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My Legacy Rebuild...


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I spoke with my machine shop on Friday, they would not bore the cylinder until they had pistons in hand.

 

I'm glad they found a bad valve, I was amazed when you told me all the valves were ok last week.

 

That's not normal in these engines.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

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wow... I'm in the same boat except the carnage from mine was much, much worse.... meaning my oil pump is probably very suspect also. I think I left that off my recent post. I'll have to take apart and see if the gear teeth in there are scored and/or on the loose side of fit.

 

At least you are able to re-use your block. Mine, eh not so much with a hole the size of a fist right out the top. It took one of the small exterior case bolts with it too, which is basically the only reason why the drivers side case is scrap metal now. (the main saddles are OK and the #2/#4 bores are re-honable.

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I spoke with my machine shop on Friday, they would not bore the cylinder until they had pistons in hand.

 

I'm glad they found a bad valve, I was amazed when you told me all the valves were ok last week.

 

That's not normal in these engines.

 

Well when I said they weren't bad I meant I did not see any bent ones. After seeing a piece of piston missing I was afraid it wedged itself between the piston and the valve on the exhaust stroke and could have bent one of them. I did not personally tear down the heads so I did not see the seats.

 

Also why wouldn't the machine shop bore a block without the pistons? I'm at a loss on that one.

 

Here's how I see it. The bore specs are set in stone... it's 99.5mm stock, 99.75mm and 100mm as overbore options, so the shop HAS to bore it to exactly 99.75mm aka 3.92717" or 100mm 3.93707" the pistons are made to be .003" smaller at the skirt to get the proper clearance (forged only). If the pistons your buying are enough out of spec to make it so you have to bore the cylinders to different sizes then I honestly wouldn't be using that piston manufacturer...

 

I pulled all 4 of the CP pistons out of the box and measured the skirts with a mic, they were ALL at 3.924" as well as I checked the bores and he had them all at 3.927 on the money, so the setup I had would have been perfectly fine or within .0005 which is nothing to worry about.

 

I'm willing to bet the piston spec card in the box of pistons coming tomorrow will say bore size 3.937" Piston size 3.934"

 

Could I have him bore it to 3.936 and probably still be fine and MAYBE have a tiny bit less diesel noise on cold start... yeah maybe, but honestly is it worth it to take the risk by not have enough clearance? I will measure all the bores and pistons again and match them the best I can as in making sure the .0005 over piston is in the largest of the 4 bores if they are off by .0005 in any way. But when your talking 5 ten thousands of an inch your just starting to split hairs... Hell he thought I was being MR Anal when I was complaining about the small mark in my cylinder still.

 

 

JP233 Just buy a whole new set of Case half's if the crank is fine, I do not believe its possible to buy only one half and try to put the two together without having crank alignment issues, I believe the crank journals are bored into this block with the half's assembled to make sure its centered properly....

 

Its only $900 online for a bare set. If you need a new crank and rods then just get the EJ257 short block.

 

 

I'm glad they found a bad valve, I was amazed when you told me all the valves were ok last week.

 

That's not normal in these engines.

 

And this statement is also a reason why I will be having my wife's new to her 04 Forester XT getting the heads re-done sometime in it's near future... I don't need another EJ255 blowing up on me.

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I'm still old school. Measure each piston then bore the matching hole.

 

I guess with today's better machines it's easy to get all four pistons the same Dia.

 

I agree you would need to line bore the block if you used different halfs.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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I'm still old school. Measure each piston then bore the matching hole.

 

I guess with today's better machines it's easy to get all four pistons the same Dia.

 

This is how the idea was sold to me, and after buying those CP pistons and seeing every one spot on spec then it just reinforced the statement.

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Got my new set of pistons today, used a 3-4" Mic to check them and they all came up at 3.934" as they are spec'd on the paper, and it says bore 3.937" and when converted that's 100mm or 99.9998mm if you want to get anal ;)

 

So even if he did have the pistons before hand the bore wouldn't be any different for each piston.

 

Not trying to change your ways Byron, but just letting you know what I'm finding because I was very leery with him boring without pistons as well. Kinda why I borrowed a 3-4" mic and also bought a bore gauge... LOL

 

Pistons also have a better valve relief cut, or closer to my originals.

 

Everyone who wants to buy CP pistons, remember SC7431 is the only PN that is specific to the EJ255 with the 8.4CR and they are 100mm bore, they don't come in 99.75mm.

 

The SC7422 ones I had were specific to the WRX STI EJ257 with an 8.2CR.

 

EJ257 on left, EJ255 on right.

20130522_085520.thumb.jpg.501e998e2ab203e433d3f7b8449bb975.jpg

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When I did my engine rebuild. Our shop sent the pistons, rods, crank, valves with the engine block. Don't know if they matched each bore, but the machine shop wanted those items.

 

As noted some do it out of habit, but if the machine shop knows that your buying 100mm bore pistons then there shouldn't be a problem, they should just bore it to 100mm on the nose, the piston mfg is responsible for making the pistons .003" below the bore size for clearance.

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Got my new set of pistons today, used a 3-4" Mic to check them and they all came up at 3.934" as they are spec'd on the paper, and it says bore 3.937" and when converted that's 100mm or 99.9998mm if you want to get anal ;)

 

So even if he did have the pistons before hand the bore wouldn't be any different for each piston.

