Calling a Cummins guru

JP Dalik · Post by **JP Dalik** » Oct 16th, '07, 20:41

What's the difference between Cummins CPL 970 this is what I'm told is a Cummins B-series 330 and CPL 1975 a Cummins B-series 330.
Is one better then the other?
My sources say that "CPL" indicates the parts in the engine.
What parts are different?
Should I care?

JohnCranston · Post by **JohnCranston** » Oct 16th, '07, 21:14

JP,
Your's are the better of the two. The difference is that your's uses the longer spark plugs, and, the carbs are different. Your's uses a Holley, and the other uses a Weber. I hope this helps.

Harry Babb · Post by **Harry Babb** » Oct 16th, '07, 21:20

Hi JP

I have a pair of the CPL 970's that I intend to use to repower DeNada. I have been told that the 6B engines started off with less than 200 HP.

By adding Turbos, after coolers, more fuel and finally with the 970's more RPM they have increased the horse power.

I am not sure at all what Cummins did go get more than 300 HP out of these engines but I think that these engines are available up to 375 HP.

A Cummins Tech friend of mine once had a "Drag Car" powered by a 6B engine and he told me that you can push these engines to nearly 500 HP but at that HP you cannot keep head gaskets on them and they will stretch head bolts.

Back to the 970's.........I understand that you must treat them and prop them as tho they are 250 HP if you expect them to last.

I am also curious about exactly what parts are different in the later versions of the 6BTA..........

I'll bet this post gets a lot of attention

Hows the fishing????

Harry Babb

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 16th, '07, 21:35

Mr. Cranston is not exactly right on, but close.

The Cummins 6B series was indroduced in the mid 80s and is an in-line four cycle, 6 cyl. 5.9 liter engine.

The early natural versions were about 150 hp at 2600 rpm, then they turbo-ed to make the 210 hp, then aftercooled it to make the 250. The "CPL" is the model # and means somthing like "Complete Parts List" or close......the motor names are: 6B is the natural, 6BT is the turboed one, and 6BTA is the turbo & aftercooled models, all on the same block.....now it gets more interesting. The 6BTA 250 like I have, CPL 1247, have a fresh water cooled aftercooler, and is a 2600 rpm engine...the next step up was the CPL 0970 that kicked it up to 300 hp by using a sea water cooled aftercooler and running the rpm up to 2800....the 0970s are considered to be sort of "tender" and need to be run like 250s, max cruise of 2400, and need the aftercoolers cleaned pretty often. Then Cummins went beserk and kicked the ole 5.9 liter block up and up by using atriculated pistons, higher pressures, and more rpms and got 330s, 370, and now a common rail 425 out of it.

Great engines, but the higher hp versions need to be handled with care, mostly avoid overpropping them.

UV

Capt. DQ · Post by **Capt. DQ** » Oct 16th, '07, 23:30

UV,

Don't your 6bta have the fresh water aftercooler like this on top?

http://s133.photobucket.com/albums/q78/ ... G_0002.jpg

DQ

nic · Post by **nic** » Oct 17th, '07, 05:15

John,

Love your work, keep it up. Maybe share some Yanmar tips soon.

Nic

Capt. Mike Holmes · Post by **Capt. Mike Holmes** » Oct 17th, '07, 08:27

John obviously tried out the electric toliet, which he was supposed to be helping me get a deal on, by the way, and probably got a shock to his system from faulty wiring.

Mikey · Post by **Mikey** » Oct 17th, '07, 09:07

John,
Sung to a sixties R&R song:

Sittin on the Vaccu,
Waitin for my Holly to come . ins!

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 17th, '07, 09:39

DQ - yep, that's what I have. It's called the "tombstone" aftercooler.

UV

RichE · Post by **RichE** » Oct 17th, '07, 10:33

JP,

No guru but did do some research on the 970's a couple of years ago as I have (2) in my garage for future repower. 300 hp 970's had cylinder head problems. Holes in head for injectors's were 9mm, later models are 7mm.
9mm heads were prone to cracks between injector hole and valve openings. I believe they also didn't have valve rotator's on the exhaust valves. 300 hp models are raw water aftercooled and the early aftercoolers were welded units prone to cracking. Replacement cast aftercoolers seem to solve this issue. Also remember something about the exhaust manifolds cracking but not sure. May have had other issues but I think these were the major problems. Tony Athens at boatdiesel.com is the Cummins guru and much of this information came from that website.

Regards, RichE

IRGuy · Post by **IRGuy** » Oct 17th, '07, 10:50

As far as the Cummins term "CPL".. it designates a parts list that was used to assemble a series of Cummins engines. (Cummins or Corporate Parts List?). I believe any Cummins guy can look up the CPL number and tell you which injector pump, hex, etc, etc, etc your engines have. Early on I asked Tony Athens to look mine up (CPL = 1928) and he gave me his opinion on this batch of engines. Mine were built in 1998, but I am not sure if they use sequential numbers for identical batches of engines, or if they increment upwards over time, so I am not sure if identical engines built at different times would have the same or different CPL numbers.

