How to do a perfectly wrong rebuild


#1

I’ll start with questions before background since this is likely to be a bit wordy:
First, If a cylinder that is misshapen is honed and new rings are installed, are the new rings likely to create as good a seat as not honing/replacing the old pairing?

So now you all get the title of this thread. Here’s the purpose, my wife and I are students. She’ll be graduating in about 10 months, I’ll be graduating in about 13 months. If her car can survive until then, we can take on a car payment. If it can’t, we’re screwed. After measuring compression on her engine, a 1zzfe in a 2001 Toyota Celica GT (nominal 218 psi, minimum 145 psi, max difference 15 psi), I wound up with figures something like cyl 4 - 215psi, cyl 3 - 100psi, cyl 2 - 50psi, cyl 1 - 180psi. There was no oil in the coolant but coolant was just disappearing, same with oil. No apparent leaks. I figured head gasket and dove into a top end rebuild. In a momentary lapse of judgment and an opportunity to pick up reputable parts for surprisingly cheap, my concern that the rings could also be burnt out lead me to go ahead with a bottom end rebuild too.

The head gasket’s seal certainly was a problem, though not because of the gasket itself. Both the head and block are out of spec, with the deck resembling a bowl shape and the head resembling a taco shape, allowing a bunch of room between cylinders 2 and 3. The block is just over the .002 tolerance. The head is way over, I’m not sure it can be resurfaced. Meanwhile, the tolerance in the cylinders is .0008. I don’t have (read:can’t afford) tools to measure with that kind of accuracy, and even with what I have I’ve managed to determine that the cylinders are out of spec, there is at least a .003 variation. To do this right, I should probably replace the head and bore the cylinders (read: replace the entire engine because it’s not worth it). But the car also has issues with the wire harness (speedo and tach work intermittantly, OBD II com doesn’t work at all) and has occasional hard shifts from the transmission, which means the whole car is a mess. Either way, I’m sure if I do get the head gasket seating well, the rounded cylinders are going to cause more problems than they did before because now there’s more pressure on the rings, which is the other factor I’m considering and the reason for all the background info. I’m not sure that the old rings (near 300,000 miles) will put up with much more time, let alone more force plus more time.

But, back to being students. Boring the block then buying pistons, and another set of new rings is going to add another $300 or so. All of this on top of needing at least an attempt at resurfacing the head, on top of the parts already bought. So I’m tempted to break the old glaze, put in new rings because at least those won’t break, hope they seat well enough to not drink more oil than the car already was, and hope it all holds together for the next little while. The bearings are alright, it looks like they can be reused without spinning, albeit only for the above stated 10 month time frame. I’d worry about it in 2 years otherwise. This has already been a bad investment and every dollar makes it worse, all for a car that could blow up in 10 months for all we care… just not sooner. So we’re trying to cut our losses and just make this thing survive short term. Any tips on the best brands of bubble gum and duct tape to use on this thing would be appreciated.


#2

Sorry if the language gets confusing in the beginning, there was going to be a second question… then there wasn’t.


#3

Price a used engine.


#4

Forget about it, do it all or feed oil and wait till you get a job.


#5

+1 for a used engine.
Modern Japanese engines are built with a level of precision that cannot be restored with a “shade tree” rebuild.

The 1zzfe has a number of innovations that make a full rebuild impractical.

http://www.spyderchat.com/1zzfe.pdf


#6

+1 on the used engine.


#7

I’ve noticed. Like I mentioned, I’m amazed at the precision of this thing, it’s not like the 10 year older Honda H series engines I’m used to.

Let me just highlight something to make sure it’s seen, since it may have been buried in the text above. I’m not hoping to preserve this car and I’m under no delusion that I can magically do a good rebuild that will last years and years. The one and only reason I’m okay with taking shortcuts with this rebuild (frankly why I went that route in the first place) is because the car doesn’t need to last even a full year. The target is 10 months. Used engines look to be around $1,250 for the 1zz’s with the rear exit exhaust. That’s over $100 per month to keep this car running, and right now we already have to be careful to not eat too much because I can only pull so much in loans.

So with that perspective in mind, would you all still maintain that a used engine really the most practical way of keeping this thing alive for less than one year’s time?

And yeah, I should have left it alone and just fed it oil. I’m concerned it’s too late for that now that the mating surfaces have been separated. Regret…


#8

Good luck.


#9

If you have already bought rings and a gasket set, I’d just hone the cylinders, shave the head and put her back together. It should make another ten months.

If you have not bought the parts, I would look for alternatives, 300k is pretty much the end of the line for this car. I would say that it will nickel and dime you to death, but you would wish it was only nickels and dimes. You will be throwing good money after bad.


