At first glance, it may seem that $1000 or so is alot of money to pay someone to "drop in" (loose NASIOC term) a set of forged pistons in the case of a "Stage 2" brand new engine using the stock rings. Let's look at what that entails:

1) Remove pistons. I use a mechanical suction device used for picking up glass / acrylic plate; It's never failed to get the stock pistons out, regardless of the clearance.

Time to complete: 1 hour

2) File fit rings. No, IMO, you don't want .008" to .010" on the top comp ring of your forged piston engine, even if you're using the stock turbo. I'm using .018" on my mild engine. Of the 3 EJ257s I've torn down, all 2nd comp rings have come in @ .014". I think that's okay in most cases, unless you're racing it on a track. I use an expensive ring grinding tool (some use a Dremel in a vice) that squares the ring on a fixture and measures the amount taken off with a dial indicator; it is imperative that the ring end you choose to grind (in an inward direction, towards the piston) be square to the ring end you didn't grind when held up to the light ( Y and Z axis) and squeezed together gently. Insert in bore at the position the ring is located at TDC, and measure. Correct? Label the ring for specific position. Continue to next ring. No? Do it again.

Time to complete: 4 hours

3) Clean / finish rings. Using 1000 grit sandpaper, I lightly go over the sharp edges of the rings (especially the part you just filed). Do not sand the ring face, for obvious reasons. Next, I use fine scotchbrite over the entire ring. Closely inspect the ring for imperfections (I use a 10x eye loupe). Lastly, I clean the ring with Brake-Kleen.

Time to complete: .5 hour

4) Clean cylinder bores. This takes a while, done correctly. One of many reasons why engines don't break in are cylinder bores not clean. I start cleaning with Type F tranny fluid with paper towels until no visible gray color is remaining, then use Brake-Kleen with lint-free cloths. You'll be surprised how much crap the Brake-Kleen picks up. Make notes.

Time to complete: 2.5 hours

5) Mic the block. Check the block for taper, even if it is new. Make notes.

Time to complete: .5 hour

6) Clean/Inspect/Measure new forged pistons. Clean the pistons with alcohol and air. The skirts, the pin bores, etc. I use my eye loupe to look into the ring lands. This is where your rings live. If your oil ring land has aluminum machining debris left in it (like mine did), you won't control the oil. If your comp rings can't move freely, you'll break something, or have a engine that won't make power. Measure the rings in their respective ring land for clearance, both Y and X. Measure the skirts for the proper piston to wall clearance. Mic the pin bores and pins. Inspect the pin retainers and grooves in the pistons. Make notes.

Time to complete: 2.5 hours

7) Install the rings on the pistons, install pistons in bores. I use a ring expander to both remove, and install rings. I'm not a fan of spinning the ring on the pistons, because it puts twist in the ring, and it scratches the pistons (esp if you have nice shiny coatings). Orient the rings properly. Make sure they freely rotate (with the exception of the oil ring assy, which should only move in the land). If you are using a band-type ring compressor (I like the tapered ones), make sure that rings stay oriented while you fit the compressor over the rings and tighten it. Install. Check for bind during crank rotation.

Time to complete: 2 hours

So, you have 13 hours in a PERFECT assembly. Trust me, it's probably never going to go perfectly. It hasn't in 25 years. If it did, I'd fully expect the engine to grenade on the first pass. :lol:

This ^ is blueprinting.

Have fun.

S.

Bump for Mod move to "built engine forum" :)

S.

Bravo!

nice contribution(s), steve. :)

golf clap. This is the most thorough explanation of a piston install that I have read to date. At least on a Subaru forum....

D_Sagan

Thanks, ya'll ;)

S.

Nice post, Steve! But you fogot to mention whether to use a lubricant or dry install the pistons. I'll let you answer that one ;) Also on the piston ring lands, I also have went into them with a very fine grit to remove any burrs just as you would the actual rings. Do you normally do that too?

Todd

...you forgot to mention whether to use a lubricant or dry install the pistons. I'll let you answer that one ;) Also on the piston ring lands, I also have went into them with a very fine grit to remove any burrs just as you would the actual rings. Do you normally do that too?

Todd

Thanks, Todd :)

In this case, I used the dry film lubricant (Quik-Seat), so the only place I put oil (1 drop) is on each skirt. I used Clevite Assy Lube (the red stuff) on the pins.

I'm not a fan of deburring the ring lands, unless I'm using a set of pistons with gas ports. I measure them with the rings installed; If they are not right, I send the pistons back. In the case of the oil ring land, I use my loupe to check the drilled oil holes for the pin oiling.

S.

Thanks, Steve.

