Head Gasket Replacement

[MontanaMike]

Ok, so the story goes like this. I'm driving my '85 Tercel over the pass blasting music and singing along. I've known for a while now that the water pump is wobbling and probably needs to be replaced. All of a sudden I notice the Battery light turn on and the engine loses a little bit of power. Staring at the dash I see the temp sky rocketing off the scale! I pull over as fast as possible. When I look under the hood I can see that the belt has slipped off of the wobbling Water pump and was no longer cooling the engine. "CRAP" ... I put the belt back on and checked the radiator fluid level. Seeing that it was low I tried to add some. It went right through the radiator and out the busted water pump.... "This is not good" So I got it towed to a station where they put in a new pump for me. Then the mechanic tells me that it has a blown head gasket too. "CRAP"

To make a long story short (I know... too late) I've decided to replace the head gasket myself and spend a little time getting to know the engine of the car I have come to love so much. So... does anyone have some advice as to where to get the head gasket? Should I get a head gasket kit with all the other gaskets and replace them too while I"m in there? Are some gaskets better then others? Should I replace the Carborator or anything else? I'd like to get this thing running great again. I know it was burning a little oil before and if I can do anything to fix that while I'm in there would be good too. What should I clean/replace? My budget is probably going to be around 300-400 bucks. I am looking to increase Mileage as always, and cut down on emisions and oil consumption.

Thanks for all the help.

Are there any really unique tools that I will need to do this job? Will I need a Torque wrench?

[ARCHINSTL]

Welcome to the Club - glad you followed up on the suggestion!
Many have vowed the Toy OE gasket is the only way to go.
A necessary step would be to take the head to a machine shop and have it checked for being true - they can warp.
The radiator on my '83 blew in '85 whilst in the care of my Beloved Sister and the head was warped. However, it was resurfaced (word?) by the local Toy dealer. Apparently this was not uncommon with the A-series motors.
In fact, it happened at some point to my Goldie down in her original home near Nashville, and a rebuilt head was installed.
There are a number of threads here concerning this, and a number of members can weigh in on this.
Also, obviously, a good time to do a valve grind and seal replacement.

An invaluable resource is the FSM available here - AND - that in the AutoZone site, at http://www.autozone.com/servlet/UiBroke ... 1b94ee.jsp ; this latter also has photos of the head work in process.
Tom M.

[takza]

While you have it apart...you might try the GROOVE THING.

http://somender-singh.com/

http://somender-singh.com/content/view/42/37/

Most people see better mpg. One member of this forum has done this.

Send Mr Singh a picture of the head and he'll tell you how to do it. He usually recommends a single groove pointed at the plug.

[Petros]

That all depends. How many miles are on the engine/head? The valve seals and exhaust valves can get pretty beat up over time, and you almost certainly will have to resurface the head. If the valves and seals are in good condition, as a minimum you will need to have the head resurfaced (almost no way to avoid it once it was overheated), a head gasket, the intake manifold/exhaust manifold gasket and the head pipe gasket (get a metal one, the fiber ones do not hold up at all). It is less costly to buy these few gasket separately.

If you have leaky valves seals, the front cam seal, valve cover, etc., then get the whole set (but they are pretty costly as a set). If you buy them separately do not get a cheap head gasket (not worth the savings). I have had good luck with Fel-Pro, but the factory head gasket is the best.

If the head has a lot of miles on it you might consider doing a complete head overhaul: reground valves (or better yet replace the exhaust valves-well worth it), new guides/seals, and I would suggest getting the performance regrind camshaft from Delta Cams in Tacoma WA (you mail them your old one and they send you the regrind exchange). All this will help the performance and not harm the economy. But this will add a few hundred $ to your gasket repair.

AS for tools you will need metric sockets, a few extensions, screw drivers, a good scraper and yes a torque wrench (AutoZone "rents" them for free).


Good luck.

[MontanaMike]

Ok, so I'll be starting this project on Saturday... My only question has to do with the Valve Grind and Seal Replacement. Are these things I can do by hand or am I going to have to bring these parts to a shop and have them work on them?

[MontanaMike]

I also noticed that the air filter has oil in it... does this mean I should invest in a new Carburetor? Was looking at them on National Carburetor... $180. Or is the oil up there from something else? Vavles? Seals?

[Neu]

I also noticed that the air filter has oil in it... does this mean I should invest in a new Carburetor? Was looking at them on National Carburetor... $180. Or is the oil up there from something else? Vavles? Seals?

oil in the air filter is a bad PCV valve. It's like 5 bucks or less at napa or carquest. (It's the valve on top of the valve cover.

