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Cat timing advance ???

26K views 39 replies 9 participants last post by  359kool 
#1 ·
I'm putting a 4mg fuel pump on a 3zj, both are b'models.. My question is whether or not each timing advance will interchange with the other pump.. The 4mg is a 4 bolt and the 3zj has 8 bolts where they bolt to the fuel pump.. Can the 8 bolt advance be used and just leave the other 4 bolt holes open???
The only other difference I see is with the center shaft in the back, where the older 4mg advance has 4 small holes and the 3zj doesn't, also the 3zj advance has a 9/16 bushing I guess and the other doesn't.. I'm sure there both hydraulic advance and return, but the 4mg engine hasn't seen oil pressure in a few years, and the center part that the weights are attached to is loose and kinda flopping around in there, so I ain't sure about it really??? I know the 8 bolt works because I've been running it, and it looks less worn overall, but I'm not gonna mix them up till I find out for sure..

I've got a service manual, but its for a 7fb, so no good in this case.. :bang
I know Tony has already wrote a good article on all this, but I can't find where I saved it, and it seems to be deleted from the original thread.. :madpoke
It would be cool if somebody could repost it here, if Tony doesn't mind of course.. :thumbsup

So what's up Tony, you got your ears on? Help! Help! :fan
 
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#4 ·
The timing advance will not fit from a B to a C. The newer style advances have both four and eight bolts. A good rule of thumb is any pump with 7W-3906 cast in the side is considered a B model. Any pump with 7E-5888 cast in the side is a C pump. The cams are different and the advances will not interchange. just my .02 worth.
 
#22 ·
Here's another bit of my hands on experience. Maybe the King won't thrash me over this. You better use the C nozzles also. The pop-off pressure is higher on C nozzles than B nozzles. Your B barrels and plungers will start wearing and leaking fuel past into the oil. Here again, I have had this to happen....twice. take it for what it's worth.
Little more info...8N-9367 was the casting number on the early B pump. It had what i call the snout type advance. In other words, it had the big coil spring, and the long snout slid in the camshaft. This type was used in all 7FB pumps, and 4MG pumps up to 4MG-03499. All had the same parts with exception of the small governor spring, which was dependent on different ratings.

4MG-03500 and up used the current style with the quad orings. The 3ZJ and certain 5KJ pumps went to the bigger camshaft and bigger advance. All advances had the same hardware except for the small governor spring. All advances had the same weights as the pump governor until 3ZJ-16182 and up had different weights.
So getting back to talking timing advances, I've got a good start on a small junkyard so I'm always interested in swapping parts rather than buying new ones lol..
The 4mg timing advance that goes with the pump I'm using had slipped internally and thats why I was considering using the 8 bolt.. This is kind of annoying to explain or read I'm sure as there is no clear name for the different parts I'm talking about.. This engine is listed as a b'model, but it has what I call a c'model fuel pump as well, with the 7e casting.. That's one reason I was switching them, and its just starting to leak fuel around the bonnets too.. So having a complete 4mg b'model for parts, I didn't have to think very long on this deal lol..
Ordered a new 8m9141 governor spring to go in the b' pump before I put it on.. I don't know what it had, couldn't find the color stripe, but it was considerably weaker, and it's the same spring that the c' pump has.. :(
And just out of curiosity, I set the rack screws on each pump with the back governor box off, and using the spring method there was a good bit of difference in rack travel between these pumps.. I didn't measure it exactly, but just guessing I'd say at least three rounds on the fuel screw before it hits the bar.. :popcorn

As for the C timing advance not fitting the B pump, it will bolt right up, just having 4 extra holes.. I didn't use it so I can't say what it would do after you crank it, thats what I was worried about.. The gears, teeth and splines are all the same everywhere, just small differences in the carriers and different weights and spring and stuff really.. For all I know they may do the same exact thing, but I kinda doubt it lol..

So what I did was take apart the slipped 4mg advance, only to find that someone had attempted to weld it before, and did a piss poor job too, four little tacks not evenly spaced or anything and they had been grinding into the big spool plate that slides against it there.. :mad:
So not having alot too lose with that advance, asa I've heard that core criteria is out the window once the weldind starts, I decided to take a turn at it myself.. So I'll get it together tomorrow and see how it all works out.. Hoping everybody else has had as much fun this week as I have! {Turkey Day Vacation}

:woot:
 
#5 ·
Here's another bit of my hands on experience. Maybe the King won't thrash me over this. You better use the C nozzles also. The pop-off pressure is higher on C nozzles than B nozzles. Your B barrels and plungers will start wearing and leaking fuel past into the oil. Here again, I have had this to happen....twice. take it for what it's worth.
 
