Cummins 4BT & Diesel Conversions Forums banner
1 - 20 of 20 Posts

·
Registered
Joined
·
12,643 Posts
The bowl shape and volume has varied a lot over years. Do you have the serial number for your engine? If so, I can look up what Cummins specs for it. Bowl design is often because of injector spray pattern or smog control. Most all 4B engines would have slightly wider bowls since the have 155 deg spray angle injectors. Also, a 4B may have a slightly higher compression ratio but that's not always true. You mention marine style bowls and that is a popular replacement type piston. True marine pistons would not be used in a 4B. They are low compression and wouldn't work well for that. Also, the 4B pistons are not the same as 4BT. They use different rings. You can use 4BT pistons in a 4B but not the other way around. Below is a photo of a 4B piston and it looks very much like the one in your photo. On the injectors, those need to be matched to your injection pumps for pop pressure. Stock injectors for you engine were possibly 4x.012 with 9mm tips. Cummins quit using those and any replacements from them are 7mm tip plus the sleeves you mentioned. 9mm heads had a bad reputation for cracks. Need to check yours. Those 5x.011 units are sort of odd size.
 

Attachments

·
Registered
Joined
·
12,643 Posts
OK. You have one of those engines that I can't tell you a lot about. The reason being is it has been rebuilt by Cummins and a new serial number assigned. Only info showing is the build date. A Cummins dealer might be able to look at the rebuild sheet and tell you info but I don't have access to that. The injection pump is a Delphi model and fairly common on industrial engines. I'm curious. Does you engine ID plate show a CPL number? If I have that I might find another engine serial number to look at. Your pistons on that units won't be the small bowl 145 deg ones because those were only used on the A and P injection pumps. The pistons usually referred to as large bowl were like the ones used on the early engines. Your current pistons would probably be part 3802064 for .040 (1.00mm) over. You could get those down at the local Cummins store for around $250 each. LOL. Need smelling salts when you go there to buy. You can find them aftermarket in the $60-80 range. That is complete kit with rings, clips, and pin. See photo below. In the second photo you see the smaller bowl compared to the large bowl marine style piston you mentioned. That style bowl is an aftermarket design. Mahle has them as well as many importers. They generally had 17.5:1 CR where the 4B was 17.3:1 so no problem using them.
 

Attachments

·
Registered
Joined
·
12,643 Posts
On the pistons, there were basically two bowl sizes and just looking at them you might not notice much difference. Injectors fired in either a 145 deg or 155 deg patterns so the bowl which is the combustion chamber needs to fit the spray pattern for proper combustion. You could use 155 deg pistons with 145 deg injectors but wouldn't want to do the other way around because part of the fuel would be spraying outside the combustion chamber. The large bowl most are referring to is the marine style bowl in that second photo above. That piston was designed by Mahle/Clevite as a sort of universal replacement but are also found under a Cummins part number. Just for info, Mahle makes pistons for Cummins. The Cummins part 3802134 for the .040 oversize. Those are darned expensive if you get them from Cummins. Near $300 each. If they don't come in that pretty brown Cummins box, you can get them in the Mahle box under part 224-3523WR.040 for $84.87 each. Bit of price markup on Cummins parts. LOL. The bowl is basically like the marine pistons only shallower so the compression isn't lowered. Below is a photo of a true marine piston. Those have a compression ration of 15.3:1 where the marine style is 17.5:1. You wouldn't be getting into those because that lower compression makes starting a bit hard, especially in colder weather. If you looked up all the pistons Cummins had for just the B series engines, I suspect you'd have a page or two of part numbers. On your rebuild, I'd use turbo type pistons because they tend to be cheaper and will work perfectly fine. 4B pistons tend to be expensive because they weren't used as much. If you get a rebuild kit that is suited for a B series engine with a VE injection pump the pistons in that kit would be for 155 deg injectors. That's one reason for those large bowl pistons since one type fits both styles of injectors.

