300+ in B

[Maddog13407]

lookin to upgrade the motor in my B. has a 707 in it now(711 with firering head gaskets) and NO its not a gasjob. have a 237 in stock but wanna stay with the triplex. also have access to a 300+. was wondering if i could eliminate the air to air on the 300 and just use a 237 intake to get away from all the extra plumbing with the air cleaner. has anyone done this? would i have to just watch the EGT or would i have to have the pump recalibrated ? or am i better off just stickin with the 237 and setting the pump to Thermodyne specs? or just run it??

[Rob]

Seen this done several ways in years gone by. My 64 B-61S, (Yellow Dog) has a 711 which has been turbocharged and runs like a scalded dog. This is the mule I was monkeying with several years ago swapping turbos, injection pumps and calibrations, and the like to get 300hp from and I did but kept popping head gaskets on the chassis dyno. The heads are now scored with a later fire ring head set installed so it would probably be alright to run, but there is no charge air cooling and the exhaust would heat quickly if the throttle were held to it.

As you know a 237 is about as close to a slip fit as you're going to get with just a few donor parts which you mostly have. A 300+ will only benefit you if planning to work the truck above what a 237 engine will provide in my opinion. If just running around as a casual use vehicle, the 237 engine will provide plenty of power.

Recalibrating the injection pump is a matter of preference. I've done both. Again if working the truck it is beneficial to have the conventional torque rise apply if the truck is working given the limitations of the existing driveline, and really won't matter much if a casual use vehicle.

A 300+ engine will fit into the truck but is snug. Ron Bogan whom used to be a participant here, (B61 Mack IIRC) has either a 300+, or an ENDT-676  installed into his and it fits nicely. I've looked the truck over quite extensively and it fits well, but is tight. To work on much of anything in the B series you are going to take things apart and the 300+ hardware is not a high maintenance item, so shouldn't be too much of a concern. Ron has air conditioning on his and modified the front shutters to allow a condenser coil installation behind them, and in front of the radiator. I know I have engine photos but cannot find them.

[Maddog13407]

have many parts, have done many B42 and B68 conversions to B61's etc. and have put a 237 in a B68.  was kinda just lookin for opinions on if recalibrating the pump on a 237 was really necessary . plus i have access to either a 285 or 300+ with the intercooler and was jw if simply taking the intercooler off as to not have to deal with the extra plumbing and filter would be detrimental to the engine

[davehummell]

I'm no expert but if you didn't use the intercooler I think you would loose some hp. I don't think you would have to redo the pump settings for a truck just for shows. I was hot to buy a 285hp. out of a r model but it turned out the engine was stiff from setting so I got a different engine I knew I would have fun running the second air intake. One of the easiest engine swaps I ever did was installing the later engine in my b.   

[Maddog13407]

I don't really care about hp. The 707 a pig when it hits a hill. I changed rear to a 4.00. so it will run but falls on its face.i figure I can get rid of the intercooler and pretty much have a 250 or so.i just don't wanna lose the triplex I'm running

[Freightrain]

A 237 and triplex is perfect in my B.  I dont split until 4th gear, even pulling my trailer.   Now there may be different flavors of 237 but mine runs up to 2100(heard some don't). Having the option to drop 1/2 a gear works well for my towing.  It runs through PA hills with the cruise set at 65 mph.

 

Would love to have a 300!  Why?  Just because you can't have enough power!

 

BTW, my local shop wanted $2500+ to recalibrate the pump and they needed specific numbers as they had nothing to go by.  I quickly decided to leave it alone.

Edited March 25, 2021 by Freightrain

[mrsmackpaul]

4 hours ago, davehummell said:

I'm no expert but if you didn't use the intercooler I think you would loose some hp.

As most of you will know I recently fitted new bearings to the tip turbine on 320 or 300 + as you blokes call them

I can definitely tell you the the intercooler makes a difference, I can more than just see the difference on the boost guage, Im  dropping at least one less gear on climbs and the pickup feels so much quicker when cresting a hill

 

Paul

[Mark T]

Do you really need to run ducting for the tip fan in this day and age ?   Seems like K & N or someone should have some form of filter that would be easily adapted to it and not take up much space . (think like cold air intake on a Dodge)  just a thought

[davehummell]

I got lucky and ended up with a 260 hp. engine and I put a double over triplex behind it with a 3.90 rear it runs pretty good.

