Outer Limits 4x4 Board

Trusa wrote:Ok, the story goes:
1 tired 3b gets rebuild and AXT turbo kit
after run in angine is serviced/checked by mechanic
1 unsatisfied owner eventually believes he has an ok engine and that he was just expecting too much
Dyno shows 36 kW at the wheels

According to AXT this is about right for the middy to be running this low output. Does anyone have any suggestions as to where to go from here power increase-wise? Please consider that this engine has cost me too much to throw away.

I would also be interested in hearing what other 3b owners have had there rigs pulling on a dyno.

Thanks, Ben

ozlegacy wrote:
The proof should be how it drives

pcman wrote:at the bottom of the dyno sheet for bj's truck it says gear 2 tho a bj42 doing 100kmph in 2nd ?????

Dzltec wrote:"First dyno figures are BULL SHIT and only good for pub talk."

Please explain. If done by a reputable operater, how can they be "BULL SHIT".

Yes, flywheel figures and at the wheel or rear wheel figures do alter drastically. There is no hard and fast rule as to how much power the driveline looses.

For 13k, everything should have been overhauled. What are air/fuel ratios and boost pressure settings?

Cheers

Trusa wrote: After $14000 on this engine and only dissapointment I'm reluctant to start on a new engine tho.

dumbdunce wrote:The later 3B-II (5 camshaft bearings, rotatry fuel pump etc) as in your BJ73, should be good for approx 100 flywheel kW with turbo, without intercooling, if correctly tuned. that should equate to about 70 rear wheel kW in 4th gear on a dyno, regardless of the tyre size. (although big tyres might slip on dyno rollers and givce an incorrect rpm reading)

as for what you have paid for, I don't know what's included in your $14000 but that sounds like a lot too much to me - a turbo setup, fully installed including a full exhaust should not cost more than about $3500, and can be done for a lot less. the engine rebuild including all new pistons, seals, gaskets, rebore, even a new camshaft and timing gears could not possibly cost more than about $5000 - a replacement jap import low km 13B-T motor can certainly be bought for around $5000 give or take a bit.

indicators of the quality of the rebuild will be noises from the engine - the later 3B motors are fairly quiet in operation - if it rattles or clumks. smoke - if it makes blue (oil) smoke, there's something not right - the rings have not seated in the bores. If it makes white smoke, the compression is poor and it is not burning the fuel. If it makes black smoke, it is overfuelling and the pump or injecotrs need attention. If it consumes any oil at all, something is not right, these motors are famous for not using a drop between changes. Test for blowby by disconnecting the crankcase breather from the inlet and feeling the breeze out of the pipe with your hand - at idle it should be barely noticable, and as you reve up, it shoild not get much more prevalent on a new motor.

was the motor built and tuned by a diesel specialist? these motors are very fussy about tuning and need the fuelling to be set up just right.

another possibility is that the timing gear on teh fuel pump is one tooth retarded or advance - it will run, but it will be rough and low on power. will probably also cause smoke of the grey or black varieties.

I don't know any specialists near you who can help in a more practical way. Denco in Wagga Wagga are very good (about 150km from Albury?) and it might be worth the trip - give them a call and ask anyway. Jon Bruest is the man to talk to.

Unless your rebuild included some pretty special stuff, and included overhauling your gearbox, transfer, diffs etc, my feeling is you have been ripped off (of course I don't know all the details) even if your motor rebuild is working fine.

If I was going to diagnose this engine, I'd first take it for a drive and see how it feels and sounds, and observe any smoke issues. then I would statically check and set the injection timing, then take it for a drive with a boost gauge and exhaust pyrometer attached. I'd be looking for exhaust temperatures peaking around 600 degrees C (post turbo), and peak boost levels around 8psi, with zero smoke - if these don't fall within expected ranges, tuning the fuelling and wastegate until they are where we want them. It should feel reasonably lively to drive (but not really all that exciting!) - should accelerate smoothly and easily, and be able to cruise at 120km/h (about 105 indicated if you have not recalibrated your speedo for the 35's) without any trouble at all.

shorty_f0rty wrote: leaning towards denco anyway.. this is more food for thought.

bj42turbo wrote:

shorty_f0rty wrote: leaning towards denco anyway.. this is more food for thought.

I was under the impression AXT were the only ones who did a turbo kit for a 3B

Dazz