[Petros]

I have resurfaced both the head face and the valves by hand in my garage with simple tools and jigs. The valves can be removed by depressing the spring and removing the keepers (little wedge like shims between the retainer and the end of valve stem). You can then remove the valves to inspect the seats and change seals off the top of the guilds. Number or tag the valves so they will go back in the head is the same place (or better, make a cardboard holder with small holes that are numbered where you put the valve stems in it). The valves will typically have large carbon build up on them that will take some chipping and heavy wire wheel action to remove all of it. It would be wise to then take them to a machine shop for them to inspect if you do not have someone who knows what you have. Presuming the shop is trust worthy they can tell you if they are not bad, or if they should be replaced or just have the surfaces reground. NAPA shops are usually reliable, but it just depends on who runs the shop.

You can hand lap the valve face with lapping paste (it has grit for resurfacing both the face and seat by spinning or rotating the valve in place with the paste or compound in between the surfaces). Lapping compound or paste is available at auto parts stores (NAPA has it). I put the valves in with compound only on the face, light oil on the stems (make sure the stems are clean and free of compound), then I put a slow drill on the stem and spin them in both directions puting light pressure on the seat. This only works if the seats are not too beat up or burned and the valve is not bent or warped. Wipe them clean and inspect the face, there should be a smooth sanded face running around both seat and the valve head. If there is any breaks in the fresh ground surface, the valve is shot and needs to be replaced. If you keep this up too long the mating surfaces gets large and rounded as it is ground away, though it will work okay it will not perform as intended (just make sure you did not make the edge of the valve too thin). when I was in collage I had no money for a proper regrind and I drove an old Volvo for many miles with this kind of a "poor man's" valve job. It only cost me a head gasket.

If the valve guides are too far worn or burned (I have seen both), or if the valves are bent, melted or badly pitted they all should be replaced. The exhaust valves are usually the worst, you can almost always reuse the intake valves. I know of no good way to replace valve guides without proper tools, you risk damaging both the head and the new guides installing them, and they still needed to be reamed to size. Though they do wear, they do not always need to be replaced.

Usually the whole job is left to a machine shop to do: disassemble, inspect, regrind the face and seats, clean and reinstall valves, springs and keepers with the new seals. they will also resurface the head while they are at it. The springs, retainers and keepers are pretty difficult to replace without a valve spring compressor (most shops rent them, again Autozone will rent it for free). You also need to know how to check the valve stems and guides for wear, they may also have to be replaced.

You can resurface the head by hand if the warpage is not too bad (around .005 or less, more than this take a lot more effort). Get several sheets of wet/dry 400 grit sand paper and tape them down to a smooth surface like a granite counter top (I have a large piece of scrap counter top I use). the surface MUST be smooth and flat, and bigger than the head by about 1 foot, a polished stone slab works best, but a large heavy smooth steel plate will also work. Put solvent or very light machine oil (like WD40) or kerosene on the paper after it is tapped down and slide the head back and forth over the sand paper in a figure 8 pattern. After about 10 min, wipe clean and inspect the surface and you can see how bad the head surface is warped. If the warpage is not bad you keep doing it until the whole face has a nice even sanding pattern on it. It could take several hours, replacing the paper and refreshing the oil as needed, but it is doable. Make sure you put even pressure over the whole surface as you do this with a hand at each end of the head. It will take many hours and lots of sand paper if it is very bad, and not worth the work if you have a machine shop near by, the resurface in a machine shop is typically only about $40-50 or so.

So doing this will all depend on the condition of the head, the valves, the seats, and the guides. If none are too bad, you can do it all your self with a few borrowed or rented tools. If they are all bad, better pay a machine shop to do it all (or get a replacement head from a junk yard, and hopefully it will be in better shape than your current head). The machine shop should crack check the head for only about $10-15, not always necessary since Toyota heads are pretty good about cracks, but it can happen. I usually skip the crack check if it is not too badly warped or it was not badly overheated on a Toyota. there are some cars I would never skip a crack check. There are dye kits to check your own cracks, but they take experience to use and cost as much as a check anyway (only worth if you have a lot of heads to check).

If you are going to do this all your self, make sure you read the manual on each of these steps several times. Check the archives on this list, and perhaps elsewhere on the internet. Also often the machine shop or parts stores will have helpful people, and there is always this list (though you may not get instant answers here).

Good luck.

[ARCHINSTL]

Petros - this was a great addition to the lore - Thanks!

MontanaMike - While all you need should be the PCV valve - I got a carb from National in late '05 and have been happy.
I did have a problem with the accelerator pump in early '07, and they fixed it (actually sent another carb) under the no-time-limit warranty, although I did have to pay the postage down to FL.
Tom M.

