rideglobally
Nullacruiser
- Joined
- Sep 16, 2007
- Threads
- 156
- Messages
- 1,279
- Location
- Los Angeles, California
- Website
- forum.ih8mud.com
Where can I purchase a MLS head gasket for a 12HT engine?
MLS gasket for 12ht
- Thread starter rideglobally
- Start date
This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.
I think mine came from ADS Injection in Australia.
- Joined
- Sep 28, 2002
- Threads
- 558
- Messages
- 8,122
- Location
- Kamloops, BC Canada
- Website
- www.shopraddcruisers.ca
I was the one who commissioned the pattern for these gaskets originally in 2014.
It was not for performance reasons, but because a machine shop screwed up my engine when they machined it, and a custom gasket was easier to do than tearing the entire engine down and having it sleeved to fix the errors.
If you want to see what happened, zoom in on the chamfer at the tops of the bores in the attached photo.
In general, I would suggest that the factory style head gasket - and proper head and block preparation- is going to be your best bet even if you’re pushing the boost up quite a lot.
My first MLS gasket failed at just under 100,000 kms. I’d already re-torqued the head bolts after about 8,000 kms as there was some slight pressurization of the cooling system.
I added 10 ft lbs to the Toyota FSM values, and this helped solve the problem for a long time.
Later it started to slowly seep coolant into the engine again and after driving it quite a lot like that, I replaced it with the second gasket I had made for this specific engine (custom bore sizes to account for the screwed up chamfer - see photo).
The second gasket has been in place for a year, but not much driving but it did go up north hunting last year towing a trailer and running about 15 psi with no issues. However, I did coat the second MLS gasket with several lights coats of copper spray prior to installing it to reduce the chance of coolant seepage.
Generally speaking, adding a coating to an MLS gasket is ill advised…
Note: if you have had your head and/or block shaved, it is critical to measure every bolt hole in the block to ensure that head bolts do not bottom out after comparing bolt hole depth to the stack height of the head + head gasket. Shave the bolts to allow for several mm to prevent bottoming out!! Use your longest bolt for the measurements.
Note 2: the head and block must be machined to an RA of 20-30 to successfully use an MLS gasket.
My advice is still to run the OEM style gasket and not an MLS gasket unless you have a very specific reason to do so on this particular engine.
~John
It was not for performance reasons, but because a machine shop screwed up my engine when they machined it, and a custom gasket was easier to do than tearing the entire engine down and having it sleeved to fix the errors.
If you want to see what happened, zoom in on the chamfer at the tops of the bores in the attached photo.
In general, I would suggest that the factory style head gasket - and proper head and block preparation- is going to be your best bet even if you’re pushing the boost up quite a lot.
My first MLS gasket failed at just under 100,000 kms. I’d already re-torqued the head bolts after about 8,000 kms as there was some slight pressurization of the cooling system.
I added 10 ft lbs to the Toyota FSM values, and this helped solve the problem for a long time.
Later it started to slowly seep coolant into the engine again and after driving it quite a lot like that, I replaced it with the second gasket I had made for this specific engine (custom bore sizes to account for the screwed up chamfer - see photo).
The second gasket has been in place for a year, but not much driving but it did go up north hunting last year towing a trailer and running about 15 psi with no issues. However, I did coat the second MLS gasket with several lights coats of copper spray prior to installing it to reduce the chance of coolant seepage.
Generally speaking, adding a coating to an MLS gasket is ill advised…
Note: if you have had your head and/or block shaved, it is critical to measure every bolt hole in the block to ensure that head bolts do not bottom out after comparing bolt hole depth to the stack height of the head + head gasket. Shave the bolts to allow for several mm to prevent bottoming out!! Use your longest bolt for the measurements.
Note 2: the head and block must be machined to an RA of 20-30 to successfully use an MLS gasket.
My advice is still to run the OEM style gasket and not an MLS gasket unless you have a very specific reason to do so on this particular engine.
~John
