I have a 97 Land Cruiser, 280,000 on it all original driven by one person. Finally got the oil in the antifreeze and minor exterior head gasket leaking at #6. Pulled motor to do a solid refresh and could use some advice to anyone with the head stud and MLS Cometic gaskets. I had the head machined and all the valves done so the head sealing with the Cometic is good but the block had some minor pitting. Give me your direction on if the Cometic will seal or if I should keep it original head gasket. And can head studs be used with a factory gasket or should I just go new head bolts. I plan on boosting it soon so I want to build it accordingly. Pulled a lower bearing while I was at it and they are like brand new, cross hatch is also intact and looks great.
Head gasket replacement advice
- Thread starter cruiserbrandon
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Head studs and oem gasket are perfectly compatible and many boost on the oem head gasket. The ARP studs are about the same price as discounted head bolts. Head bolts from the dealer are pushing $20 each and we all know studs allow for more even clamping, something you are interested in after you boost it.
If you go with studs, use the old oem washers as they have a slight thicker cross section and greater diameter.
It’s pretty much universally accepted that, to use an MLS gasket, you need to deck the block.
If you go with studs, use the old oem washers as they have a slight thicker cross section and greater diameter.
It’s pretty much universally accepted that, to use an MLS gasket, you need to deck the block.
Finally some nice high quality photos showing the details - well done. Seeing how nice the bearings on yours look at 280k it makes me feel better about mine at 300k.
- Thread starter
- #5
1 vote for oe stuff. Can I get a couple more chime in's
- Thread starter
- #6
Sorry Baldilocks must have been posting at the same time. I talked to the Cometic distributor and he advised to not use the ARP head studs unless I went with the MLS gasket because of the torque to yield. I personally think he is full of it but can anyone address that. BTW I am a Master Tech of 15 years experience and have probably 100 head gaskets under my belt but all the MLS gaskets that I have done are on very late model stuff that was in great shape. And usually all aluminum.
I used head studs like several other members here. No problems. Torque to 80lbft and forget them.
I was skeptical about not re-torquing but ARP told me to just follow the gasket makers instructions. Others have gone before us.
Nothing is stopping you from pulling the cams and performing a re-torque of the nuts on the studs if you want.
TTY head bolts were not invented because they are better but for ease of assembly at the factory.
@jcardona1 is a memeber I know of of who used this combo and never re-torque. I confered with him back in 2015 when I did mine.
I was skeptical about not re-torquing but ARP told me to just follow the gasket makers instructions. Others have gone before us.
Nothing is stopping you from pulling the cams and performing a re-torque of the nuts on the studs if you want.
TTY head bolts were not invented because they are better but for ease of assembly at the factory.
@jcardona1 is a memeber I know of of who used this combo and never re-torque. I confered with him back in 2015 when I did mine.
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I believe @scottryana did his with ARP studs. He should have some good input.
Also, the torque is DIFFERENT for the ARP studs VS the Toyota head bolts AND they have a different methodology. Ryan can give his input.
The old rule of thumb is OEM bolts with the fibrous OEM gasket and ARP studs with MLS gasket. Both have their positives and negatives.
OEM gasket will seal small imperfections better, but probably won't last as long.
MLS will take more abuse if you decide to get crazy with boost, but surface prep is key.
In my first boosted truck that routinely sees 15-16psi and as high as 19psi, I wasn't originally going to turbo it so it has OEM gasket and OEM bolts. In my big turbo build I have an MLX gasket set aside and ARP 625 studs. OEM will be fine for 95%+ users but really the decision is up to you and what your future plans are.
OEM gasket will seal small imperfections better, but probably won't last as long.
MLS will take more abuse if you decide to get crazy with boost, but surface prep is key.
In my first boosted truck that routinely sees 15-16psi and as high as 19psi, I wasn't originally going to turbo it so it has OEM gasket and OEM bolts. In my big turbo build I have an MLX gasket set aside and ARP 625 studs. OEM will be fine for 95%+ users but really the decision is up to you and what your future plans are.
ARP specs the torque value for their stud, which is 80lbft.
Depends on the stud, they also make an aged 625 which is 110ft/lbs, but yes you use their torque value for the particular stud you bought not the factory torque and 90 degree turns like OEM.
Question from the viewers.... if head studs are fitted can the head be pulled while the engine is still installed in the truck?
The studs are threaded in after head placement and removed prior to head removal with the block still in the frame. One end of the stud is keyed for and allen wrench.
OEM head gasket and bolts. Did mine. Similar miles as yours. Still have original hone marks on cylinders. No issues.
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- #15
TTY head bolts aren't necessarily better but they can handle the stretch of heat cycles better according to the Cometic guy I talked to. Again I think he's full of it so I ordered a factory head gasket and head studs. Lots of Supra guys have done that for years and it's never been an issue even with 30 psi of boost I'll be happy with 7psi or whatever the factory ECU will allow without piggyback or stand alone ECU.
Where did you order the studs from? Which kit did you order? I used this kit. https://paradiseracing.com/shop/engine-components/1fz-arp-head-stud-kit/
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I had the same issues as you. Pitted block at #6 cylinder maybe a little worse than you. Thought about taking a chance and slapping a new head gasket on and calling it good. I just didn't want to risk all that work for nothing. Pulled motor apart and had the head machined as well as the block surface. I had 175000 miles at the time and crank measured new at the shop so new OEM bearings were bought and installed. Can't remember how much I had taken off the block but there is a small window you can shave. If I remember correctly the shop took off .006 to remove pitting . Used factory everything on assembly and replaced wear items while I was in the motor. That was over 2 years ago and 30,000 miles ago and no issues. I'm happy with my choices. It was more expensive but it's been trouble free for me.
COMETIC MLS gaskets will not seal if both head and block arent machined to COMECTIC specs which is perfectly flat and smooth.
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- #20
1FZ-FE ARP Head Studs Installed with Part#
I referenced this article when I did my last build, it was a full build including bearings, crank and aftermarket pistons. I had the block Zero decked and ran a cometic with head studs and have had no issues. But it was a full build with an RA of 27 according to the machine shop. I just searched the part number for the arp studs and it took me to AMAZON being the cheapest. Pics are from the last build for reference of what a perfect finish looks like for a Cometic.
