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WJM is at it again...N/A EA82


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As the title says...I'm brain storming and its REALLY soaking in here.

 

I am waiting to hear back from Delta cam on a set of cams and springs to be safe to rev to 8.

 

The real question is...can the bottom end handle the revs and can the oil pump keep up the demand?

 

I will be on MPFI heads, spyder intake, delta cams, appropriate valve springs, borla header, high flow cat, and a custom cat back with MegaSquirt as EMS. Ofcourse, a custom intake as well as a 2.5" throttlebody.

 

 

WJM thinks I should just rev the F*** out of it until it blows....that'll tell WJM if its ok or not. :burnout:

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The real question is...can the bottom end handle the revs and can the oil pump keep up the demand?

 

 

I've seen an EA82 hold up to the Tach being pegged for long enough that the cat melted down. After that there was too much back pressure to keep the rpms up. We were trying to kill the engine, crap occurs I guess.

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From the looks of it, harmonics may come into play around 7k, but the belts may help some. You might need a damper to go to the other side of 8k though.

Whay not put the heads and cams on a junker block, put it on a stand, and rev that till it blows? Then you'll know.

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...Besides, SOHC and 2-valve-per-cylinder isn't exactly a high-revving design.

I have a SOHC 2-valve-per-cylinder that I routinely run to 12.5k and has seen 13.5k. Come to think of it, the crankshaft length is about the same as the EA82's...

 

The timing belt could also be a problem at high rpm, as the load on them will increase greatly with RPM.

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valve float?????

 

and springs to be safe to rev to 8

 

there's your answer ;)

 

I think the crank and bearings and so forth can take the 8k, but I think you will run into some unsuspected problems, like cambelts ripping apart, disty's blowing up, they were never designed for 8k, and thus are not as balanced as the crank is (not that THAT is designed for 8k, but a hell of a lot more balanced than a rotor)

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IThe timing belt could also be a problem at high rpm, as the load on them will increase greatly with RPM.

 

I seems there is a 3.5 flat 12 with timing belts that turned to 12,500....

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Yes actually I think the HLA will be the problem at 8-9k rpm..once you get stiffer springs in there the valve springs won't be the cause of float.. 8k isn't that high and lets not forget rally prepped ea82s ran to 7500rpm with approx 12psi of boost.. but they had shim adjusted mechanically locked HLAs in there..I just think the HLA relief system will cause them to lose pressure at that rpm..maybe not, but we'll find out if Will does what he likes to do..

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I seems there is a 3.5 flat 12 with timing belts that turned to 12,500....

I wasn't meaning to imply that a high-speed engine CAN'T use toothed belts cam drive, just that the existing design MIGHT not be able to handle it. Strains go up with increased RPM, exponentially IIRC, and stiffer springs just add to the strain. Durability might become an issue. :)

 

And too much oil pressure can be as bad as too little. Flow becomes more important, as this is waht props up the pressure. One street-turned-race-engine that I read about (Datsun's L24) had issues with the oil being thrown out of over-zealously drilled conrod journals at high RPM, and starving the further-from-the-supply journals of oil. (They also had some nasty harmonic issues due to crank length, but not terribly applicable here.)

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Either way, it doesnt look like this is actually going to happen anytime soon.

 

EJ22E is 4 parts away from getting the green for go on a weekend thrashing to get it roaring to life.

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