No machine work on engine: stock headgasket or MLS?

[soldave]

OK, as part of my rebuild I'm obviously going to need a new headgasket, and am currently working out which one. Okinawa (where I live) has no machine shops to speak of and I don't want to send the head or block away to either the mainland or the States for machinework as this is pretty much a stock rebuild. Question is, what type of headgasket should I use?

It currently has a 1.2mm HKS one in there from the previous owner, but I know that a MLS headgasket really needs a machined finish to seal properly. Am running a T04B 50-trim and running 24psi of boost (spiking to 27psi) if that's any help. I'm also using ARP headstuds. Was thinking of getting a stock headgasket, cleaning up the block and head as much as I can and then torquing the headstuds to spec, but would appreciate any opinions from you guys.

 

[92AWDHX40]

Stick with stock if no work was done, it can hellp with imperfections using that gasket, mls require machined head and block if im not mistaken.

 

[donniekak]

I would use a composite type gasket. You may pull off a mls if you pass the fingernail test. If you can slide your fingernail all over the head with no catches anywhere it has a good chance of sealing. A used head stands a very small chance of not being dented, especially from using a mls before. It probably has indentations in it around the cylinders from the mls gasket. Of course check it for flatness.

 

[kahl23]

I wouldn't even bother with the MLS. AFAIK the issue isn't so much scratches in the head so much as it is slight warpage, and without a machine shop its hard to know for sure that your head is ok. I would just use a stock composite and go with the ARPs. That setup has worked for many people and is pretty much guaranteed to seal well. The only caveat is that it takes much less knock to blow the composite than a MLS.

 

[soldave]

Yeah, I think I'll just have to make sure my tune is ultra conservative and lose a little power for now. The only machine shop in Okinawa has the heads or blocks spinning around on a lathe!!!

 

[donniekak]

I wouldn't even bother with the MLS. AFAIK the issue isn't so much scratches in the head so much as it is slight warpage, and without a machine shop its hard to know for sure that your head is ok. I would just use a stock composite and go with the ARPs. That setup has worked for many people and is pretty much guaranteed to seal well. The only caveat is that it takes much less knock to blow the composite than a MLS.

A straight edege is pretty cheap. If i get a head that is warped at all i usually junk it. The problem with milling a warped head is that when you torque down a warped head it usually bends back to where it it almost straight and the cam journals line back up. When you mill it it doesen't flex when bolted down any more so the journals are out of line. It's usually cheaper to get another head than to have it milled and line bored. You can also have them heat relieved. I get them milled to clean them up before a mls, if it's warped i don't use it. I use a machinists straight edge and a .001" feeler gauge as a go, no go.

 

[soldave]

Was gonna post up here showing you the block after a bit of a clean with parts cleaner, but looking at the photos you can see that about 30 minutes after the clean a fine layer of rust was starting to develop! Yeah, that's what the rainy season does in Okinawa (30C and 92% humidity at the moment). Have doused everything in WD40 and covered it with a towel and will keep making sure it's fully coated with WD40 to try and keep the rust away. Damn oxidization...

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[92AWDHX40]

Looks good i would get a razor blade and clean off all the leftover material. I used brake parts cleaner when i had the block tore down. I used oem gasket with arps, thats a great combo for many dsmers around here. Just dont get carried away, and monitor your engine, for knock. You should be happy with the setup.

 

[toofast82]

Go with the composite like many have said! Combined with ARP head studs, it is a very capable setup

 

[DirtyBirdRacing]

I use a machinists straight edge and a .001" feeler gauge as a go, no go.

Hi,

Sorry to hijack your thread, but where did you get a percision straight edge like this? I have been looking for one for a week or so now so that I could check my block deck for flatness.

Thanks,
Bill

 

[donniekak]

Hi,

Sorry to hijack your thread, but where did you get a percision straight edge like this? I have been looking for one for a week or so now so that I could check my block deck for flatness.

Thanks,
Bill

I bought a 24" one from the machinist i use all of the time. It was only like $40.

 

[kahl23]

A straight edege is pretty cheap. If i get a head that is warped at all i usually junk it. The problem with milling a warped head is that when you torque down a warped head it usually bends back to where it it almost straight and the cam journals line back up. When you mill it it doesen't flex when bolted down any more so the journals are out of line. It's usually cheaper to get another head than to have it milled and line bored. You can also have them heat relieved. I get them milled to clean them up before a mls, if it's warped i don't use it. I use a machinists straight edge and a .001" feeler gauge as a go, no go.

FWIW we ran a head that had been warped through 2 resurfacings with no noticeable issues on the cam journals, nor any need to line-hone it. Eventually there was not enough material left on the head and it kept warping, so we scrapped it, but the cams looked fine when they came out. YMMV.

 

[slowgsr]

i used mls mitsu gasket twice on my stock 6 bolt with arp's and copper spray. no problems. gone 11.7 @ 123 on pump @ 24lbs on a s258. A friend with a 2.4L in a neon (similar to our engines), does the same thing, mls w/copper spray and arp's no problems. He also runs over 20lbs. Both no machine work to block or head.

 

[soldave]

Well I have the composite one and hopefully in the next few days the head might be put back on. Then it's just a matter of seeing if everything holds up.

 

[tsiAWD91x]

Well I have the composite one and hopefully in the next few days the head might be put back on. Then it's just a matter of seeing if everything holds up.

