Engine alternatives

[Petros]

Since my last post I learned a few things:

I am not losing any oil. The "smoke" is steam not oil, now I am losing A LOT of water, about a quart every 60 miles, and there is no visable leak. At idle the exhaust is cooler and it is condensing at the exhaust pipe-looking like smoke, under load the exhaust is appearantly hot enough not to condense to visable mist (FYI pure steam in invisable, only condenced water droplets appear as a white mist). And now it clearly is starting on only 3 cyl., once warm it runs a bit rough but is driveable as long as there is enough water to keep it cool.

So it appears to be the head gasket....again. The second one in only a year, maybe the 11:1 is a bit too high? Or maybe I just need a better quality head gasket? (anyone have trouble with aftermarket head gaskets?). I have not had this trouble before at 11:1 (even higher) on other engines, but my machine shop guy says the current gas quality wreck havoc in the compustion chamber (too much ping). He recomends 10 to 10.5 to 1 max (which was actually what I was aiming for). The other times the head gasket was bad I had to pull the head anyway because of the burned exhuast valves.

I had milled the head 0.020, used flat top pistons, and overbored the engine 0.040 (1.0 mm). Each of these tend to raise the compression by about 1/2 CR each. But when I checked the chamber volume I found it over 11:1, so I enlarged the chamber as much as I could and reblanced them.

The flat top pistons were made by Sealed Power (a federal mogul company). The are pretty inexpensive, only about $26-29 each or so, but they had several serious problems. The "set" were way out of balance, so they MUST be balanced. The other was that the deck height was way too high, at top dead center they actually proturded above the top of the block. I took them out of the engine, pressed off the connecting rods, and had about 0.015" milled off the top (and rebalanced them again). This gave me about .009 clearance. The piston tops are real think and will tolerate the machining just fine. Perhaps I should have taken more off to lower the CR.

I would rather replace the head with a 4AGE EFI set-up. The problem is I need to fix it right now, and do not have time to see if I can find and adapt 4age EFI head to it. I can replace the head gasket pretty quickly, but I need to grind out the combustion chamber to lower the CR, and prehaps replace the reground exhaust valves with new ones as Typrus recommends (since I will have the head off anyway). I have a whole spare head that has not been resurfaced. I could have it rebuilt first (it will need new guides, valves, seals, perhaps resurface, etc.), and then swap out one evening. But it means I would be putting a lot of money into it, which I would rather not.

Oh-well. Like I said in an earlier post. It appears this engine is just too fragil for too much tweaking. And the trans too. What should I do now?

[GTSSportCoupe]

I always highly recommend using Toyota OEM headgaskets. Also, you might consider aftermarket head studs and over torque them beyond Toyota's recommendation for the 3AC? What a bummer after all the work you've put into that engine.

Note that the 4age head may bolt to the 3AC bottom, but remember that the bore is less on the 3AC. (~1500CC vs ~1600CC). I don't know if this would have any negative impact at all. You might be able to use a thicker performance head gasket for a 4age. There are a number of aftermarket headgaskets for those engines.

[Typrus]

Copper headgasket perhaps?

So 11:1 might be too high to aim.....

They were that bad?

Can you get any pics by chance?

Sorry to hear it... I'm having my own chaos as well right now.....

[keith]

Its been awhile, but I think I remember seeing Belleville washers on the head bolts. If I remember right, then these should be replaced, and make sure not to get them in upside down.

[Petros]

I have another car to drive and replacing the head gasket I can do in only about 4 hours (presuming I have everything I need ready). It will only cost about $20 or so worth of parts. but I do not want to keep doing this twice a year, so I want a permanant fix.

I figure I can lower the compression about 1/2 a CR by removing about 2 cc from each combustion chamber when I have head off. Or I can switch to using premium fuel (rather costly in the long run), or buy octane booster (also adds cost).

Also I am starting to wonder about the quality of the aftermarket head gasket. I have used several brands and often the factory will buy from the same supplier as the aftermarket guys. GTS recommends the dealer head gasket, do you know it is actually better than the aftermarket, can you tell the differance? The factory often buys based on minimum bid, and then charges 3 or 4 times the aftermarket price. So it is not necessaryily better. Is there a particular brand of head gasket anyone would recommend?

I am not sure I want to experiment with copper or alum. or any home made solution. I thought about o-ringing it (a groove is cut in the top of the block around each cyl and a copper wire is pressed into it). This is what we did on engines with 13:1 and above CR, and turbocharged race engines. Never thought I would need it on only 11:1.

Keith, what are Belleville washer? All of my Toyota engines have simple hard steel washers on the head bolts. I do not see how replacing them could make any difference. I clean the bolts and holes (debur them if necessary), lube the treads and the washers and torque them in several steps. I then retorque the head once after first warm up (first 20-30 min of run time), and then again at 500 miles. I also check the valve lash at that time too since newly cut seats can change a bit when they first seat in. I always torque to the middle of the specificed range, perhaps I should go the high end limit?