[MontanaMike]

Ok guys... just wanted to give you all an update. I did spend the day working under the hood with a decent set of tools. Keep in mind this is my first serious job. I got everything off alright, all the way down to the head gasket. I couldn't take out two of the screws all... ( the cam shaft was in the way, but I did get them loosened up all the way and they didn't cause any trouble when we lifted the head off. It was almost dark when we got it off so I didn't really have time to inspect anything. We also took out the Head with the Intake and exhaust manifolds still attached. Should I even bother replacing the gaskets on them? Or should I just leave them be? Is there a good way to inspect them tell if they have leaks?

Also, I've noticed that some cylinders have more carbon build up then others. I plan to clean them up tomorow. Is there anything I should watch out for?

Lastly, I have a feeling that my head will need to be leveled. I don't have the tools to check it. Should I just bring it to a machine shop? And does anyone know what it should cost to have them do a valve job? I'm sure this engine could use it, but I am still trying to stay on budget. If it costs more then 250 I think I am just going to scrub it up as best I can and put it back together and hope for the best.

Thoughts? I'll post some pics tomorow for you all to have a look at.

Thanks again for all the input. It's been invaluable. BTW, FSM is way better then Chilton garbage.

[takza]

You'll have to remove the manifolds to get a machinist to work on it? Though they might take a look at it as is to give you an opinion.

Easiest way is to just lap the valves in with compound and replace the valve stem seals. You'd remove the valves...check the exhaust valves for serious damage...lap them in...put it back together with new seals. You then have valves that seal a little better and less oil consumption.

Clean up all the carbon with a dull tool and especially any valve lapping grit.

You can check the head for warpage with a quality level with a ground surface...might give you an idea at least...you use a set of feeler gauges anywhere you think you see some light.

Dump oil all over the cam, followers, valve stems before you put the cover back on.

Cost? head gasket....lapping kit....seals....valve spring compressor... Cons? you might not see something critical that needs fixing

[keith]

FYI, I bought new exhaust valve at one of the major auto parts store, don't remember which but they were only about $4 ea. For that money, I would not even consider grinding the old ones. Besides I've never had exhaust valves that were ground hold up more than a few miles (<100 miles).

[MontanaMike]

Ok... so the Plot Thickens...

As you all know I got the Head Gasket off and took a good look at the cylinder head and the block. When I looked at the Gasket it appeared to have NO REAL DAMAGE TO IT!!!! (My first thought, "But the Mechanic said I had blown the head gasket...") After further inspection I noticed two things that would cause him to believe that I had a blown head gasket.

1. The exhaust valve on cylinder 1 has a small piece missing out of it. (I believe this would cause a compresion check on this cylinder to come up short)
2. Secondly I noticed that inside one of the Cylinder 4, their is actually a small groove that starts about halfway down, and continues out of site below the piston. (I believe that this small groove may also be causing some pressure loss.)

Considering the fact that I got the car for 500 bucks, I don't really feel like pulling out the whole block, boring out the cylinder and inserting a sleeve... I'm sure it's not worth that much time, effort, and money. However, what about puting on a new cylinder head? Do you think I would get some more mileage out of it if I replaced that? Or should I just put a new Head Gasket on and drive it until it won't run anymore?

I've been looking online and I have found some Toyota Cylinder heads for around 250... It's a bit more then I want to spend but if I could get another year or two out of the car I would be happy. What are your thoughts?

[ARCHINSTL]

MY first thought (although based on head work on Morris Minors) would be to have the head checked for trueness and if OK, do exhaust valves, all springs and seals, and lap the intake valves.
My impression is that is not a good idea to reuse the gasket.
I dunno about the groove - if no anecdotal info here - maybe do a Google Search.
Those who have 3-AC experience can add a lot.
Tom M.

[takza]

I can tell you a little about the groove. I bought a school bus that turned out to have lost at least one hardened valve seat and the results was hard metal deposited (welded) to the side of the piston on maybe 2 cylinders...one not very bad though.

So I replaced the rod bearings, rings, and had the head redone. The head at the bad cylinder had serious pockmarks on the surface inside where the pieces of valve seat had hit.

This engine still did at least 1500 miles to the quart though.

So you probably have some metal attached to the side of the piston...might be a loose piston pin? I'd just leave the bottom end alone...put in those $4 exhaust valves...lap in the others...new seals...new head gasket. You could do all this without removing the manifolds. Probably last 2 years at least?

Might soak the rings in Seafoam or something to loosen them up some...just put some oil down on them before starting it up though.