Pony Pinion Latches

The prices on pinion latches from Cat are very expensive and we appreciate that they are available when all else fails but is there something that can be done to provide a more realistically priced latch? Not that we want to get into a ruckus with Cat over their prices but is there something else or another way to provide economical latches? I have not looked closely at a "used" latch that no longer works but is it because of the latch face, the wearing of the pins or what is the prominent failure mode. If it is the latch face, it would be quite easy to build up the face and mill and grind back to spec. Is that against Cat rules?

How many "common" latches are there? D2 and D4 for the most part I believe are similar but what commonalities are there for the D6 -D9? Just wondering.

Thought I would throw it out there for some ideas.

My two bobs worth,
on mates 212 (D311) Grader pony latches even after rebuilding the pony drive with best parts of two units that were in good condition his latches popped out when ever compression was activated sometimes and most often when opening the governor to start the D/E.
Adjusting the latches made little difference as noted above.
The Diesel was hard to start--only hit on one or two cylinders with lots of black and grey smoke-- thus kicking out the pony pinion before the Diesel engine could be started--needed butchery by holding pinion engaged by hand to get a start even when hot. The diesel also ran with puffs of eye watering white smoke and an occasional miss.

We decided to check lifter settings and found as per below :-
Rack Setting Book gave a lifter setting of 1.736 +/- 0.002" @ TDC, we aimed for 1.734" to keep on the advanced side of the lifter measurement.

Findings were as follows :-
No 1, 0.015" low--that is retarded injection timing.
No 2, 0.028" low.
No 3, 0.032" low.
No 4, 0.042" low.
After setting all lifters to 1.734" we got a clean instant start on the first cold and subsequent starts after lifters were reset, with no signs of pinion latch kick out whilst on compression before opening governor--we reasoned with much skepticism that with the late injection timing there may have been residual fuel in the cylinders from the previous run that was trying to fire off when compression was engaged and so was kicking the pinion latches out due to erratic firing of unwanted fuel--leaking dribbling injectors could do the same.

It could be assumed that if you have Diesel engine firing attempts even with the governor in the shut-off position that this could be kicking the pinion latches out early.

ANYWAY these were our observations/experiences this week and the remedy we applied on my friends 212 (D311) Grader engine, make of it what you will--your experience may vary. We also noted that the Diesel ran cooler with cooler exhaust port temperatures as measured with an Infrared thermometer.
Cheers,
Eddie B.

EDIT
this is what I found after being asked how many degrees retarded the 0.042" low lifter setting was :-

Found that a 0.042” low lifter setting was around 20 Degrees Retarded—ie After Top Dead Center—the standard lifter setting of 1.736” +/- 0.002” set @ TDC sets the Injection Timing @12 Degrees Before TDC so this cylinder would have been firing @ around 32 Degrees Retarded—any wonder it was Smokey with whitish eye burning exhaust and difficult to start.
Cheers,
Eddie B.

Eddie, that is good stuff.
.042 low on the one lifter sounds like a lot!! About how many degrees would that affect the injection or in other words how much too late was is in degrees? I readjusted the ones on the D4 about 10 years ago but they were off less than .010. Should have checked the wear on the plunger and yoke but I didn't.

Hi Jim,
sorry, I did not have time to evaluate the amount of retard in crankshaft degrees but have thought about it since we did the settings on Wednesday.
The pony electric starters are both well worn with worn out arcing brushes--they are away being repaired using parts from both as needed and new brushes if available at a local Auto Elec. shop now, so I will need to go back and fit one in future.

the low lifter settings are certainly a significant amount and would point to the pump being set on the bench with a degree wheel, as we did at The Dealer, but using the incorrect degree setting for each cylinder as read from the charts we used. They may have used readings for some other model engine by mistake?????

The failed engine originally in the Grader is part dismantled and still at the site--if I get back sometime I may take the time to check the 0.042" low reading against the flywheel position.
Thinking further on it now it would be easy enough to check on this replacement but well used engine, by turning the engine to get a 0.042" low lifter measurement and see what degrees we have by another Cat Chart giving crankshaft degrees by piston position.

The intermittent firing at start up causes the Diesel engine to surge and so kicks the pinion out even with the latch springs set correctly or often even when over compressed.
This unit did not need resetting from the original setting I had them at when I overhauled the unit earlier this year--we have been in Covid19 lockdown here for nearly 6 months until 2 weeks ago so am now back to complete the task.
Cheers,
Eddie B.

EDIT,
this is what I found after being asked how many degrees retarded the 0.042" low lifter setting was :-

Found that a 0.042” low lifter setting was around 20 Degrees Retarded—ie After Top Dead Center—the standard lifter setting of 1.736” +/- 0.002” set @ TDC sets the Injection Timing @12 Degrees Before TDC so this cylinder would have been firing @ around 32 Degrees Retarded—any wonder it was Smokey with whitish eye burning exhaust and difficult to start.
Cheers,
Eddie B.

Great info EdB. I would deifnately like to check my settings. I wouldn't say it fires up super clean. Once it is warm enough I give it a quick waft of starting fluid to keep the drama to a minimum. Otherwise it chugs and smokes a fair bit before it runs smooth. Here is my progress for the day. The nose of the drive was previously broken off. I will clean it up and check out the braze job a little closer. Also note the copper sheet that is screwed to the side of the block.

Hello,
Working on pulling D47U pinion, and can’t seem to get it to magically fall out, turned and twisted and just about stood on my head....Now looking to pull the governor. Mangoman, is this the 1/4” link that you removed, and then it sounds like you pulled, wiggled and waggled on the governor housing? Also, just so I get them all, how many cap screws/nuts to remove to pull the governor housing. Any other assistance/photos appreciated. Thank you.

Outbackrider,

Yes that is the correct bolt. I cant remember for sure maybe 5 total? Thank goodness there is a long through bolt that goes from the cover into the pump itself. That would be the middle of the side closest to the block. No need to work a minor miracle to take out any of the bolts. After that it should come off with a little tap or pry. Noting too scary.

D4Jim wrote:

Pony Pinion Latches

The prices on pinion latches from Cat are very expensive and we appreciate that they are available when all else fails but is there something that can be done to provide a more realistically priced latch? Not that we want to get into a ruckus with Cat over their prices but is there something else or another way to provide economical latches? I have not looked closely at a "used" latch that no longer works but is it because of the latch face, the wearing of the pins or what is the prominent failure mode. If it is the latch face, it would be quite easy to build up the face and mill and grind back to spec. Is that against Cat rules?

How many "common" latches are there? D2 and D4 for the most part I believe are similar but what commonalities are there for the D6 -D9? Just wondering.

Thought I would throw it out there for some ideas.

if it is wear on the pivot hole it could possibly be bored and sleeved with a speedy sleeve or brass/bronze bushing and drilled back to size. no reason why it couldn't be refaced.
cat actually published service bulletins discussing parts reclamation so there is no problem there. the only issue is it would have to be done correctly so no cracks are formed etc and to keep the correct balance. and of course certain parts cant be reclaimed for safety reasons such as governor weights. also no reason why you couldn't copy that part and make one. it only becomes an issue if you start producing parts and distributing them especially if your selling them. on most of this old stuff the patents ran out long ago.

well i was told d4 engines have the same internals as a d6 of the same vintage the common parts being bearings, piston assembly, valves, rockers etc