Engine Over Rev

[drft86]

Hey all

my engine is a 4age 16v 7 rib block with out oil squirters and a bigport head

When i purchase the motor i pulled it apart expecting to rebuild it to my surprise it had balanced rods of an unknown descent along with some over sized pistons and other foreign objects

After speaking to ken streeter about it , he belives the motor was built by some special workshop in japan(with the blueness significant to the workshop)

Anyway after some new parts and seals fitted the motor goes hard every day and never misses a beat

My current computer's rev limiter is set at 7500 and pulls hard all the way, after some slight testing with an aftermarket computer we found the car was still pulling hard at around 8200, my question is how hard should i rev the engine??

I understand the more i raise the revlimiter i lessen the life span of the motor, but im unsure of how hard i should rev the motor since i don't know what the motor exactly is, how much punishment will the standard bolts take before one of them lets go??

Any info would be greatly appreciated thanks

Jason

[DRFT - 86]

man... Im not one to take note of here, but... I know that the original jap spec Ge 96kw in my sprintang has seen the 8 G line day after day when it was in the hands of its former owner..... still goes strong... no oil leaks... smoke... kicks over first time every time still...............

although.......... I dont treat it so harshly as the engine pitch goes horrible now after about 6 G's... needs new valve springs....

but still.......... its taken more abuse than a $2 hoe...

just thought Id let u know....

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so with the solid internals Id say it shouldnt do it to much grief... if its going to be thrashed for extended periods hook up an oil cooler for sure.... and use tha smick oil....

peice...................................

[crazy86]

The closer you get to getting over the 9G mark the more well balanced/lighter/straighter your components have to be. Especially the crank, which as well as being balanced, needs to be straightened. Unless you can be sure that everyhthing necessary has been done, I would stay the low side of 8.5, but thats just me http://www.ae86drivingclub.com.au/forums/emoticons/wink.gif

[mattysshop]

i would also look into some decent valve springs, and maybe solid lifters..

[mattysshop]

doi you have any pics of these parts?

[mikes86]

Well Jason you know my rev limiter is set on 8200 on a stock motor and it has had a hard life and only recently given me any shit. 8200-8500 is a nice revlimiter not so easy to hit and isnt too crazy

[mattysshop]

my old GE, and my old GZE used to live on the limiter..only on wheel spin, and flat changes etc..maybe the odd missed gear http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif ohh yeh..and that time at band camp jokes..top speed run..5th limiter.. speedo about 3" past 180..i know gauges arn't accurate..but i did the maths with the gears etc..i was clocking up about 215km/h, and it was hitting it hard with plenty of stick left!..i noticed that it backed off till nearly 8G..i thought the GZE limiters came in at about 7700 or so..meh?

[drft86]

Thanks for the comments guys

i don't actually have any pictures of the parts, but there in there

I do know that rods and crank have been balanced but im not sure how well, the head has been ported and also has some foreign cam of unknown duration

i was going to set the limiter at around 8500/8600 thinking that that should keep me out of trouble

What is usaually the 1st thing that is likely to let go if the motor cannot take this sort of abuse?

What sort of revs can standard engine bolts handle?if they are standard??

A standard crank is able to handle up to 9k if im correct, if this is so then should i have no problems reving to 8500 or is that an extremly well balanced crank??

[drft86]

oh and its has a factory 4agze oil cooler, will this be sufficient

i haven't had any oil problems yet

[crazy86]

Over-revving can cause a couple of things, first, your valve gear might fail, which isnt so bad as you wont damage much else, second, you might break a Conrod or crankshaft, which is an engine fatality...Not good.

High RPM's in general will also just reduce the life of the crank bearings etc.

[mattysshop]

a big end went in my old JDM 4AGE..i had ordered a GZE half cut already..so i sat it on the limiter for a while..the rod cap gaveway, piston shattered into 4 large peices as it smashed into the head, then flew back down and the big end journel flew around just in time to smack it through the wall of the block..i gave it to Anthony, and he threw the whole motor in the big http://www.ae86drivingclub.com.au/forums/emoticons/smile.gif whoops..i'll take a pic of the piston when i get home..he gave it back to me..in a bag..

[jnr 13b]

hmmm that is funny.
I would have put the car on a dyno and see at what rev is the power start to drop.
take my car for example (standard silver top 20V)

Peak power at 6250rpm.
but i have steddy power all the way to 7500+.

so my rev limit cut out @ 8g.

anything be on that is a wait of time. you are better of change to the next gear.

but a work enigne........
well i quess it'll have to depend on the person who build it.

but if you ask me.
10kw drop or less from peak is where the rev cut should kick in.

then agian my engine is only standard.