It seems to me the problem is with the gasket and the poor quality gasoline. It runs great for about 8000 miles each time. If my machinist's idea is correct, the pre-ignision will erode the gasket away. Which is what is happening. If the was simply a matter of bad gaskets, they would fail I would think within the first 500 or 1000 miles. If there was one availible with a stronger steel rim around the cyl it might hold up just fine.

After I find the best head gasket I can I think I will just remove as much as I dare from the combustion chamber and reintall it. Torquing to the limit. And perhaps try premium fuel (or even half regular and half premium-it can boost the octane higher than the average of the two and still cost less).

Any other suggestions?

[TreeKiller]

I would consider a 4ac head since you bored it out already and the larger head might drop the compression a tad. Then of coarse use the best parts from the heads you have. Bigest cams etc..
I would use the spare head you have to compare to a high compresion or supercharged 4age head gasket. Those would be the best gaskets I would think.
Seems to me that Toyota usualy overestimated their head bolts. Most of the time if you modify them you need to throw in some better bolts.
Just my experience.

[keith]

A belvil, or belleville (both spellings are acceptable) washer is also known as a spring washer. When new it looks like a flat washer with a crown toward the center, As you torque it down, it flattens out and will provide more even pressure as aluminum contracts and expands. It was developed for use on aluminum.

I'm not sure that the Tercel uses belvil washers, its hard to tell when they get old. I looked at a couple of old spare headbolts I have from the blown engine and they have a chamfered edge which is what a belvil looks like when it gets flattened out.

[takza]

It seems to me the problem is with the gasket and the poor quality gasoline. It runs great for about 8000 miles each time. If my machinist's idea is correct, the pre-ignision will erode the gasket away. Any other suggestions?

http://www.mpgresearch.com/viewforum.ph ... e587bc89d5

Supposed to reduce pinging...and increase mpg and power...they purposely up the CR before doing the grooves. Check it out?

[ARCHINSTL]

Neither the FSM nor the AutoZone site mention Belleville washers. It would seem to make sense to use them.

And what are thoughts on reusing the head bolts? I've seen reference somewhere (here?) to a special type of bolt whose name escapes me - something about a bolt which "stretches/deforms" in some manner - does Toy use this as OE? Again, not mentioned in the FSM or the AZ site.
Tom M.

[Typrus]

AFAIK, we do not have Torque-to-yield bolts. BUT, using new bolts is always recommended regardless. Now, in the case of our engine, it becomes a parts-hunt. Will head-studs off of a 4AC or even 4AGE head work for us? If not, I dunno if we can get reputable aftermarket.... I know the con-rod caps are crosscompatible, so long as using the earlier 4AC and 4AGE engines as reference.

As a start... Who do you buy your head gasket from? There are definitly varying quality levels....

Toyota doesn't use a bid-system I don't think. I believe a lot of their stuff is in-house. Well, not literally, but I believe most of their stuff is tied to the mainship. Or at least was. Like Toyoda P/S pumps. Note the "D" in Toyoda. Nippon and Toyota seem pretty well tied as well.
I could be 100% wrong about that though.

[keith]

The Tercel doesn't use a torque to yield bolt. I still don't know whether it uses Belvil washers or not, but I'm thinking not because you typically have to use another flat steel washer between the belvil and the aluminum or else the belvil "bites" into the aluminum.

Toyota does use a bid system now, sort of. To become a supplier to Toyota, you have to prove your quality is sufficient and consistent. Its a real hurdle, not many qualify.

[tercel4wdrules]

I've seen reference somewhere (here?) to a special type of bolt whose name escapes me - something about a bolt which "stretches/deforms" in some manner - does Toy use this as OE? Again, not mentioned in the FSM or the AZ site.
Tom M.

Well, a reference I remember is when former member Teddy said that the flywheel bolts are stretch bolts, that is, they stretch when they are torqued or something like that.

[keith]

I hope the flywheel bolts aren't torque to yield because they are not reusable and I reused mine. They didn't look like special bolts.

[Petros]

There are no deformable bolts in the toyota or the manual would say to replace them. Both the head and flywheel bolts are hard steel, they do not deform.

I got my head off yesterday and it gasket failed between the 1 and 2 cyl. oddly the compression was still okay despite the fact it was using about a quart of water every 30 miles or so. Also odd is the gasket is thinner between the 2 and 3 cyl. both my head and block are flat.

The last two head gasket failures I used an inexpensive head gasket by ROL (about $15), I will try a fel-pro one this time, only a few $ more. The dealer head gasket is about $32, not a lot more but they could not get one for 2 days. So I am going with local suppler.

I think I will try grooving the compustion chamber, I like the idea and it is easy to do. It creates a jet or vortex to improve combusion and reduce ping and improve power/economy. The idea is sound, I read of experiments as long ago as 25 years ago trying to develop a way to do this, no one thought it would be so simple!

I should have it runing tonight, I will report back later.

Peter

[TreeKiller]

Pictures while your at it? Just wondering.
j