Now on injectors. The number 5x.011 means that the tip of the injector has 5 holes that are .011" ID. Your stock injectors were likely 4x.012 or something similar which had 4 holes that are .012" ID. Those 2 injectors would flow almost the same fuel. More holes of smaller size make for a better burn in combustion. Many companies advertise injectors of so much HP gain. That is junk info and not technical. The 5x.011 you found is what should be shown and I'd think they know what they're talking about. If you have your old injectors there should be some numbers on them. Even the tip has a number etched on it. The actual Cummins number is sort of hidden. It is just below the threads when the injection line attaches and usually hard to see unless you know where it is. On the side of the injector body will be several numbers. One very important one will read like 245bar. That is the pop pressure at which the injector fires. Just for info that is 3553 PSI so that gives you a idea how much pressure is in those injection lines. For safety sake you should always wear face protection and keep the hands away from the fuel line connections when it is operating. A tiny leak could fire fuel through your skin. Blood and diesel don't mix too well.

On your engine ID plate, 4-390 tells me it's an industrial engine and that part normally is associated with Case tractors. The 4b/4bt was a joint venture of Case and Cummins. An actual Cummins dealer may be the only one who can access info about your engine. Might try and contact member CrewCab59. He is a Cummins dealer and may be able to shed some light on your engine. If I had the model number of your skid steer I used to have a source where I could look up parts but that company is no longer associated with Case. In older parts, a Cummins part that begins with the number 3 would begin with the letter J in Case.
 

Attachments

·
Registered
Joined
·
12,643 Posts
That manual is worth it's weight in gold. OK. Your injector part number is J914472 and rebuilt number is JR914472. The Cummins part # is 3914472 for the 9mm model. Those have been discontinued but Oregon Fuel Injection does rebuild them for $99 each plus a $30 core. So if your cores are good you get that back. Those would still have 9mm tips just like the originals. Nothing wrong with rebuilt injectors. Those are 155 deg spray pattern. The Cummins number is discontinued and no longer available. Nothing wrong with the newer replacements that come with the 7mm to 9mm sleeve. So long as they have the correct nut size on top which is 12mm and the correct pop pressure. The part J919331 which is Cummins 3919331 is no longer available from Cummins. Don't know about Case but there are tons of those in the aftermarket but those are not genuine Bosch units. Not sure that really matters anymore. Those are all coming out of China and are usually under $200 per set of 4. You'd just need to get the little sleeves for them and those aren't very expensive. Those are Cummins part 3919358 and cost around $7 each.

On the pistons, your OEM units would have been 17.3:1. The marine style bowls are 17.5:1 so not enough difference there to matter. True marine pistons are the low compression 15.3:1. You don't have to worry about those. They aren't in the running for you application. The A77412 is the Case part for the .040 over piston kit which is Cummins part 3906208. Those are non turbo pistons just like your originals. See photo below. You can find those for about $60 each. That Allstate listing you found is one I saw. They are cheap and there are some even cheaper. If you want to use turbo grade pistons that is not a problem. They have a better keystone ring at the top. Have to remember a vast majority of these parts are coming out of China and so they are very cheap. Also remember that they are one of the few countries still producing the 4bt engine. They haven't been made in the USA for about 15-20 years.

One area of your rebuild you haven't talked about is what bolts to replace. You will need new rod bolts as Cummins does not recommend reusing those. Not super expensive but all the Cummins part # is 3900919. If you want an upgrade ARP units are part 247-6304. You will also need a new set of head bolts. There you have an option to consider. Original head bolts are not terribly expensive but they have a sort of weird torque procedure. An option would be to use studs instead of the bolts. ARP part for 4bt studs is 247-4206. These are not required, just an option. Main bolts in the bottom end don't need replacing. Another area that gets attention on these engines is the head gasket. Some aftermarket gaskets are perfectly good and some are junk. Hard to gauge that without actually seeing them. Even though you usually buy the gaskets and seals in a kit, lots of guys will spend the extra money for an OEM Cummins head gasket. Do you plan to do the actual rebuild yourself. These engines are not hard to work on. Just have to watch out for a few of those gremlins that might be hiding. LOL. If you have the block hot tanked and cleaned I'd replace all the freeze plugs. There you may stay with Cummins parts as those things are metric and hard to find correct fitting replacements. Be extra careful to make sure you replace the ones in the oil galleries or you wont have any oil pressure. We've seen that happen before. If when you tore it down you must label the cam tappets as to which hole they were in. Otherwise they will have to be reground or replaced. They are cheap.
 

