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Discussion Starter #1
A month ago or so, I managed to find a rare engine and bought the thing. It's the QSB4.5-30 which was made in 2004 and came from a genset. The guy I got it from picked it up for another project but decided to go another direction.

Here it is the day I got it.
IMG_20210117_165525 by Paul Abbott, on Flickr

IMG_20210117_165515 by Paul Abbott, on Flickr

IMG_20210117_165506 by Paul Abbott, on Flickr

IMG_20210117_165459 by Paul Abbott, on Flickr

The previous owner told me the previous, previous owner took it apart and loosely put it back together. I confirmed this today by tearing it down in anticipation for a VE pump swap.

Here is some proof.
IMG_20210225_145655921 by Paul Abbott, on Flickr

Yikes.

Here is the cam.
IMG_20210225_151813660 by Paul Abbott, on Flickr

I swapped the timing cover with one off a 1st gen 6BT. While in there, I made a KDP tab.
IMG_20210225_155700973_HDR by Paul Abbott, on Flickr

And I got it timed right.
IMG_20210225_161724207 by Paul Abbott, on Flickr

The injection pump I found is coming from China, of course. It has a part number of 0460424326 which is from a Chinese 4BTA found in buses. Their engine model is EQB125-20. The pump's Bosch number shows as VE4/12F1400R866-8. That should be a standard on road pump. The kicker is that it is brand new (we shall see about that) and I paid $706 + taxes for it. I felt really good about that. When it shows up, I will post up some pics.

I believe the VE lines and VP have 12mm delivery valves so I should be ok there.

I have some questions about the injectors for this engine. Do you think I will be able to use the VP-30 injectors? They are part number 0432133773 which the internet pulls up 3964919. I can't seem to find any details about the angles or pattern.

Also, are there any measurements you want me to take on this engine before I put it back together?
 

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Well, I know a bit about the engine you have since I have one of those on my Quick Serve list. That particular engine is sort of an odd ball in the Cummins line. It's the old 4bt 4.5 with a VP30 injection pump. Similar to the VP44 used on the 24 valve Dodge. Be thankful you aren't replacing that pump because it's in the $5000-7000 range. As for the injectors, those have a pop pressure of 260 bar. Those would work with a P7100 injection pump but 245 bar is what a VE pump needs. Those won't work. Need to pull one an verify the diameter of the tip. VE engines originally had 9mm but later engines changed to 7mm. I suspect your head is 7mm. Also, don't know the spay angle of your pistons. VE pump injectors were 155 deg except the IC Dodge which was 145 deg. You may need to contact Bosch to find out what you have. You can use 145 deg injectors in a 155 deg piston but don't want to go the other way around. if you need part numbers for VE pump injection lines or injectors I can look those up. All current injectors come with 7mm tips. Must keep in mind you have an engine that is different. One thing I'm not sure of is whether standard VE injection lines will work because your engine block is about 1/2" taller that the stock 4bt 3.9. Half the parts of that engine are unique. What measurements are you looking for.
 

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Discussion Starter #3
Well, I know a bit about the engine you have since I have one of those on my Quick Serve list. That particular engine is sort of an odd ball in the Cummins line. It's the old 4bt 4.5 with a VP30 injection pump. Similar to the VP44 used on the 24 valve Dodge. Be thankful you aren't replacing that pump because it's in the $5000-7000 range. As for the injectors, those have a pop pressure of 260 bar. Those would work with a P7100 injection pump but 245 bar is what a VE pump needs. Those won't work. Need to pull one an verify the diameter of the tip. VE engines originally had 9mm but later engines changed to 7mm. I suspect your head is 7mm. Also, don't know the spay angle of your pistons. VE pump injectors were 155 deg except the IC Dodge which was 145 deg. You may need to contact Bosch to find out what you have. You can use 145 deg injectors in a 155 deg piston but don't want to go the other way around. if you need part numbers for VE pump injection lines or injectors I can look those up. All current injectors come with 7mm tips. Must keep in mind you have an engine that is different. One thing I'm not sure of is whether standard VE injection lines will work because your engine block is about 1/2" taller that the stock 4bt 3.9. Half the parts of that engine are unique. What measurements are you looking for.
Thanks char! So I was reading that the 260 bar injectors do work on a VE pump, at least that's what POD injectors sells for VE trucks. I have a 1st gen 5.9 head pulled off that still has the injectors in it. I will pull one and compare. I will also get the mic out and see what diameter they are.

I know this is a very strange engine. I was wondering if YOU wanted me to pull a con-rod or something and compare it to a standard 3.9/5.9 connecting rod. I know there was some debate that perhaps the rods were different.

I have the VP-30 pump and harness and computer all tucked away. Do you think I should just throw it on eBay or something?
 

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I've got the same engine sitting in my shed, waiting in the wings for my 4BT to blow up. Came out of a specialized crane of some kind. I intend to do the same thing you're talking about here, put the timing cover and VE pump from my 4BT onto this QSB block.

The bore and/or stroke would have to be different to make up for the .6L displacement difference over the 3.9L 4BT. Pull the head off to identify the pistons, measure the bore, and measure the stroke.

