learning to set timing on with a DB2 IP

[dbrannon79]

Hey guys, since I have been able to drive this new to me 93 truck that has a DB2 pump, I have noticed that when driving the engine is LOUD! the clatter is what I would call extreme compared to my 95 but it's nice n quiet at idle. I was reading up on what might cause this and came across some forum posts leading to a few possibilities. One being the timing could be advanced, another was injectors, others mentioned that the fuel screw on the IP is turned up some. Well I figured since I had learned how to time one with a DS4 using a laptop, I figured I had better learn how to time a mechanical truck now that I own one.

I know to do this properly I will need a timing light made for diesel engines, that I don't have but plan to get one if I need to invest. I was searching online and some mentioned you can get them really close doing it by ear.

I found this thread on DP that sort of explains it in the #2 post, but I wanted some more input from your guys since y'all have experience with DB2's.

DB2 Timing Questions

www.dieselplace.com

iirc I did read somewhere in the threads where this truck had a ATT turbo and the fuel was turned up as well as the timing advanced. Not sure if the engine was de-tuned when he put the GM turbo back, but one thing I would like to do is verify it was and know how to set timing along with adjust the fuel screw on the IP to or as close as possible to the stock setting. I have also read that if the fuel screw is turned in, it can also lessen the life of the IP. I want to give it as much of a long life as I can.

I know I have a lot of work to do on it yet, it has a GM-8 turbo installed but the boost actuator is broken. the waste gate lever was completely removed so it acted like a N/A engine. I temporarily wire tied the waste gate closed (left it slightly cracked open) but this was only temporary until I can ether get the turbo-master installed he gave me or put the other GM turbo I have on the 6.2 engine which has a working spring loaded actuator like this engine would have had from factory.

anyway, what tips and pointers would you guys have for me to at least check and see if the timing is too far advanced and the fuel adjustment is within spec.

 

[Will L.]

Line up the two timing marks on top center of the ip when installing ip.
NEVER adjust timing with engine running.
Seat of pants adjustments will give you best results.
I should stop typing here.

No specialty tools involved: engine running, use a prybad and push in on the advance cam actuator (the little plunger thing on the passenger side lower end that has an arm that pushes on it). Ideally, the engine runs smooth- you push it in and the idle becomes rough. If the engine dies you are too far advanced. If nothing happens you are too far retarded. Turn off engine, loosen 3 nuts and adjust as required. This will have you in the happy zone. I REALLY should stop typing here. For perfection zone- learny learn time.

Gm never put out an exact timing spec for this. The reason is the different pop pressure of injectors causes changes in the timing. Imagine 1600 psi is perfect timing. Now a set of 1800 psi injectors- it takes a hair longer of the pump turning to build that extra 200 psi. The timing is now retarded because of the pop pressure increase. GM didn’t spec the injectors that accurately in manufacturing.
Your stock turbo injectors have a target psi of 2250. Depending how accurate and well matched they are can swing your timing dramatically.

I know you are used to ds4, so…
This is why some people swear by -1.94 on a ds4 and the other guy says - no use 1.2. Some say 2.02 . Well, The 1.94 guy has his popping all within 25 psi of each other and st 2250 psi. While guy who likes 2° after … he is running worn out mismatched crap. The 2.02 guy wants more clatter and mid range power over 0-60 numbers…
When everyone was working together and doing testing- gm was dialed in by then with accurate built injectors within 100psi of each other - they were able to learn best settings. But 100,000 miles wear and you might have better results elsewhere.

Apply same logic to the db2. Timing chain stretch, worn or mismatched injectors, different quality of fuel- all these things affect your best performance as much as a few degrees timing by number does. I don’t get into the BS of timing on ds4 because it’s so picky just following the rules keeps people’s trucks on the road.
Screwing around with ds4 adjustments has left many 6.5 in the “wont run” zone.

Part of why db2 always outperforms ds4 even when pushing same fuel amounts is the best way to fine tune. First- pick what is most important: 0-60; acceleration while towing from 45-70; mpg; desired rattle; smooth idle- just whatever you want “best”. Set the timing to the happy zone. Drive and record what’s happening. Adjust it 1mm at a time testing for your preference improvement and recording it.
I found using a self adhesive measuring tape with 1/32” marks stuck on the timing cover made it easier to track when testing without any special tools.

As to tools to measure the actual timing:
You can get a couple different types. There is a couple snapon and a kentmoore that is hard to find-uses an optical sensor that goes in place of the glow plug and has a magnetic sensor that goes into the hole of the timing indicator.
There is also the type I own (mine made by Mac) that clamps onto the injection Iine as the trigger and uses a timing light like a gas engine tells you that way. I tended to use this to write down a recorded setting and the results of performance. But when rebuilding engines over and over you can set exact parameters.
But when something changes by wear say chain stretch- understanding no just the injection pump is now offset from the crank but also the valve timing has changed. So 30,000 miles ago -3°btdc might have been best but now -5° might be. If you are just going for descent running truck- every 30,000 miles seems to be enough chain stretch that a bump in timing usually helps enough to be worth while. If you add in the timing gears- now everything advanced a little from day one- so where timing is will be slightly different than a base timing number.