Attachments

·
Registered
Joined
·
12,643 Posts
Sounds like the 7mm injectors you got are OK. As for the tips being slightly long, I think the sleeves make up for that. See photo below. You'll find those little devils priced all over the board. If they come in that pretty Cummins box they go up in the $20-30 range each. Aftermarket versions are around $7 or less. Here's a set of 6 out of China for $15.45. About a month delivery time. 6PCS Injector Adapter Car Modification 3919358 Accessory For 5.9L 89‑93 | eBay The injector tip protrusion into the head is important. It affects the timing.

On the head gaskets, those notches they are probably speaking of are marks put on the cylinder block indicating it has been surfaced by so much. During the rebuild, the important info is how much the piston protrudes above the surface of the block. If it's more than standard then you need a thicker head gasket. In a normal rebuild there would be X's stamped on the top of the block indicating how much it has been cut. I believe each X represents .010". This is one thing you have to measure after assembly to be sure what you have and which gasket to buy. If protrusion is too much to be covered by a thicker gasket then the pistons have to be shaved a little. Don't want the pistons colliding with the head. That gets ugly.

The bolts you found are typical. Like I said they aren't very expensive. Head studs run a bit over $300 and are highly recommended on engines being built for higher power. In your case that isn't an issue. The ARP rod bolts I mentioned are a little over $100 per set of 8. Again those are more for a high performance engine build.

On the pistons, that is the company I spotted. Have to be careful on some of the cheaper ones because they may just be the pistons only without other parts. That one from All States has pistons, rings, clips and pins just like you find in the OEM Cummins kit.

Any other questions feel free to ask. I don't know everything and if I don't I'll say so and recommend someone who knows.
 

Attachments

·
Registered
Joined
·
12,643 Posts
On the injectors, I suspect once you slip those sleeves on there and measure the distance all will be fine. The actual distance that is important is to those little tiny holes where the fuel exits. You notice on you old one those holes are almost at the tip and I believe the new ones may be farther down so the difference isn't as dramatic as it looks. 9mm tips are still available from sources in China. You'll notice that rebuilt 9mm are more expensive that new 7mm. The parts to rebuild them can get expensive and US labor is a tad more than China. Especially those tiny little shim used to adjust the pop pressure. Those little devils cost like $7 each and there are 30 different thicknesses. A rebuilder could have thousands of dollars tied up in those alone.

One item you haven't mentioned is the injection pump. Do you plan to have it checked out or is it in good shape. That's one area where cost can get crazy. Rebuilds sort of hinge near the $1000 mark and buying a new pump is very hard on the bank roll.

Yeah, on gas engines the piston don't get quite so close to the head as with a diesel. As to whether to cut the head or the block sort of depends on condition. If they don't need it you don't do it. If you cut the head then you have to watch for valve protrusion. There should be info in your service manual as to clearance that is acceptable. You could always order a rebuild kit with a thicker gasket. That wouldn't affect your compression ratio very little if it wasn't needed. I'll post you some videos you can look at concerning head gaskets. This guy is pretty old school and his videos are very helpful.

On the Case part conversion that sort of has to be looked at one part at a time. Case started using their own suppliers other than Cummins and some parts have new numbers. Any part you see beginning with the letter J you simply change that to the number 3 and you have the Cummins part. One bit of info you do not have on your engine is the CPL number. You'd need to contact someone at a Cummins store and see if they can provide that. I notice that parts supplier you listed asks for that number. There are not all that many parts that are unique on on various CPL numbers. Pistons is one that does vary. Buying all from one store is not a bad idea. AG Kits specializes in parts for farm and industrial applications.

You've worked on engines and the 4B is about as basic as a gas engine with a few differences. The engine has piston cooling nozzles in the upper webbing of the block. I believe the rebuild kit has those even though they don't mention them. Those are important. The kit has new rod bushings. You may need a machine shop to install and size those to your pins unless you have a Sunnen honing machine. Of all the gasket that come in the kits, the one least used is the one for the front gear cover. Most use RTV on that as it doesn't leak as bad. When you get to the point of installing that, the crank area where the front oil seal sits must be absolutely free of oil. Clean it with brake cleaner or some good solvent. Any oil on there will cause a leak. Rear crank seal doesn't have that issue. Just don't install it backward or you'll have a nice oil leak. Some guys have found that out the hard way. Also, be careful in removing the old seal from that aluminum frame. A gouge from a tool can make that part useless.


