Loud Tapping/knocking

[Neu]

One of them threw the rod, the other one we dont know, we never got into it.

I've also had a few dealership techs tell me that unless you flip the engine and actually do the job the right way with the cam involved, you'll most likely throw it out of spec.

Also a few ASE master techs have told me the same thing.

[CT9A]

Thanks. I'll have to check into it and see if I want to take the risk.

[takza]

Haven't seen too many engines where you can get the piston out from below without removing the crank.

[CT9A]

Haven't seen too many engines where you can get the piston out from below without removing the crank.

Really? Is the 3AC one of them? I've done it on various other motors (mostly Honda and Acura motors). It was just a matter of spinning the crank and manipulating the connecting rod and pulling the piston out. Maybe I will have to pull the head. Crap.

I'll give it a shot and report back on whether or not I was successful.

[takza]

Can't say for sure...maybe someone with an engine partially apart could test it for you?

[ChrisC]

If you havent determined your problem yet and before tearing it down. Just take a look at the cam bearings, its not too hard and If you say there is a knocking sound It could very well be. It could happen to be something simpler then teariing the engine down. Just my $0.02
Good luck hope its not something really involed

[Petros]

"CT9A" wrote:

>Crap, that's exactly what happened with cyl. 1.

Just to make sure what you mean by "that's": With the engine running you pulled the no. 1 spark plug wire, and the knocking stopped? If so, it means you have a serious piston/wrist pin/rod bearing problem. Do not drive it, or you can throw a rod and have to replace the whole engine.

>... tell me if this is do-able. Drop the oil pan, pull the piston, re-ring and/or replace the piston/connecting rod/wrist pin/etc.

NOT do-able. You have to pull the engine, you can not get to it from under the engine. The trans-axle is in the way of the oil pan and there is no way to get to the crank and connecting rods. It is easier to pull the engine than the trans axle anyway (use the free hoist rental from AutoZone if you do not have a hoist). And I can not see how you can remove the piston from the low end anyway, there is not enough room. I have rebuilt 4 of these engines, I do not think it could be done even if you could pull the pan. And I do not see how you can compress the rings to get them back in either, not enough room in the crank case.

Even if you could do it, it would not affect the camshaft, who ever wrote cam will be "off" must have been thinking of something else. Once the engine is out, the head is off and the bad piston is removed it is possible to just replace the piston/rod/bearings on that one cyl, but I am not sure it is worth it at that point (depending on what caused the knocking). You many only need a connecting rod bearing (best replace all of the connecting rod bearings, they are only about $20 for the set). If you are careful you will only need a head gasket, and a pan gasket, and possibly a head pipe gasket (where it meets the manifold-about $40 all together). You leave the intake/exhaust manifolds on with the carb, and sometimes the head pipe gasket is reusable if it is metal and in good shape. You could probably do this, and replace all of the connecting rod bearings (with one bearing shot, the others will soon follow), and the rings for about $100. Once you have the pistons out you should make sure they are not damaged. If any are damaged, all of the pistons need replacing, but for low budget, if any hard parts need replacing you should just get a used engine and drop it in. You can pull your own engine from a Pull-a-Part wrecking yard for only $150.

This is what I suggest:

1. First pull the head (it has to come off anyway), leave the intake/exhaust manifold, and the cam shaft bolted to the head. Than rotate the crank and observe the piston movement. I have had the piston skirt fail on two different high mileage engines (cylinder wear caused piston slap which eventually failed the skirt). The engine was still running, it just made a loud clacking noise, and with the head off you could see it rocking back and fourth about 20 degrees when the crank was rocked back and fourth. Also inspect the exhaust valves while the head is off, I have seen burned exhaust valves on a number of stock engines. If the klacking is the piston skirt, the bores and pistons are worn, they have to be over-bored and new oversized pistons installed. Unless you want to go the full overhaul, if the pistons are worn and slappy, it is time to replace the engine (just get a used one), or part out the car, or just sell it to a wrecking yard.

2. If the valves are okay and the piston movement looks good (up and down only, no side to side slap or rotation) , then you have to pull the engine. With the head off, the engine is light enough for two strong guys to lift it out with a lifting strap over a 6 ft beam or pipe, one guy on each end of the beam. A third person to help pull it loose from the trans and guide it out is a big help. Or borrow an engine hoist (tip: if you have an overhead beam in the garage or shop, or even a stout overhead tree branch, a simple hand winch or "come-along" will do it).

