Engine Rebuilding Questions, need some expert advice

[Gro Harlem]

I've been doing some searching & researching & think I am on the right track but I've never built a motor before (done tons of motor swaps on mazdas/hondas/toyotas, just never opened them up). I have a few stupid n00b questions.

First off, my car is a 02' Bugeye with ~115k miles on its stock EJ20. It has a VF34 w/STI pinks & shows no signs of knock & i did a compression test when I did the turbo upgrade & all the cylinders read 155-160psi (cold during winter) so I'm pretty confident the motor is good.

I plan on practicing building a motor with a 2001 Subaru Legacy Outback wagon my friend just got that has a head gasket problem. It runs fantastic until it warms up, once it warms up the #3 cylinder misfires & the engine overheats. Researching on the SOHC 2.5L EJ251's apparently this is a super-common problem & requires head gasket replacement. So here's the plan & questions:

Top End/Cylinder Head:
I plan on removing all the valves (labeling them of course) and inspecting each for any wear/damage as well as the head's valve seats. I also plan on replacing the valve stem seals. Using lapping compound & a tool to lap the valves into their existing seats to rub off any tiny pits or corrosion.

1: Assuming the valve seats on the head aren't damaged & the valve is straight & undamaged, there shouldn't be a problem with reusing them after lapping right?
2: If I find a damaged valve & or valve seat & replace it, a new one should fit the existing valve &/or seats correct? Or should they be replaced together?
3: Any reason to replace the valve guides if they don't show wear? or can they be reused safely...anything special to look out for w/these?
4: Any reason to replace the valve springs and/or retainer clips or can I reuse these parts without an issue?

Bottom End/Engine Block:
I also might as well open the engine block up. I plan on stamping the endcaps & rods with 1 2 3 4 & removing the rods/crank & measuring the journals roundness & thickness to see if its within spec. Also maybe removing the pistons & rings.

5: If the crank main & rod journals are within Subaru spec of wear, should I re-use the old bearings or replace them with new OEM-thickness ones? I would think you might as well replace them if you are going this far but I may be wrong.
6: If the cylinder walls show no signs of wear, is removing the pistons & replacing the rings pointless and/or a bad idea?
7: I plan to inspect the oil pump for wear, what am I looking for? I've read that the aftermarket oil pumps are much more likely to fail and finding a good used OEM one is actually a better option in some cases.

I also plan on replacing timing belt, getting new head bolts, water pump, full engine gasket kit and replacing those, new clutch and any other parts my friend wants to pay to replace while the motor/trans is out.

If I get this right I'll be taking my motor out soon (clutch needs to be replaced anyways) and doing similar.

I'll upload some pictures as I get into it with possibly more n00b questions

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[kpluiten]

What is your budget?

Also, I see absolutely no point in opening a factory sealed motor that is running fine. You won't get it back together any better than the factory. I promise you that. Now if it was broken, that's another story.

[Gro Harlem]

budget is ~500 bux for a new timing belt, full gasket kit, water pump, clutch, etc. (i know that's low but we are talking none-performance parts). The main goal of this is to just check that everything is OK in the legacy motor & replace anything that shows wear so that the car will run for another 50k+ miles without issue.

It is going to be a daily driver and he plans on doing zero modifications to the car. Just to get it running reliably again so it doesn't overheat & since we are removing the engine/trans and taking the heads off I might as well check tolerances & rebuild part of the motor if needed.

[Groundup]

I don't see you acquiring those parts you listed for $500 bucks. Some more room in the budget is needed imo. Good luck either way

[Gro Harlem]

engine gasket set w/new head bolts & valve stem seals runs $210, timing belt 26 or 117 for a GATES with new tensioners/pulleys, water pump 30, oem clutch kit 140. If i replace rod bearings: 28, main bearings 42, piston rings: 52.

We aren't talking performance parts here....plus I don't care how much it costs, its not my car. My biggest question is still unanswered:

If i remove the crank & measure the journals to be within spec, should I reuse the old bearings or should I might as well replace them?

Also what to check for with the valve guides & whether or not reusing the valve springs & retainers is advisable......

[quazimoto]

http://forums.nasioc.com/forums/forumdisplay.php?f=144

[wrx1392]

the specs for the crank are really tight ..not sure you can get it back with just new berings. if you have never built a engine ..these are not what i would call good training grounds....they are a kot harder to rebuild. lapping valves .....my engine rebuild class in college the teacher would have laughed you right out of the class. lapping valves is for when you are stuck somewhere and it's the only way to get home...better than nothing,but... . i assume you have all the mics to measure the crank ,rods and berings to make sure you have the oil clearance correct?if i knew now what i did'nt know when i started my build ....i would have sold the car and saved 7,000 bux

[Gro Harlem]

Originally Posted by wrx1392

the specs for the crank are really tight ..not sure you can get it back with just new berings. if you have never built a engine ..these are not what i would call good training grounds....they are a kot harder to rebuild. lapping valves .....my engine rebuild class in college the teacher would have laughed you right out of the class. lapping valves is for when you are stuck somewhere and it's the only way to get home...better than nothing,but... . i assume you have all the mics to measure the crank ,rods and berings to make sure you have the oil clearance correct?if i knew now what i did'nt know when i started my build ....i would have sold the car and saved 7,000 bux

Indeed, i just spent the better part of 4 hours watching this guys excellent videos about building 4G63's which would apply to any motor:

http://www.youtube.com/playlist?feat...971FF4F38CC85F

They pretty much answered the majority of my questions. Still not entirely sure replacing the bearings is a brilliant idea. On most of the threads (on other forums) i've read it seems perfectly fine to replace the bearings w/new ones after checking the crank for out-of-round or abnormal wear. I'll take my bottom-end apart & inspect them, if theres no bad wear i'll probably just retighten the bottom end stuff & do the valve job along with the head gasket. He covers how to inspect the decks on the block & head for warpage which I never knew how to do properly so I'll defintiely be doing that.

I have all the tools needed except a good brass wire wheel for my bench grinder. That guys vids even show you how to clean up the factory valves to look brand-new before lapping and I'll definitely need a brass wheel to get that done.

I figure measuring all this crap & getting a feel for it on my friends EJ25 is better than me trying to build-up my own motor & doing something stupid. I have 4 spare toyota 2ZZ-GE's + a 2AZ-FE in my garage that I can experiment with also & I might build one of those up (including machine work) with some cams & pistons before I mess with my EJ20.

[danny522]

Yeah, better to mess his up rather than yours. Lol