High Mileage Engine Question

[MoldyOldy240]

Hey gang,

I'm planning on doing a beefy rebuild on my engine (91 KA24DE) when it hits 300K. All the sensors, gaskets, pistons, springs, valves and cams will be replaced with OEM or better components.

I have some concerns with the block; being that it's mileage is so freakin' high. Other then getting the block magnafluxed, is there anything else I should do to make sure the block is in good enough condition and worth rebuilding?

[tero404]

if the engine hasnt been built before i would send it out to get machined because most machine shops test it for cracks and weaknesses before they give it back to u, but if it would make u feel better, u can just buy another block for cheap and machine that

[MoldyOldy240]

I'd love to keep the same block; I'm very proud of the condition of the engine right now with the high mileage. Kinda stupid, I know, but it makes me happy

I've been reading a little here and there and where I am standing right now is:

Have the block tested for cracks and weaknessCleanedBore to fit a +.020 Forged CP PistonPauter Forged RodsKnife and balance the crank (also check for weakness)Crower Titanium retainers and springs with oversized valves3 angle valve jobCrower Cam 264/264 duration

If anyone has any input or other ideas, feel free to suggest.

My overall goal is to make a KA24DE as bullet proof as I can through the after market, and hopefully free up a little more power while staying in the California emissions guidelines (if not, then I guess I will have to get a spare lol). In the future I may turbo, I may not. So low comp pistons aren't an option for me.

[comatoseculture]

My instructor always suggests doing a cylinder leakage test. It is an inexpensive, quick/easy way to check for major/obvious issues. It is sometimes better suited for testing then a compression test, such as, when you cannot start a motor (out of vehicle, etc.) Not revolutionary, I know, but i thought I'd suggest it.

[dirtyfingers2]

damn 300,000 thats good.just do what you had listed.good luck.btw turbo the **** out of the ka. it'll handle it.just make sure you get a good tune for it.

[spank044]

My '92 had 338,246 miles on it when I pulled it out and the bottom end was still in spec. I had the rotating assembly balanced and the block decked for $260 and rebuilt it myself with ARP head studs and a MLS. Now it boosts 27psi daily and couldn't be more fun.

Didn't you know that Nissan's come bulletproof from the factory!

[blackRB240]

When a block gets machined after being magnafluxed and checked for cracks, it is practically brand new again. You could have a motor with 800,000 miles and it wouldn't matter as long as there are no cracks.

[liquid_cool]

not all machine shops are good ones..trust no one in the world of engine machining..you need to buy (T-Handle style telescopic meshuring instermends) forget the name off hand..and a micromeater set and a digital caliper...all can be had at (horbor frieght ) for about 60.bucks..next

you need to double check there work buy meshuring your bore in (MM)..take a minimum of 6 meshurements in each cylinder..top and bottoms....verify there bore..take your time and be carefull..write each meshurement down...after 6 or so times..if your getting larger meshurements at the top..and smaller at the bottom..or vs-versa..then your taperd...you may allso want to check for alighnment of each cylinder..there are many ways to do that..at a machine shop..for home..i dont know..maybe another nicco head would know..next..i would meashure all my main journals..making shure there the same (line honed would be preferd)...last but not least...i would look over the cylinderwalls for sighns of pitting...pitting comes from the casting prosess making bubbles in the metal surface..if there are alot of them..or large ones..they can be fatal to your build...id allso look for proper decking...if ya want to understand more about looking at a block in depth..then i HIGHLY RECOMEND! ( Engine Blueprinting) one of the SA brand books found at any bookstore...good luck bro..let us know how its going from time to time.

[blackRB240]

^^^

[liquid_cool]

^^^

dont know why you would say wierd to that man..it seems you dont understand ....i suggest you read the same book..after a few of your comments (quote"let it rattle , its no big deal") you could benifit by reading some more...im not flaming ya down..just questioning your judgement.