Loaner Timing Meter?

[john8662]

Well, I'm playing with my '86 6.2 and I wanted to get the timing set on the new engine. I took a journey to the local shop that I usually have my timing checked at.

We hooked up the timing meter (stanadyne pulse type) and took a reading.

At my first assumption, I figured the timing was retarded because the engine was relatively quiet, didn't sound advanced.

Well, upon taking the first reading, the timing meter showed ~12 BTDC!

So, we moved the pump, where I now have nearly 1/4" line mark towards the passenger side. The reading then read ~8 BTDC and the engine really didn't have much rattle then.

I'm thinking something is up with the meter personally, or something wrong with the IP (advance piston). The engine also got harder to start after moving the pump to retard the timing.

Starting was perfect before touching anything, very easy start, good power, etc.

This is a new engine, with ~50 miles on it now, just wanted to get it timed correctly from the start.

So... Anyone got a timing meter that they can loan?

Oh.. (this is for Casey) this timimg set is not near as noisy as the previous set was...

[arveetek]

John,

Did you rebuild the engine yourself? If so, did you make sure that the timing tab was set at exactly TDC? I've measured the timing on my engine, and came up with a nice running engine at 4.5* ATDC. However, after doing that, I realized my timing tab on the front cover was NOT adjusted to TDC when I assembled the engine. In fact, I used another front cover off another engine, so I know it's probably not right.

Since the magnetic pickup probe is placed in the holder on the timing tab, the timing tab has to be in the proper place in order for the meter to take proper readings. As you are aware, the timing tab has slotted holes in it, allowing for adjustment.

When assembling the engine, the timing tab should be bolted on to the front cover before the heads are bolted on, and then a dial indicator is placed on the piston. The crank is rotated to find exact TDC on piston #1, and then the timing tab is adjusted to show TDC in relation to the balancer.

After saying all this, I have found, in my experience, that the timing is best set by ear and by the EGT and boost guages. The meters don't really help.

Casey

p.s....is this the same engine that the gear set made noise on? You swapped the gear sets and the noise went away? I'm still not sure what to do about mine, but it's so noisy it drowns out the diesel rattle at warm idle. But man, it sure does run good! :D

[john8662]

Hey Casey!

Yep I rebuilt this engine myself, I used all the same components that came with the engine. I did not set the tab on the front cover when I had the heads off, I did think about it after things were already bolted down. I'm using the same timing cover that was originally on the engine, same crank, same rods (in the exact same cylinders they came from), but with a new camshaft.

I don't really see the tab being that much off using the same guts. Except that the cover has been off the block, and they do move on the pins, etc.

I'm receiving a timing meter from another member to verify the timing with an MT480 lumy type meter, a pulse type adapter was used with the stanadyne setup. If it's way off again then I can suspect one of two things:

a. The timing tab is off
b. I missed a tooth on the timimg set somewhere.

As far as timing from ear, it sounds like it's not that advanced to me (and I've had the engine n/a advanced plenty to know how noisy it can get). Coolant temperature is low, just where I like it, EGT's are not a problem, boost is a little slow to respond (not impressed so far on the turbo aspect). Maybe I had a kick butt n/a engine before..

I don't really know why this set is quieter, but I'll keep you posted as it wears in. I haven't had the engine oil that hot yet, as I've just driven the truck short distances once up to normal operating temp.

DSG still has my original set, they sent it to their supplier to be looked over, they said it was fine (I guess they didn't see light pitting on gear surfaces one direction). It's supposedly back in DSG's hands now and they said they wanted to run it in a dyno engine and see how noisy it is. I haven't heard any feedback on that as of yet...

I'm not getting the quality of idle that I'd like with the fresh engine, so I might be collecting parts for a DB2 to DS4 conversion... I HATE BEING SHOOK!

J

[mdregister]

If you are interested, there is a Snap-on MT480 probe for sale on ebay right now. In fact, I think I may have sold the probe in the auction to them some time ago.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4616963859&fromMakeTrack=true

[john8662]

Well, shortly after I posted this thread an offer was made to borrow an MT480 meter from a member here on the board. Bob (bmiszuk) loaned me his MT480 very graciously to get to the bottom of the odd readings I was shown at the local diesel shop.

Well, after warming up the truck fully (running down the interstate a little) and then getting back to the shop to connect everything, I took a first reading.

The first reading I took was pretty much what I expected (and had hoped to see) the reading was retarded. I was showing ~1 degree ATDC. So I shut 'er down and loosened the pump bolts and rotated the pump to line up the timing marks on the cover (just for grins). Cranked it back up, let it idle a bit, then took another reading. This time I got ~1.5 BTCD, and it's hard to hold the RPM steady (but I managed). So, I shut it down once more, since I know about where I'm at, and moved the pump not even a lines width towards the driver's side and then tightened the bolts. This time I got my measurement that I was looking for, it was at ~2.5 BTDC, thats where I want to run it for awhile.

A couple of observations on the timing and performance of the truck (still not broken or broke in yet).

With the timing retarded, I was making great boost with the turbo (spikes up into the 13 psi range). After the adjustment I got the standard 9psi. I haven't had it on the freeway yet to see if it'll still spike and stay high like it did before. I think 13 is a bit too high for the stock C/R, I'm hoping it's a little safer now.

EGT's are a bit lower but I didn't have any trouble with EGT's before (hmm, 3.5" exhaust working nicely). But, I'm in West Texas, it's pretty flat here, so thats just telling it how it is..

With the timing set where it's at now, the truck feels more purky off the line, even w/o actually building any boost.

I still need to get the exhaust leak fixed on the x-over tho..

Well, that's it, just the update.

I feel more confident in the MT480 meter's readings verses the pulse-type stanadyne meter used. Maybe a wrong number was punched, I dunno, ain't my meter!

J

[Yukon6.2]

Hi
A trick i use to keep the idle at a constant 1300rpm,i disconect the green wire from the high idle soliniod.Then hook up a jumper from 12v source to the high idle soliniod,and adjust to desired rpm.Reconect the green wire after timing,and set your low idle speed.