 

Not trying to change your ways Byron, but just letting you know what I'm finding because I was very leery with him boring without pistons as well. Kinda why I borrowed a 3-4" mic and also bought a bore gauge... LOL

 

Good to hear the pistons are in spec. Now if the cylinders all come in about 3.937(+/- the spec) you should be good.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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As I noted before when I had the block back the first time they were 3.927 on the money and since I brought the block back with complaints he know's I'm being anal about this so I'm sure they will be 3.937 on the money as well :)
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FINALLY I got my block halves back today. I will be starting on short block assy tonight. Heads will be done tomorrow. He didn't order enough exhaust valves the first time... I guess he had a mental block that its 8 not 4...

 

Deck looks good and cylinder no longer has the chip in it... SO thing's are looking up.

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Got my new set of pistons today, used a 3-4" Mic to check them and they all came up at 3.934" as they are spec'd on the paper, and it says bore 3.937" and when converted that's 100mm or 99.9998mm if you want to get anal ;)

 

So even if he did have the pistons before hand the bore wouldn't be any different for each piston.

 

Not trying to change your ways Byron, but just letting you know what I'm finding because I was very leery with him boring without pistons as well. Kinda why I borrowed a 3-4" mic and also bought a bore gauge... LOL

 

Pistons also have a better valve relief cut, or closer to my originals.

 

Everyone who wants to buy CP pistons, remember SC7431 is the only PN that is specific to the EJ255 with the 8.4CR and they are 100mm bore, they don't come in 99.75mm.

 

The SC7422 ones I had were specific to the WRX STI EJ257 with an 8.2CR.

 

EJ257 on left, EJ255 on right.

 

Those look nice!

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Ok well I'll be honest, this is my first time building one of these so I have an excuse... LOL

 

I got to put the bottom end together TWICE!!! lol

 

Once without the coolant o-ring and the second time with it ;) Hey I got to see if my method of applying the silicone worked out and it appeared that it would have so I did it the same way when I put it back together.

 

I guess you could say its better that I realized that I forgot it and it NEEDED to be there because of what the pipe was, but the illustration I was working on pointed out three o-rings and not the fourth so I overlooked it. Once I realized it was a coolant passage I was like WHOA wait here that's right in the crankcase it NEEDS to be sealed.

 

You can see it missing in this photo... lol

http://i257.photobucket.com/albums/hh201/3400modified/FB_IMG_13693470467342426_zpsb14bda8f.jpg

 

The cute little crank with the rods.

http://i257.photobucket.com/albums/hh201/3400modified/FB_IMG_13693476562255875_zpse7075668.jpg

 

And finally almost a short block

http://i257.photobucket.com/albums/hh201/3400modified/20130523_214749_zpse17063ef.jpg

 

Just need to gap the rings and install the pistons.

 

http://i257.photobucket.com/albums/hh201/3400modified/20130523_214803_zpsaedd5fa4.jpg

 

http://i257.photobucket.com/albums/hh201/3400modified/20130523_214814_zps51f4e5b3.jpg

 

And yes the motor will be seeing some paint before it goes in, no way to clean all that crap off without sandblasting it... Just plain ole aluminum silver though, nothing fancy.

 

Bores came up perfect for clearance, 3 and 4 were .0003 tight so I'll re-measure the pistons and see if any are slightly smaller and put those in those two cylinders, but .0003 isn't enough to sweat over. Either way none of them are larger than 3.937 which is good since I don't want any excess noise from extra clearance.

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A few pics from my D5200 Haven't really been able to play with it much, so I'm still learning.

 

http://i257.photobucket.com/albums/hh201/3400modified/DSC_0151_zpscaf005ab.jpg

 

http://i257.photobucket.com/albums/hh201/3400modified/DSC_0152_zpsddd34e08.jpg

 

http://i257.photobucket.com/albums/hh201/3400modified/DSC_0154_zpsc17b7c46.jpg

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Nice. you're not the first who put cases together and forgot one of the o-rings, I'm sure.

 

Did you use some moly lube on the rods and mains, or just engine oil?

 

Last one I did, I painted the cases before assembly. Just make sure all grease prints are off the aluminum, or the paint will flake off in about 2 minutes after it gets heated up from the engine running. Not like you can see the block much on these turbo cars though when it's all back together!

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Make sure you do not paint any surfaces that are a ground path, like the block to tranny, head's to chassis and the one up by the fuel lines.

 

Keep them ground paths clean.

 

Long story but it cost me $200 to pay someone to figure that one out back in my Honda day's.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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the one up by the fuel lines.

 

That mother :eek: That's the one that had me troubleshooting for almost an hour and a half after doing my upper gaskets. It was bolted but loose, not enough to make a connection so I had a error showing up on the cluster and it wouldn't even attempt to turn over. I thought I cooked something important.

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You can paint over the ground spots, you just have to sand off the paint before you put it all together :) but it easier to just tape off those spots and not paint them. However I'd still sand those spots to get some fresh metal for the ground spot (I do the same thing for the ones on the body/frame too) so.... it's a little work either way.
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