Why do a head gasket as preventative maintenance?

[baldilocks]

thats pretty much how i live my life

Have drink on me…

 

[FMC80]

TLDR: bring an extra 80 with you. You’ll be fine

 

[LINUS]

@Marco Lau - like your plans.

Seems like you’re really thinking this through / do it right once. Props.

Since I had 2 other 80’s in succession to my black 80, and a few BMW’s I drove & a old ‘88 Turbo ‘Yota minitruck (22rte motor) - I kept miles off my black one.

I’m just shy of 148K on the powertrain but new HG & viton seals on valve stems, but like you I did all new motor/body/susp bushes as age doesn’t know or care your odometer.

If need ever comes, I could put it on BaT, but that’s not something I plan anytime soon.
I drive the Tundra since it’s basically disposable, but I love my 80 & have countless hrs into all sorts of stuff nobody would notice like dielectric grease in every last wire socket underhood & underneath in the e-locker pigtails.

I just love that thing.

 

[SpenserAK]

Don’t have a specific reason to assume it’s been done before, but on an 80 or in general, are there by chance any telltale signs that it has been? Main PO that had it here locally is a wrencher and cruiser head, so wouldn’t be surprised if he had done it, had it been necessary. Luckily no current issues at 220k, confirmed all around.

 

[baldilocks]

Don’t have a specific reason to assume it’s been done before, but on an 80 or in general, are there by chance any telltale signs that it has been? Main PO that had it here locally is a wrencher and cruiser head, so wouldn’t be surprised if he had done it, had it been necessary. Luckily no current issues at 220k, confirmed all around.

220k is low miles. My 1fz is at 307k and that’s not really impressive. My hg was done by PO at 265k bc it let loose. Most cars are junked by 265k so I don’t understand the criticism the 1fz gets for the hg’s.

 

[zapatius]

It's hard to tell, but what I would look for is the the main wiring harness wrapped in additional heat resistant tape (or similar)

 

[SpenserAK]

Oh I’m not worried about the mileage at all, the thing runs like a top - no 1fz criticism here - was just curious if I could look for specific signs. Really just for my curiosity. If the day comes during my ownership, the PO had a full gasket/seal/hose kit, much of which he didn’t need, so I already have the parts on hand.

Thanks, I have been meaning to take a closer look at the harness anyway

 

[fjbj40]

My observation with Toyota head gaskets. I have replaced the old style Toyota fibrous gaskets with Toyota MLS gaskets on several engines. They were not the 1fz but a 3b diesel. Not once did I have the decks refinished to the “ra” specs people cite. I just cleaned it with red scotchbrite then heated it with a torch to suck oil to the surface and cleaned.

The head was rebuilt and resurfaced, both are still running with well over 300,000 miles

 

[Irish Reiver]

I would like to move this discussion in a slightly different direction but still relevant to the thread.
Lets assume your LC has 250k miles on the clock. All 6 cylinders have compression reading within 10%. Engine has never knowingly overheated. Engine has no codes. You decide to do the head gasket as a PM to resolve the quart of oil the engine is burning every 1000 miles due to the valve stems seals being oil and crusty.
In this particular scenario does the cylinder head need to be taken to a shop for resurfacing or can it be cleaned up and put back together with a new gasket?

 

[landtank]

the truck I drive curently was bought with 278k on it. Pulled the head, lapped the valves to check the seats, replaced the valve stem seals cleaned the mating surfaces and slapped it back on. Then put on a SC and it now has 315k on it. no burning of oil and runs great.

 

[flintknapper]

I would like to move this discussion in a slightly different direction but still relevant to the thread.
Lets assume your LC has 250k miles on the clock. All 6 cylinders have compression reading within 10%. Engine has never knowingly overheated. Engine has no codes. You decide to do the head gasket as a PM to resolve the quart of oil the engine is burning every 1000 miles due to the valve stems seals being oil and crusty.
In this particular scenario does the cylinder head need to be taken to a shop for resurfacing or can it be cleaned up and put back together with a new gasket?

