KevinAndrew

Hey guys, I recently got an s13 and was hoping to start building her up and maybe make a thread on here of it but I came into a bit of a problem. I've got a pretty brutal rod knock, I took the car to a shop in town and one of the mechanics said I'd need a new rod and crank. I don't have a lot of money and I know not to always trust an auto shop so I was wondering if anyone could give some insight on what might have caused this or if anyone's had the same problem.

Thanks!

curo72

Post a video of it.
What causes rod knock? Bad rod bearing. Usually a result of something going wrong with the lubrication system. Low oil, bad oil pump, clearances too tight or too loose. Or it might have just been seriously ragged on. It's one of those things that common sense will usually prevent.
If it is rod knock you'd likely be better off just dropping a junkyard engine in it.

mechanicalmoron

The mechanic's right.

Before getting an engine, you might get a quote from the mechanic on doing the rod and crank from below, with the engine in the car. I assume since you're dealing with him, you're not the one who would be fixing it or swapping motors - I'd guess the price of a motor AND his labor to swap it would be considerably more than just his labor and the parts to do the rod.

KevinAndrew

That's the thing I'm not completely sure I don't have a garage or enough room in the driveway to pull it myself or I would so I could look for myself. The mechanic said I need a new rod and crank and I know that's going to be expensive. If I could look and see what exactly is going on I'd be more comfortable buying the parts myself and taking the car up to the shop. Thanks for the advice, I'll check my oil pump, my oil levels are good. And I'll get a video up on here tomorrow hopefully.

KevinAndrew

That's a good idea, I'm not sure how they were planning on doing it but I definitely couldn't afford for them to pull the engine and fix it that way. Thanks for the idea!

KevinAndrew

Extra info, it's a ka with nearly 300k miles that's been bored .5 over on cyl 1, 3, and 4. Cyl 2 is .6 over and I've had problems with it before, also the mechanic that looked at it when I had the head cleaned up said cyl 2 has has problems before. It also has cams, not sure of the size as well as a chip. I'm strongly considering throwing in a stock KA from an s14. My only reservations with that is the head it clean as a whistle I spent $1800 on it getting all cleaned up already I really don't want to scrap the engine as a whole.

Kingtal0n

oh my god. Get another engine- complete with around 100-150k miles should cost you $300-$500 max. Get one thats never been opened.

I just saw a local KA24 from a 1998 go for $300 complete with automatic trans, all accessories and wiring and ecu. It had 98,000 miles.

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KevinAndrew

well if you happen to stumble upon another let me know, I can't seem to find any that haven't been butchered.

mechanicalmoron

Well what problems have those cylinders had, specifically? If your motor has bad compression or something, get a new one, but if it's all good, that may not make sense, especially with your money into that one.

KevinAndrew

I'm not completely sure but when I had to have my head cleaned up it was due to the amount of fuel that the chip was telling my injectors to send, ended up frying the piston rings and clogging my injectors. The mechanic told me that wasn't the first time that cyl 2 has had issues, he said he could tell it had been worked on multiple times before.

curo72

I'd be extremely hesitant to just replace a single rod and a crank. Extremely. Like you said, pison two has had issues before, and it sounds like the current setup has been less than reliable before. In order to replace the rod and crank you'll have to replace the bearings on the other ones. If chunks of bearing didn't get embedded into the other bearing surfaces, they'll at least need to be matched to the crank properly, being that OEMs make bearings of very slightly different sizes to make up for slight variences in the manufacturing process, and to allow for machining.

Also, small bits of bearing might have gotten carried up to the head. You'd be gambling a bit if you don't get the head cleaned, as that could score cams or make it's way back to the sump, and as a worst case scenario, it could make it's way back to the bearings again, which could result in yet another wrecked rod bearing and eventually rod knock.

KevinAndrew

That's a great point, I was really not wanting to just replace the crank and rod anyways due to the "oddness" of the block itself. My friend has a stock block I can buy but cyl 2 and 3 have about 2 inches of very slight surface rust at the top, which isn't good but I've heard it's not the worst thing if I just get it all polished up. I also plan on getting rid of that chip. All this will cause a pretty significant drop in power but i really don't care at this point aha. I just want to be able to drive my baby again. Also i can't risk my head getting messed up again because as I said I've put $1800 into it for it to get all cleaned up and machined and other good stuff.

curo72

So... I realized this morning that I've been getting a few things mixed up here. I think it's usually the crank bearings that have to be sized matched. I'm not sure about the rod bearings. I imagine they would have to, but I'm really not too sure. And most bearing material *should* either stay at the bottom of the sump, or get caught by the oil filter. Only time it would make it to the rest of the engine is if some of the oil would get by-passed the filter, which isn't terribly uncommon, but... I just don't know.
Regardless, it is becoming apparent to me that I don't know enough to really help you out, and worse, may be spreading false information. I'll humbly bow out of this conversation and wish you the best.

KevinAndrew

Gotchya! Thanks for trying still though. Some points you made did help! And Mad props for owning up to your mistake! Thanks again.

240BrittonHatch

I spent over 1k just at the machine shop to rebuild mine...

KevinAndrew

Congratulations.

Kingtal0n

I have a spare KA24DE in my backyard with 145,000 original miles. Runs great doesnt burn a drop of oil. has a 5-speed still on it. PM for more details and price if anyone is interested. I am capable of shipping it as well, it will go on a pallet, wrapped up and strapped down.

I would never have a KA rebuilt. Not worth it. An SR20DET engine by itself, S14 with around 60,000 miles can be had for around $1500. There is one local to me right now for that price in fact I was looking at.

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5.3/4l80e/turbo 240sx playthrough:
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