L634t Vs. 12HT

[gifu]

Hey guys... thought this might be of interest.

I realize my LJ60 (L634t engine) isn't really an "international" cruiser... unless I took it to another country... but this is about as close to a diesel cruiser board as there is.

I saw my friend Luke over the weekend. he was driving an HJ61. we compared and contrasted the two different diesel set-ups.

Specs for the HJ61: 12ht of course, h55f, 3.73, 33's, OME, bumpers. Stock exhaust.

Specs for LJ60: 1987 Onan L634t (IDI 3.4 inline six) of questionable past (ie: came from UPS truck... could have a trillion miles for all i know), H41, 3.73's, 33's, 4" springs. engine has 3" exhaust with 3 chamber flowmaster. i'm using a smallish mitsu air filter. no intercooler. fuel not turned up (turned down, actually, to control smoke a bit).

The Onan is a bit louder, but the HJ61 has much more insulation (hood, firewall, fenders, skidplate... everywhere). The 12HT is confusing to even look at... the Onan is simple simple simple. The 12HT has tons of power at idle and right off idle. compared to the Onan, the 12HT power curve is very linear... you can just barely "feel" the turbo kick in. The Onan, has no power from 800 to 1300 RPM... then the power comes in... feels more like a OM617...that "turbo" feeling when the engine just really brings on steam.

From a stop to about 50 MPH (we ran out of road), the Onan and the 12HT were Neck and Neck! And bare in mind, it takes much more to get mine off the line (H42, 3.73, 33's), the HJ61 had 3.73, 33's and h55f (lower first gear).

So... I guess i'm not quite as jealous. On the other hand, his HJ61 does have ARB's, bumpers, nice paint, becker-mexico stereo, hidden comparments, extra fuel tanks, suspension seats, better dash, etc.

So... operation "make my LJ60 as cool as HJ61" has started. Tires, bumpers, seats, 5 speed, intercooler, snorkel, and more stereo.

does ARB make a snorkel for the left side of truck?

still pissed that we (the US) didn't get HJ61's.

dammit.

[beanz2]

Brian, did you guys have a drag race after I left?

You can now get an HJ61 in the US, see Wayne's thread on this forum, but I'm sure you'd be the one smiling when it comes time to find spare parts . . .

Dave

[gifu]

yeah... I waited for him on the way out. Brett was driving, and judging from the way he flogged my rig, i'm sure he had the 12HT spun out.

[beanz2]

You guys are crazy, that canyon road is not as quiet as it seems.

Tech content: gifu's Onan diesel bolted on his cruiser 4 speed through a Chevy adapter

Dave

[theSherpa]

very, very cool, now I know what the Sherpa's future looks like a little better

Brian, how loud is the exhaust on the LJ? Which Flowmaster?

Steve

[gifu]

i can't hear it when driving, though people tell me it souds cool when i drive off. At idle, you can't heat it over the clattle (clackle?). Once I sound deaden the firewall and under the carpet... should be pretty darn quiet on freeway... 5th gear should help too. I think it's a 3", 3 chamber flow. Came off another truck. I would have gone with a straight pipe, but I had it sitting around, and I like my trucks quiet.

[bad_religion_au]

a h55f 5 speed still has a 1:1 5th, the same as 4th in the 4 speed, so your engine revs should be the same... or am i missing something?

[beanz2]

The H55f has an overdrive 5th I think. I think I'm sure

Dave

[theSherpa]

BZZZZT!

H55F has .845:1 5th gear, 1:1 in 4th. Ratios are (nearly?) identical to H41, plus the OD. Translates to about 15% RPM reduction, compared to most OD's with are in the 25-30% range, so it's a nice split for 2F's and diesels.

Steve

Originally Posted by bad_religion_au

a h55f 5 speed still has a 1:1 5th, the same as 4th in the 4 speed, so your engine revs should be the same... or am i missing something?

[bad_religion_au]

well i'll be a monkeys... someone told me that the 5 had a 1:1 final gear... ooops.

[theSherpa]

There's so much I don't know about cruisers, that I get a little cocky when there's something I do know What I do know is that I *love* the H55F, best thing I've done to my 60...30% lower crawl and it slows the motor down at speed. I've got 33's...I drove an HJ60 lately with an H41 (same 1st gear) and 28's, and first gear is too slow with shorty tires, IMHO.

Steve

Originally Posted by bad_religion_au

well i'll be a monkeys... someone told me that the 5 had a 1:1 final gear... ooops.

