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subarubrat

It blowed up real good

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This BRAT has been an experement in pusing the limits of allot of hardware and technologys. Like any experement there is success and failure and I just had a failure. On the way home from work I was cruising along and the oil pressure dropped and the engine died. I thought perhaps the timing belt broke so just for S&G I fired it up and it sounded fine and the oil pressure was fine. I drove about 15 more miles then the oil pressure dropped again, this time with allot of lifter ticking and a sharp loss in power. So I shut it down right away.

 

The lesson here is that the ER27 may not be happy in the 11:1 range, then again it may have been unrelated since it was almost certainly a main bearing failure. A teardown later will make that clear. In the mean time I am swapping the heads/cams, intake, and ignition over to a stock shortblock for a while. I need to examine the cause of the failure and the condition of the crank/pistons/rods. As long as the pistons and rods are OK that is what matters cause that is where the money is.

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11:1 shouldn't be too high.. what was the stock compression?

 

the 10.5:1 in the EJ25 was normal.

 

It could be them damn tires your running.. i could've told ya they were too big.

 

wanna buy an EJ25 drivetrain for that BRAT :brow:

 

just kiddin, nice thought though..

 

mmmm EJ25 powered BRAT :slobber:

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"Expensive" is a relative term. I would much rather be experimenting with a totally bada$$ brat like that one than just spending the money on a new car.

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Damn, I hates when that happens! And I've had that happen a few times to my own engines.

 

Hopefully there's no major damage to the lower end.

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ER27 from the XT6.

 

I think the damage is going to be bearing/crank, but the rods and pistons and heads are fine, and so long as that is the case I am out very little money.

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good luck with that. i just got done going through your website and i didn't realize how easy the 6 lug conversion is. thatnks for the info and whatnot from your site. keep on a'climbin:headbang:

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Originally posted by Battle_Wagon_Medic

It could be them damn tires your running.. i could've told ya they were too big.

 

 

na they're not too big, the brat turned those just fine.. lol i've seen it in person..

 

sorry to hear that scott... seems we're both havin subie troubles now.. :-\

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isnt that the weak point with the xt6 engines? the heads always hold together, but the lower end gives out.

 

does that engine have the same number of bearings as an ea82? or something that makes the lower ends poop out earlier than the 4bangers?

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i dont know dude

 

ER27s are tough horses, i think they were stronger than EA82s.

 

i knew of one that overheated so bad it stopped running, when it cooled down it was fine...ive also seen many do well over 220K.

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All Subaru engines have stout bottom ends compared to other makes. The cranks are very strong, because the boxer design allows them to be shorter. Rods are rarely thrown.

 

And from what I've heard, yes the ER27's were actually stronger than EA82's...

 

Brat, I'm thinkin you spun a bearing, nothing hugely expensive...

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if your compression is 11:1 then I would suspect crank and rod bearing damage from detonation. even with aluminum heads, 11:1 compression is a lot to run with pump gas. usually, when compression is raised, like in a performance application, the cam is swapped out for one with more lift and duration. the additional duration can help bleed off cylinder pressure at low revs (effectively reducing compression) and this will allow the motor to survive. i don't recall if you still have the stock cam or not, but the low speed torque building properties of a stock cam will further complicate the issue by causing the motor to build a great deal more cylinder pressure than the motor can survive. one solution can be to use a die grinder to remove ANY sharp edges from items in the combustion chamber - spark plug bosses, piston crowns, etc. the additional pressure can cause sharp edges to act as a glow plug, which causes preignition or detonation, which causes the cylinder to fire before the spark plug initiates combustion, which is like hitting the piston with a sledge hammer on its way to TDC. look for greyish specs of metal on the spark plugs- that is metal coming off the pistons. also examine the ring lands at the top of the piston, and make sure the rings still seat square in tyheir grooves. hope this helps. good luck!

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I am 100% on all those points, I was running a xzylene booster on top of the 93. The engine was done as a system, the heads and cams both recieved allot of attention.

 

I was able to do a postmortum today and it did in fact shred a bearing, the chambers are virgin with a slight ammount of soot (better rich than lean).

 

So in the mean time I am swapping in a temp while I rebuild.

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4wheeln2 - AAaaaahhh. A little light has gone on with your explanation about high-lift/duration cams in performance engines. The engine in my RX was not 'breathed on' but fully rebuilt by rally mechanics (as in they worked for a rally team). When i did a lifter fix I noticed she has 30-70/70-30 degree cams (as painted on the billet). Has NO guts at all off idle and has a massive unburned hydrocarbon count for exhaust gas measures, and a low compression test. Hit 3000rpm and she lifts her skirts and moves. I guess this explains whats going on here!

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please read.. " TIRES ARE NOT TOO BIG "

 

 

they really aren't but a couple inches taller than mine, just a little wider is all.. and being that he's got over twice the power and engine that i do, i don't see tires as the problem.. my hatch turns mine just fine with the 70 hp its got.. i can still do 80 on the flats, and tear up the mud pits..

 

in fact, when these tires get worn out, i'm doin a 6 lug swap and puttin some real meat under it similiar to Scotts (not as wide tho).

 

i figure i may have to get creative and tear my diff's apart and get some 4.11 gears.. or slap an H6 in there for ****s and giggles..

 

 

 

 

:moon:

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