bigredbrick

Based on the modifications in my signature what do you recommend? Just installed the governor spring and fuel pin. Reasonable EGTs and low smoke are important. No rolling coal! I lowered the idle speed, might need to raise it back up a little. I had turned smoke screw in a little quite a while ago, but don't remember how much. I just bled the rear brakes today so I can take it out on the road tomorrow.

j_martin

I installed an M&H dynamic timing advance and a 3200 governor spring. Woke it up nicely, and still smooth and strong on the low end. I pull a double with a tight automatic, so turning the fuel pin was all I needed in that department.

bigredbrick

Drove it this evening. Wow, different truck, even sounds different. Need to play with fuel screw and I guess the star wheel. Clean at idle, initial acceleration moderate black cloud then clears up right away and goes.
The idle still needs to be increased. Idling around 700rpm. Put it in gear with foot on brake and it drops to 500rpm and shakes. One thing I'm noticing is at idle it's not steady, it will intermittently drop 25 or so rpm. When it drops it sounds like a load is briefly put on the engine and then taken off. That's the best way I can describe it. Kind of like an AC clutch going on and off, but not as much and my AC is bypassed. Got any ideas on that one?

bigredbrick

I've heard of the M&H timing advance but don't know much about it. I think I've done all I'm going to do to the engine, for now. Now I need to do something about the transmission. It's not going to like the power increase. Better get started on that V 10 version 47RH that's been sitting in the garage taking up space for a long time.

nonrev

Try turning that smoke screw CC till it is flush with the inside of the afc cover

oliver foster

I would look into ordering the stiffer AFC spring that the earlier NON intercooled trucks came with.
It will help you tune how fast the fuel comes on in relation to boost, now that you are running much more boost pressure #s.

I have seen them on The Hungry Diesel website for pretty cheap.

bigredbrick

Backed the smoke screw til it is flush. Turned the fuel screw in 1 1/2 turns. Seat of the pants says it's a little quicker now and still have that initial cloud. Looks like I might need to adjust the star wheel up a little according the directions from Dieseltuff.
I left that nylon washer out, the one that goes around the fuel pin under the diaphragm. Should I put it back In?

Thanks

nonrev

I usually take a black marker pen and "paint" the face of the fuel pin to see how deep it rides, if it goes past the deepest part of the pin it will start to defuel so you may need to put the washer back in after you shave it to get it right.

oliver foster

I do the same as Vernon, but I use some clean grease.
On the THD pin, you will likely find the nylon washer is not needed.

On my '89 RC I found the stock fuel pin rotated to the deep side was a better pin for me than the THD pin and on that engine I shaved the nylon washer down to about 1/2 it original thickness. I just rubbed the washer on some sand paper till I got the right thickness. It took several test runs will a dab of grease on the pin to get it perfect. I just kept pulling the washer out and sanding it down till I was at the deepest part of the pin.

You do not want to have the fuel pin bottom out as it can bend that rod that slides on it.

oliver foster

I run the THD pin on my black crew cab and my '91.0 W250, I just found that my '89 RC 12V ran too fuel heavy on the top end with the THD pin and the stocker was a cleaner running pin for me.

nonrev

These trucks are a lot like old Harleys as what works for one doesn't always work on one just like it.

oliver foster

You got that right 100%. I have a decent guess as to what the perfect tune MIGHT be for each build, but I have to really end up taking test and tune runs on each rig. Then change stuff around to get good power with out excess smoke or ETGs anywhere in the RPM range.
Even the three '89-'91.0 non IC'ed 12Vs trucks I have needed a slightly different recipe to get it where I wanted.

maybe368

I had a '66 Porsche 912 that was made in the time that each car was built by a single worker (with some help when needed), no assembly line. Each part especially for the body, was adjustable to fit the car exactly. Because of this, if I ordered an engine grill for it, which I did, It had to be adjusted to fit my car. My Harley was kind of the same, every component seemed to need some tweaking in order to work/fit right. The old saying goes, show me a Harley that doesn't leak and I'll show you a Kawasaki. (I have one of those too) ....Mark

nonrev

Show me a older Harley that doesn't leak and I will show you one that is out of oil

bigredbrick

When I pulled the AFC cover the diaphragm and fuel pin came with it. I had put a very light smear of Lubraplate on the fuel pin and it looks like that slide pin is right in the zone on the ramp.