 

·
Registered
Joined
·
12,643 Posts
The style of your injection pump is rotary. VE is a Bosch model, CAV is a Lucas model and your Delphi is also a CAV. Delphi bought the CAV division of Lucas in 2000 so now it is their model. Your original pump was likely a Lucas brand. There are also VE pumps made by other companies under Bosch license.

I contacted Cummins and the reason there is no info is that is a 3rd party engine. It was licensed by Cummins but they did not build it so it has no CPL number. Only Case could tell you who actually built it. Don't think that is really needed but at least we know some history.
 

·
Registered
Joined
·
12,643 Posts
Not having the CPL number is not going to be a big issue. Don't even have to worry about an exact match of piston numbers, but if that info is there that's OK. Just for interest, I found a 4B engine made at the Cummins plant in Rocky Mt, NC. It's serial number is 44888261. Has the CAV injection pump like yours, has 3906208 17.3:1 pistons like yours would need, shows the 7mm injectors and sleeves, and guess what. It doesn't show a CPL number either. Whether it has one I don't know. I may email Cummins to see just for kicks. You could use this one on Quick Serve to cross reference with your Case parts manual. Just for info, the injector they show is part 3802338 or 3802338RX. RX is a rebuilt part. Here's the factory diagram.
Liquid Fluid Art Font Ornament
 

·
Registered
Joined
·
12,643 Posts
The Cummins 3802338/3802338RX replaces a lot of different Case numbers and Cummins numbers. Basically, that is Cummins go to number for most all the old 9mm injectors and some 7mm units. Here's 28 part numbers that can be shortened to 2.
Case Number Cummins Number
------------ 3802198
------------ 3802336
------------ 3802338
------------ 3802338RX
J914472 3914472
JR914472 3914472RX
AR77553
J903383 3903383
J909475 3909475
J909476 3909476
J913992 3913992
J917661 3917661
J915568 3915568
J919319 3919319
J919331 3919331
JR919331 3919331RX
------------ 6760525
 

·
Registered
Joined
·
12,643 Posts
On the rod it is interesting that the part numbers for that have all been discontinued. 3901569 was the oldest number which was replaced by 3925232 which was replaced by 3942581. I guess Cummins figured no one would ever need rods again. LOL. AG Kits has them under part number K3901566 for $69.68. 3901566 was the casting number for 3901569.
 

·
Registered
Joined
·
12,643 Posts
The $80 rebuild cost is reasonable but you'd probably want to wait and see what condition the head is in before you went that route. You'll want to do the killer dowel pin repair while your doing everything if that hasn't been done already. On the rod, you can find good used rods on ebay in the $40 range. Some from USA, some from England. The 6bt rod is exactly the same as yours up to 1998 when they changed to a cracked rod. Since you're going to rebuild the other 3 a used one would make sense.
 

·
Registered
Joined
·
12,643 Posts
The KDP is an alignment dowel located inside the front gear housing. It's only purpose is to align the housing when you install it. Unfortunately, the engineers made the hole in the housing the same as the dowel so it sometimes has the bad habit of wandering out and getting into the gear housing. One of several things can occur. One is it just winds up falling out and ends up in the oil pan, two, it gets wedged between as gear and the aluminum housing causing it to break, and three it gets into the gears and you don't want to know how bad that can be. The fix is simple. There is a bolt right beside that hole. You can make a little tab of metal to install under that bolt to cover the hole. No rocket science there. While doing this, you should remove all those bolts inside the gear housing. Clean the holes good and reinstall the bolts with blue loctite. Those bolts often work loose and can cause disasters too. Didn't know if you were replacing the oil pump or not. That one has a special torque sequence on the bolts. New pumps are often part of a rebuild and not all that expensive. On the oil cooler, don't often see them replaced unless it has ruptured. The 4b will have a 5 plate cooler and you should stay with that type. The 6bt has a 7 plate cooler and will fit but isn't recommended unless you were building a twin turbo engine. The oil filter housing has 2 valves. The oil pressure regulator valve is located under the hex plug on the front and the oil pressure relief valve is on the back side. Not sure which you are referring to. Also, pay attention to which style gasket your oil filter housing has. There are 2 different ones and rebuild kits often include both. There is only on type behind the oil cooler. Below are photos of the two gaskets. Yours is probably the first one but never know. That second style was used with the STORM blocks which started around 1998.
 