I've always assumed the stroke was longer in this engine, so measure and let us know what you find!
 

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Discussion Starter #5
I've got the same engine sitting in my shed, waiting in the wings for my 4BT to blow up. Came out of a specialized crane of some kind. I intend to do the same thing you're talking about here, put the timing cover and VE pump from my 4BT onto this QSB block.

The bore and/or stroke would have to be different to make up for the .6L displacement difference over the 3.9L 4BT. Pull the head off to identify the pistons, measure the bore, and measure the stroke.

I've always assumed the stroke was longer in this engine, so measure and let us know what you find!
I have the head off so I will do just that. I won't have any precision measuring equipment, but a tape measure will get close enough. I am running up to get a set of 60lb springs and a 4K governor spring. But some time this weekend, I will get those measurements and post them up!

The one advantage I have read about these engines is if you have the stock turbo, the exducer is larger than what came on standard 4bts, right?
 

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The standard 4bt 3.9 which we're mostly familiar with has a bore of 4.02" and stroke of 4.72". This 4.5 4bt has the same bore of 4.02" but the stroke is 5.39". To my knowledge no other Cummins engine has this bore and stoke combo. The 16 valve 4.5 shares the same bore and stoke with the 6.7 which is 4.21"x4.88". These engines have a higher torque to HP ratio than the standard 3.9. You might use a 260 bar injector on a VE pump but it may not like them very long. First off, you'll need to change the timing. With the higher pop pressure your timing will be late. Even the A inline pump doesn't use the 260 bar units. Why would you want a 4000 RPM governor spring in a VE pump and where are you going to get it? VE springs come in 3200, 3800, and 4200 RPM. You're not going to be able to run that 4.5 at 4000 RPM. Rod angle is getting pretty extreme with that stroke and small bore. Seems like these came with 99 [email protected] RPM and 305 lb ft [email protected] RPM.

+
 

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I have the head off so I will do just that. I won't have any precision measuring equipment, but a tape measure will get close enough. I am running up to get a set of 60lb springs and a 4K governor spring. But some time this weekend, I will get those measurements and post them up!

The one advantage I have read about these engines is if you have the stock turbo, the exducer is larger than what came on standard 4bts, right?
My 4.5 didn't come with a turbo, so I don't know.
 

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Discussion Starter #8
The standard 4bt 3.9 which we're mostly familiar with has a bore of 4.02" and stroke of 4.72". This 4.5 4bt has the same bore of 4.02" but the stroke is 5.39". To my knowledge no other Cummins engine has this bore and stoke combo. The 16 valve 4.5 shares the same bore and stoke with the 6.7 which is 4.21"x4.88". These engines have a higher torque to HP ratio than the standard 3.9. You might use a 260 bar injector on a VE pump but it may not like them very long. First off, you'll need to change the timing. With the higher pop pressure your timing will be late. Even the A inline pump doesn't use the 260 bar units. Why would you want a 4000 RPM governor spring in a VE pump and where are you going to get it? VE springs come in 3200, 3800, and 4200 RPM. You're not going to be able to run that 4.5 at 4000 RPM. Rod angle is getting pretty extreme with that stroke and small bore. Seems like these came with 99 [email protected] RPM and 305 lb ft [email protected] RPM.
Here is the top of the pistons. No discernable markings other than "Front" and "A."
IMG_20210226_163720745 by Paul Abbott, on Flickr

And you are right about the bore vs stroke.
IMG_20210226_163555255_HDR by Paul Abbott, on Flickr

IMG_20210226_163537324_HDR by Paul Abbott, on Flickr

No idea if its in the rods vs piston.

I drove up to Joshua Tree and just got back with just the 60lb springs. The seller said he had 60lb springs and 4K governor springs. Turns out the governor springs were for a P-pump. He didn't really know what he had.

The only reason why I would want to spin it that high is because that's what normal folks do. If the displacement was increased due to the piston size, then the rod angle wouldn't be a factor. If it is all in the rod, then yeah, I get what you are saying. I think I will source a 3800 RPM governor spring and call it a day.

Regarding the injectors, I will take them and some 5.9 1st gen injectors in and get them pop tested. If the 260s are worn out and popping at a lower pressure, then they might be ok. Not in a huge rush here so I have time to figure things out.

Looks to be close to 7mm?
IMG_20210226_170320893 by Paul Abbott, on Flickr

My 4.5 didn't come with a turbo, so I don't know.

That's where I got the 12cm figure. No idea if its right.

IMG_20210226_170558683 by Paul Abbott, on Flickr

Looks to be 2.5" ID and 3" OD on the exhaust side. Now that I look at it, I have no idea where the 12cm figure even comes into play. 2.5" ID = about 6.35 cm and 3" OD = 7.62 cm.
IMG_20210226_170520085 by Paul Abbott, on Flickr
 

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The 12cm thing is more on the 6bts. The 4bts usually came with 6cm hx30s. It's stamped on the turbine housing inlet.

The pistons look like 145* pistons to me, but it's been a while.

The injectors look like 7mm nozzles, but you've got to measure with calipers or something. Standard tape measure doesn't cut it.
 