Ask Tony.. he has provided this info often to Cummins owners. I provided him with my CPL and serial numbers, and he was able to tell me the warrantee history of my particular engines, which was interesting, since they were supposed to have been derated for the first boat they were installed in.

dougl33 · Post by **dougl33** » Oct 17th, '07, 11:56

I thought CPL referred to the "Common Parts List". I have a set of the 970's in my 33 Bert.

As noted above, the main trouble points were:

Heads
9mm injectors
welded rather than cast aluminum after-coolers (as far as I know, all of the 6BTA's have raw water cooled after-coolers).

If these have been addressed and the engines are propped to reach 2900-2950rpm at loaded WOT, then the concensus is your good to go.

I cruise mine at 2400-2450 rpms and see 22.5-24 knots depending on load and conditions.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 17th, '07, 13:04

Doug - the 6BTA 250's (CPL 1247) have fresh water cooled aftercoolers that look like the one DQ posted pix of. There is a petcock on the back of it where you bleed air out of the fresh water cooling system, and since it's so high - actually above the radiator cap on the expansion tank - that they came with an extension adapter that replaces the radiator cap for filling and bleeding air. The are not as effecient as raw water cooled aftercoolers but require no maintaince.

UV

JohnCranston · Post by **JohnCranston** » Oct 17th, '07, 14:04

I had a 1990 26' Shamrock with a 300 cummins that developed a hole in the raw water colled after cooler. Destroyed the engine, but Cummins put in a new one. I remember that they had that problem with alot of those engines, but they really went out of the way to fix the problem. Mine was out of warranty, but they took care of me anyway.

dougl33 · Post by **dougl33** » Oct 17th, '07, 14:24

Thanks for the clarification UV.

I know I have seen many new/newer 330B's that have the same exact after-cooler that I have.

bob lico · Post by **bob lico** » Oct 17th, '07, 20:18

jp were do i start? riche was hitting on the main points but in reality the cummins cpl 970 and the present day (2002 and newer)m-2 6bta have nothing in common a complely differant engine.ok i stand corrected the fluid damper (harmonic damper) is the same . the block has been reinforced and is now called the storm block.the new cylinder heads do not even resemble the 970 heads and yes riche the new heads have valve rotators with case harden valvekeepers.camshaft totally inproved with larger cam journels.pistons complely changed and i might add much better volumetric effiencty at a lower temperature.with this change and the new disigh exhaust manifold the overheating of #6 hole during hard running was eliminated.a diesel is only as good as the fuel injection pump,the 970 nippendenso pump was eliminated around 1993 and the replacment was the cats ass---bosch -7100.so much that they renamed cummins 6bta diamond series around the tail end of 1994 to beginning of 1995.cummins then completly revamped the aftercooler/cooling system and in 2002 the block /startermotor/alternator/sensors/belt tensioner,etc all of the latest changes became the start of the qsb common rail engine but tryied and proven on the mechanical 330/370 hp models.i have skip over a lot of information jp but you can see from the information i have given you the new cummins is a totaly differant engine they even changed the oil pan to a much more user friendly style.

JohnCranston · Post by **JohnCranston** » Oct 18th, '07, 01:24

Ditto what Bob said.

Rawleigh · Post by **Rawleigh** » Oct 18th, '07, 08:58

Mikey: I think your aftercoolers were replaced by Merritt Foster after they failed on him, weren't they? I seem to remember him suing Cummins over it, and that was the reason he changed over to Yanmars.

Mikey · Post by **Mikey** » Oct 18th, '07, 09:52

Rawleigh,
Think you're right.
Hope you're right!

RichE · Post by **RichE** » Oct 18th, '07, 10:28

Mikey,

I looked at the pictures you posted in your engine mount post and your aftercoolers are the upgraded cast units. I think Tony Athens has an article at boatdiesel.com on maintainence of these units. Nice work by the way.

Rich

bob lico · Post by **bob lico** » Oct 18th, '07, 11:34

the first design of the cpl 970 aftercooler was a welded box -disaster this is the second design about 1990

and the second design about 1995

bob lico · Post by **bob lico** » Oct 18th, '07, 11:44

this is the latest and greatest even has a auto drain to keep bottom of aftercooler dry after shutting down .a flawless design on all current 6bta started around 2002 .

bob lico · Post by **bob lico** » Oct 18th, '07, 11:53

this picture is from boat diesel .com.the real cummins expert tony at seaboard marine.

harry they are pulling about 650hp from the 6bta.there are no headbolts in pro engine builders we use studs and no head gaskets.we cut a .050 grove in the block and use a "o" ring.same for gas engines no gaskets we use "tubby"to assemble.gas engine pro stock about 18 to 1 compression at 9500 rpm 500 cubic inch engine limit.

