Lucas CAV rotary injection pump math

[fitterski]

Today, I opened the pump for real

http://trixtar.org/3/tinkerings/12valve208hp/missing-weights.mp4
1 - 2 of 6 flyweights are missing (unless 4 in 6 slots is normal)

http://trixtar.org/3/tinkerings/12valve208hp/camring-race-worn.jpg
2 - Cam-ring race shows heavy signs of wear (1000 hours?)


http://trixtar.org/3/tinkerings/12valve208hp/camring-lever-tool.jpg
3- Cannot change it cause cannot remove this lever

http://trixtar.org/3/tinkerings/12valve208hp/worn-pump-drum.mp4
4 - Wear showing on pump drum:


All this in addition to the very large valve lash found earlier makes me think someone's been in there before

 

[dodge man]

Probably time for a new pump. What is the application for this thing, some kind of pump or gen set? I actually might question the hours on the thing also.

 

[fitterski]

Probably time for a new pump. What is the application for this thing, some kind of pump or gen set? I actually might question the hours on the thing also.

It comes from a fire-pump, it's going on a snow blower or...

 

[dodge man]

That would make a heck of a snow blower.

 

[fitterski]

That would make a heck of a snow blower.

If the mailboxes don't run screaming then your snow-blower is a ***** :cool2:

 

[thepumpguysc]

1] 4 weights is normal..
2] Don't worry about THAT wear on the face of the cam ring.. its the lobes that are the wear portion..
3] That piece is called the cam ball.. it takes a special tool to remove it.. its made of soft metal & will round over if the tool is not used.. I've gotten them in rounded over & the trick is to clamp the "ball" in a vise & "smack/turn" THE PUMP..
4] Don't worry about the wear on the "drum".. THATS called the head & rotor assembly.. the part your showing w/ wear is the "rotor".. Absolutly no problem there..

 

[fitterski]

1] 4 weights is normal..
2] Don't worry about THAT wear on the face of the cam ring.. its the lobes that are the wear portion..
3] That piece is called the cam ball.. it takes a special tool to remove it.. its made of soft metal & will round over if the tool is not used.. I've gotten them in rounded over & the trick is to clamp the "ball" in a vise & "smack/turn" THE PUMP..
4] Don't worry about the wear on the "drum".. THATS called the head & rotor assembly.. the part your showing w/ wear is the "rotor".. Absolutly no problem there..

Obviously you've seen a few dandies :laughing: Mine might become one too, I can't even put it back together so if I ever send it to be rebuilt it's gonna be a box full of parts!

These are the only question-marks I found in the pump, I guess a pro would put it on the test-bench and find a dozen more on the gauges that I never could. The bad news is that if the pump is basically OK then I'm up the creek with very few other suspects, maybe the question of the circlip not being in the middle of the timing window under the 'cover-plate' where it's supposed to be, I still have to wrap myself around that one

According to one pro mechanic here "if the compression is 420-425 then there is NOTHING wrong with the engine itself". If I make a mistake I double my costs and that's no peanuts. When I first saw those marks I figured I might just replace the 'head-n-rotor' and the 'cam ring' on spec ...and see what happens (the transfer pump is already done). All the springs are like new, all in the correct holes, etc.

The one thing I find a little strange (mostly because this is the first pump I open up) is that everything that moves feels fragmented as opposed to other oil-bath mechanisms that just glide along, it might be a characteristic of diesel/heating-oil lubrication.


1
I wasn't sure because while a 4-cylinder Delphi C2126T manual shows 4, but the CAV manual shows a diagram with 3 adjacent ones.

3
It's the threaded part of that 'cam ball' that worries me, I've already put some big torque ft-lbs to it and any more will break the screw in the hole (I'm presuming it's turn-left to unscrew). I tried it in the wise but mine doesn't give the accessibility I need, I've already done some rounding. I'll figure out something. I find these manuals extremely flimsy and superficial

 

[fitterski]

..up the creek with very few other suspects, maybe the question of the circlip not being in the middle of the timing window under the 'cover-plate' where it's supposed to be, I still have to wrap myself around that one

ok, here's a nother one, THIS could be pay dirt:

http://www.trixtar.org/3/tinkerings/12valve208hp/half-pump.mp4

A pair of dead cam rollers would cut pump volume in half, I don't know what it would do to pressure though, and pressure being a dynamic auto-advance parameter.

