ForcedFirebird's m20 dyno thread.

[zaq123]

I meant thrust crank clearance.. I'm sure you got it but just in case.... Thrust bearing is the reason you should not use an impact wrench on that crank bolt btw. Hand tools only

[McGyver]

I appreciate both of your perspectives on this! The cylinders have all been bored for 0.50mm over pistons, main and rods have all been cut and bored to match the crank. Plastigauge will confirm there weren't machining mistakes. It would be cool to get the actual measurements, but I don't think that justifies buying tools with enough precision to provide a real measurement.

I plan to file the ring end gaps per cylinder for a Turbo application. I'll also measure/swap piston/rods to get even piston height at TDC for all six cylinders. And I'll balance the piston assemblies as best I can. I'll also check valve clearance to the new guides with the new cam and check piston to valve clearance with the new-but-crushed head gasket. Should be good!

[digger]

Plastigauge should not be frowned upon. Most backyard mechanics are doing this with measuring equipment not upto the job because proper equipment is expensive and cannot be justified for a once or twice off endeavor so plastigauge is probably more accurate in some circumstances than using junk equipment without experience

[zaq123]

plastigauge is fine. It has a pretty good range to get you in the ball park. I would not worry about the bore gauge ( gotta trust your machinist somehow), just make sure you measure piston ring gap once in the in the bore and adjust it accordingly. Piston to valve clearance is a must so get a second head gasket on hand...just in case. Also make sure to measure crank trust clearance ...very important

[McGyver]

most is pretty generic, the only thing thing kinda specific is the intermediate shaft bearings

I've reached the stage where I'm ready to start measuring and assembling the engine. I don't have a bore gauge or OD mics in the 0-6" range. I know that I should double check my machinist's work, so I bought plastigauge for the main and rod bearing clearances. I'm not building a 10/10ths engine, just looking for some decent longevity on a 2.7i that will get a turbo in the future.

Is plastigauge good enough?

I don't really want to buy a bore gauge right now, especially because it would only make sense to get one that reads in 0.0001" and I'd need a 0.5-1.4" for the small end of the rods, 2-6" for everything else, and a set of 0-6" mics. I plan on building at least another engine in the future, so I would get more use out of the tools. But it would also be nice to have time to find a quality used set on eBay instead of getting a cheap set of Chinese tools.

[zaq123]

I plan on using Redline Assembly lube for the whole build. Any suggestions for the break in oil?

Also, I have new mahle 84.5 pistons (11251714810). This should be roughly 9.0:1CR and then will get boosted. Should i use the rings that came with the pistons? Looks like a shiny barrel top ring, grey Napier 2nd ring, and oil control ring.
I plan to measure/gap the rings for boost.

driven br40 for the oil. follow instructions.
Mahle are good rings. Follow Mahle instructions for break-in. Keep in mind that cam break-in supersedes rings break-in but it's all plus minus the same.
Easy on the oil when assembling rings and on cylinder walls.
I recommend using Marvel mystery oil for that, coat piston bores with it and coat rings/pistons with that. Good assembly Lube on all bearings, cam, crank. If you gonna crank the engine after the assembly, plugs out so no to squeeze the lube with compression from crank bearings. Drill with long extension and 6mm socket to prime the engine before first start. Setup ECU (I assume wont be stock) to prime fuel pump so it starts asap. Didn't start withing first 3-4 sec of cranking? STOP and Start troubleshooting. Don't just sit there and keep on cranking the started while polishing your bores and messing up new rings.

https://www.us.mahle.com/media/usa/motorsports/mms-break-in-recommended-procedure-web.pdf

some general info from JE just to give you an idea

https://www.jepistons.com/ring-installation-guide-4032-pistons-instructions/?srsltid=AfmBOoqU1gvaNFd_N5MQMHX-eERzJ5wh719O9WvxCWX2NF1LyhZ44atp

[McGyver]

I plan on using Redline Assembly lube for the whole build. Any suggestions for the break in oil?

Also, I have new mahle 84.5 pistons (11251714810). This should be roughly 9.0:1CR and then will get boosted. Should i use the rings that came with the pistons? Looks like a shiny barrel top ring, grey Napier 2nd ring, and oil control ring.

I plan to measure/gap the rings for boost.

[zaq123]

don't use Lucas assembly lube or any green/blue coloured assembly lube. I almost had a heart attach when I was adjusting valves after the first start, opened the valve cover and saw some green residue mixed with gold coloured break-in oil sitting in the head.

[digger]

I'm almost to the point of assembling my 2.7i engine. I'm sure I could slap it together and it'd work just fine, but I would prefer to do it right the first time.

Would a generic step-by-step engine building guide be sufficient? Are there any m20-specific things that I need to look for?

most is pretty generic, the only thing thing kinda specific is the intermediate shaft bearings

[McGyver]

I'm almost to the point of assembling my 2.7i engine. I'm sure I could slap it together and it'd work just fine, but I would prefer to do it right the first time.

Would a generic step-by-step engine building guide be sufficient? Are there any m20-specific things that I need to look for?

[AWDBOB]

My buddy eight~deuce turbo'd his E30 got it tuned last week.

-ClassicDaily M20 Turbo Kit and ECU using Kangaroo Cast Mani and Pulsar G30-660 w/ .83 a/r open scroll T3 hot side
-Stock M20b25 with head studs and a cylinder head refurbishment

Pump graph: 14psi
Ethanol graph: 18-19psi

(dynojet rollers with YourDyno software)

Screen Shot 2024-07-13 at 9.23.49 PM by Bobbie Morrone, on Flickr

[NightOwl]

Bumping my favorite thread!

[It's Soda Not Pop]

I, too, like the idea of ITBs, particularly on a high revving engine. I gave up on that though. I estimated the price of a 280hp+ 2.8L ITB build for my car, because I don't want any more than 10lb/hp, and I arrived at well over $5,000 just in the ITBs and head (upgraded valve train and porting).

I've been going back and forth on what I want to do. I was sold on ITBs for last 2 years or so. But the power a turbo can give is hard to pass up. Plus overall it will be cheaper. I can always switch over to ITBs later down the road if I want. Or just buy another E30. I do have C10 that I need to work on as well.

[varg]

I've been wanting ITBs for awhile now, but I miss my old turbo car. So I'm thinking of just refreshing my bottom end and hanging a snail on it. I have (in case you didn't guess by now lol) a seta with a 885 and 284/274 cam.

I, too, like the idea of ITBs, particularly on a high revving engine. I gave up on that though. I estimated the price of a 280hp+ 2.8L ITB build for my car, because I don't want any more than 10lb/hp, and I arrived at well over $5,000 just in the ITBs and head (upgraded valve train and porting).

[turbdan]

Boost has a lot of advantages. Can make a buttload more power than any NA build, with a stock cam, pleasant driveability and good mileage.

Are you already running standalone injection? That removes the main obstacle. If the motor isn't using oil and runs well I wouldn't worry about freshening up either. No need for all the foreplay, just get right in there and boost it.

I've never run a hot NA cam with FI. I did try the catcams mild turbo conversion cam. Not a bad option bit the B25 cam spools earlier and makes more power from the bottom up until about 5k. I don't know which I prefer.