Resurfacing to correct 'warp' would depend on how far out of spec it is.

I pulled my head at 316K checked it with a precision straight edge (it was well within tolerance). I cleaned the head, cleaned the valves, LIGHTLY lapped the valves in, installed new valve guide seals, checked valve spring tolerances, new head gasket and head bolts, slapped it back together. I'm at 330K now...so far so good.

When it is time to rebuild the lower end...I will have the head professionally rebuilt/serviced.

 

[SaturnAscends]

So does anyone actually advise resurfacing the block on a PM HG/valve job?

I've heard some minor pitting on the block surface isn't uncommon on these engines (perhaps due to small undetected HG leaks), but is this just not a significant factor on these tractor motors when fitting a refreshed top end?

 

[Irish Reiver]

Thanks guys. My thought process was based on if the head was good before removing it then it should be good after refitting it. I know having the head cleaned and resurfaced would be considered best practice but shops round here have lead times of a week or more or double the price for a 48 hour turn round. That can be a long time for a truck to be off the road.

 

[peacesells63]

I would like to move this discussion in a slightly different direction but still relevant to the thread.
Lets assume your LC has 250k miles on the clock. All 6 cylinders have compression reading within 10%. Engine has never knowingly overheated. Engine has no codes. You decide to do the head gasket as a PM to resolve the quart of oil the engine is burning every 1000 miles due to the valve stems seals being oil and crusty.
In this particular scenario does the cylinder head need to be taken to a shop for resurfacing or can it be cleaned up and put back together with a new gasket?

I just had a head done that came off of a 350k mile motor that overheated due to a blown head gasket. The head was very slightly warped and 1 #6 exhaust valve had a very small leak. The machine shop said he would have just resurfaced, replaced valve stem seals and run it.

If you have a machinists straight edge and a valve spring compressor you can check your head out, replace valve stem seals and put it back on with some confidence that it won’t blow again. If you don’t, I would take it to a shop to have it looked at before bolting it back on.

 

[peacesells63]

So does anyone actually advise resurfacing the block on a PM HG/valve job?

I've heard some minor pitting on the block surface isn't uncommon on these engines (perhaps due to small undetected HG leaks), but is this just not a significant factor on these tractor motors when fitting a refreshed top end?

Definitely need to resurface the block if you want to run an MLS gasket. Other than that, if it doesn’t have much pitting and checks out good with a straight edge, no reason to.

Every 1fz I have seen with a blown head gasket still had a good block surface. I have thrown a few 2rz/3rz blocks in the trash due to deep pitting. Those tend to leak externally, and it always seems like taco owners top off with straight water everyday and drive the truck for a year before trying to fix it…

 

[flintknapper]

If you have a machinists straight edge and a valve spring compressor you can check your head out, replace valve stem seals and put it back on with some confidence that it won’t blow again. If you don’t, I would take it to a shop to have it looked at before bolting it back on.

Yep, clean the head real well. Disassemble, check for straightness. Lightly lap valve and valve seats, check valve springs for proper pressure at installed height, install new valve guide seals and you're probably good to go if valves do not require any significant shimming, mine didn't.

 

[FMC80]

There goes @flintknapper dropping knowledge again. One day, I’ll be “in the neighborhood” and swing over and you can teach me how to work on cruisers

 

[flintknapper]

There goes @flintknapper dropping knowledge again. One day, I’ll be “in the neighborhood” and swing over and you can teach me how to work on cruisers

You are welcome any time, but I assure you....I am ever the 'student', not the teacher here.

 

[77mustard40]

There goes @flintknapper dropping knowledge again. One day, I’ll be “in the neighborhood” and swing over and you can teach me how to work on cruisers

Agreed, he’s not that far from me. Hell I’d go for the BBQ, cold beer and opportunity to hang out with a wise man who’s knowledge far exceeds mine. What else is there? Happy New Year Mudders.

 

[FMC80]

You are welcome any time, but I assure you....I am ever the 'student', not the teacher here.

Humble. I like that. I’ll bring the scotch.

Happy New Year everyone.