 

[thepumpguysc]

There are 2 pairs of plungers under/behind the shoes& rollers.. 1 long set & 1 short set.. the long set will move when you push the rollers, the short set wont..
IF you take them out for inspection, its important to get them back in the correct position.. not so much EACH plunger but in the correct holes in the head..
They are opposing plungers so long goes w/ long, short goes w/ short.. don't put a long w/ a short..
I noticed you took off the main fuel adjustment.. the gizmo that has the 2-12pt screws.. that sits on top of the shoes.. I sure hope you marked it..
The C clip in the housing wont ever be centered in the housing.. its moved for timing purposes..

 

[fitterski]

There are 2 pairs of plungers under/behind the shoes& rollers.. 1 long set & 1 short set.. the long set will move when you push the rollers, the short set wont..
IF you take them out for inspection, its important to get them back in the correct position.. not so much EACH plunger but in the correct holes in the head..
They are opposing plungers so long goes w/ long, short goes w/ short.. don't put a long w/ a short..
I noticed you took off the main fuel adjustment.. the gizmo that has the 2-12pt screws.. that sits on top of the shoes.. I sure hope you marked it..
The C clip in the housing wont ever be centered in the housing.. its moved for timing purposes..

And I thought I had found IT..

Unless I missed something, never more than 1 piston was out and then I put it back in the same place. But on their way to the glass full of lamp-oil two of he rollers fell on the shop floor, I found one in minutes but the other one only after an hour of vacuum-cleaning the floor because it had never fallen off the bench. That adjustment-plate has notches in the edge identical to the plate underneath the pump core, I was relying on those for re-alignment, didn't mark it otherwise. As for the circlip the manual says to place the marker edge near the window center, I wasn't sure where that road would lead so I took a snapshot




At the moment of the false flash-in-pan my idea was that IF something was amiss in that assembly then I would get a new one; the whole rotor/head goes for around $150.

The biggest problem is that now I'm back to square one, as far as the TS goes.

Have a nice weekend, I think I'm gonna do something else for two days and then come back with a fresh and positive attitude ...and my 10 pound sledgehammer :laughing:

 

[fitterski]

Did some research about part #'s, I'm thinking a Head & Rotor Assembly as a possible expense (on spec just like the TxPump parts were). I've asked Sparex but sofat they haven't matched theengine No. with anything they have. Also managed to lose most of the test-run videos but recovered the essentials from backups.

http://trixtar.org/3/tinkerings/12valve208hp

I've got so much time into this pump I might just make a utube video

 

[thepumpguysc]

Your wasting your time & money replacing the H&R..
The H&R is deemed replaceable if, A> its worn beyond meeting starting specifications on the test stand.. does the engine start?? YES? H&R is good..
& B> if the H&R is seized.. we know its not seized because you can rotate it in your hand AND the engine starts..
The P# for the H&R is Delphi P#> 7180-727L
It costs $574.32 list price from the factory.. MY PRICE is OVER 300.00 & I'm a dealer!!! So if your paying 150.00 from Sparex.. it aint new.. maybe aftermarket new, but not FACTORY NEW..
There is a "note" when I looked the pump up.. it states, Cummins speced the engine at.. a 4 HOUR ENGINE LIFE at full load.!!!

 

[fitterski]

Your wasting your time & money replacing the H&R..
The H&R is deemed replaceable if, A> its worn beyond meeting starting specifications on the test stand.. does the engine start?? YES? H&R is good..
& B> if the H&R is seized.. we know its not seized because you can rotate it in your hand AND the engine starts..
The P# for the H&R is Delphi P#> 7180-727L
It costs $574.32 list price from the factory.. MY PRICE is OVER 300.00 & I'm a dealer!!! So if your paying 150.00 from Sparex.. it aint new.. maybe aftermarket new, but not FACTORY NEW..
There is a "note" when I looked the pump up.. it states, Cummins speced the engine at.. a 4 HOUR ENGINE LIFE at full load.!!!

The $150 price was for some Lucas-CAV pump Head & Rotor Assy's on e-bay, Sparex has not quoted yet. I did see a 3063F523 elsewhere on the net for less than $800 but no way to take it any further (probably a typo).