#6 ·
Little more info...8N-9367 was the casting number on the early B pump. It had what i call the snout type advance. In other words, it had the big coil spring, and the long snout slid in the camshaft. This type was used in all 7FB pumps, and 4MG pumps up to 4MG-03499. All had the same parts with exception of the small governor spring, which was dependent on different ratings.

4MG-03500 and up used the current style with the quad orings. The 3ZJ and certain 5KJ pumps went to the bigger camshaft and bigger advance. All advances had the same hardware except for the small governor spring. All advances had the same weights as the pump governor until 3ZJ-16182 and up had different weights.
 
#7 ·
As afore-mentioned, you spoke so I'm out. You are wrong on several points tho. A shelf full of parts and SIS make for good casting number displays tho eh?? And no, I don't recall thrashing you on anything, hence the lack of responce, etc... And one more time, drop the King sht man!!!!!!!!!!!!!!!!!!!!!!!!!!!! Just cause I talk doesn't mean I want you crawling around in my ***. :rantoff
 
#9 ·
And no, I don't recall thrashing you on anything, hence the lack of responce, etc... And one more time, drop the King sht man!!!!!!!!!!!!!!!!!!!!!!!!!!!! Just cause I talk doesn't mean I want you crawling around in my ***. :rantoff
Here we go again............................... :thumbdown DOWN Tony, down. ;) :haha (I understand though........)
 
#10 ·
Just hands on bro. That's all it is...purely hands on. Like you, I've done alot of trial and testing. Just giving my experiences...that's all. I guess I've stepped on your turf again. I personally have not built 1700 engines, Mr. S on my chest, but I have done alot of rodding and parts changing. I have spent a great deal of time working on various engine models. Seeing what will work here, what part will work there, etc.

Sure, Ive got SIS. It helps me with my trucks. I don't work at a dealer. I operate a small trucking company and diesel garage. My local Cat dealer set me up on SIS so I could look up parts, and get the info I need without the hassle of being on the phone all the time. And parts on the shelf? I sure do. Many, many different parts from various jobs I have done.

I'm just trying to figure out what I'm wrong about. Maybe you will enlighten me? Like you, I have tried to keep my cool listening to you and your bull. Like you say about me, some things you preach are correct, while others are pure bull*****.

Keep your gown down, ok? The sun will rise tomorrow. Just chill. Hurry back to work so you can build another 1700 engines. Maybe one day I will be as intelligent as you. Maybe I won't brag about ***** that puts me older than I really am. Better to be thought of as a fool, than to open thy mouth and remove all doubt.
 
#12 ·
sledman i know you are tryin to help,but no one is gonna listen to you pretty soon if you keep trashin tony in every post.tony has helped alot of people,and never led anyone astray...as far as i am concerned anyway. PS the mr s and king is gettin old fast.
 
#13 ·
Will one of mods close this chit down, this is getting old. On one hand you got a mechanic that sees all how it is, then the other you got a truck driver that thinks his way is the best.

Seriously sledman, your constant bashing of the Bmodel cats is what gets on my nerves, something tell me you had your azz handed to ya by a few straight B models on the road and its got your panties in a bunch.

You may speak from experience, but when all you talk about is the bad ones with your Bs it gets old, cause there are plenty of people running them that dont have trouble. I can keep going all day but the chit is getting deeper by the minute.
 
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#14 ·
To ktw900....I never bash until I'm told I'm wrong. Would he do the same? I would bet yes. As far as leading astray, the man he told to put a B pump on an A block, was being led astray. It simply cannot be done. The block won't accept it. I found this out the hard way. My 79 KW had an A model in it. I got the bright idea to put a B pump on it. I pulled the radiator, swapped the B timing covers, gears, etc. Got down to the pump, and guess what? It bolted to the timing cover perfectly. The oil supply holes were several inches off. I simply didn't want this man to go through the same trouble I did. I had to put everything back the way it was, until I could afford another engine.

Now, on to SmokinCat. I have never bashed a B model on here...ever!!! I bash the hell out of an A model, sure. My personal opinion is the B and C were the best made, until the C-15 came along. I've owned every B and C made at some point. If me, sticking up for what I know for a fact is wrong is called bashing...be that as it will.

Had my *** spanked? Sure have...many, many times. Pissed me off? No. It made me do my homework and build a C model to go in my 79 KW that will spank most B, C, E, or most C-15's around. I was telling some guy what parts I used, when someone chimed in telling me how wrong I was.

