Quote:
Originally Posted by sre30s14
So if I buy a new long block I can't tell if its been opened before as well. So how do you approach that dilemma?
My engine builder opened the block and found out the pistons were scored from the previous owners mistakes in their rebuild.
But say if I buy a new block how would I know if that will run fine? That it too doesn't need a rebuild?
Sorry for derailing, my thing became a mess as usual. How simple things start I guess.
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It takes experience to inspect an engine. From 2005 to 2012 I inspected around 1000 imported JDM engines and installed and tuned many of them.
Some rules:
Never take the engine with modifications, always look for factory air box, OEM air filter, OEM nuts and bolts, OEM silicone color (is it white around the valve covers? iirc).
Must have factory turbo and complete factory PCV system.
Inspect the intake, compressor, and throttle valve for signs of pitting due to improper air filtration.
The engine should not appear washed (pressure washed) look for signs of being harshly sprayed (oblong or strange marks in the filth where a high pressure stream left signs)
Its OK to pressure wash the engine but YOU should be the one to do that
Look at all the plugs for signs of abuse they should all look the same and be pretty clean, but not NEW or recently replaced (look for good looking old plugs with factory heat range 6)
The rest is experience I guess, you have to be able to detect modifications and errors in the setup easily. What you want is a 100% untouched stock engine with 80k or 150k miles, those are ideal. But sadly there are none left so this is all moot....
In todays world your best effort is to find one that hasn't been apart, still has all the OEM equipment, its okay if the turbo is leaking or smoking as long as its factory, check the plugs and health of compression and stuff, make sure all the pcv is there, everything is good its just tired. Make sure its always had a paper air filter, factory air filter or similar (ONLY PAPER).
If you get the 100% factory stuff, paper filter, well maintained, smoking turbo leaking engine, 250,000 miles, it should still have clean looking oil if there was a full PCV system and PAPER air filter, that is the ideal candidate to rebuild back to stock. Hone the cylinder throw in some new rings and use the color code bearing system and its good to go with a new chain and some head refresh.
Reverse checklist (same thing but what NOT to buy or do)
Never take or try to rebuild an engine with:
1. modified PCV system
2. aftermarket air filter
3. aftermarket turbo
4. internal modifications
5. "head" work or "cam" Upgrades
6. very dark/black oil
If the PCV system or air filter is modified there is a good chance that any rebuild no matter how careful you are will fail due to debris inclusions ingestion which is undetectable by the human eye and can not be washed out by any machine shop or process we have.
IF the turbo was modified there is a chance the engine suffered some abuse due to erroneous tuning or fuel quality etc...
Any internal or head mods also lead to failed rebuilds frequently because most machine shops and individuals do NOT know enough about SR20 engines to effectively perform those mods
Very black oil and dark oil is a sign of poor maintenance and lack of suitable PCV and air filtration during operation, the black tar-like goop you see is MUCH worse in the stagnant reservoirs of JDM engines (in other words, if you can see dark oil on the dipstick or from the oil pan, it must be MUCH worse in the places you CAN'T see) And this leads to oil system issues (varied) which can not be corrected by any general means we have available and likely the reason the engine is for sale or ruined.