I think it would be worthwhile if you could list the specific measuring tools you make use of as well as their rough price.

jblaine,
Great idea!! I second that Steve.

:)
D_Sagan

Wonderful, STANDING OVATION!

Thanks, Steve.

I think it would be worthwhile if you could list the specific measuring tools you make use of as well as their rough price.


Wow. Let's put it like this.

When I was younger, I went to a local tool sale, and bought everything listed (Cheapo Chinese, of course) for less than $400. If you were to buy the good stuff (as I did when I was older and could afford it) such as Mitutoyo, etc., it would cost ~6x as much.

An idea:

Mitutoyo pn 950-910 ~$900.00
calipers, dial indicator, magnetic stand, outside micrometers (0"-3")

Mitutoyo outside mics (can't read the pn), 3-4", and 4-5", ~$165 ea

Mic anvil kit (Cheapo) ~$45.00
these are needed if you are measuring anything other than a flat surface

Depth base for dial indicator ~19.00

Mitutoyo pn 139-201 ~175.00, inside mic 0-6", in .0005"

Dial bore guage, Cheapo...~$175.00


If I were doing 1-2 engines a year, I would not buy the expensive stuff. I've never seen a difference in indications / measurements between the brands if you take care of them (keep them clean, do NOT drop them).

It takes practice using these tools. One hack can measure an outside dia of 3.916", and someone with experience can measure 3.914" using the correct technique. That's why there are so many variables in the world of engine assembly. Sure, a hack can use the tools, but is he getting the same measurements as Hotrod, Toyo, Ron, Quirt, etc? Probably not. In HP engines, a half a thou on the rod clearance is huge.

HTH

S.

Net gain .2 hp ;)

:lol:

Phil
www.elementtuning.com

Net gain...peace of mind ;)

:lol:

Phil
www.elementtuning.com


Fixed that fer yeez. ;)

:lol: S.

That's what I figured, and why I asked (half rhetorically) to get it in plain sight for people. I'd looked into prices on decent-quality mics and such before :(

Totally unreasonable cost-wise unless you plan to build your blocks for life.

Fixed that fer yeez. ;)

:lol: S.

So true.

That's what I figured, and why I asked (half rhetorically) to get it in plain sight for people. I'd looked into prices on decent-quality mics and such before :(

Totally unreasonable cost-wise unless you plan to build your blocks for life.

The cheapo stuff can be had for <$300. Everything...and it works well.

I forgot one: Ring grinder (can't tell the manuf, it's under a Childs&Albert logo)...$350.00...but it's a dandy.

S.

I forgot one: Ring grinder (can't tell the manuf, it's under a Childs&Albert logo)...$350.00...but it's a dandy.

S.

I wish I would have bought one of these the first time around! I'm about to build my third motor this week (Honda 2.3L/H22 Sleeved block with forged 89mm Wiesco pistons etc etc). I think I may use that piston ring quick-seat stuff too. I've heard good things about it!

Note: I'd like to add that I am NOT a professional engine assembler. I have learned to assemble engines by doing and reading, speaking to folks smarter than I, and blowing them up. Many mistakes have been made while doing this.

But given all that...I can also say that my last amateur-assembled-in-my-garage-engine went 8.61 @156 on 31X10.5 street tires, in a 2660 lb driver, and has over 300 passes / 15k miles on it...so the haters slighting the amateur engine assembler can kiss my ass. :D

S.

Right on, Steve. I just made my third trip today (Charlotte to Atlanta and back) and my motor has over 4k miles and running strong. Although you've got more experience at this stuff than I, it's worth noting than even after a mishap, it's quite possible for the amateur to build a good motor! I don't have any bragging numbers yet though so that will have to wait a bit. I did stop by Topspeed today but they weren't able to help out as they were already busy. I need to tune my knock sensor and I'll be straight. I just don't feel comfortable moving forward until I know whether the knock sensor is doing it's job.

I'm a fan of de-burring ring lands. They're in a really good place to score cylinder walls during a critical period.

As far as I know, Subaru does not balance the cranks and connecting rods in matched sets.

One thing I like to do when I have an engine apart is to match the connecting rods and pistons. All it involves is a very small grinder (dremmel works too) and a good scale (drug store "weed" scales work well).

How this is done is to suspend a loop of string from above that ends near the level of the scale. Pass the loop of string through one end of the connecting rod and place the other end on the scale. The connecting rod should now be parallel to the table with one end on the scale and the other end hanging. Write down what the scale is reading. Continue this until you have a weight for both ends of each connecting rod. Find the smallest measurement for both the big and small ends. Using your dremmel remove TINY amounts of material from each end and continue weighing the rods until all the big ends have the same weight and all the little ends have the same weight.