[bad_religion_au]

taht's cool... so a h41 (non us spec 4 speed right?) and a H55F got the same 4 gear ratios??? if you believe the aussie mags, a h55f is basically a 5 speed version of the H41, with 5th being tacked on

[crushers]

bingo, you got it...

[ridgerunner]

What kind of pump is on the Onan? I know they came with an inline Stanydne, or a Bosch VE. I've played with my pump enough that right off the line it works really well. For more torque you can also bump up the advance.

Too much messing around will net bad mileage, but the torque's great.

[theSherpa]

Gifu's pump is a Bosch VE rotary distributor-style pump. as are all the Onan L634T and Cummins 6AT automotive version engines. The Stanadyne pumps that came on the industrial versions aren't inline, they're also distributor pumps, the DB2. Pretty much the same pump as mechanical-pumped 6.2 GM and IDI 6.9 and 7.3 Fords, except the governor is set-speed, instead of min-max. That's why the Stanadyne doesn't work for running on the street.

Those are the only two pumps that came on these motors.

My industrial L634T came with the Stanadyne DB2...I swapped it for a VE. What's your motor in, ridgerunner?

Steve

[gifu]

i plan on playing with the timing, the off-idle fuel (smoke), and the max fuel screw... after I install some gauges (pyro and boost).

i just swapped out the UPS-truck fixed blade fan for a chevy 7 blade clutch fan... made a nice difference in noise. A bit quieter, and more importantly, now I can really hear the "whooosh" of the turbo.

i heart turbos.

wonder if i can put one on my ancient (285K mile) Honda? Would be cool for 20 min till I melted the pistons... and well worth it.

[ridgerunner]

Steve- man- It's Brian AKA Greenpig.

Gifu-
Where in California are you? I'll be driving down the California coast the 19-21 this month. If you want you can check out the 55's 6AT. Shoot me a PM if you're interested.

[gifu]

Originally Posted by ridgerunner

Steve- man- It's Brian AKA Greenpig.

Gifu-
Where in California are you? I'll be driving down the California coast the 19-21 this month. If you want you can check out the 55's 6AT. Shoot me a PM if you're interested.

Brian... man, i just saw this post. If you are checking email, shoot me a line. Let's compare these old boat anchors. I'm in Palo Alto, just south of San Francisco.

-B

[Landpimp]

nope, at least I am pretty sure not :(

Originally Posted by gifu

does ARB make a snorkel for the left side of truck?

still pissed that we (the US) didn't get HJ61's.

dammit.

[dieselcruiserhead]

Originally Posted by theSherpa

very, very cool, now I know what the Sherpa's future looks like a little better


Steve

Why will I believe such an idea only when I see it?

[dieselcruiserhead]

Very very cool brian. A 60 with a 6AT (or dialect) makes me all queezey inside


Nice that your is quiet. I have mine "tweaked" right now and the thing is like a rocket ship. I might turn it down a hair but 17 psi of boost is nice, and it feels almost like a V8, but with torque - lots of it But the mileage has gone down and the noise difference is nearly deafening especially when tweaked, so that concept of "tweaked = louder" is beyond true at least for this motor (and perhaps direct injection?). At idle it is about the same but under the mildest load it almost sounds like a 24 valve (which makes sense since they yield so much more power out of the same block). Anywhoo.... But I am happy. I need to do the same thing as you brian, except I don't even have carpet! Just spray in bedliner and ear plugs

Andre

[gifu]

i was just cruising around listening to the turbo spin and wheeze... thinking what a cool project this has been. I do still have some issues; i don't like the clutch and will be switching out for the Advance Adapters special (centerforce). I should have learned my lesson with the V8J60 (took the tranny out 9 times in one year)... better to just pony up and get the correct clutch the first time.

second thing is vibration; at 60 i get a drivetrain vibration. at 65 it goes away, but i start getting a low frequency groan. It's either the transfercase or the engine doesn't want to be spinning that fast. I'm hoping it will be gone after i install the h55f and rebuild the transfercase.

lastly, i still need some gauges. all i have right now is engine temp. can only afford so much so fast. once i get gaugs, i will mess with the pump, the timing, etc.

and i also need to find an intercooler.

but, in all... it's very sweet. and as much as I lust after HJ61's, the fact that I can get parts at Napa makes this an easier motor to work on. And replace if I ever destroy it (Lewdon has tons of them).

-Brian

[gifu]

Originally Posted by dieselcruiserhead

Brian I have a sweet intercooler that came out of the bread truck. I'll snap pics of that too, I'll be down there tonight. Very heavy duty probably "worth" a fortune but you might be interested in it for $50 + shipping?

good idea. can you take some measurements?