GOD your going to hate your self later. Did i mention your goin to hate your self later? . you should take the time and do it right this time. try and do your best to find a machine shop or get an idea what it would cost to ship it.Composite or not you should resurfaced at least both block and head and hone (bottle or stone). this would be bare min. Other stuff should be done to provent bearing wear and logitivity. Im not trying to FLAME in anyway and i wish the best for you but im just saying from experience.
wish ya best of luck bro! if ya need some help id be glad to

 

[soldave]

GOD your going to hate your self later. Did i mention your goin to hate your self later? . you should take the time and do it right this time. try and do your best to find a machine shop or get an idea what it would cost to ship it.Composite or not you should resurfaced at least both block and head and hone (bottle or stone). this would be bare min. Other stuff should be done to provent bearing wear and logitivity. Im not trying to FLAME in anyway and i wish the best for you but im just saying from experience.
wish ya best of luck bro! if ya need some help id be glad to

As I said in my original post, there are pretty much no machine shops in Okinawa. And I didn't fancy sending my head up to mainland Japan for machinework ($1000+) or the US (with high shipping costs from here), and as this is a stock rebuild I'm just doing what I can with what's available.

 

[90rslaser]

if you have a machined head(resurfaced), then you can use a cometic gasket. many have done it, and many succeded. mls gasket with resurfaced head plus arp's equals great setup!

 

[soldave]

if you have a machined head(resurfaced), then you can use a cometic gasket. many have done it, and many succeded. mls gasket with resurfaced head plus arp's equals great setup!

Thanks for the advice but read the thread title! I could not have a machined head or block.

 

[bling5tatus]

Man, you'll be fine w/ composite hg and head studs... the composite gaskets are MUCH more forgiving than MLS... plus as an added benefit when you have shit go wrong in your combustion chamber, it blows the gasket and not melts a piston or breaks your ring lands. I'd MUCH rather change a head gasket than pull a block so that's fubard from a broken ringland or cracked piston.

MLS is good for some people but they will not be the weakest link when your motor gets pre-ign knock. Composite will not hold up to knock as much and will blow easier, but like I said, I'd much rather be changing a head gasket than pulling a block. Of course people will not agree with me on this, but that's their opinion vs. mine.

 

[dsm-onster]

^^^ completely agree. I'd rather crack a head gasket from 4 counts of knock; instead of the counts to continuing to 8 and crack a ringland.

GOD your going to hate your self later. Did i mention your goin to hate your self later? . you should take the time and do it right this time. try and do your best to find a machine shop or get an idea what it would cost to ship it.Composite or not you should resurfaced at least both block and head and hone (bottle or stone). this would be bare min. Other stuff should be done to provent bearing wear and logitivity. Im not trying to FLAME in anyway and i wish the best for you but im just saying from experience.
wish ya best of luck bro! if ya need some help id be glad to

The RIGHT way to do a motor is to put on a combination of parts that is successful with the right technique. Successful parts are ARP head studs and a composite gasket. The right technique for installing a composit HG is simply to clean the surfaces and torque the bolts/s stud correctly.

If the rod journals are fine, why does he need a machine shop? If the mains arn't damaged why does he need to pull the main bearings? WRT even honing? Click. It's all opinion, but I've still swapped in new rod bearings on a good crank in a block that had no main bearing issues. Then installed rings where the crosshatching was still good on the cylinders with out a hone or bore. And the compression was at or above factory spec every time for all 7 times This last motor has seen over 30psi with an hx35 for over a year now, VERY frequently driven.

 

[tsiAWD91x]

^^^ completely agree. I'd rather crack a head gasket from 4 counts of knock; instead of the counts to continuing to 8 and crack a ringland.



The RIGHT way to do a motor is to put on a combination of parts that is successful with the right technique. Successful parts are ARP head studs and a composite gasket. The right technique for installing a composit HG is simply to clean the surfaces and torque the bolts/s stud correctly.

If the rod journals are fine, why does he need a machine shop? If the mains arn't damaged why does he need to pull the main bearings? WRT even honing? Click. It's all opinion, but I've still swapped in new rod bearings on a good crank in a block that had no main bearing issues. Then installed rings where the crosshatching was still good on the cylinders with out a hone or bore. And the compression was at or above factory spec every time for all 7 times This last motor has seen over 30psi with an hx35 for over a year now, VERY frequently driven.

your right eveyrone has an opinion. ME i tend to be annal and going back to the mains and what not i can bet they wern't measured to check for spec. (not knockng dave at all) I think it all falls down to if you know what your doing or not. someone with experience and the right micro kit can measure all specs to see if they are within tolerances. DEFF not an average joe type of task here. The MLS gasket on the other hand you cant be more safe then to deck both of your surfaces..(why not?! its appart) its deffantly insurance but hes not going with that anyway so nevermind. And my post above (i appreciate you looking to it that way i really didnt think of it that way) was just trying to seer him in the *right direction* technically if you have a motor appart (i feel strongly about this) you should hone/bore-line bore-head inpeciton-recond rods (if used) hot tank and deck-ballance assembly.. again you cant go wrong with doing it that
way but its alot more $$$$ i appreciate the concern dsmonster.prob should of worded my last post diff tho good call


sorry dave not tryin to yank your post here forgive me bro

 

[dsm-onster]

No big deal. Just wondering why you might think a crank has to be mic'ed if it ain't nicked . Anal or not, if the mains arn't contacting the bearing before you tear it down, then why would they contact after?

 

[tsiAWD91x]

No big deal. Just wondering why you might think a crank has to be mic'ed if it ain't nicked . Anal or not, if the mains arn't contacting the bearing before you tear it down, then why would they contact after?

was refuring to the block mains, not crank btw.. and the rod bores (just as important though) (i once bought a crank from SBR and it was out of round thank GOD i check i had to send it back) Anyway somtimes over time esp on high milage motors (beaten) the mains get out of round *leading* to failure even though that might look decient coming out spec wise, they could be very close to spec failure, more less rod bores then mains though. i was says before i always check the stuff even though they look good ya kno