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I'd agree with Johnny, those appear to be 145 deg pistons. That would be sort of logical with the electronic injection pump. They aren't really a problem so long as you get an injector to match. One question would be what size are the threads on the top of the injectors. Injectors used with the VE pump where M12x1.50 threads. Later 260 bar P pump units were M14x1.50. If yours are M14 you can't use standard VE pump injection lines. You'd need something custom. The turbo 4035052 is sort of like the rest of this engine. Not the normal size. That one has the 42mm inducer and turbine housing 3539250 which I suspect is 12cc. The only way to know for sure is take it off the exhaust manifold and look in the exhaust port of the housing. If it is a 12cc Johnny can tell you it's not the ideal performance item on a 4bt.
 

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Discussion Starter #12
So my 87 6bt head has injectors that are much larger at the nozzle than the ones on the 4.5. I was going to pull them out, but saw how much larger they are and said "forget it." I'll just source a set of 240 bar injectors that will fit my lines so I don't have to deal with it. Having trouble finding my calipers. Somewhere in this damned house...

I am doing my best to split the turbo housing apart so I can clock it the direction I want. Its being a bitch. Its starting to come apart but I will eventually get it. While I am at it, I got 3 of the 4 manifold to turbo flange bolts out easy, but the last one is rounded off and no amount of heat will help it. So I am going to cut that stud out and replace it with a nut and bolt.

Char, did you mean 12cm turbine housing instead of 12cc?
 

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I believe turbine housings are stated as centimeters squared which is "cm2". For some reason I got into the habit of using "cc" which is cubic centimeter. Sorry about that. Separating a turbine housing from the center section is often a pain. That tolerance is very tight. Sometimes take penetrating oil, heat, a good whack with the hammer or all of them. Smear a little anti seize compound on the joint once you get it apart. If you can cut off that one bad nut you may be able to extract the stud. If vice grips won't do it then maybe weld a small bar of steel onto the end of the stud to use as a wrench. Your '87 6bt would have had 9mm injector tips. Cummins went away from those after a while because heads with 9mm holes were more prone to crack. The 9mm tips are no longer sold. New injectors are 7mm with a 2mm sleeve to fill the hole. 245 bar injectors with 7mm tips should be no problem but need to make sure they have the 145 deg spray angle. The injectors used on the '91.5-93 Dodge 6bt may be a possible solution.
 

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Discussion Starter #15
You guys are rad. Thank you for the knowledge drop. I have done a ton of reading on this site as the search engine works great.

One idea I had about the difference between the 6cm vs 12 cm housing is essentially you are increasing back pressure on the exhaust in order to induce the impeller to spin up quicker. Why not just introduce the back pressure by a narrowed flange at the turbo housing? Just put a restrictor plate between the exhaust manifold and the turbo? Its not ideal, but wouldn't it do the same job?
 

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Don't think so. Turbo housings are engineered to high degree. It's not just the opening that is smaller but the entire turbine housing. The problem with a 12 cm2 housing with a 4bt is its exhaust volume doesn't spool that one all that well for higher power. With only 99 HP you don't need a lot of boost level. Same was true of the 4bt 105 HP engines that had 16 or 18 cm2 non waste gated housing. Their boost level usually maxed out around 18 PSI or a bit less. When Cummins came out with the 130 HP P pump 4bt they used the HX30W 6cm2 turbo with an intercooler. Boost comes on much faster and can reach a level of a bit over 30 PSI for higher power if desired. Stock boost was around 20 PSI but you had the potential for more.
 

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Discussion Starter #17
Don't think so. Turbo housings are engineered to high degree. It's not just the opening that is smaller but the entire turbine housing. The problem with a 12 cm2 housing with a 4bt is its exhaust volume doesn't spool that one all that well for higher power. With only 99 HP you don't need a lot of boost level. Same was true of the 4bt 105 HP engines that had 16 or 18 cm2 non waste gated housing. Their boost level usually maxed out around 18 PSI or a bit less. When Cummins came out with the 130 HP P pump 4bt they used the HX30W 6cm2 turbo with an intercooler. Boost comes on much faster and can reach a level of a bit over 30 PSI for higher power if desired. Stock boost was around 20 PSI but you had the potential for more.
Aha, so it won't spool as fast AND it will limit the top end of boost production. I see the issue.
 

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Discussion Starter #18

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Paul, when you installed the 60 lb. springs, did you remove the injectors and use air, or a rope or?

Thanks, Ed in CO
 

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Discussion Starter #20
Paul, when you installed the 60 lb. springs, did you remove the injectors and use air, or a rope or?

Thanks, Ed in CO
Hello Ed!

My application doesn't help much if your engine is in the vehicle still. My cylinder head is pulled off for inspection so I didn't have to keep the valves in place the usual way.

I did notice that when the engine is at TDC, cylinder 1 & 4 are all the way at the top so you won't risk dropping those valves there. Reason stands that if you rotated the crank one revolution then 2 & 3 would be at TDC making sure the valves stay there. So you could do that sequence: find TDC, swap out springs on 1 & 4. Rotate the crank 360 and then do 2 & 3.

That sound right Char, Dougal and Johnny?
 
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