The ***ALL NEW*** AUSubaru.com.au Forums

this turned into useless info. Links in posts below don't work anymore

Just in case photos (to be added) disappear in the future.

OK, 1989 NA mpfi EA82 slugs below



here is a description of a piston found in an mpfi EA82 NA 1989 casting date on block
imagine a flat top piston, now see arrows indicating towards front of engine block, and other markings indicating R or L, R are fitted to block same side as a driver sits in RHD worlds.

Next pic, below is from hmmm, EA82 Turbo mpfi, piston tops a few thou above the deck, and according to the previous, previous owner was a strong EA82T until it blew a hose - Fury Leyland Vortex, with a single wire knock sensor in it





You still got image of flat tops in head ? Well there is a recess in piston top, it is not equal as it is deeper on the lower side of what look like a pair of cuircular depressions for valve clearance, ramping up to the flat top of the piston.

Word is if you use EA82 NA mpfi pistons you get higher compression than that of carb or turbo pistons.

What I have trouble conceptualising is if we have three different piston designs - how are all of them same cc's ?

EA82 mpfi TURBO pistons, running 7.7:1 comp ratio in 85.86 models have flat top with an even depth recess in the centre

There are pics if you search under EA82 NA pistons , not sure if these are carb or SPFI .
This was one I found

http://homepage.mac.com/dgiessel/.Pictu ... 240020.JPG

Cheers A .

look the same to me, including the arrow marking

I think the purpose of this post was to show pic of the piston tops to continue a discussion re EA82 pistons of 8.5:1 and 8.7:1 comp ratio - there appears to be listings of both ratios for EA82. I have factory manual that lists 8.7:1 as the carby comp ratio yet others have mentioned 8.5:1 as another comp ratio

Adrian, you got 87 88 manuals? what is the comp ratio for the EA82 carb?

Jonno, your photo didnt work.

So here it is


Disco.... looks like that piston would be nearly 10:1 comp just from the carbon build up

I'll grab my 88 turbo pistons for some comparisons next time im at dad's.

thanks Gannon, dunno what you did - I tried all options available to me.

Was there only one picture?

The trick is to get the image information, (by right clicking on the image and selecting 'properties' and copying the image address

http://img514.imageshack.us/img514/231/dsc00764o.jpg

then put [img]and[/img] either side of the above link

was only 'meant' to be one picture. Did you see more?? Those addresses all showed up on same pic

Yes the ones in that pic are pretty grotty , from one of the American boards I think .

I suppose the next one that could prove interesting are EA81 pistons , I'm curious to see if they have a shallow dish in them to get around 8.7 to 1 CR .

A .

No dish at all from my experience, both sets of new EA81 pistons made in Taiwan fitted to my engines were smooth flat tops, listed for EA71 and 81's. Only ever pulled out flat tops too out of about four or five EA81's from 79 to 84. So if fitted and work may not be free spinners anymore

Five years later, and I am looking at pistons again.

Pics to follow, and will got to first post.
Revisiting an NA mpfi block I got to drive, pulled well, but may have turned air cooled on the drive home - no idea of where coolant went - next day, all it wanted to do was die, so rather than diagnose it, I dissembled for parts. Today I find the rear PCV baffle outlet pipe is jammed packed with brown and black carbon. Poor thing !

Thinking to do something never done before - pinch used pistons and rings and shove in another engine - EA81. Or just clean it up, reassemble and fit somewhere to compare carb pistons to efi pistons.

If you have pics of known EA82 pistons tops carby, mpfi, turbo etc , please feel free to update. I think spfi got mpfi pistons in USDM

What about EJ20 Pistons in the EA?

waiting for someone else to do that

I have enough crap to play with, without spending

reckon the twin port inlets, centre inlet valves of the EA82 (same arrangement as EA81S) is a pretty good platform to play with. Leaves the slugs and rings where I found them. Test driven too, was quiet and didn't blow too much steam

I found a pic on usmb for the carby slug, has a combo of two different shape decompression divots. Absolutely no idea what is in my current EA82 plaything other than known carb block made in late 86

This is what my carb pistons are, if thats any help.



J.

Helps confuse me - they look like the mpfi NA pistons in pic at top of thread. Thanks (for confusing me and others now )

Next measure taken is gudgeon pin to top of piston. Maybe our carby EA82 got higher comp than the US ?

I am thinking the US style carb slugs with their two different decompression shapes would have rung a bell with me when I saw them on usmb post, your carb and my mpfi pistosdo look familiar....

Hey steptoe there are no optical illusions or trickery with my pics or slugs, The block was inverted when I took the pics for cleaning purposes:o To my knowledge the second owners changed the block (therefore engine # from original) due to overheating or whatever but all the extra "spares" supplied with the car at the time point to a carby EA82 donor block. This carby block stills goes really well, so if the comp ratio works for your purposes then go for it I say!!

BTW those bores may look too shiny in my pics but were actually in really good nick, plenty of x hatching still visible.

J.

aha, the giveaway then would be that block with those pistons and shiny looking bore would not have the fuelie PCV breather pipe at the back, nor the baffle plate visible behind the flywheel then ?

There has been enough discussion that differing years got differing comps, maybe differed between markets as well. A guy on usmb reckons the EJ 20 pistons mak for nice EA engine builds - partly for round oil return holes instead of slots behind oil rings, maybe also their flat tops ?

and could revive this discussion while Jay is on air - just try find NA EJ20 pistons on ebay or google for that matter, let alone OS ! Looking at EA71 specific not multi EA fit pistons for an MPFI block at the moment

EDIT : whoops, he's gone again, not wanting to be reminded of his beautiful build EA82 stopping being a nice engine - still to explain, or maybe I forgat ?

HaHa nice one Jonno. Not sure if Im going to rebuild another EA82 though

still waiting for you to finish that other awesome EA82 T !

I am a renewed EA82 convert yet to venture towards EJ in MY. These twin port EA82 heads got me attention at the moment