I was "thinking" of replacing the Head & Rotor seeing that I found no other significant problems in the injector to explain the unacceptably stumbling test runs. Also I figured that until I discover otherwise, the pistons & rollers might be part of that sub-assembly so since I'm not equipped to measure the total pump roller travel as shown in the manual, replacing the whole sub-unit seemed like a path to explore. Remember, I have an unacceptable running signature while the setup is stock Cummins for which I have NO explanation but for which I have to find FIX. Mechanics swap sub-units out all the time, they pull one that's suspect & charge the customer, if it doesn't fix they pull another and so on. The only other area I can think of looking into is pistons and rollers especially if those are not part of a Head & Rotor sub. I've measured them several times and got very precisely 5.96mm on ALL rollers and 6.97mm on ALL pistons so there again are again signs of a hardly used pump consistent with just 1290 hours.

You could be right that I'm barking up the wrong tree, you've said that before and it too is as valuable as all the other info you have given, I appreciate it. I am a little surprised about the 4 hours not being anywhere on the net

Reviewing everything at my disposal and short of deciding to rebuild the engine right away I'm going to put the pump together and abandon the stock timing to only 5 degrees of static advance (using gear letter G) in favor of the common 10 degrees of static advance (using gear letter D). I've already improved on its original running condition A LOT. Then I'll make test runs with that setup only and get a lot more opinion. The current engine on my snow blower is a Deutz 4-holer and it runs very smoothly up to around 1900 rpm but then begins to 'sound weird' up to 2500 rpm to a person more used to the sound of gas engines. This high-end sound is what seems much more pronounced with the Cummins added the stumbling. The short of the long is that I'll leave it at that if all the opinion I get says "it's normal, don't sweat it". In all other cases I'm going to strip the engine and really go for a blue-printing exercise, maybe reverting the setup to a more common automotive or tractor configuration including a VE pump, appropriate injectors and possibly cam (I would NOT want to build an engine good for only 4 hours, and as I said the bottom end seems just like new).

 

[thepumpguysc]

The rollers & shoes come seperatly from the head.. as do the check plates..
all you get is a head & rotor & pumping plungers.. & its still up to you to set the fuel output..

 

[fitterski]

The rollers & shoes come seperatly from the head.. as do the check plates..
all you get is a head & rotor & pumping plungers.. & its still up to you to set the fuel output..

The new (special order) pump would cost me $4,356.19 cdn + $650 tax, total $5,006, this is insane! Even if the Head & Rotor Assy did include the pump/piston section I wouldn't pay the prices you mentioned earlier. Fortunately all pistons measured identical as did all rollers so I think they're really like new.

So far the interventions that did make a difference were the valve lash and the bottom spring in the inlet fitting. I really SHOULD have done the other test run also at that last stage with 10 degres of advance (gear letter D) ..but I was too tired.

Right now I'm waiting for a seal kit and putting it back together (3-4 days). The next run will decide the next steps. My son says "Dad, there's NOTHING wrong with either the engine or the pump", but to that I counter with 'then do expalin why it's bogging/lugging like a dying donkey?'

 

[fitterski]

Stripped & built the pump, nothing major found although the lack of familiarity, documentation and test-bench resources may well have hidden some! The youtube is uploading and should come up later tonight with a search for

'Partial strip & build of lucas CAV injection pump'


Bottom line is that compared to the as-received state the engine runs better although still very FAR from acceptable with stock timing. With another 5 degrees of advance (using the pump gear-letter D) the engine runs almost normal. I'm happy with this result for the time being. The last 2 test runs (top of page) are @

http://trixtar.org/3/tinkerings/12valve208hp/index.html

One interesting detail is that during the second run the engine starved for fuel. The stuttering and missing during this time were VERY similar to the symptoms plaguing the engine all this time.

 

[dodge man]

I don’t know if you covered this, but are the injectors o.k.?

 

[fitterski]

I don’t know if you covered this, but are the injectors o.k.?

First thing i did was have them professionally checked for misting and pattern, they were just leaking like sick cows so I had them rebuilt. Result: nothing observable. What I do not have is the setup to test pump high pressure output. What if it's low or peaks only briefly? Could that be a possibility, could it be at 1300 hours? Like I said before, my diesel knowhow is one big zero

What i have found about the 4-hour life is that these engines were required do demonstrate continuous full power until fuel-tank exhaustion at 4 hours.