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Old 03-02-2008, 12:08 AM   #1
wrxG
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Default Built motor.. first startup knock.

So I have built EJ257 with Eagle rods, Wiseco pistons and Cothworth Crank bearings with 2.0 WRX heads. I stardet the car up few days ago and it started knocking right away. I have no idea what could of went wrong. Some people tell me its the rod bearings, I have no clue how could that get messed up, but other people tell me that it could be the Wiseco pistons, they say Wiseco pistons dont fit well and it could be really bad piston slap that I'm hearing.

If anyone knows what could be wrong or give me some advice please do. It took me alot of time and money to do this the right way and it seems like it was all for nothing.
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Old 03-02-2008, 12:45 AM   #2
reddevil
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First off, did YOU build the motor?

Did you lube all the bearings, crank, cams with engine lube as you assembled? Basically did you grease all the contact points?

When you first fired it up, how did you do it? You should discconect the injectors and plugs and turn it over about 20 seconds at a time with 20 seconds (the way I do it) between until the dash oil light turns off. THEN you can turn it over for real.

At this point you can fire it up. And it WILL make funky noises. Sometimes for 5-10 minutes. And if its making funny noises AND you are lucky, those damn funny noises will just DISSAPEAR! Had it happen to me about 4 times or more. Its just stuff ticking away until it either wears in or gets fully lubed.

Or you could just be ****ed.
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Old 03-02-2008, 01:49 AM   #3
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Wiseco Pistons are very noisy when cold..... I would have used a different piston set up, but let the engine warm up every time with those or you will pay the price.... I raced jet skis for 10 years and was sponsored by Wiseco and had lots of bad luck with the pistons and rings..... Good Luck
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Old 03-02-2008, 07:21 PM   #4
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Yea i used assembly lube and i did crank over my motor for like a minute to get oil going through the motor.. I did build it myself, this is my second time doing it.. first time went well and im not so lucky on my second time and i did everything by the book.
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Old 03-02-2008, 08:10 PM   #5
WRXINTX
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did you get oil pressure for sure????

knocking only happens for two main reasons...

1. lack of oil pressure

2. too much clearance
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Old 03-02-2008, 11:06 PM   #6
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no im really not sure if i am.. i dont have a gauge or anything.. how could i check?
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Old 03-02-2008, 11:15 PM   #7
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you should have already bought one.
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Old 03-02-2008, 11:17 PM   #8
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Here's a bunch of questions for you.

Is the EJ257 block new or used?
Have you matched "bored" the cylinders to match the pistons, or did you just drop in the pistons?
Did you check the piston to cylinder wall clearances?
Did you check clearances before assembling? (Plastigage the bearing mating areas when torqued down to spec)

Sorry for all the questions, just want to understand your build. Maybe more questions to follow depending on the answers.
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Old 03-02-2008, 11:58 PM   #9
wrxG
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Quote:
Originally Posted by JoeT View Post
Here's a bunch of questions for you.

Is the EJ257 block new or used?
Have you matched "bored" the cylinders to match the pistons, or did you just drop in the pistons?
Did you check the piston to cylinder wall clearances?
Did you check clearances before assembling? (Plastigage the bearing mating areas when torqued down to spec)

Sorry for all the questions, just want to understand your build. Maybe more questions to follow depending on the answers.

Its a used EJ257
I ordered stock bore size pistons, i did not check for clearances though. I didn't think i would have to since the pisons should be the same size right?
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Old 03-02-2008, 11:59 PM   #10
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Quote:
Originally Posted by blahhblahh View Post
you should have already bought one.
Yeah i know .. but now i dont want to buy anything else for it
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Old 03-03-2008, 01:42 AM   #11
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Quote:
Originally Posted by wrxG View Post
Its a used EJ257
I ordered stock bore size pistons, i did not check for clearances though. I didn't think i would have to since the pisons should be the same size right?
First, you need to check your bearing clearances! You can get "Plasti Guages" which are cheap ~$2.00 and very accurate. Second, you need a honed surface to seat your rings. Then best thing to do is to take the block halves to a machine shop to have them checked.
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Old 03-03-2008, 02:07 AM   #12
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however, pistons dont need to seat (right away) to cause knock....
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Old 03-03-2008, 02:13 AM   #13
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Quote:
Originally Posted by reddevil View Post
however, pistons dont need to seat (right away) to cause knock....
I was thinking down the road. All though a non seated piston may not cause knock, it would still be nice for it to seat one day;-)
Also, dropping an unmeasured piston into a bore that you have not measured, but "think/hope is stock" and praying you are not running too much/too little clearance is asking for funny noises.
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Old 03-03-2008, 05:28 AM   #14
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Quote:
Originally Posted by wrxG View Post
Its a used EJ257
I ordered stock bore size pistons, i did not check for clearances though. I didn't think i would have to since the pisons should be the same size right?
from the factory they use 2 different size pistons, marked A and B. who knows where the clearances wound up!
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Old 03-03-2008, 07:55 AM   #15
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Wiseco supplies recommended clearances for their pistons, and a knowlegable machine shop would also know how to properly size the bores to match pistons.

