Diesel Timing

[AgDieseler]

I finally got the chance to use my new toy: a Snap-On MT480 luminosity timing meter. Non-electronic diesel like mine or Mike's are harder to time than newer engines, but this tool makes things pretty easy.

A fitting with a quartz lens replaces one glowplug hole (#3 in my case) and looks at the flash in the cylinder head, and a magnetic pickup senses an indentation on the crank. The two are compared to get a timing result.

I found that with the timing marks perfectly aligned, TDC was at 1400 RPM. With a turbo engine, you typically don't go past 3* advance, so in order to chart the progress I did just one degree advance this first time. EGTs were about 50-100* lower, and there was less smoke on acceleration runs. Power didn't seem to change. I'm shooting for about 2.6* BTDC at 1300 RPM since that should give good turbo respose, lower EGTs, and less smoke.

Mike, let's find a time to do your engine since I brought the meter back with me. We just need to find #3 glowplug, and advance it to whatever 7.3Ls are supposed to be. PM me whenever.

[chevsu]

why don't you just put some better spark plugs in there and that would help it out alot or just better yet swap a cummins in it.

[AgDieseler]

I think I'll go wit PLATNUMS fo da bling facta.

[AgDieseler]

We got Mike's 7.3L IDI NA timed yesterday. Stock timing was 4* ATDC at 2000, and over three seperate increments we went all the way to 5.5* BTDC at 2000.

As the passenger, I noticed a significant increase in the amount of black smoke throughout the power band, but it only came around on acceleration and cleared up quickly while cruising. The fuel is turned up some from the stock 58.2 cu mm per stroke, so I think turning that back down will probably be the next step. That should clear up most of the smoke. Timing spec on that engine is 8.5* BTDC at 2000, but to go that far we'll need to crack injector lines since that pump gets very tough to turn!

Mike, I'll let you take it from here to tell all about whatever seat-of-the-pants improvement there was.

[fbronco86]

well the real test will be when i get to pull the bronco with it. I think before TCC i am going to turn down the pump a bit and then we will see what happens. I did notice I lost power from the low end but i gained it in the top end not really sure about that.

story time: When my truck starts off from a stop a big cloud of black comes out. Well I was driving around today and a Z71 was next to me and had his window rolled down. Yeah it was great the smoke went right into the window.

[uglyota]

that was me!
ass


just kidding

[Graystroke]

Hey David, want to time a 636 c.i. Mack engine for me? Right now it has about 250 Hp. Suppose to be able to squeeze around 350 Hp out of it by timing it. It black smokes like a coal train. I love going down to Prarie View A&M and shifting into fifth and making it lug in the middle of campus. I've made cars move to the shoulder many of a time.

[AgDieseler]

Originally posted by Graystroke
Hey David, want to time a 636 c.i. Mack engine for me? Right now it has about 250 Hp. Suppose to be able to squeeze around 350 Hp out of it by timing it. It black smokes like a coal train. I love going down to Prarie View A&M and shifting into fifth and making it lug in the middle of campus. I've made cars move to the shoulder many of a time.

If the lumy probe fits the glowplug hole, and you have a timing mark on your dampener, and your offset is either 20* or 99.5*, then I can time it. It's actually very easy to time a diesel. It's a little more involved that just rotating the distributor until it sounds right. It's a lot of fun actually. Hey, I'll try anything once!

My MT480 was initially designed to time the 3.8, 4.3, and 5.7gas conversion diesels. Then came the 2nd generation with its accompanying probes (the one I have) which could time the 6.2 and 6.9 diesels. 6.5s and 7.3s are basically just big brothers, so they will work too.