3. With the engine out, drop the pan (after cleaning it off) and remove the connecting rod cap and inspect the bearings. If there is any copper showing, or there is flaky gray metal in the upper bearing, than that is likely the problem (the engine was run "dry" of oil). You can then replace all of the connecting rod bearings for only about $20. If the bearing journals are scored or streaked it can be polished out with 800 grit sand paper with a cord wrapped around the journal several turns, with the sand paper and solvent around the bearing. It is not likely the main bearings were damaged, these are pretty tough and you usually will throw a rod before a main bearing fails. I would not hesitate to reused the main bearings if the lower half is evenly worn and there are no flakes or copper showing. DO NOT MIX UP THE ROD CAPS, typically the Toyota factory does not number them, so it is up to you to scratch or scribe a mark to get them back on the right way and on the right rod (they are NOT interchangeable). Tip: if you carefully remove the pan without tearing up the pan gasket (not usually possible on an old engine) it is possible to reuse the old pan gasket. I have done this, use a knife to carefully cut it free from the block side, leave it stuck to the pan. Do not be too concerned about it however, this gasket is only about $10 IIRC.

4. If the bearings are good to fair, all gray (even if streaked), and the crank journal is in good shape, the problem is probably at the piston/connecting rod. Slide the piston up and out and carefully inspect it for slop in the writs pin (this should be a very tight fit). Any clearance than it is junk, same with the piston skirt (there should only be 0.003" between the piston bore and the piston skirt), any damage on the skirt and/or ring grooves, the pistons are junk. Probably cheaper to replace the engine at this point with a used running one if the pistons, writ pins and/or bores are damaged.

Realize at this point of tear down you have not spent any money except to get the hoist and tools to pull the engine. It would take me about 3 or 4 hours to get to this point with a hoist available. This is the best way to go, doing only one step at a time and only going as far as you have to. Remember, all tool rentals at most AutoZone store are free (you pay a deposit, and they refund the money when you return the tools).

If it turns out to only be the rod bearing, I suggest replacing the rings while you are at it. They are only about $30 for the set (I suggest the plain cast iron or "economy" rings, they cost less and seal better than the "premium" rings), you will have to rent or borrow a cylinder hone and ring compressor to put the new rings back-in.

If you find you have to replace engine "hard" parts, the cheapest way to go is replace the engine with a cheap used one. You could also opt for a full blown overhaul at that point as well. It will cost a lot more, perhaps $600-700 and take more time. But it might be worth it if the car is in good shape. You will have to replace the pistons and overbore the block, new rings and new front and rear seals, as well as new bearings, and a valve job with new seals, head resurfaced, etc. But the engine will be good for another 200k miles or so.

Good luck.

[CT9A]

Why would I need to get the cylinders over bored, do they not make a stock size?

I would like to rebuild the car, it's a freaking tank and has gong everywhere it's been asked to.

Thanks for the write up. I'll probably be starting down this path tomorrow. Let me know about the piston/over boar issue. Is it possible to just over boar all 4 cylinders and put performance pistons in (if the exist for this engine)?

[takza]

My guess? If you can find a decent original Japanese built engine...you would be better off than going the rebuild route.

[Petros]

They make std. size pistons, but If the cylinder bores are worn enough to allow piston slap, they have to be overbored and new oversized pistons installed. i learned this the hard way once, a piston skirt collapsed and caused a klacking sound. Not ever have this happen before, I thought I could just hone the bores and put in 4 new std pistons (they were only $22 each at the time) and new rings and bearings too. My reasoning was that with new pistons would have less clearance than the old worn ones that caused them to collapsed. I did not measure the clearance since it was the best I could get with worn but rehoned bores. It ran well except at certain rpms there was a noticeable chatter noise, which was piston slap caused by the extra clearance. within 3 months of daily driving, the new pistons also lost their skirt and the exact same klacking noise came back, burning oil and lots of blue smoke this time too. I did the whole rebuild over again, this time paying for 4 new pistons and overboring it. I have had no problems with it since, and the engine runs quiet since there is no piston slap or chatter.

So my rule now is, if the bore is worn enough to cause piston slap and skirt failure, then they have to be overbored. If one is worn enough to cause piston skirt failure, than the others are not far behind, they all need it. You also want all the pistons to weigh the same and to displace the same.