Capt. DQ · Post by **Capt. DQ** » Oct 18th, '07, 13:08

UV,

I know you are saying your 6BTA/250 has a # (CPL 1247). I went and check mine out an has a # (CPL 0953) on my 6BTA/250. Big difference in CPL #'s for the same year models that You & I have.

DQ

In Memory of Vicroy · Post by **In Memory of Vicroy** » Oct 18th, '07, 14:47

Doug - yeah, the CPL # seems to be in no particular sequence - anytime a part changed they changed the CPL....for example, my CPL showed a Sherwood 15000 raw water pump with an inch and a quarter intake and output, but the ones on the motors are inch and a half, which is a different CPL....I guess the Coonass that had AJ then decided to put the bigger pumps on at some point, probably before he installed the engines...Mine were built in Nov. of 89 and installed in 91. The engine serial #s seem to be more of a sequential # tho.

The fresh water cooled "tombstonte" aftercoolers on the 250s as I understand it were cast from the get-go and the welded ones were on the 300 hp CPL 970s. Apparently Cummins replaced all the welded ones on the 300s and up free of charge when the corners cracked. Since the raw water ones use ambient temp raw water (Diuhhhhh?) to cool the turbo air they do a lot better job of cooling down the turbo air than the fresh water cooled ones like you & me have that use 185 degree coolant to do the job.....now on the other hand, the raw water cooled ones need a lot of maintaince or they will crap up big time....Tony Athens has a whole section on boatdiesel on how to clean the raw water ones, looks messy.

UV

Mikey · Post by **Mikey** » Oct 18th, '07, 15:23

Whew! Thanks, Rich, one less thing to worry about.

JP Dalik · Post by **JP Dalik** » Oct 18th, '07, 16:03

Bob,
Thanks, I figured this was sort of up your alley.
We've got CPL1975's, coupled with your information plus what the folks at Cummins are tellin me I guess we'll keep her for a few more decades. We'll keep her propped for 330hp knowing we've got good guts.
Thanks again all.

John Cranston,
Your a funny guy
I recommend the Ice Blue paint in a latex satin finish. It looks sweet on the hull.

JohnCranston · Post by **JohnCranston** » Oct 18th, '07, 16:27

JP,
We're taking your advice on the ice blue. Moving the boat this weekend to the shop for the re-power, and then, back to the paint man. All of the glass work is done,and I want to post some pics, but I'll think I'll wait for the finished product. Thanks for all of your help, JP in the past, and I'm sorry for being such a smart ass.

bob lico · Post by **bob lico** » Oct 18th, '07, 16:30

jp if you let your 6year dauther or son teach me how to catch one of those 40lbs stripers i am sure i can get those cummins to rock especially now that i know you have 12hundred series instead of cpl970.
for some reason i just can`t get the hang of livelining with the treble hook thru the nostrals of live bunker.i know they use 5' of flourocarbon then a 4oz. drail but i don`t have the feel i guess?

JP Dalik · Post by **JP Dalik** » Oct 18th, '07, 17:14

Bigger is better with the treble hooks, if you go circle hook treat em like a goggle eye and tie wrap em through the eyes. Make sure the hook is big enough. Throw the drail away, use 5 ft of 30lb fluro to a spro swivel and an egg sinker above that on your main line with enough weight to get the bait where you want it. The egg helps you feel the bite. If you can't get bit lighter leader or longer leader. Just like tunas.
We just started eelin this week and then its back on the troll through December.
Come on down, we'll be fishing till December 1 for sure. Bring your tool box.

bob lico · Post by **bob lico** » Oct 18th, '07, 21:46

thanks alot jp.the live bunker are 12" in lenth and i use very sharp treble hooks with 1 hook thru the nostral.i assume this would be the best way not to harm the fish (keep him alive longer).doesn`t putting a hook thru the eyeballs kill him?the sucessful guys here on long island bays hunt for bunker pods then liveline under the pod with a drail or sinker.i just can`t get it together with the big bass seen!!maybe i should have started a new post under livelining i am sure there are alot of pros out there.

Charlie J · Post by **Charlie J** » Oct 19th, '07, 04:49

bob
the only time i use a treble hook is when i snag a bunker in the pod with my spining gear, let him him down right in the middle of the pod. ill make 2 or 3 passes thru the pod if nothing happens move on and find another pod thats holding fish. when live lining with a coventional rod i use 40 lb main line with a egg sinker 2 or 3 oz just anuf to get the bait to the bottom, then go with a barrell swivel, 10' floral carbon leader 60 lb and finished off with a 9/0 gamagotse circle hook. keep the reel in free spool with your thumb on the reel spool, you will feel 1 or 2 sharp wraps then a steady run off let him run for awhile 5 sec to get the bait down, lock it up and your in, remmember if your using circle hooks just lock up the reel no need to drive the hook home.
looks like jones is just starting to heat up took a 26 lb yeaterday

bertram31.com

Calling a Cummins guru

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