Pump timing

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Farmallgray

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In general how do you know where to time a high performance mechanically injected turbo diesel? This would be without being able to use a dyno. I know if the timing is late the EGTs will be high so you will want to advance. How do you know when you went too far? At the moment I think I need more water injected too. I'll try that first but I may need to play with the timing from there.

I'm not giving specifics because this is an oddball engine that very few people have modified. So far I have advanced it about 3 degrees from its stock non turbo factory spec. It is also turning a lot more RPMs than it did stock.

I just need some general guidelines on how to know which direction and or how far to go.
 
When the headgasket goes, you've gone too far.:hehe:
Timing is a tricky thing, and varies so much with different engines and combos. If you dont have guidelines, adjust it, and test drive it. That's how I ended up with a few of the trucks I've done. If you go way too far advanced, it'll be a terd in the lower rpm, but great at the top. I'd say to hike it up a couple more degrees. If it has high compression from being non-turbo, you cant run too much timing.
 
Here is what I'm working on;
[ame="http://www.youtube.com/watch?v=M8_WNasShfU"]http://www.youtube.com/watch?v=M8_WNasShfU[/ame]
68 ci 3 cyl. Pump and injectors are stock, governor weights lightened. I'm putting 360cc/min of water in at 250 psi. Cam is reground for higher rpms and turbo. Compression is slightly lower than stock.

I'm guessing that since I'm getting a flame out the stack but not a lot of smoke that it needs more timing. It is telling me that the fuel is still burning while it is coming out the exhaust ports. Egts on that run were 1600. I know it could use way more fuel but that isn't an option right now. But I want it to run as good as it can with what I have to work with. I can easily advance it another 2-3 degrees but to go more than that takes a little more work.
 
they usually run very little timing advance as a factory setting. it sure cant hurt especially at higher rpm. I also saw the post on the yahoo group and I disagree with the one fella that timing will increase egts. MOST of the time it actually decreases them however I cant really say wether that will be the case on an IDI engine. I actually ported the prechambers on my mitsubishi diesel on my garden tractor. Im still undecided if it helped, I hant stay on top of the turbo. Im suspecting that I have removed too much and the compresion is too low for the fuel im running at higher rpms. I still need to lighten my flyweights for more fuel at higher rpms.
 
also ill add that the head gasket, at least on my mitsubishi, is way overkill I have reused the stock allen head 12.9 bolts and even the factory head gasket numerous times with a little rtv to help seal water and oil. I have witnessed a 80 psi boost guage peg numerous times and saw the 1600 deg egt peg just as many. These little engines are TOUGH.
 
Well, drip timing isn't real precise. As near as I could tell it was at about 20 or 21 degrees before TDC. I took the last shim out and now it seems to be about 25.
It seems to rev a little better and build boost easier. I'll see how it works next weekend.
 
cool. never checked my timing all i did was take out all the shims and toss em. as a general rule higher rpm=higher timing. I finally bought a tach for my tractor, now to get a sensor and install it lol. maybe Ill check the timing while im at it. what clutch are you using for your tractor?
 
I'm running a double clutch based on the Cub Cadet setup.
Check out this website;
http://www.gardentractorpullingtips.com/clutch.htm
Near the bottom of the page is a diagram that shows how they work.
On mine the drive pins thread into the flywheel. I'm running an 1100# spring
and the discs are from Vogel mfg.

A buddy of mine mentioned rotating the barrels in the pump all the way counterclockwise for max fuel. I asked him to explain but haven't heard back yet. Do you know what he means or how to do it?

I just found out that Tiny Tach makes a diesel version. It uses a transducer to sense the fuel pulses in the injector line. I may try one of them since I don't have any kind of tach on mine.
Tiny-Tach: Diesel Tachometers
 
The timing didn't seem to help.

I had another pull Saturday. I can't get the videos from the cam to the computer at the moment.

I wound it up a little more and built some boost at the line on all four hooks.

Seemed to run ok on the first hook but still ran out of power on a biting track. EGTs were 1650 or so. Boost was only about
20. I have seen as high as 28 before.

I added another 180cc water nozzle (in addition to the 3 90cc nozzles in the intake ports) after the first hook. It was too much; engine was spitting and missing pretty bad till late in the run. Made two hooks back to back because the sled was re geared. EGTs weren't much lower maybe 1500. Only about 16# boost.

