1973 Questions for all other cars Timing dwell testing

1973 ALL OTHER MAKES ALL OTHER MODELS
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GERRY_H
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Engine Performance problem
1973 Questions for all other cars 4 cyl Two Wheel Drive Manual lots miles

Actually it's my Allis Chalmers loader/tractor. A mod. 615 ind. The wife says I love that tractor more than her...
The engine (an A.C. 160 power crater industrial), is running rough.
In trying to check the dwell (spec'ed for 24 BTDC) - (note: it has a oem 4 cyl. 'gas' engine w/all Delco ignition components).
I could not adjust a reading below 29-to-30 degrees dwell no matter what rotation of the distributer ???

I was checking the dwell with a new Actron DMM auto service meter (w/dwell). First time i've used it. Can only assume it is accurate, (having it tested now).
Assuming meter is correct (i.e. little to no adjustment range of timing dwell - rough running), what in the world could be causing that sort of symptom?

Thanks Rob Harris
Aug 19, 2010 at 8:48 PM
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MHPAUTOS
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When it is running how much dwell variation do you have at around 1200 rpm?

mark (mhpautos)
Aug 19, 2010 at 9:59 PM
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GERRY_H
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[quote:028c1a4c6a="mhpautos"]When it is running how much dwell variation do you have at around 1200 rpm?

mark (mhpautos)[/quote:028c1a4c6a]

Specs. [Allis Chalmer 615i tractor w/oem bucket loader. Gas eng. model w/160ci 4cyl. AC Power Crater engine. Electrical sys. all Delco Remy.]

Hi Mark,
I'm back. (lost my PWord).

Checked it through full range 1000 to 1900 rpms - results odd??? All ranges gave same readout (bounced) 29 to 30 degrees dwell.
As mentioned - this is a 'new' Actron automotive type test DMM, i've never used before - it could be the problem. Haven't tested yet with a timing lite. (So. Fl. we've had pretty steady rain lately, and the tractor is outside). I'm not complaining, we needed the rain ;-)

I did have a break to discover a little contamination in the fuel sys. Have the carb. off right now to clean - it a pretty simple task.
By the way - a timing chain can be ruled out - this eng. uses helical gears in a cluster w/ a cam gear drive.

Q: could ign. points some how cause a lack of response to manual (distributor) timing adjustments?

Checking point gap from 0 to max. opening, seems to imply that dist. shaft lobes are OK.

Clue: When manually turning the dist. from full CW to full CCW, (w/engine running). - At the two (full) 'extremes' of dist. rotation the engine would load noticeably and drop a hundred or so rpms - but, no audible engine changes could be heard throughout the mid-portion of rotating the distributor.

That indicates something - I think :-D
Aug 24, 2010 at 10:54 AM
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