2f rev limit

[xlogre]

I'm curious as to what the consensus is on the 2f's rev limit. Mine never sees over 3700 rpm.

 

[Output Shaft]

It better not!
This the 2F we're talking about.
Not a DOHC job.

I think 3600 is pushing it when trying to gun the cruiser up a sand dune for a few seconds in 2nd gear 4wd Lo. I've done that several times.

Anything higher and it seems like the world is going to end.

IMO, 9% below red line (with any engine) for more than a few seconds is pushing it.

On a stock kinda in-tune 2F... definitely.

At least that's my opinion.

 

[xlogre]

That's about what i figured. I'm used to the 1uz in my sc400 and the near 8k rev limit.

 

[RockDoc]

Post quoted from an old thread by someone who knows these engines very well.

3000 rpm is extremely conservative unless you are talking about very long duration. The 2F is rated for peak horse power at 3600. I've cruised a 300,000 mile FJ60 at 3000 rpm from Anchorage to Faibanks and back (about a 600 miles round trip). The biggest concern in that kind of situation is good oil and good oil pressure. I worry most about general wear and tear and heat generation (leading to oil breakdonw) when turning the engine high for long periods. The rob bolts are not a concern at all at this rpm.

For long hill climbs (I assume that you mean long highway grades, not steep off road hills?) I would probably not be comfortable over 3500 with a 2F that was not in fairly new condition. For short duration (like an off road hill climb or running through the gears) I am perfectly comfortable turning just about any 2F to 4000. These numbers are based on concern for worn bearings, worn out oil and (again) general increased wear. I don't worry about the rod bolts 'til around 5000.

I have also seen a couple of engines which stretched rod caps and spun bearings. These *seemed* to be attributable to routine, sustained operation on the highway in the 3500-4000 rpm range.

This is all based on experience, first hand examination of damaged engine, grilling the owners/operators of failed engines, successful use of engines that have (so far at least) survived and educated guesses.
I can't really quantify it or show you numbers to prove it.

 

[Output Shaft]

& when shifting up through the gears when "really trying to accelerate", nothing is gained by shifting at 3700 rpm vsv shifting at say 3200 rpm..

The 2Fs real power (torque) drops off real fast above about 2600 rpm and the engine becomes more and more inefficient as the RPMs increase from there.

It's the torque that pulls you up the hill, and the 2F cranks that out best around 21-2300 rpm (even though the spec says 1800).

So for shift points that will drop you down to best torque, shift when the next higher gear will start pulling at 2100+ rpm or so.

At least that's my experience with the beast...

 

[White Stripe]

I rev mine to 5k once in a while. Its only got 7:1 compression.

 

[Cruzerman]

Revving it above 3700 should not be an issue. Holding it there might be one. The snippet from Mark W. says it all.

 

[Spike Strip]

A stock engine vs one that has been properly rebuild and balanced are two different animals. The 2F in my 60 had all the rotating mass expertly balanced and revs effortlessly up to 5K, though I only go there by accident. I try to always keep it below the 3500 and shoot for the 3000 point when I'm paying attention to the tach. I also drive slow and piss off all the little fawk-head Generation a****** slicky-boys in their black BMWs and bald-tire white Mercedes paid for with daddy's Medi-cal fraud money.

I run high zddp engine oil and change it regularly, too.

Wow, did I go off on a tangent...