How to Replace a Head Gasket: Petros method

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stefando
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My tercel:: The Caribou: 1983 SR5
Location: Norcal

Re: How to Replace a Head Gasket: Petros method

Post by stefando » Sun Oct 07, 2018 11:39 am

Really helpful.
Last edited by stefando on Mon Mar 25, 2019 10:35 pm, edited 2 times in total.
1983 SR5 Brown
Salmon River California

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
Location: Arlington WA USA

Re: How to Replace a Head Gasket: Petros method

Post by Petros » Mon Jan 21, 2019 5:31 pm

Heads up: I have added some new photos and edited the text on the procedures to add some recent experience. the changes are instructions for chasing the head bolts threads to get a good even torque up, with a home made thread tool (with pictures), and changing the recommendation for re-torquing the head gasket. and adding the recommendation to install a new thermostat as part of the head gasket replacement. it is not worth the risk of reusing the old t-stat.

Despite the marketing that the new gaskets do not need to be re-torqued, I blew the head gasket on my rebuilt engine at about 500-600 miles and spent Saturday replacing it on my new engine. On the replacement head gasket, I ran it for 20 min and checked the head bolts again, I found that 3 to 4 of the ten head bolts were well below the torque I set them at. This was not an hour after I very carefully torqued it cold, with the new head gasket and with cleaned and lubricated head bolts. I got it started, ran it for 20 min, than shut it off and pull off the valve cover and rechecked the head bolts with the engine warm. I found the head bolts I set at exactly 44 ft-lbs (factory setting for 4ac) with the engine cold, 3 or 4 were torquing below 40 ft lbs. the others were exactly at 44 ft-lbs. I intend to drive it about 300 miles and than re torque it again for good measure, with the engine warm. that should be the final torquing of the head gasket.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

Iggzmon
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My tercel:: '84 Truckcel 4wd
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Re: How to Replace a Head Gasket: Petros method

Post by Iggzmon » Sat Nov 02, 2019 1:14 am

You're an absolute legend for this write up!

Thanks for your time!!!

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TercelCars5
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My tercel:: 82.83.84.84.84.85

Re: How to Replace a Head Gasket: Petros method

Post by TercelCars5 » Fri Jan 24, 2020 12:49 pm

Does anybody know what size holes to put into the head gasket? I know the larger one goes to the front, and the smaller one to the rear. The picture showing the hole sizes seems to have been lost and is blurry.

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: How to Replace a Head Gasket: Petros method

Post by Petros » Fri Jan 24, 2020 3:45 pm

I replaced the photobucket pics with fresh uploads, so you should be able to read it.

when I have more time I will upgrade all of them. photobucket changed their policy and wanted to charge money so I can see my own pictures (it was free if the data was below a certain size, so after you opened an account and filled it with pictures to share, they changed their policy. their site was a PIA to use anyway). At the time the forum did not have the ability to up load pictures directly, so all of the old threads can now be up dated, and good bye to photobucket and their blackmail policy.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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TercelCars5
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Joined: Wed Aug 12, 2015 9:26 pm
My tercel:: 82.83.84.84.84.85

Re: How to Replace a Head Gasket: Petros method

Post by TercelCars5 » Fri Jan 24, 2020 7:12 pm

Perfect. Thank you. I have 2 3a motors I am building now, and have a 4a I hope to finish first.

I realize that the 4a gasket (ITM brand) has a hole for the coolant between all the cylinders on the opposite side of where the added holes would go, and the OEM Toyota 3a gasket has none.

Should the 4a gasket still get the added holes? I am leaning against it if they have some already. Not sure though....

Has anyone added the head gasket holes to a 4a head gasket?
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LowBuckCanuck
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My tercel:: 1986 DLX 4wd Wagon "Jenny"

Re: How to Replace a Head Gasket: Petros method

Post by LowBuckCanuck » Sat Jan 25, 2020 12:25 am

TercelCars5 wrote:
Fri Jan 24, 2020 7:12 pm
Perfect. Thank you. I have 2 3a motors I am building now, and have a 4a I hope to finish first.

I realize that the 4a gasket (ITM brand) has a hole for the coolant between all the cylinders on the opposite side of where the added holes would go, and the OEM Toyota 3a gasket has none.

Should the 4a gasket still get the added holes? I am leaning against it if they have some already. Not sure though....

Has anyone added the head gasket holes to a 4a head gasket?
4a motors have a reputation of having better cooling than the 3a, so I wouldn't see any reason to add holes to the 4a head gasket. I've never heard of it being done at least.

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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: How to Replace a Head Gasket: Petros method

Post by Petros » Sun Jan 26, 2020 1:00 am

I did it on mine, even though the whole cooling passages are different on the 4ac. I wanted more coolant to be directed to between the exhaust valves, held up well. I have other mods (ported, performance regrind cam, and 2" exhaust) and I wanted more cooling between the combustion chambers.

the 4ac has a much more reliable head gasket, so you can do it at your option.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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