Compound Turbos on a 2nd Edition B Engine (5 Viewers)

[Busted Crank]

ive been wondering this for a while now....
How did you shim the timer... guys gotta know

with the timer on your bench, remove the circlip, and slightly twist while pulling the two halves apart, dodge the flying shrapnel, then pull apart the other two timers you have from the other broken engines, stack all the shims together and reverse installation.

all jokes aside, it can be done by hand, but its kinda like reassembling a pullstart on a lawnmower.
I think I currently have two timers worth of shims in there now

 

[bj70bc]

awesome

 

[bsweaty]

with the timer on your bench, remove the circlip, and slightly twist while pulling the two halves apart, dodge the flying shrapnel, then pull apart the other two timers you have from the other broken engines, stack all the shims together and reverse installation.

all jokes aside, it can be done by hand, but its kinda like reassembling a pullstart on a lawnmower.
I think I currently have two timers worth of shims in there now

Any chance you can post a photo? I’ve been hitting megazip incredibly hard, I can’t seem to find what I’m looking for regarding this timer. Thanks!

 

[bsweaty]

So im talking about the early 3B inline pump, looks similar to a p-pump 4bt. now picture someone fitted a timing advance like a distributor to the timing gear that drives the injection pump.

Never mind! I found the timing starts and stops on my pump. It looks entirely different. For what I am working on. It’s on the side of the pump for me. I’m wondering if this pump will respond to a turbo the way the older style 3Bs do?

 

[Busted Crank]

Any chance you can post a photo? I’ve been hitting megazip incredibly hard, I can’t seem to find what I’m looking for regarding this timer. Thanks!

 

[bsweaty]

Actually. I just found my engine manual. I have one just like that. I couldn’t find it on megazip. Thanks again for this beta. You likely just saved my crank.

 

[Busted Crank]

Actually. I just found my engine manual. I have one just like that. I couldn’t find it on megazip. Thanks again for this beta. You likely just saved my crank.

View attachment 3608239

Yep thats it, Its very sensitive, it was a fair bit of trial and error for me, you will get good at pulling the timing cover, i used a timing light after to get a ballpark of the changes but seat of the pants seemed to be best.
the hx30 from a 4bt seems to be a good fit now, boost is very easy to come by, i think i had it topping out around 17psi, somewhere around 10 psi by 1800 rpm. its been a while since i drove it ( its motor and frame right now)

 

[bj70bc]

so im assuming you loaded up the 'outer' shims on the diagram

 

[Dougal]

Also. Direct injection engines run a whole lot more timing advance than indirect injection engines do.

 

[KiwiDingo]

That's the opposite to what I've experienced with VE pump calibration test plans. All the pumps for indirect injection motors were running more timing advance than the direct injection motors.

 

[lacalvette]

ive been wondering this for a while now....
How did you shim the timer... guys gotta know

Same for me, was wondering if springs got less strong.

Was wondering if it could be possible to use a device which take position of the crank and pressure from cylinder (glow plug).
These device take #1 TDC and compression and peak pressure of the cylinder, that give a Pressure/ Volume diagram.
You can see what’s going on with timing.
I only saw it on big stationary engine, newer engine have a factory install system that you can monitor live all time.

I need to take the timing cover off now !

 

[iliketrucks]

@RufusTheDufus
Post 55 in this thread... (I saw your old thread as I began researching the subject)

 

[Busted Crank]

so im assuming you loaded up the 'outer' shims on the diagram

On my 3b it only has the outer springs, no inner springs. so probably the equivalent of shimming the outer springs here

 

[Busted Crank]

That's the opposite to what I've experienced with VE pump calibration test plans. All the pumps for indirect injection motors were running more timing advance than the direct injection motors.

I'm quite certain that the indirect injection non turbo engines run the most timing advance. Mechanical cummins engines run no advance mechanism.

Have a look at this table, every degree of pump timing is two degree of crank rotation.

 

[KiwiDingo]

I'm quite certain that the indirect injection non turbo engines run the most timing advance. Mechanical cummins engines run no advance mechanism.

Have a look at this table, every degree of pump timing is two degree of crank rotation.

View attachment 3609989

Yep, exactly what I have found. When you look into the way indirect injection actually works inside the cylinder it makes complete sense for them to run more timing than direct injection engines.

 

[Dougal]

I'm quite certain that the indirect injection non turbo engines run the most timing advance. Mechanical cummins engines run no advance mechanism.

Have a look at this table, every degree of pump timing is two degree of crank rotation.

View attachment 3609989

Advance angle is the change in timing. It's absolute timing you want to compare.

Isuzu engines are spill timed. That's where you rotate the crank until the injection pump starts to deliver fuel.
4BD1 (direct injection no turbo) is 10 deg BTDC
4BD1T (direct injection turbo) is 13-14 deg
4BD2T (indirect injection turbo) is 8 deg. (11 deg in California)

Just noticed this pic of the 2L engine. Tag beside the engine shows base timing to be 0 deg BTDC

https://forum.ih8mud.com/attachments/img_3083-jpeg.3519320/