Yes, I did put in performance pistons. I suggest putting in flat top pistons to raise the performance, if you have to replace the pistons anyway. They are available from Sealed Power (part #12151P) in std, 0.5mm and 1.0mm oversize. I went with the 1.0 mm oversize to get the most power out of it. I did the major overhaul because I wanted as much power as practical, so I when flat top pistons, performance reground cam shaft, port and polish, resurfaced the head, new later style oil pump, lightened the flywheel, and balanced all the moving parts. New bearings while I was at it. Later I put in new exhaust valves after several of the old ones burned up, and I advanced the timing to 10 deg.

Now I got great power and decent economy (27-29mpg mixed, 34 mpg hwy). But I have to use premium fuel and I have had head gasket problems, which I may have solved (I will have to wait and see).

A lot cheaper way than this is to just buy an imported low mileage crate engine from an importer. I would have done this if I was not trying to get more power out of it. It is cheaper, less trouble and great value to get the imported crate engines, I have done it on other cars I own.

Good luck

[CT9A]

What makes the imported motors so much better? Where would I go about finding one? I can't even seem to find a used 3AC at all.

[takza]

search "JDM"?

[Neu]

What makes the imported motors so much better? Where would I go about finding one? I can't even seem to find a used 3AC at all.

If you can't find an imported (i couldnt) goto a junkyard. My engine cost 350 dollars.

JDM is superior because the japanese have emissions laws/efficiency. After 30k the engines are going downhill from there, and they replace the engine, and ship it over here. Most crate engines are around 30k, I think, it might be a different number thoug.

[Petros]

What makes the imported motors so much better? Where would I go about finding one? I can't even seem to find a used 3AC at all.

What these are is used low mileage engines imported from Japan. There very few of the cars get more than 30-40k miles on the engines because of government mandated service intervals (There it is cheaper to get a new engine than overhaul the engine that came in the car). So the wasteful "make work" policies of the Japanese government is our gain. These are usually the "long block", though many importers are including the whole running engine, but usually the intake/carb and exhaust system will not work our cars. You have to switch the intake and exhaust systems, and usually the oil pan, and sometimes the front pulleys and flywheel. Even with that, these are excellent engines typically in the $400-500 range, which would be less expensive than gaskets, bearings, rings, pistons, all machining, on an overhaul, not even counting your own labor.

Most major cities have importers of these engines and even transmissions too. Look in the auto section of the local major newspaper for ads. You can also find them on-line, but they may charge you a shipping charge. The local supplier will sometimes even deliver the engine to your place at no extra charge.

For getting a good running factory spec long block, they are a tough deal to beat. The 3A or 3AC engine is getting more rare, but they are still available through some suppliers, also check for 4A or 4AC, these are almost identical engines with a bit more displacement. But if you want to teak the engine for more power at all, this would be a tough call since you would have to take it all apart and replace gaskets and internal parts anyway.

Good luck.

[keith]

I lived in Japan for 3 years. 30 or 40k miles may not sound like a lot of miles to you, but in Japan, thats a LOT of miles. I completely wore out an engine in less than 40k miles. You spend a lot of time idling in traffic and moving very slowly. Its tough on clutches but transmissions don't get a lot of wear.

Its hard to covey the concept of how bad traffic is there, but when I landed in San Francisco, I took a cab through downtown at 2 PM on a weekday and felt like I was in the wide open spaces. Its not just the traffic. Housing is so crowded, you can't imagine it. I saw a house built on stilts over a train track. The only reason we didn't have but one neighbor is that the duplex we lived in was sitting on a cliff. We had to climb 64 steps from the parking space to our home. It was another 64 steps to the housing above us. Our first 2br 1ba apartment would fit in our living room here, and we don't have a big house. That was considered a luxury apartment too, it was at a country club located above the emperors winter palace at Hayama.

BTW, they rarely replace engines in their vehicles. Its the safety and beauty inspection that gets you over there. Its very expensive, almost the cost of a new car. The first inspection is required at four years, then every six months after that. As soon as the car reaches 4 years old, it goes to the junkyard and a new car goes into the parking spot, which BTW, the rent on the parking space can be more that the rent on the apartment.

The Japanese compensation system encourages large purchases as well. Salaries aren't all that high but workers get huge bonuses once or twice a year. Each bonus can be as large as the annual salary in a good year. The bonuses go toward the vehicle or large electronic purchases or vacations.