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Login to post Forums » Grassroots Motorsports » Has anyone here ever blueprinted an engine?

March 15, 2010 12:32 p.m. The_Jed Reader

I finally found the time to begin the tear down of the EJ251 that I bought off of Stinkycheesemonkey ( I think that was his screen name) and I am planning a "blueprinted" rebuild. I pulled the heads off last week and was shocked to see crosshatches and feel absolutely NO ring groove on an engine that I was told had over 200,000 miles.

I had originally intended to use the crankshaft from my EJ18 (after significant turning/servicing as it is locked up) in the EJ251 short block to improve the rod to stroke ratio a bit and then toss on a pair of EJ22 dual port heads to regain some of the lost compression due to the shorter stroke, perform a gasket match on all of the ports and reuse the stock EJ18 intake. But why change something that has proven itself to be reliable.

The main focus of the rebuild is on longevity; I am not planning any "performance" upgrades ( maybe some efficiency improvements) as this engine will be mated to the stock Brighton gearbox and rear differential and it will most certainly remain naturally aspirated. I have researched a lot and have come across quite a few differing opinions as far as rings, bearings and gaskets go and was wondering if anyone here has an opinion or any useful insight. I found the articles written by those that build custom, light duty aircraft with Subaru engines to be especially informative but I couldn't find any specific reference to bearings, gaskets or rings. Thanks in advance for any information or advice. Jed
March 15, 2010 12:35 p.m. Kramer HalfDork

Blueprinting can range from notes on a napkin to hundreds of actual blueprints detailing the specs for each part. Which is not worth it, at a Grassroots level. Find a good machine shop, make, take and keep lots of notes, and tell everyone you have a blueprinted motor.
March 15, 2010 1:25 p.m. 914Driver UltraDork

I thought blueprinting was to bring it back to factory specs, factory blueprints.

Dan
March 15, 2010 2:11 p.m. John Brown MegaDork

Investing time balancing the rotating assembly and removing casting flash in and out is by far a better investment.

If you want take a picture of the disassembled picture and toy with the photo so that it only shows as cyan colors. Print it and Voila!
March 15, 2010 2:13 p.m. Giant Purple Snorklewacker SuperDork

John Brown wrote:

Investing time balancing the rotating assembly and removing casting flash in and out is by far a better investment.

If you want take a picture of the disassembled picture and toy with the photo so that it only shows as cyan colors. Print it and Voila!

Bluing can be done at home in the bathtub and leaves a nice finish.
March 15, 2010 5:17 p.m. The_Jed Reader

racinginc215 wrote:

Or you blueprint it yourself by measuring and weighing every component and having the prints made. that's where you would measure every inch of the block depths of bolt holes sizes of bearings before install and after crush. make detailed scale drawings of every part and part number. you would also have to measure every part and drawing.

Expect this to be a very costly and time consuming job. as you will have to farm out almost every piece of it. from align boring torque plate boring rod resizing and rod bolt replacement. magnafluxing everything. figure 2000.00+ in machine work.

This is what I had in mind; a DIY rebuild with more exacting tolerances. I don't need a schematic of the engine or to have it blued.

What I meant by "blueprinting", primarily, was measuring and setting: the PTW clearance, the oil clearance (of the mains and rods), the rod side clearance as well as the ring end gap and side clearance. I guess my terminology leaves something to be desired, perhaps there is some term that encompasses all of that (besides "blueprinting") but I am ignorant of it, if it exists. I have had the engine for quite some time and have only just begun the tear down process so time is not an issue but money is. I do plan on doing as much as possible myself, I am a machinist by trade and have access to a machine shop. I also plan to balance everything, assuming I can find a scale that is accurate and precise enough.

Any recommendations on bearings?

Cometic seems like a good source for head gaskets, any opinions?

Thanks,

Jed
March 15, 2010 6:47 p.m. zomby woof HalfDork

Blueprinting is the correct term.

Modern manufacturing makes it pretty much unnecessary.
March 15, 2010 7:18 p.m. spitfirebill Dork

If the original engine made that kind of mileage, why not go back with the OEM stuff. Rings and bearings that is.
March 15, 2010 8:17 p.m. EPcivic New Reader

When I think of blueprinting, I think of racing classes that require stock components that meet factory specs, usually with no machining allowed. The process is to take apart about a dozen motors and measure all the parts, then build one motor stacking all the manufacturing tollerances in your favor. This hideously expensive and time consuming process might yield a couple of percent gain in HP. Probably never worth it, but it makes some people happy is suppose.

-Chris
March 15, 2010 9:19 p.m. Wonkothesane New Reader

My job is to train people that buy our CNC machines how to blueprint blocks on them, so I may be able to offer some assistance.

When an engine shop uses the term blueprint, it's referring to making sure the normal features of the block/head are proper with respect to the factory blueprint. And example of the measured features are:

Deck(s) angle vs. Crankshaft

Deck height vs. Crank

Bore angle vs. Crank

Lifter (if applicable) vs. Cam

There may be more or less depending on the application, but most of the time "blueprinting" means deck angle, bore angle and lifter bore angle.

Usually on a maching center, the cam & crank will be probed with a CMM style probe, then everything is aligned to 'em that way.
March 15, 2010 11:28 p.m. oldeskewltoy New Reader

not sure about Subaru engines(cylinder heads) but a mild porting job with attention paid to the valve seat to head will go a long way to improving economy and power.

MILD is the key... finding a porting specialist who knows the difference between a street port and a race port.

Another thing you might want to check into is combustion chamber equalizing. The thought here is eaul chamber volumes, equal power made from each cylinder

The overall shape is barely changed, but the flow has improved by nearly 10%
March 16, 2010 5:58 a.m. 914Driver UltraDork

You could also do things like chamfering the entrance to the oil return galleys or paint the top of the block with [Glymol?] a thick paint that lets the oil flow better over the surface. None of this is on the blueprint but can't hurt longevity.

Dan
March 16, 2010 11:06 a.m. The_Jed Reader

Thanks guys.

That's a valid point about the OE parts, Bill.
March 16, 2010 12:07 p.m. Trans_Maro HalfDork

Glyptol..

It's for potting motor windings but works well inside an engine.

I think Eastwood sells it.

Shawn
March 16, 2010 8:11 p.m. Appleseed Dork

Don't forget the Nth degree of checking rocker arm ratio, cam bucket heights, oil pump clearances, piston and rod weights. Also, make sure you are in a climate controlled room while doing so, so your mics and calipers don't shrink or grow with the temp changes. When you think you've gone too far, go a little further. That's real blueprinting.

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