In the end- no computer has a db2 owner instead of spending hours timing it to the computer screen, doing actual performance testing to what they prefer and getting better results that way. Get the fuel pressure correct and monitoring it from the dash 100% of the time. Know that a db2 will give a different clatter. Get it in the happy zone and drive it to become familiar with it. Then after a month, come back and play with fine tuning.

 

[WarWagon]

I time mine by ear. Warmed up engine at 45 MPH. Go from no throttle to some throttle. The IDI clatter should go away as you get into the throttle and the precups heat up.

Too much advance causes a rust like texture of erosion on the glow plugs.

Altitude also affects these engines and you may see a second set of timing marks on the IP if a shop set it for high altitude in the past.

As Will noted the timing mark is only good for a chain with less than 30K miles on it. Somewhere in a manual it says to adjust the timing every six months and typical 15K miles a year you can figure out how fast this chain stretches out.

I wouldn't spend 10 seconds or 10 cents on the GM8 turbo or any of the Turbo Master stuff. Your time and money is better spent on a better turbo for this engine, period. Unless the trans programming is going to lug the hell out of it below 2200RPM. Even then decide how your are going to use it and get a better turbo to match that use and RPM band. My ATT that may not be the proper choice for you and is no longer in production, last I checked, paid for itself in fuel saved when I was towing.

 

[dbrannon79]

Thanks for the advice. right as it is now, it's similarly quiet at idle like my 95 is, but when you accelerate it get super loud clattering. the higher the RPM, the louder clattering it does. this is why I'm thinking it's the timing. there is a military DB2 installed that supposedly is still 24v. the fuel shutoff solenoid is not connected but has a remote solenoid on the top of the intake that had the return fuel line going from the IP to it and then to the return pipe over the timing cover.

 

[Will L.]

Thanks for the advice. right as it is now, it's similarly quiet at idle like my 95 is, but when you accelerate it get super loud clattering. the higher the RPM, the louder clattering it does. this is why I'm thinking it's the timing. there is a military DB2 installed that supposedly is still 24v. the fuel shutoff solenoid is not connected but has a remote solenoid on the top of the intake that had the return fuel line going from the IP to it and then to the return pipe over the timing cover.

Pics? Video?

 

[dbrannon79]

I will try to get some pics and a video of it running tomorrow evening if it doesn't get too late, if not, Friday. planning on making one last trip up to see Deejaaa in the morning to pickup the last of the spare parts he has along with the programmer for the trans controller

 

[dbrannon79]

Line up the two timing marks on top center of the ip when installing ip.
NEVER adjust timing with engine running.
Seat of pants adjustments will give you best results.
I should stop typing here.

No specialty tools involved: engine running, use a prybad and push in on the advance cam actuator (the little plunger thing on the passenger side lower end that has an arm that pushes on it). Ideally, the engine runs smooth- you push it in and the idle becomes rough. If the engine dies you are too far advanced. If nothing happens you are too far retarded. Turn off engine, loosen 3 nuts and adjust as required. This will have you in the happy zone. I REALLY should stop typing here. For perfection zone- learny learn time.

@Will L. I had some time to mess with the truck some. I tried pushing the advance actuator in with it idling... well the engine still ran smooth but it quieted down some I am curious if that means it's slightly too far advanced and or the timing chain has some wear and the IP needs a minor adjustment.

My thinking is the arm pushes the actuator in on the bottom of the IP rotating the internals counter clockwise (from looking at the front of the truck)
If I were to loosen the IP and tweak it ( top of IP towards the passenger fender) every so slightly this would put the timing in the position as if when I pushed the actuator in ??

 

[dbrannon79]

Here is a short video on it idling and when I press in the actuator. I know the audio is kinda wonky using my phone. oh yeah, that remote fuel shutoff solenoid I mentioned is right there on the intake you wanted a pic of. all the fuel lines to it are some sort of clear tubing with push-lock fittings too. the engine is louder in person lol.

 

[dbrannon79]

Well I decided to tweak the timing a little. Now when I push in the actuator the engine will go into a rough idle. The pic shows just how much I move the ip (top towards the passenger fender). I used a white paint marker to reference the original setting.

 

[Will L.]

You should feel a little better acceleration now. Yes it was a little retarded.
I can’t tell which way you moved it in the pic. You should have bumped the top of the ip towards the driver side a little. Like 1 mm little from where you had it.

Post #52 is where I put the picture of my timing tool btw. MAC ET18DPM diesel pulse adapter. With that tool in the red plastic case, you use any old school timing light and you can read timing like a gasoline engine.
No luminosity probe involved. They are impact sensitive and cleaning the line where the clamp goes on is critical. But like I mentioned above, GM never said “X°” is correct. Best to write down the timing, test drive, and readjust. Learn what you like, then use that setting.
So honestly the timing tool isn’t required. Doing it like you did with paint marker then whenever you find a happy spot- make a scratch fine chisel.

 

[dbrannon79]

I moved it towards the passenger side slightly

 

[Will L.]

At the 4:50 time stamp he shows testing the advance plunger properly.
Some of his info isn’t the greatest but that part I suggest copying.
When you push in the advance it runs rough. That identifies correct area of timing.

