40 pony upgrade- worth it?

osd9: very nice numbers indeed. After flirting through the hundred or so performance specs of a 01Z, I can't recall a 390. So you must have had a decent tech set a few things to the high side of spec.

A few things I noticed was a 16:1 compression ratio and 15*static timing up to 375 horse... 15:1 and 12* timing there on up.

tobnpr: I read the service bulletin and it calls for some fuel pump bonnets, sea water pump work, heat exchanger, ... looked expensive. The real power comes from bumping up the fuel setting and raising the high idle rpm! It's been my experience that a Cat always could handle a little more in it's stock form. I still do not know what your stock settings are! But a 435 has a high idle setting of 3186. If you did nothing more than set your high idle to that upper range, opened up your fuel screw as little as 1/4 turn, you could see gains close to osd9's. Advancing the timing to the high site of spec which is 17* static helps big time, but head gasket failure seems to follow later down the road. So I would stay away from that if it becomes recommended by your tech.

...Ron
 
The 3116/3126 motors are spec'd for rebuild after 30,000 gallons of fuel. I put about an average of 60-80 hours a season on my boat. I have just under 500 hours on the boat now in 7 seasons. I shouldn't need a 'spec'd' rebuild for another 20 years.

I don't have flow scans, but I 'Average' over 1 sMPG.....I keep very accurate logs of my hours and distance traveled. I notice no difference in fuel consumption what so ever the re-tune.
 
osd9: very nice numbers indeed. After flirting through the hundred or so performance specs of a 01Z, I can't recall a 390. So you must have had a decent tech set a few things to the high side of spec.
..Ron

Ron...I have 1ZJ.... 3126 motors...I don't have 3208s....
 
Holy crap, Ron...I knew of the bonnets, but had no idea of the heat exchanger and raw water pump upgrades.

You def seem to know your way around these things- mind if I ask where you got your experience?

Off the record- do you think CAT might be overly conservative about needing all that work, would it be possible to "safely" do the injector pump/settings and stay "stock" with the other stuff?

Funny you mention high idle setting...
A few months ago I checked my no-load rpms at the dock and was only getting around 2930 or so. Called my mechanic and he told me to first check to be sure that at WOT that the lever was pushed all the way to the stop on the block. I did, and sure enough there was still probably 3/8-1/2" travel left. So I adjusted the cable and she now runs up to 3100+ at no-load. High idle spec (it says "on dyno") is 3030, with a min of 2930 and a max of 3130.

So I'm almost to the max high idle setting, but I'm not understanding. All I did was adjust the cable to allow full travel of the throttle- there were no governor adjustments made. My other engine is making 3000, so I haven't even checked it to see...

Certainly I didn't gain horsepower by maxing out the throttle travel, did I??

I'm soooooooooo confuzed...
 
tobnpr: I've been with Cat as a tech for 20+ yrs. In 1990 I spent 2 wks at Cat manufacturing plant getting trained on performance tuning 31**, 32**, 33** and 34** fuel systems. Until ECM controlled fuel systems took over, repairing and tweaking fuel systems was my main thing.

If you do nothing more to your 355's than set your high idle to the rerated spec of 3190, your horse power will continue to build those 160 rpms. 3190 - 3030 = 160.

I mentioned before the fuel rack hard stop!... ie: Your throttles are set WOT, your rpms are coming up, fuel rack is pinned against fuel screw(maximum spray duration), mid 2700's your gov spring will start backing off fuel rack(shortening up the spray duration) until 2800, now your making 355 hp. ... With a high idle extended the 160 rpms. The whole process is identical except the gov spring doesn’t give up any fuel till 160 rpms farther up the hp curve. Your engines continue to build hp untill output and demand balance. Most likely 80 rpms or so.

This would most likely be your 40 horse. I really don't think at this point you would see any difference in temp indicating the coolant system couldn’t keep up. This is the simplest mod one can do to a 3208 with common tools kept on the boat. Pm me and we'll talk about the other screw if you want ...Ron
 
Yes, thank you Ron...I'll be checkin' my high idle setting after installing the Aetnas tachs...:smt001

Ron where should I read the right value ? :smt017
 
tobnpr: No problem. I live for this horse power stuff. You take good car of those old Cats. An old Cat guy like me may need to own a pair one day.

Pietro: You should have a rating tag, most likely on one of the valve covers. "Bare engine high idle" is what your after. That will be the high idle rpm that Cat set when calibrating your engines rated hp. Due to parasitic installation loads like trans, alt demand, ..., The actual rpm will be just a bit less. Most likely 20 rpms ish.

You can also check your control linkage statically(engine not running).... Move throttles to full, visually look at the governor control lever on the side of gov housing. The lever has a break over spring. The control linkage needs to be set to full throttle plus a little more to enter this break over area. This area often seizes up cause it never get a shot of periodic lube as maintainance. Hope that all made sense!

...Ron
 

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