Attachments

·
Registered
Joined
·
12,643 Posts
Yes, 1991 would be the older style gasket. If you do a water pump, there were more styles of those darn things than you can shake a stick at. In general, they came either open impeller or shielded. In general the shielded is preferred so if it fails you don't have little bits of metal all over your cooling system. Some newer models have plastic impellers. Some models you'll find look like they might fall apart if you sneezed on them and some look like they are built like a tank. And prices for those darn things runs all over the board from dirt cheap to very expensive. That last version is normally an OEM Cummins. The current water pump listed for your engine is Cummins part 5473238 which costs around $200 from the good old boys. See photo below. You notice how thick the blades of the impeller are and it's an open design. I suspect that is one of the newer plastic models. Metal blades were usually much thinner. The previous part numbers were 3286275, 3286278, and 3802971. 3286275 was a shielded impeller design.
 

Attachments

·
Registered
Joined
·
12,643 Posts
No, a Cummins water pump is probably the easiest one on any engine to change. Have you checked your fan hub. Not sure which one you have but it may be like the one in this diagram.
Font Auto part Circle Audio equipment Bicycle part


If so, that unit has a weak point. It has no bearing. I have never figured that one out but I assume some engineer thought it was a good idea. The diagram shows it mounting to the block but the notes say it's mounted to the head. One of those two is wrong because the bolt pattern on the head and block are different. Part 3909890 shown in that diagram mounts to the block but the same type that mounts to the head is part 3909888. It too has no bearing so I don't know which one you may have. The part number is usually on the casting and your parts manual might show a number too. Be interesting to know which you have. If it's tight or feels rough I don't know of any repair procedure on those other than replace it. If it happened to be the one in this diagram it is very expensive. Near $400. Here's photo of an actual unit. Of course 3909888 isn't going to be outdone so it lists for near $500 but you can get those made overseas under part number 4932912 for about $80-90. Bit of price markup there. LOL. Of course yours may be different than either of these.
 

Attachments

·
Registered
Joined
·
12,643 Posts
Yes, those are the piston cooling nozzles. Is it possible the one you are missing was the bad cylinder? Those aren't totally necessary for a non turbo but having one missing on a turbo engine is death. Those little nozzles are made of plastic or nylon and you have to be careful when you install them not to break them. There are aftermarket aluminum replacements that are around $10 each. Mostly, those are for guys running higher performance turbo engines.
 

·
Registered
Joined
·
12,643 Posts
A good head saves you a good chunk of cash. Your parts kit should include new valve oil seals. There were 2 different styles of those. An early type ad a later model that was better. No telling which one you have.
 

·
Registered
Joined
·
12,643 Posts
The injectors you have with the 7mm tips should be perfectly fine. Those are the replacements for the 9mm tips. You just need the little adapter sleeves which cost very little.
 

·
Registered
Joined
·
12,643 Posts
Your lift pump on that engine is not a high pressure type. Probably about 10 PSI before the filter and maybe 6-7 PSI after when running. It won't do much at all until you get the air out of the lines. The position of the engine cam can affect the hand pumping action. Also, those diaphragm pumps have a bad reputation for failure. There is a piston type pump that was used on some industrial engines. Dieseltuff sells the upgrade kit for $270. https://www.dieseltuff.com/product/14psi-low-pressure-piston-lift-pump-install-kit-4bt-ve-cummins/ Be patient on the fuel system priming. Sometimes it goes quickly and sometimes it tries you patience. When you first crank up also keep an eye on the oil pressure. Sometimes engines are slow to pickup oil. On the hydraulic oil, there are some systems that use just regular motor oil. I have a Case lawn tractor that operates on that. No additive on it but don't know about your equipment. If an additive is required it should state that in the owner manual.
 

·
Registered
Joined
·
12,643 Posts
You ask about signs of a bad lift pump. Low fuel pressure when operating is one sign. You'd generally need a fuel pressure gauge to spot that. When one of those pumps fails it will often put diesel in the crankcase. Check the oil level often and if it seems to get overfull that is a possible problem.
 

·
Registered
Joined
·
12,643 Posts
Yes, need to have an oil pressure gauge present when you start one up. If you have no pressure there could be several issues. Could have a leaking gasket on the oil pickup tube, bad oil pump, missing plug in the oil galley behind the tappet cover, problem with the pressure regulator valve in the filter housing, wrong gasket there, and maybe other issues. Can do damage to engine bearing and especially to the turbo bearings.
 
1 - 20 of 20 Posts
Top