I don't know where you got the idea I was bashing B models, because I never have. As far as a truck driver goes, I guess I am one. I had drivers in all of my trucks and I ran my diesel garage for years. But, now due to the economy, and sorry ***** drivers, my shop is slow, and I am driving again.

In the end, I will never bash until provoked, ok? Fair enough? I'm sorry I ever joined this board. I was simply helping out the fellow poor like myself with some useful tips and advice. I don't have unlimited resources to work with. 90% of my tools are homemade. My liner puller, nozzle puller, ATAAC pressure tester, injector cup puller, front and rear seal installer...all homemade. I have to make do with what I have. Do I have the money to take my trucks to the dealer and pay $80+ per hour? No. Do I have as much experience as ynot? Probably not. I'm 40 years old, and have worked on Cats and Cummins since I was 15. Everything I say, I have done...tried and tested. I would never lead anyone astray either. But, I do my homework, I research everything I do, then I try it.

To all, I apologize if I have offended anyone. I just get upset when told I'm wrong. This is out of hand, and I WILL stop it here and now. Everyone have a safe and joyful holiday season.
 
#17 ·
Dear blackdog106. I told I was done with this Springer Show bull*****. I never tried to "top" Tony. I never tried to "take over" or whatever you say I'm doing. I simply stated my hands on experiences for help and TWICE, he shot me down. Politely told me I was wrong. I never bashed until I was. Obviously you never read all the posts, so you have no clue what you are talking about.

I'm tired of this third grade bully bull*****. So he is the Cat God. Who cares? I certainly don't. Does he steer wrong? 99% of the time, no. Just like me, he is human and subject to human error. Twice I chimed in and posted some of my personal info, and was told I was wrong. Talk about mole hill into a mountain...this is rediculous.

Again, I'm done with this bull. I was just trying to help...that's all.
 
#18 ·
Well, you have done it again Sledman: While you posted #14 i was writing #15. When i read your post, i thought you were going to be decent about this and in your words "This is out of hand, and I WILL stop it here and now."So i did the decent thing and deleted my post. I saw no need for more:poke. But in your predictable way, you continue to battle.....:bangSo in my clueless (your words) way, i write one more time.I regret deleting the previous posts, but i see no need to rewrite them. It is going to solve nothing.
As i said before, this is gotten pathetic. I am sorry to say this, but hopefully the Moderators will take some action, here.....:damnit
Tony, i hope you stick with us through this BS.......
Nuff said......:happymugs
 
#19 ·
Just because you delete them on here, doesn't mean I don't get an email with your posts. Who stopped again?
 
#21 ·
Well chit, here I've been working on my truck and missed all the exctement! :knight
I don't have nearly enough feathers in my hat to start getting in the middle of a serious dispute.. I've been known to gouge somebody ever once in a while, but only on special occasions of course.. Seriously though, myself and alot of others need all the help we can get sometimes, and it seems like there should be enough room here for everybody.. I've found out I was wrong about something plenty of times before, just by reading threads and listening, but when bogus information gets posted, then by all means somebody should correct it, or further discuss the matter until it becomes clear to other readers.. That's the only real purpose of the board, or at least that's what I thought! :mafia1:

I've heard this bickering quite a few times lately, and it doesn't seem to be meant in a humorous context.. LOL

I don't know anyone here personally, not that it would matter anyway, but I look at this chit kinda like the cb rambo stuff, when it goes in that direction just turn it off if your not in the mood! :roflol:

So... I want to say thanks to Tony again, he's been around here along time, and I've got alot of respect for the man for taking the time to post the stuff he does.. Its pretty obvious that the ones of us that are still running mechanical cats are very loyal to him.. I would think he deserves a certain level of respect on here, not called out like a newbie, because even if you don't agree with him, theres always the chance that somebody misread a post or something, and there is always gonna be a few freaky exceptions and variables with engines and trucks and about anything else.. :fan

Now... I owe you an apology for the "A" model block deal Sledman, to be honest I really didn't give a rats arse about it, and its very likely that I just aggravated the whole ordeal, but you made your point so I would let it go now.. :guitar
I don't feel you deserve to be shushed without being corrected either, but on the other hand I wouldn't pick out the baddest m/f'er in the bar for a fight either.. Soooooo..... :wiggle
 
#23 ·
hey 359 kool, are you needing a 4mg pump and timing advance. i got one from a 425 b. the timing adavance is in great shape. actually earler this summer tony gave some good part numbers for the pump and went through it also, so i know its in good shape too. i change everything on the engine over to 7 fb except turbo. anyways....not really sure if ya was needing one or what, but let me know if your interested......:happymugs
 
#26 ·
Changing these fuel pumps out really made a difference in this motor.. Using the extra washer and the governor spring like Tony says might have helped the other old pump as well, but I'm not changing them back.. ;)

I'm wondering about the timing now though.. When I put the 4mg pump on, I just pinned the pump and the engine, or field timed it.. I assumed the pump pin hole would be different to the 3zj pump? This engine would rattle before if you bumped the timing even a half a hole.. I just kept messing with it till I finally got it where I wanted it..

