Blown Headgasket, What to rebuild?

[jcwhitty]

My 1994 just lost a head gasket after turning 250K. I plan on resurrecting her, as I am the original owner and love the vehicle. I am happy with the current power plant, and have no desire to change the motor. The engine ran very good until the "failure", used a quart of oil every 1000 miles or so. I have someone lined up to do the work. I therefore do not know the extent of damage.

At the current time, I had planned to rebuild the head at the same time. In discussions with friends, they suggested not rebuilding the head since any added compression as a result may be detrimental to the bottom end. They suggested to save the money, provided the head is not damaged, and just replace the head gasket.

I understand that the bottom end of these motors are pretty much bullet proof.

Any comments would be appreciated.

Thanks in advance!

John

 

[bigredmachine]

i dont know why you wouldn want to get the head taken care of. fresh valve job, replace valve stem seals, adjust the valves, check and deck the head if it needs it. just getting your valves cut isnt going to raise compression and if the head gets decked you can go with a thicker gasket to make up for what was taken off.

 

[Heckraiser]

I would, at a minimum, at least take the head in to the machine shop to make sure it is 100% flat. If it needs to be decked, no big deal. As you mentioned, these motors are tough and pretty low compression to start with. A little extra compression wont hurt a thing.

 

[TheAmerican]

250k...Get the head rebuilt and gasket done/end thread

 

[LINUS]

If the head needs a decking, that's fine.

New stem seals will cure any oil loss between changes, barring ring issues (slim to zero chance of that)

At a bare minimum, get the head checked for flatness. But really stem seals are a no-brainer while it's out & getting checked.

 

[nukegoat]

Definitely replace the head gasket itself

 

[LINUS]

Definitely replace the head gasket itself

That would be a 'new low', even for the newer, budget-forward owners.

Reusable HG's

 

[riffman12]

Definitely replace the head gasket itself

 

[nukegoat]

That would be a 'new low', even for the newer, budget-forward owners.

Reusable HG's

I guarantee someone has tried rtv

 

[toyofan]

I would do the head job for sure. Then you ask yourself "while I am there" what else can I do. Some suggestions

-Clean/recalibrate fuel injectors
-Replace PPH, and some other heater hoses that are hard to reach
-Replace coolant hoses, belts
-New fuel filter
-take care of oil leaks (if any), i.e crankshaft, oil pump cover, ect
-spark plugs
-put some bling and paint the valve cover

Can't think of anything else, but I am sure I am missing something

 

[Rifleman]

I guarantee someone has tried rtv

I'm sure your right, can you just imagine that look on their face of, OH SH1T, now i have to take it all apart again when it failed!

 

[jcwhitty]

Thanks all. You have definitely reinforced my original position. I will rebuild the head. As for the other items, I have it serviced on a regular basis, and six months ago I personally took care of the crank seal, oil pump seal, power steering pump seal and distributor seal, along with belts, throttle cable, and coolant hoses. The only one leak remaining is the rear main, which I can live with. A new water pump, and the PHH is already on the table.

I don't believe I will ever get to 400k, but if I do, hopefully it is still plugging along like it did for the first 250k. By the way, in all the years I have had it, I have only put approximately 16k into the vehicle, so I figure another 5k is not a problem.

 

[BILT4ME]

On mine, the HG was done by the PO at 145K by a Toyota dealership. They rebuilt the head with all new seals, checked the valves, the whole 9 yards.

I got the truck with 196K on it and it needed a LOT of driveline maintenance.

My truck now has 263K on it and it burns NO oil in a 7000 mile oil change using 5W30 Quaker State dino oil. The Blackstone analysis tells me it's in great shape, seeing minor wear.

It has great power (for a 1FZ) and it starts and runs very well.

I believe that rebuilding the head at that stage is what has contributed to my truck being an excellent truck, in spite of it needing all the driveline rebuilt. My truck was the PO's son's first car and he beat the CRAP out of it (drove over a guardrail, into a house (literally))

Rebuild it rather than doing it again in 50K and watching it burn oil the whole time.

 

[LINUS]

You **may** want to consider a new fuel filter & a PHH while your guy has the intake out. Esp if you never changed either.

It's ~$75 max of well spent $$ in this opportunity.

It's 1/8 as hard to do these 2 items with the lower intake out.

 

[Sc0-]

When my head gasket blew i had the head rebuilt, new valve stems, valve seals, valves and seats regrinded and everything else checked.

I SHOULD HAVE ALSO: replaced timing chain guides, resealed the oil heat exchanger, used ARP fasteners...

 

[Peru Darrell]

When I did mine, Beno recommended timing chain tensioner, guide and follower, also Don't forget the head bolts

 

[inkpot]

That would be a 'new low', even for the newer, budget-forward owners.

Reusable HG's

Pulled my head off to deal with a burned valve problem. I have put 105,000 miles on this rig and the aftermarket gasket was put on with the S C but I don't know exactly when that was. Gasket is clean and shiney on both sides. It did not stick to either the head or block. I really think it would work OK if it was reused, but I wont since I had a new one handy.