IP Timing, 6.2 NA

[Bruzersdad]

To All:

My question seems relatively simple, but I haven't yet found a direct answer. I have an '86 Beauville with stock 6.2, with a rebuilt DB2 4502 pump. I have a SnapOn 14XX Timing Meter, and I'd like to set the timing. The pump is currently indexed about 1/32" to the drivers side of the stock timing mark.

Can anyone recommend a setting? 2 degrees BTDC @ 1400?

Thanks!

[gmctd]

Welcome to the forum............

Do a search on member Brittanic - he posted in-depth 6.2L timing instructions

[Bruzersdad]

I'll follow the string to Brittanic, and hopefully his information will answer the question. Timing is critical, and it's the first step along the path, but the adjustment isn't rocket science.

The engine, a Jasper rebuild, has about 100K on it. The throttle shaft seal was leaking on the original 4502 pump, so I replaced it. I also replaced the injectors with rebuilts, and the glow plugs with AC 60 series. I replaced the stock glow plug control with a manual version (starter solenoid and control button), and it starts instantly. I also installed a J-series manifold, without EGR. The exhaust is clean, until I push hard (as in merging onto the interstate), and then I generate black clouds that would make a B-61 smile. The heavy duty pumps that I installed (tried a 4523 first, and then a 4544) REALLY put out the black smoke, so I went back to the light duty 4502.

The problem could be injectors, but they were rebuilt by a competent fellow. The engine always idles well, and responds smoothly all the way through the throttle range. Power is good, but the black smoke is excessively bad. Also, the mileage is not as good as it should be; I have no fuel leaks that I can find. The air filter is new and clean. I haven't run without the intake muffler, but it appears to be clear and solid, with no signs of collapse.

Thanks again for the help!

[gmctd]

How's the intake path?

Dirty air filter causes black smoke.

Might try stacking two air filters in the housing with a longer stud, ala the good Doctor, and maybe turning down the fuel adjustment in the IP.

Blocked fuel-return can cause black smoke - causes low housing pressure, which prevents advance.

While you're checking the return pipes, pull the return line fitting from the IP, or pull the cover to check for blockage there.

[Bruzersdad]

Thanks for the direction. I had not considered that the return lines might be clogged, but they're very easy to check. I've replaced all the fuel return hoses on the engine, but I haven't gone beyond the connection to the return line to the tank.

The air path is clear, unless there is something funky going on in the air intake muffler at high air flows.

Thanks for the suggestion! I'll test the return lines first.

[arveetek]

After years of wrenching on my 6.2L's, I have come to the conclusion that the timing on these mechanically-injected engines is better set by ear and feel than by a meter. It seems that everyone who has set these engines with a meter comes up with different numbers. A large part of that, I believe, is due to the fact that the timing reference pointer on the front of the engine is bolted on with slotted tabs, so it can be adjusted. If the pointer is not set to show top dead center when the piston is truly at TDC, then any timing numbers are completely useless.

If the front timing cover has ever been removed or replaced, or the harmonic balancer replaced, there's no way to really know if the pointer is in the right place.

I've used a Snap-On digitial timing meter on my engine, and I finally gave up and just set it by ear, feel, and the EGT guage.

Casey

[JeepSJ]

Along the lines of what Casey said, someone had posted a method of timing by ear a while back. IIRC (and someone please correct me if I'm wrong), is that when the engine is warm and you energize the cold start advance, the clatter should get much louder. That should get you into the ballpark. I need to use that method on mine, as the engine went together without the pointer installed and now I have no way of determining true TDC to install the pointer.

[britannic]

My username is "britannic" (1 "t" and 2 "n"s), that'll help you find the links quicker. Non turbo 6.2s do better with the timing set between 2.6-4 BTDC, but make sure that your timing pointer tab is actually set up properly - mine was bent, so I had to fix that first before timing the engine.

Here's a search link for my posts: http://www.thedieselpageforums.com/tdpforum/search.php?searchid=31648

[gmctd]

Thanks, britannic, and apologies for the mixup..................

[Bruzersdad]

Further disassembly to find a persistent fuel leak into the valley revealed that the advance shaft seal on my 4502 pump is defective. A warranty replacement is on the way; if UPS is wonderful, I'll change it this weekend. As a start, I'll set the new pump index about 1/16" to the drivers side. It will probably rattle vigorously cold with the HPCA.

I opened the tank, and tested the return line with a soft blast of compressed air. The line seemed clear; the two hoses in front were OK, but I replaced them anyway, and the line at the tank will have to wait for another day.

The air filter is new, but I'll change it, just for the sake of experiment.

If all this DOESN'T clear the smoke, then I'll run a compression test.

Thanks for all your help! Happy New Year!

[Bruzersdad]

All:

The replacement 4502 pump has been installed, and I'm very pleased to report that it works well. My excessive black smoke problem has gone away, and my power is still totally acceptable (I can race Geo Metros and win!). Yes, I still have some smoke with a full throttle, but that is a requirement. Perhaps this pump was set up with a turned-down fuel feed screw.

Thanks for your help!

[opto]

My username is "britannic" (1 "t" and 2 "n"s), that'll help you find the links quicker. Non turbo 6.2s do better with the timing set between 2.6-4 BTDC, but make sure that your timing pointer tab is actually set up properly - mine was bent, so I had to fix that first before timing the engine.

Here's a search link for my posts: http://www.thedieselpageforums.com/tdpforum/search.php?searchid=31648

This link doesn't work for me and I've really tried to find the information by searching

Anybody knows where to find that information about the timing, I think I read that thread before where there was a lot of discussion which timing setting would be the best

Have anybody tested to read the timing both with a luminosity probe and a pickup (on the injector line) on the same engine just to see what difference they show?