Does anyone know the exact purpose of grades of the OEM KA24E/DE engine components such as pistons and main/rod bearings? When I tried to order some aftermarket ones online and asked them about my respective grades retrieved from the block/crank/pistons, they said:
"Thats not how aftermarket suppliers work,they are all grade 1 you just order them by size and both in pistons and bearings(std,010,020 etc)Sincerely,PhilTech/Sales DeptFlatlander Racing/IPP(603) 378-0090"
What do you know about this? Please don't tell me to go measure my stuff and order what I need, as I will do that later, but right now I want to know what relation the grades have to the sizes of the components.Here is the odd thing: One of my spare blocks has the following piston grades (1 through 4): 1 1 2 2. The other has 2 2 2 2. What difference does it make?
sil80
The purpose of grades of internal components?
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sil80drifter
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Re: The purpose of grades of internal components? (sil80drifter)
Probably about .0001".sil80drifter wrote: What difference does it make?
I think the word "grade" is getting confused with 2 different meanings. The grade that the sales guy is talking about is probably material/quality. He may have not been there very long. "Grade" as used by the FSM is to differentiate between various bearing sizes. When they machine the holes, they can't control the diameter *perfectly*. There's always a little variation. But they can measure the difference and they use different thickness bearings to compensate. Differences are *tiny*. A sheet of paper is about .003" thick. The bearings differ by around .0001" between grades, or 1/30th a sheet of paper. The FSM should tell you the exact sizes for each bearing--just correlate them with the stampings from the engine. If your vendor doesn't know which grade is which, just give them the sizes from the FSM.
EDIT: It could be that the sales guy is correct--maybe vendors don't make different grades of parts. Whereas you could get .1000", .1001" and .1002" thick bearings from Nissan, perhaps the aftermarket only sells .1000 thick ones. You still need nominal diameters from the FSM.
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sil80drifter
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- Joined: Sun Aug 18, 2002 5:53 am
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Thank you fro the response. I happened to e-mail a technician from Clevite and he said:
"The O.E. makes a ton of pistons at once, and they put a number (Grade) on each run. Those pistons are size and weight matched so that they don't put 2 different weight pistons in the same engine. It does not necessarily mean different size pistons. Sometimes it does though I know like in the case of the Chrylser 4.0L jeeps.
In the aftermarket you buy a piston first, then bore your block to fit the pistons, so there are no grades. So as long as you replace as a full sets, and you are not doing a high performance build, you will be fine."
All I really wanna know is, if I have this stock engine (with 70k miles on it), and I wanna replace pistons/rings/bearings, can I just order aftermarket ones that are standard sized, and not have to do any machine work?I really don't wanna spend time/money on machine work.... *sigh* stock is stock dammit.I hope.
sil80
"The O.E. makes a ton of pistons at once, and they put a number (Grade) on each run. Those pistons are size and weight matched so that they don't put 2 different weight pistons in the same engine. It does not necessarily mean different size pistons. Sometimes it does though I know like in the case of the Chrylser 4.0L jeeps.
In the aftermarket you buy a piston first, then bore your block to fit the pistons, so there are no grades. So as long as you replace as a full sets, and you are not doing a high performance build, you will be fine."
All I really wanna know is, if I have this stock engine (with 70k miles on it), and I wanna replace pistons/rings/bearings, can I just order aftermarket ones that are standard sized, and not have to do any machine work?I really don't wanna spend time/money on machine work.... *sigh* stock is stock dammit.I hope.
sil80
If the maintenance has been good for those 70k, then the answer is "probably". But it's impossible to know with certainty without actually measuring things. Bearings, rings pistons and blocks do wear over time. So what the factory installed 70k ago is at least a tiny bit worn now. If the bearing clearance was .0015 when the engine was new, it could be .0020 now, or maybe worse.
The bottom line is that if things were in perfect shape, you wouldn't need to replace any of those things. 70k really is NOT all that much with good maintenance. Have you already checked compression and oil pressure? If the numbers are good, I'd leave the internals alone, unless you need to upgrade for forced induction.
The bottom line is that if things were in perfect shape, you wouldn't need to replace any of those things. 70k really is NOT all that much with good maintenance. Have you already checked compression and oil pressure? If the numbers are good, I'd leave the internals alone, unless you need to upgrade for forced induction.
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sil80drifter
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- Joined: Sun Aug 18, 2002 5:53 am
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Technically the block is in an unknown shape. It was given to me by someone who didn't need it after it was taken out due to timing tensioner failure (common for SOHCs). There was coolant in the oil, but the engine was shut off immediatly and not used since.I haven't been able to test compression and oil pressure because it was out of the car when I got it.I am rebuilding it for turbo, as my own turboed stock SOHCs rings went south. Worst case scenario, when I take the 70k block apart and see that there is crank damage, I'll use my crank from the other engine, and rebuild the other block instead of the 70k one.
My logic is: 70k block is better (even with having been out of comission due to timing chain issue) than my 140k block, that I've beat on continuously. My 140k block has seen overheating, low oil pressure and obviously bad rings. the 70k one only saw a bit coolant on the oil and supposedly no damage from it (I'll be certain of that this weekend).
sil80
My logic is: 70k block is better (even with having been out of comission due to timing chain issue) than my 140k block, that I've beat on continuously. My 140k block has seen overheating, low oil pressure and obviously bad rings. the 70k one only saw a bit coolant on the oil and supposedly no damage from it (I'll be certain of that this weekend).
sil80