When buying a used block, it's always a good idea to check the bore size to make sure that the clearances are within the acceptable range for the intended pistons. Normally when using "used" block, it's a good idea to get a 1 over piston (oversized) then have the block machined to match each piston. While they're at it, the machine shop can also "gap" the rings for you.

From there it's a matter of checking the other clearances like, big end (crank bearing clearance), connecting rod bearing clearance, etc. etc. using a plastiguage. It's also good practice to have the crank surfaces re-polished while it's out.

Things to note: If your bearing clearances are too wide, your oil pressure will be low.

In your cast, my guess is that you've got excessive clearance between "stock sized" wiseco pistons in an enlarged bore from a used EJ257.

I used to use Arias Pistons and Pauter Rods on one of my engines, that was noisy, since the Arias recommended tollerances were wide. I'm currently using Wiseco Pistons on Eagle Rods, and it's a quiet combination. When warm it's almost as quiet as OEM, when cold there is a bit of slap but not much.
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Old 03-03-2008, 08:35 AM   #16
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the last built engine I sold took 5 minutes of cranking to prime the oil pump.... that was with the fuel pump disconnected....

that means that there was no oil pressure until that point....

sometimes it takes packing the oil pump with vaseline or pumping oil into an oil galley hole above the oil pump to help it prime...


1. if you started it without getting any oil pressure..... bad...

2. if you didn't hone the cylinders or check clearances on a used block...bad....



GOOD LUCK man, and sorry you didn't ask "what should I do?" before this all happened....

RYNO
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Old 03-03-2008, 08:53 AM   #17
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Is this possible? They drill a hole and chamfer it on the rod journal face of cranks for V8's. Does anyone do that for our cranks or has tried it? It improves oiling in that area, supposedly. It's a pretty standard thing on V8's...
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Old 03-03-2008, 10:08 AM   #18
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I did get my halves cleaned and rehoned. But if block is honed or unhoned i really dont see how that would case knock. The first time i rebuilt this block with stock subaru parts. I got my cranshaft balanced and machined caz num 3 rod bearing was spun, and i didn't rehone the cylynders but i still made 180 psi compression in allfour cylinders.

I remember when I put the Wiseco pistons in I moved the piston from side to side and seemed like it had way too much play on cylinder three. But one of my friends with "expirience" told me oh thats normal. Now im 90% sure thas the problem unless like some of you are saying .. i didn't crank the motor over enough to get the oil pump going and it could of started with any oil pressure and caused a rod bearing to spin or something.

Right now I don't even touch my car .. im so mad at it. So much time and I cant even drive it still. All of my friends with hondas are laughing at me.. they're telling me to get a honda =( .. but I know once it going to be done.. the right way.. im going to have alot of fun with it this summer killen them hondas!
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Old 03-03-2008, 10:21 AM   #19
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Old 03-03-2008, 10:23 AM   #20
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Old 03-03-2008, 11:26 AM   #21
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No oil pressure gauge is impossible to comprehend;NEVER start a new motor until it is fully primed.Sorry you are having a problem.
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Old 03-11-2008, 02:24 PM   #22
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guys, don't be hard on him.... so many people don't even know why the oil light comes on.... even people you would assume know better.....


If you don't have an oil pressure gauge, you can watch the oil light on the dash to see when it goes out when priming the engine.... once the oil light goes out, you know you have enough oil pressure to start the engine....


An oil pressure gauge is obviously recommended, but not necessarily needed....


RYNO
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Old 03-11-2008, 02:39 PM   #23
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The hydraulic tensioner for the timing belt can rattle pretty good and take 5-10 minutes to pump up.
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Old 03-11-2008, 03:48 PM   #24
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our oil lights come on at like 2-3 psi aka not enough to start an engine on.
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Old 03-11-2008, 04:07 PM   #25
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Quote:
Originally Posted by WRXINTX View Post
guys, don't be hard on him.... so many people don't even know why the oil light comes on.... even people you would assume know better.....


If you don't have an oil pressure gauge, you can watch the oil light on the dash to see when it goes out when priming the engine.... once the oil light goes out, you know you have enough oil pressure to start the engine....


An oil pressure gauge is obviously recommended, but not necessarily needed....


RYNO
absolutely, the trick is to watch your oil pressure light to go out within 30 seconds of starting your engine up. It should build pressure immediately and that light should go out.
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