Head Milling Question

[johnod]

Am rebuilding top end, GS1000S, and have found some head pitting.
The machinist has suggested surfacing/milling the head, it is mainly pitting not warpage.
Is there any reason this can't be done, as I see no mention of it in the manual.


If it can be done, how much can safely be removed, and is there then any need to make changes to valve train geometry, such as valve stem length etc.?


Thanks

[Big T]

It can be done.
As long as minimal amount is removed, nothing else needs to be done
You could degree the cams to be sure

I'm sure Greg T had some experience in this

[fastbysuzuki]

Am rebuilding top end, GS1000S, and have found some head pitting.
The machinist has suggested surfacing/milling the head, it is mainly pitting not warpage.
Is there any reason this can't be done, as I see no mention of it in the manual.


If it can be done, how much can safely be removed, and is there then any need to make changes to valve train geometry, such as valve stem length etc.?


Thanks

i had .006" skimmed of my head mainly due to pitting as I was going to use the muttilayered stainless steel head gasket.
and whilst I was there I put in new piston rings and I gave the valves a quick lap in and renewed the valve stem oil seals with Viton seals and re- shimmed the valve clearances . One thing to note is do not attempt to rotate the engine when there is no shim in the buckets.
you could give renewing the piston rings a miss if yours are ok
But I would recommend getting Oem Suzuki gaskets and not copy's though, not forgetting you will need a cylinder base gasket as the seal will / have broken and renew the tear drop orings
The was no problem with assembly regarding your question other than the valve timing mark may not precisely line up this is due to the head being skimmed. It is obvious if you are a tooth out though.

[johnod]

i had .006" skimmed of my head mainly due to pitting as I was going to use the muttilayered stainless steel head gasket.
and whilst I was there I put in new piston rings and I gave the valves a quick lap in and renewed the valve stem oil seals with Viton seals and re- shimmed the valve clearances . One thing to note is do not attempt to rotate the engine when there is no shim in the buckets.
you could give renewing the piston rings a miss if yours are ok
But I would recommend getting Oem Suzuki gaskets and not copy's though, not forgetting you will need a cylinder base gasket as the seal will / have broken and renew the tear drop orings
The was no problem with assembly regarding your question other than the valve timing mark may not precisely line up this is due to the head being skimmed. It is obvious if you are a tooth out though.

What's the multi layered head gasket, I've ordered a stock Suzi part number? The rest I'm doing already. Thanks.

[fastbysuzuki]

The older style head gasket was made out of an partly flexible compound the new style gasket is a multilayered steel gasket there is no need to put on any gasket sealer on that gasket it has an very thin layer coated on the surfaces which activates under heat.
The new head gasket should be the steel one unless the dealer you have ordered from has old stock in which case I personally ask for it to be changed for the new steel one.
one other thing is you do not use the oring that goes around the cam chain tunnel when using the steel gasket

[GregT]

The multi layer gasket appears to be the current OEM Suzuki replacement. It'll almost certainly be the type made for the late head with an extra stud in the front of the camchain tunnel. If your engine doesn't have this, it doesn't matter. use the gasket anyway.

Less than .010in off the head would be perfectly fine for a street motor using stock cam timing marks. It'll be a little off but you'll never notice.
More than that and I'd dial the cams.

[johnod]

The multi layer gasket appears to be the current OEM Suzuki replacement. It'll almost certainly be the type made for the late head with an extra stud in the front of the camchain tunnel. If your engine doesn't have this, it doesn't matter. use the gasket anyway.

Less than .010in off the head would be perfectly fine for a street motor using stock cam timing marks. It'll be a little off but you'll never notice.
More than that and I'd dial the cams.

Thanks, don't know anything about dialing cams, is that in the manual?
It's night here, and it's in the garage.

[GregT]

Thanks, don't know anything about dialing cams, is that in the manual?
It's night here, and it's in the garage.

Not in the manual. Several tutorials on line. I wouldn't bother if you're just having a very light skim done on the head.

[johnod]

Not in the manual. Several tutorials on line. I wouldn't bother if you're just having a very light skim done on the head.

At this time it's just an estimate, but, 10 - 15 thou.

That a problem?

[GregT]

No.........It's going to retard the timing fractionally. Only a dyno will be able to tell the difference.

[Nessism]

It's not necessary to remove all the pitting, just that around the critical sealing areas. The deepest pitting typically occurs in the vicinity of the stud holes because crud falls down. You don't need to remove all the pitting there and trying to do so won't add value to the process.

[johnod]

Thanks. again.

[johnod]

It's not necessary to remove all the pitting, just that around the critical sealing areas. The deepest pitting typically occurs in the vicinity of the stud holes because crud falls down. You don't need to remove all the pitting there and trying to do so won't add value to the process.

Frankly I was wondering what caused it.

[Steve]

When I went through my engine this past summer, the machinist took 0.002" off the top of the cylinder block and 0.009" off the head, for a total of 0.011". I did not take any measurements regarding cam timing, valve-to-piston clearance or anything like that, I just put the engine together. Could not tell anything different on how the engine ran, so I have to assume one of two things: 1. eleven thousandths less material does not really matter or 2. I got extremely lucky.

I agree that valve timing will be retarded just a bit. One of these days, I will take some measurements and do the math to see how many degrees.

.

[GregT]

When I went through my engine this past summer, the machinist took 0.002" off the top of the cylinder block and 0.009" off the head, for a total of 0.011". I did not take any measurements regarding cam timing, valve-to-piston clearance or anything like that, I just put the engine together. Could not tell anything different on how the engine ran, so I have to assume one of two things: 1. eleven thousandths less material does not really matter or 2. I got extremely lucky.

I agree that valve timing will be retarded just a bit. One of these days, I will take some measurements and do the math to see how many degrees.

.

Camchain stretch has a bigger effect....