 

[Twisted Steel Performance]

Looking at your marks and the paint mark you are extremely retarded....

 

[Will L.]

Looking at your marks and the paint mark you are extremely retarded....

Well that’s not a polite way to say it!

 

[dbrannon79]

The paint mark is just an indicator to tell me where I started from. I marked it before I attempted to move the IP. there is a factory mark on the IP but nothing that I can tell on the timing cover.

as of right now ideling it's smooth and a minute amount quieter. pushing the actuator will make it idle rough and throw a little smoke. before when I pushed it all it would do was get quieter on the top end.

but yes I know I am a little retarded HAHA.

 

[dbrannon79]

Took it out today for the first time with the family to my daughters house, she was having a Sunday family bbq. the truck drove perfect engine and trans wise. on the way home we had to detour onto the freeway since the access road was under construction. the on-ramp is a steep incline, maybe a 30% grade. I went easy at first then fed it some onions (not much) it got up and went leaving the person behind me in the dust! it seems to have better pickup than my 95 does. engine doesn't seem to be as rattly loud as it was before I moved the IP, but time will tell.

I'm driving on 8 year old tires so I need to take it easy until I can find another set, though I put a spare in the bed with the jack just in case.

 

[dbrannon79]

Just curious on this engine, so far it's running fine and has decent power as I have driven it a couple of time out of town and back, but this engine is still louder than my 95. at idle it's quiet but under acceleration I can hear the clatter VERY well LOL. the clatter is much more pronounced under acceleration while the RPM's are upwards of 2k. deceleration gets very quiet.

is there an easy way to make sure this racket is all valve train clatter and not a cam knock or piston slapping going on? or are db2's a little louder than a ds4?

 

[dbrannon79]

Well, I'm back at messing with the timing. I have driven it for a bit after retarding (i thing) the timing trying to get the engine to quiet down some.

I posted in "what did you do with your gmt400" thread on this earlier today. I will quote what I posted here..

Just out of curiosity since I'm a noob to the db2's. I like how my 95 (electronic) has the high idle switch for fast warm up and when I'm running the AC sitting still. is there any such thing for the db2's? I can see the idle solenoid is not strong enough to kick up the idle with out a little help touching the pedal.

Once the weather warms up and after I get a oil catch can installed, I want to address the loud rattleness on the 93. my 95 is much quieter, this 93 is as loud as or louder than a Cummins going down the road that's cold!

The db2 procedure is, As you get in the rig- press the pedal all the way to the floor then remove your foot from the pedal before cranking engine.
I do this while putting the key into the ignition.
The high idle solenoid should hold it there. It is possible the solenoid could move but be worn out and not hold proper position, but that is really rare.
The shaft is a screw that can be adjusted for proper rpm.

That rattle is probably just timing. So long as you adjust timing with the engine off- you can’t hurt it. Just play with it. Db2 is WAY more forgiving about being out of time.

Which way should I move the IP? I had already bumped it toward the passenger side since before when at idle pressing the advance lever it had just got quieter. now idling if I press the lever it gets quieter plus goes into a rough idle with a little smoke out the tail pipe.

Edit: it will also roll some coal in acceleration unlike my 95. but has more power than the 95 too. I think the fuel screw has been messed with.

Correct me if I am wrong but from what I am reading online, rotating the IP top towards the drivers fender would be advance, top towards the passenger side would be retard?

I found this quote from another forum....

"The IP rotates opposite the crankshaft and a V-belt driven fan. It rotates the same direction as a serpentine belt driven fan (which also rotates opposite the crank).

Advance = Opposite direction of IP rotation.
Retard = Toward direction of IP rotation. "

I need to start the truck and look at the belt and crank rotation but this is what I am understanding. if so, when I bumped the IP before, I was retarding it.

 

[dbrannon79]

when I started messing with the IP I used a white paint marker to indicate where it was before moving anything. there is also another scribe line on both the IP and the timing cover I noticed. before I bumped it to the passenger side and this did make the engine somewhat quieter but as TSP said he thinks I made it too retarded.

Here is where I'm at now after moving the IP again as @Will L. just play with it!

I moved the IP to the drivers side and now the scribe lines are closer to each other along with my white paint mark is now aligned in the other direction towards what I think is in an advanced state. Please correct me if I am wrong here..



the engine I really can't tell if it's any quieter but seems to idle smoother now. pressing the advance lever only makes it quiet down. revving the engine I see no smoke from the tail pipe as I was getting a tiny amount before this movement on the IP.


Are there any other helpful tips on "guessing" the proper timing without having a timing light?

 

[dbrannon79]

I found my inspection mirror! Yay me LOL. I immediately took it to the truck to try and get the numbers off the IP since I was told this was a military pump. below are the pics I was able to get I rotated and flipped them so there readable. There is another tag on the passenger side of the IP that looks to be hand written but it's very hard to read. This blue tag is on the drivers side. Anyone know or is able to decipher anything off this?

Here are the numbers I got...

Blue Standyne tag
K5 DB2 831-5149
12550433
1255043
11432463