Last hook I took the 180 nozzle out and put a 90 in. Ran pretty good but still spit once or twice. EGTs were still around 1700 and boost was still only 18#.

I am going to pressurize the system and check for boost leaks.

It seems odd that even with too much water, the EGTs are still so high.

I think I have one more chance to try it this year. I'm thinking about putting the timing back where it was and see if the boost comes back up.

Any other ideas?
 
as timing goes up, Usually boost comes down with all other things being equal. 1650 for egt is not too high for a pull, Ive seen way higher than that before sounds to me like your out of fuel. time to sent that pump off and have it cranked up more. I had talked to a few places and it was in the $5-700 range for basically 3 times the fuel you have now. Does that pump have delivery valves? have you cut them yet? In my tractor which is a mitsubishi engine, backing the fuel screw out added fuel so i took it out and threw it away, i cut the delivery valves, drilled the delivery valve holders, took all the shims out for timing, and wired the gov spring so it couldn't spring any more. I did some porting on intake and exhaust, and also on the fuel chamber since it was IDI. I think some of the port work on the fuel chamber has lowered my compression too much and i need some more fuel up high in the rpms. this winter i plan on cutting the gov flyweights and clocking the cam for the pump one tooth so i can get more timing advance. i can then put shims in to adjust the timing back down if need be. I may also send the pump off for some more fuel too. As for a tach, you can use any gas tach just use an inductive proximity sensor triggered off of the flywheel bolts. Its the same setup many of the gas pulling tractors use. Ask around I'm sure someone can show you first hand. i also think brian millers page has info in the tach setup using an inductive proximity sensor.
 
if the engine was spitting after adding a water nozzle Id also take away a little water. Also believe it or not, overfueling will actually cool egt to some extent. Your pulls look good, id possibly even gear down just a little and use rpm to your advantage since these little engines will make so much rpm.
 
I pressurized the intake side last night and found 3 leaks. Simple fix but I doubt they were enough to lose a lot of boost.

For the last hook I changed the one nozzle for a smaller one which seemed to take away the sputtering for the most part.

I'm sure I need more fuel, but I'm not ready to send the pump out just yet.
I'm still just pulling exhibition so I'd like to get the most out of it the way it is.

I'm also still exploring the possibility of adapting a 3 cyl Bosch A pump to it.

I would like to know more about cutting the delivery valves. What does that involve? Is it something I could do myself, or would I have to send it out?
 
dremel tool will suffice. let me look at the ubota i have here and see if it even has dv. If so ill take pics and tell ya what to do.
 
I don't know if you can tell anything from this pic. I was told about turning the barrels for max fuel which apparently is the balance adjustment. It appears from this pic that #2 is already maxxed out. So assuming it was balanced right at the factory (and wasn't tampered with since) turning the other two would throw off the balance, right?

According to the service manual the pump does have delivery valves.


Here is another video. This is probably my best run so far.
[ame="http://www.youtube.com/user/farmallgray#p/a/u/2/2fo_zfCN09I"]http://www.youtube.com/user/farmallgray#p/a/u/2/2fo_zfCN09I[/ame]
 

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If the pump had delivery valves they will be under the holders that the injection lines screw on to. take off the lines then take off the holder. Be careful it should have a spring and maybe shims under the holder. Pull out the delivery valve and with a dremel tool, ( or best case a lathe) cut off the shoulder. do all 3 valves, clean em up and stick em back in. should be more fuel, although I don't know how much more. Ill still try to get pics up tonight.
 
I did have one of them out but I can't remember exactly what they looked like. I was having trouble getting fuel when I first put it together. Then I figured out that I didn't have the rack pin in the right slot in the governor arm. I do remember there being a spring under it but no shims. I do have a lathe so I can do it that way.
 
heres some pics. in the last picture there is a shoulder that you can cut completely off. also drill out the delivery valve holder ( piece the inj line screws on) while you have it all apart. clean it up good with brake cleaner and reinstall. should be more fuel.

SDC11417.jpg


SDC11421.jpg
 
The shoulder I'm talking about is the tiny shoulder in the middle of the Delivery valve ( ive tried to open this in paint so i can make an arrow but cant seem to succeed). This delivery valve is from a D850 so it should be similar if not the same.
 
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