#10

Sounds to me like the engine is out of the car and is dissembled, right? Head off, pistons out of the block…You have determined that it is junk…Your options are:

  1. Find a used engine you can afford and install it.
  2. Scrap the entire car and make due without a car. Buy a couple of Bicycles…
  3. Contact local charities and ask if they have any donated cars that need a good home…SOMEBODY must get those donated cars, why not you?? Also, try begging for a car on Craigslist…“Wanted ! Starving student needs drivable car…”
  4. Get a part-time job, earn enough money to buy a $1200 beater…

#11

Unless you do a total rebuild and have the block and head machined and all new bearings and rings, you are throwing away your money. If done this way it may only last two days or two weeks, but I doubt that it will last 10 months.

Maybe you should check at your school. Are there Automotive classes. You might tell your story to whoever is the instructor. Maybe they would do the labor as a class project while you pay for the used engine. If they are willing to do this, arrange a day and treat the class to a pizza lunch as a thank you.
it’s a long shot, but all you can do is ask.

Yosemite


#12

Band aid would be to have the head machined, lap the valves by hand, new gasket set. Is it the proper repair, nope. It will get you down the road for awhile with the least amount of money. Dont touch the bottom end the low compression was a result of the head gasket failure.


#13

Not that I know anything about it but an old mechanic told me never to open up an engine with a lot of miles on it. Either leave it or replace it. I think I would just shave the head so you can get it back on and forget the rings. If you don’t do a valve job, you won’t raise the compression to push more oil through.


#14

"The bearings are alright, it looks like they can be reused without spinning, albeit only for the above stated 10 month time frame. "

This looks like to me the engine is completely torn down…One question: Is the block still in the car??


#15

its a little late now, but I think the beater route would have saved a lot of stress.


#16

Call LKQ for an engine quote. We found a V6 for a friend’s '99 minivan and it was delivered to our driveway for $350 with an additional $100 core charge. We swapped it out and they came back for the locked up and damaged engine and returned the $100. The engine was a complete assembly and we only needed to swap over the A/C compressor, alternator, and power steering pump. That was 2 years ago and the van is still running like a top. Driveway rebuilds with this much wrong is going to be a waste of good money. A used engine would be the most economical and reliable use of your limited funds. If you feel you can do a driveway rebuild, you can do an engine swap. There are tool rental companies that rent engine hoists.


#17

I’m on the “price a used mill” wagon here. Putting any work at all into the existing one is going to be a waste of effort. Drop a used motor in there and watch the maintenance for the ten months you need. Otherwise, shave the head, ignore the rings unless you’ve already trashed any hope of them going back where you found them, feed it oil either way (because it’s a cinch that the new ones won’t seal against oil loss either) and hope it runs that long.


#18

To answer your original question, honing a misshapen cylinder will not allow new rings to seal or seat properly.

IMHO if you rebuild this engine without going total (reboring, milling, new bearings, regrinding the crank, new valvetrain components,… the whole nine yards), compression will quickly begin to drop, you’ll quickly develop passage between the water jacket and the cylinders, the coolant and the oil will quickly become polluted with combustion byproducts, the bearings will spin and/or seize from loss of proper lubrication, and you’ll have a boat anchor on your hands. I doubt if it’ll last 10 months. Perhaps not even 10 weeks.

I truly think a used motor is by far your best bet. Clearly you’re more than capable of installing it yourself, and you should be able to find one pretty cheap working with a local boneyard. You have all the peripheral stuff, the alternator, starter, etc. etc., so that too should keep the cost reasonable.

If you proceed to attempt the original plan, I sincerely hope I’m wrong. I really do care, and am not trying to scare you. You’re easily knowledgeable enough to know the issues, and I’m only offering an opinion.


#19

You really need to halt this process as it’s not likely to turn out well. Even boring the block is not as simple and as cheap as you might think it is.
Even if you went so far as to bore the block and get a new piston set and rings, etc, etc there’s the issue of technical expertise in setting things up correctly. One flaw and 5 minutes of running could lead to a screeching halt and a pile of scrap metal.

Do some footwork on a used engine; eBay, Craigslist, or LKQ as mentioned.


#20

If the cylinder head and the block are both warped this engine must have been allowed to get very hot. The common practice in this case is to discard the damaged engine. With the block deck distorted by .002" this engine may not hold coolant unless the the deck is resurfaced. Multi-layered steel head gaskets are not as accommodating to surface variance as composite head gaskets.

Installing new rings in distorted cylinders will result in an engine that burns oil for an extremely long break in period, like ten to twenty thousand miles before the rings match the cylinders.

A used engine would be a safer bet. A cheap used car would save a lot of labor.