First Time Engine Work

Advanced discussion of improving KA-T components
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theultimatehero
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First Time Engine Work

Post by theultimatehero »

Ka-t folks! I really enjoy this forum and I've come across a ton of useful information. I have done some searching and I really hope someone can either point me in the right direction or maybe write up some advice.

I bought a full KA engine that has a mysterious past. I have been told a couple different stories. It may have had some engine work done at some point. Apparently it may have a built bottom end, machine work etc. I really have no idea. The other story is how it came into my possession. The engine was in another guys car and it blew a coolant line. Evidently the owner was a bit ignorant and drove the thing as it overheated and eventually died. So I bought it with the intention to take it apart and see if the engine can be saved.

I have found a good amount of information on building engines but I'm looking for information specifically pertaining to a KA if it has overheated to that extent. What can I expect to find? How will I be able to determine the work that has to be done in order to get it into good running shape?

My plan is, assuming it is salvageable, to rebuild the engine with just slightly upgraded components and with correctly fit bearings, rings, etc. Of course including whatever machining will be required. Then swap it into my s14 with the intention to boost it. This is my first time building an engine so any tips to make sure things go smoothly would be appreciated. I work in mechanical engineering as a tech so I am confident when it comes to mechanical stuff, measuring, etc.

Thanks for your input!
SIL8D
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Re: First Time Engine Work

Post by SIL8D »

You would straight edge the deck of the block and the head to see if anything is warped.maybe a pressure test the head also
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airman
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Re: First Time Engine Work

Post by airman »

An overheated engine can suffer these [catastrophic] things in order of least **** to most ****.

- Blown head gasket with no other damage. Usually this goes in-hand with a warped head/block combo, but not always. A good resurface/decking is definitely recommended. A good plastic scouring pad can clean up leftover gasket material on the block surface, this is much less likely to warp.
- Can valve stem seals handle an overheat? I imagine they could, I don't know. I think the melting point of Viton is around 400 deg F so probably alright unless it was a really bad overheating...I always put in fresh ones anyway :)
- Warped head. If under 0.010" out of flat, this can be machined okay. I wouldn't take off any more than that though, most good machinists will tell you a new head is ideal. Either way, if your head is warped, you'll know it - head gaskets will not last. You may even leak coolant/etc.
- If the engine overheated enough to warp the head, then chances are you may have glazed over the cylinder walls. This is a good reason to give your cylinders a fresh honing and replace the rings.
- Oil gets too hot to properly lubricate engine. Spun rod bearings/etc.
- Cracked head/block - complete replacement

You seem to have the right idea! I'm sure this isn't anything you don't know, but I felt it's relevant info for others :)

Practically any time I am building an engine that belonged to someone before me, I have the head and deck resurfaced (50Ra or better on the smoothness since I typically go MLS gasket - don't forget your upper and lower timing covers! This is a nightmare if you forget to have them machined at the same time...), a good hone (and a bore if the cylinders are undersized for my pistons, I usually go 0.020" over since it's best to match the piston to cylinders so sidewall clearance is even. This is why it is a good idea to bring the pistons to the machinist so he can properly set the sidewall clearance in each cylinder), and a good crank journal polishing.
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TrackStarGT
Knows Some Stuff About 240's!
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Re: First Time Engine Work

Post by TrackStarGT »

these KA iron blocks can take a beating and some moderate overheating and be just fine as far as still being usable, machining being necessary of course. The aluminum heads however are not so resilient. Aluminum heats up and cools a little faster than ferrous metals. Which means better chance of warping and cracking. Airman pretty much said everything that needs to be said. I am currently running a block that was overheated and it is doing just fine. But checking for warpage and cracks will be your determining factor as far as re-usability. Then of course all your run-of-the-mill machining will be necessary for a rebuild. With boost being slated for this motor, all that would be happening anyways, whether it was a perfect, healthy, low-mile engine to begin with, ya know.
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theultimatehero
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Re: First Time Engine Work

Post by theultimatehero »

Thanks for all the input guys! One of the things I have heard about is having a block/head inspected for cracks. There is some kind of common NDT procedures used for checking these things I assume, is that something I should look into? Considering the possible serious overheating I am fearful if there are cracks somewhere I might miss it due to lack of experience. Do engine machinist typically offer something like that?
Missile
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Re: First Time Engine Work

Post by Missile »

They can check for cracks with a procedure called magna fluxing its usually not real expensive either.
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