2011 F115 TLR head machining

[tttraveler]

2011 F115 TLR torn down due to head gasket issue, took the head to the machine shop to get blocked and they indicated it took .013" to get flat. What is the max tolerance the head can be milled without issues with interferences with the valves/piston?

Don't want to continue down a bad path if it can't take that tolerance.

[boscoe99]

[tttraveler]

Thanks boscoe99 that says it all .0039 Looks like i have a paper weight.

[boscoe99]

I would talk to the machine shop about the use of a thicker gasket in conjunction with a cut of 0.013", before I condemned the cylinder head. Yamaha is overly conservative in my opinion.

Or maybe have your shop just shave off 0.003" and take a chance on a standard gasket getting the job done.

What happened such that the cylinder head needed to be removed in the first place? Over temperature event?

[tttraveler]

since my paper weight is what it is.....what is the difference between CYLINDER HEAD COMPLETE

68V-W009A-05-9S68V

And
CYLINDER HEAD ASSY

68V-11110-03-9S

there is no description beyond above is it a difference in the in the production run time? don't want to buy the wrong one. both are listed for this motor.

my serial # is 68V 1120512

[tttraveler]

May have stated w temperature along the way, but, started consuming massive amounts of oil blowing back through the breather. Literally had oil laying all the way through the intake system fouled plugs etc.

Cylinder walls look in really good shape

[boscoe99]

since my paper weight is what it is.....what is the difference between CYLINDER HEAD COMPLETE

68V-W009A-05-9S68V

And
CYLINDER HEAD ASSY

68V-11110-03-9S

there is no description beyond above is it a difference in the in the production run time? don't want to buy the wrong one. both are listed for this motor.

my serial # is 68V 1120512

Cylinder head assy is the head only. Cylinder head complete is the head plus a bunch of other parts. Valves, springs, seals, etc. Stuff shown in the box next to the cylinder head.

[brian3006]

So correct me if I am wrong here... but the OP has a warped head and is asking if it is alright to mill the head surface by .013 to get it back "true". The figure in post #2 (.0039) is the tolerance that the head can be warped across it.. We are assuming that it was beyond this point since the shop wants to take .013 off to get it squared up. The .0039 figure has nothing to do with how much can be milled off of the heads before clearance issues arise does it???
This is just taking .013 off of the head. It should be able to handle that without issues, shouldn't it? I always though it got questionable around .020 or so...

Again please correct me if I am reading this wrong

[99yam40]

I read that they already miller it down .013.
valve and piston clearance could be a problem with them hitting.

[boscoe99]

[QUOTE=brian3006;n238039]So correct me if I am wrong here... but the OP has a warped head and is asking if it is alright to mill the head surface by .013 to get it back "true". The figure in post #2 (.0039) is the tolerance that the head can be warped across it.. We are assuming that it was beyond this point since the shop wants to take .013 off to get it squared up. The .0039 figure has nothing to do with how much can be milled off of the heads before clearance issues arise does it???
This is just taking .013 off of the head. It should be able to handle that without issues, shouldn't it? I always though it got questionable around .020 or so...

Again please correct me if I am reading this wrong[/QUOTE

Yamaha does not address the milling of the head by any amount. They simply provide an in spec limit of 0.0039". Within spec, OK. Out of spec, replace the head.

I don't know, and don't know of anyone that does know, how much the head can be milled without something adverse happening.

[boscoe99]

I had not thought about a change in the compression ratio and any effect on the timing belt.

[99yam40]

I had not thought about a change in the compression ratio and any effect on the timing belt.

sounds like a solution for the OP.

but what does the +.020" refer to since it says the head gasket is .073" overall?

[ausnoelm]

I think you might be way over thinking this, machining the head such a small amount will not allow the valves to hit the piston....IF the timing is correct, if machining that amount off allowed that, the compression ratio would be so high that standard fuel would be unusable. Machining tolerance may be related to other possible "issues". Thicker gaskets were/are common to maintain factory specs and have been available for years for all sorts of engines.

[boscoe99]

Where have you been?

[zenoahphobic]

sounds like a solution for the OP.

but what does the +.020" refer to since it says the head gasket is .073" overall?

I assume it means the big holes in the gasket won’t be a problem with bores drilled out .020 to .060