Now place each piston on the scale and record the weights. Remove material from underneath each piston until they all weigh the same.

Needless to say, make sure material is always removed evenly and never from anything structurally critical (such as the rod beams and wrist pin towers).

This takes lots of patience and a steady hand to do this, but it's worth it. Having all the parts within less than a tenth of a gram of one another will have a huge effect under sustained high RPM use. The engine will also run smoother driving around town. There will be less parasitic drag at high RPM's (moving at a few thousand feet per second, a gram grows into hundreds of kilo's of force) and a higher possible redline for the short block.

Just passing along bit of experience I've picked up over the years.

no coast punk- One thing to add, It always a good idea to call the rod and piston manufacture and ask them where to take the material from.

When I had my engine balanced, the stock rods were by far the most out of balance. Surprisingly, the flywheel was pretty good, along with the crank, both only out about 2g-3g before balancing.

Apparently the rods when they come from the same run are pretty close from what I could tell. I actually had a bad rod on my last build so I ordered another one to replace it. They were from different production runs and and when we weighed them the new one was approximately 9 grams heavier on the big end than the other three. This was weighed on a device specifically for rods (both big and small ends are weighed). The other three were VERY close though (within 1 gram IIRC).

My crank on the other hand, was not all that balanced in it's original form. I don't remember how much though. Stock flyhwheel was out of whack too!

It's best to have everything sent out to a good machine shop that balances the crank, flywheel, crank pulley, rods and pistons together on a dynamic balancer. It costs $ but is worth it if you plan on living in high RPM land for extended periods. My bit was aimed more towards DIY guys.

One thing I forgot to mention is to go to Target or some such thing, go to the ladies hair care section, and get one of those empty "spritzer" things for applying various hair care products. They are designed for much more viscous fluids than regular spray bottles. Fill one full of ATF and spray down all surfaces before they come in contact with other metal bits. Or if things are going to sit for awhile, spray down EVERYTHING. It prevents a bit of oxidation if you're in more humid climates. Adding too much ATF can be bad.

Oh yeah... make sure that you don't get ANYTHING on the backside of bearings or the races before installing them.

Why atf? If its because its thin, its about a 20weight, so you could use some 5w20. The additive package in atf is weaker than in motor oil, and most assembly lubes are packed with additives.

Assembly lubes are great for lots of things, but not all. Would I smear cylinder walls with assembly lube before running pistons in? Absolutely not. Would a nice thin coating of ATF work well? Absolutely. The only thing I use assembly lube for are the friction surfaces of bearings.

The reason I like ATF is that the stuff has an insane detergent content. Most of you who have assembled engines don't do it in one shot. It's a process that can take days and days working off and on. Anyone notice how there's lots of dust in this world? Especially in shops and garages? You think some of that will finely coat an engine? Notice how stubbornly some of that dust clings to stuff? Dust can be pretty abrasive to stuff like oil pumps, bearings and lifter bores. When you do the first oil change (you change the oils 20 miles after startup RIGHT?) everything that's not supposed to be there gets picked up by all the detergents.

It's the little things that mean the difference between an engine with perfect compression and oil pressure after 100,000 miles and a marginal engine after 100,000 miles. Friction surfaces pick up their surface hardness during the break in period. If they get scuffed or abused during this process, they just won't last as long.

The problem is, atf does not have more detergents than motor oil, not even close.

ok...

The problem is, atf does not have more detergents than motor oil, not even close.

Everyone has specific techniques they believe in. Mine work for me.

For the record (let's not make this into something it's not), I do not like the idea of assembling an engine using ATF, for any surfaces. I use ATF only for pre-cleaning the cylinder walls.

Why do I use it? It seems to "pick up" debris.

Why would I not use it for assembly? Because a) I use assembly lube, and b) any "other" surface, I'd rather use oil. :)

S.

The problem is, atf does not have more detergents than motor oil, not even close.


i believe it does :)

What makes you think that? Every analysis ive seen shows atf having much lower amounts of additives than motor oil.

Heres a couple examples or atf and motor oil within the same brand:

http://63.240.161.99:8080/bitog/voalibrary/cenex-mercon-dexron-atf.jpg

http://63.240.161.99:8080/bitog/voalibrary/cenex-autogold-10w30.jpg

http://63.240.161.99:8080/bitog/voalibrary/hyde-atf.jpg

http://63.240.161.99:8080/bitog/voalibrary/hyde-15w40.jpg

(let's not make this into something it's not)



How about please?

Let's not make this another NASIOC pissing match about something irrelevant.

Thanks :)

S.