OM617952/MW : IP adjustment advice Low/Mid End : Snapshots!

[Cadin]

Hey Gang,

I am getting ready to tear into the IP (OM617.952/MW) and wanted to know peoples advice and experiences on the matter.

I have read a lot of write-ups, and I think I know the major path I plan to take (Not intending to remove rack limiter); but I would be grateful for any and all's real world experience. Since my survey of the literature indicates that this topic has been covered exhaustively in detail; let's keep it brief and keep the detailed debates for those threads.

I'm just really curious about folk's real world experience in The Realm of Moderate IP Adjustment.

That said my rig (1992 FJ80) is listed at 2,084 kg (4,594 lb) curb weight per Wikipedia, so mid and low end improvement are my primary focus, whilst not impinging on reliability. I'm particularly interested in folks' experience with towing/lots of weight.

What kind of plan is turning the torque control ~1 turn CW ; the Rack Limiter ~1/4-1/2, and I guess idle to taste? Do I adjust with the motor running? How should I adjust boost to suit (~13.5psi?).

I have adjusted valves, ALDA, timing seems right on, but haven't drip tested, (IP is recently "staked"). Boost is around 10-12psi. Never smokes apart from initial startup, not even at full load. Seems like I might be missing out on a little power. EGT's ~ 1100F at 80 Mph flat; dog in the mountains except ~15mph.)


Anyway, Weigh In, Weigh In! Any and All! (But please keep it a brief summay of your adjustments and results!)

[winmutt]

The only change that was pronounced was turning the db holders. Everything else was moderate.

[Cadin]

Do you mean the DV's? Wouldn't that destroy the idle?

[Diesel911]

Do some reading over on the superturbodiesel website.

[Diesel911]

Originally Posted by Cadin

Do you mean the DV's? Wouldn't that destroy the idle?

Moding the Delivery Valves can mess with the idle.

However, I remember when I was a Teen back in the 1960s when People hot rodded their Engines with the Various Camshafts available and end up with the whole Car shaking at a Stop. If it gave more power they simply did not care about the idle smoothness.

Also the rough idle was considered along with an open Exhaust considered Cool.

[winmutt]

Originally Posted by Cadin

Do you mean the DV's? Wouldn't that destroy the idle?

It would if you didn't do it on a bench. I didn't do it on a bench, ran like **** at idle but gave me 20-3hp more power.

[Mölyapina]

Originally Posted by winmutt

It would if you didn't do it on a bench. I didn't do it on a bench, ran like **** at idle but gave me 20-3hp more power.

That's a pretty wide range...

[Cadin]

Right on, it's good to have folks pitch in their views!

I'm really focused on lowering the effective torque curve and maybe gaining a little power in the process. (I'd like to keep a smooth idle vs the Harley or 454 loping idle, and I have no bench.)

If I were going to alter the delivery valves; this may be the ticket when it comes to full fruition:
OM617 MW pump experiment

(Of course I always wonder about MeOH/H2O injection (1:1) for extra fuelling; but that only seems to lowere EGT's vs making power; from what I've read in the OM617.)

If I was going to try to make this a power machine the OM603/606 seems like the proper arena; but my approach is using the OM617 to push a rig that is somewhere between a W123 and a UniMog.

Winmutt: Precisely what do you estimate by moderate?

Diesel911: I have done quite a bit of reading at STD, and still more awaits!

I haven't altered any settings yet, and I will scribe the initial position. Is maxing out the Full Load screw pretty much just compensating for the spring in the IP weakening?

It seems the plan is to step it up slow (1/4 turns) and record my results.

Confirmations:
Which direction shifts the torque capsule lower in the rpm range? CW?
Which direction shifts the rough idle the equal amount to compensate CCW?

(I will use some needle nose vise grips wrapped in silicon tape to pinch the fuel line in case of a runaway situation.)

Does anyone suggest doing this adjustment with the motor running? Do I need to re-install the IP cover before every run?

Thank you all for your input and experience!

[winmutt]

Originally Posted by Jooseppi Luna

That's a pretty wide range...

It's a seat of the pants range. It's the one adjustment that put a smile on my face. Smiles usually get a 30HP boost

[winmutt]

Originally Posted by Cadin

Winmutt: Precisely what do you estimate by moderate?

Did not make me smile, but was enough to notice.