It runs real good as is, exhaust temp and boost pressure are right where they should be.. It just sounds to me and starts up real easy like the timing is like it was with the original 3zj pump field timed, but it doesnt chug the white smoke at idle or anything?

So am I wrong about the pump pin holes being in different locations on the pump cam? I'm wondering if they are the same and the engine cams create the difference when field timed?

If this is the case, I can bump it a little and get some more mojo out of her then ??? :guitar
 
#27 ·
My comments probably are not welcome, but here goes. You are pushing C nozzles with a B pump. Your 4MG pump is probably static timed between 16 and 21 degrees (I'm shooting in the dark), where your 3ZJ was 11-10.4 making the timing different. The slots in the cam are closer to the #1 lobe tip the lower number (numericaly) timing is. You won't have as much clatter as a 4MG has. I did this same thing years ago. I built several engines from scratch, using 4MG pumps on C engines. The clatter just wasn't there. The usual C cold smoke and rough running wasn't ther either. Anytime I used C nozzles with a B pump, the B and P's started leaking fuel in the oil. A good friend of mine in research and development and Cat in Peoria, Ill., said the pop off pressures are higher on C nozzles. When Cat went to the double slotted, and longer plungers, the pressure went up. I guess that explained my issues.

Also, be careful bumping the timing up. You'll burn a hole in a piston if you go too much. Here again, I speak from experience. With the flywheel pinned, looking in the pump hole, I never set more than, 1/8 inch of the cam slot showing on the bottom of the hole.
 
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#28 · (Edited)
So the timing pinholes are different in the pumps..
I think I'll leave it alone till I can get on a meter, because its running real good like it is.. :happydance
Maybe during the xmas break I'll swap out the injectors or nozzles to prevent any pressure related problems later on..
That all makes sense to me sledman, thanks for the reply..

Another thing weird thing with this motor is the water temperatures stay low according to the gauges? Already changed the thermostat for a new, 180 I believe it was, added a new manual gauge from stewart warner, plus I got a electronic pete gauge and about 175 is the warmest I've seen on the gauges.. :(
I'm thinking the accuracy of the mercury filled lead wire on the manual gauge could be compromised due to the neat job of wire harness routing I did, about 170 is all I've seen from it?

I used a 195 n/o switch to engauge the fan solenoid though, and it kicks in everytime I take off or pull a slight grade.. Guess I should've gone with the 205, but I could be mistaken the way water flows from the radiator and just have all this chit arranged wrong?

What I have now is the 195 fan switch in the center plug of the head above the turbo.. The manual gauge with 9' lead is routed in with the wiring harness for the jakes alternator and stuff down and around the back of the engine and screwed in the pipe plug hole in the front end of the head right now, have moved it to the back end of the head with only a slight drop in temp according to the gauge.. :(

The electronic temp gauge sender is screwed in the water manifold in the bottom of the housing, or below the thermostat, it reads a constant 175 pretty much, even when the fan kicks in..

Was thinking the water flows out the bottom radiator hose through the oil cooler then from back to front of the engine? All advice much appreciated!

:bluesbros
 
#31 ·
My guage and fan stat are in the front holes and the kysor is by the turbo, 3ZJ c, the kysor will shut the engine down some times before the fan comes on, by my estamates the hole by the turbo can be up to 15 degrees warmer when you first start to pull, on a long pull when the stat stays open every thing seems to level out :happymugs
 
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#29 ·
Hi 359Kool: Not alot of experience to give you here, but...... The last couple of thermostat changes i did, i wish i hadnt. Both motors warmed up good and stayed warm with old stats.
Replaced stats, just as preventive maintenance when changing water pump. New stats warm up engine alot slower and when engine is loafing, doesnt stay as warm....:mad:
I recently read somewhere that Cat redesigned stats this summer but still using same part #'s.
If i can find it again, i will post it. Maybe the Cat gurus can shed some light on this...........:happymugs
 
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