[Rob]

Back in the mid 1970's when I was a young guy and the 711 engines were still fairly plentiful, they had a tendency to be hard on the exhaust valves and I was grinding sets a couple times a month for different trucks with my trusty "Sioux" seat and valve grinding set. Certainly did a lot of them starting out and always had a spare set of heads ready to go. A lot of those engines didn't make 100K miles before the heads had to come off..... My thoughts followed Mack engineering by installing a low pressure turbocharger onto those engines and they would yield a good long service life, and a little more power. My B61S has a Mack factory upgraded induction system with this type turbocharger installed. It may make 5-6psi of boost but the point is the valves on that engine needed cooling air and this supplied it. It has run a lot of miles in the years and the chassis is no longer roadworthy, but the engine runs perfect.

I've seen guys simply bolt on a 237 turbocharger and manifold onto 673's, and 711's and have good service, and seen some scatter the engines shortly afterward. In fairness, a guy running his own truck usually fared better where employees, well..... Blown 237's used to be almost as common as dirt so parts were easy to come by but I don't know about nowadays as have been away from truck repair a lot of years now. 

Anybody can do whatever they want of course but I have a 58 B-61ST which has it's original 673 engine and I'm going to install a 237 induction system onto it and keep the original triplex to make use of the truck someday. I am going to regear it to 3.65 ratio from the current 5.05 to get the road speed up into the modern era. I'm the second owner of that one so wanting to keep it close to original in appearance.

[theakerstwo]

Rob if you put a turbo on a 673 one thing you need to do is remover the fuel pump and replace the syncrovance and install a direct drive on the pump and set timing to 28.Mack sure the air cleaner is larger and there is a adapter that goees in between the compressor and block for the turbo return oil to go in.Both of the parts may be hard to find.The set the rack out about two rounds.

[davehummell]

I worked at a truck company and they had 37 f's and r's and one b for the yard. There were mack 675's torn apart every week never had to repair a maxi 5 speed and I never repaired any mack rears just changed springs and bushes for the suspensions. My boss clamed they got only 100,000 miles out of the mains and rods. I don't know but I changed a lot of bearings at that garage. One guy did coast to coast with a f model with a juced up 237 5 speed. That was so long ago I wish I could remember all the stuff bosso did to those engines to get more out of them. A year after I left the owner bought a bunch of freightshakers with 3406's and began retiring the macks.

[Rob]

13 hours ago, theakerstwo said:

Rob if you put a turbo on a 673 one thing you need to do is remover the fuel pump and replace the syncrovance and install a direct drive on the pump and set timing to 28.Mack sure the air cleaner is larger and there is a adapter that goees in between the compressor and block for the turbo return oil to go in.Both of the parts may be hard to find.The set the rack out about two rounds.

Hi Glenn;

I'm going to use the pump from the former military engine I have which is now rebuilt on that engine eventually. This is that engine we worked with many years ago, (ENDT673B) on a stand in the shop. It's not been run since the rebuild and does have the oil drainback connection for the turbocharger. I may install it's induction system if it will clear too as another option. I've still not converted this engine to standard flywheel housing or any of the like and it sets bolted to the same stand. 

[Maddog13407]

I like the sound of the 711, mines a 707 version and is stamped end707 and has the fire rings.  Last year on the trip to allentown it blew both belts, I replaced and noticed the balancer wobbly.i replaced the crank hub and balancer. I found the balancer started to come apart and hub was loose on crank. Replaced with a gun that fit snug and a balancer....it still wobbles about a quarter inch. Motor was probably rebuilt in the 80 and with me gearing it up.its fine cruising but a dog on hills when pulling a trailer. Id like to find an Endt673 b or c motor but they are scarce. I have a 237 in stock and have access to a 285 or 300 plus.going to look at this weekend.its getting the gas axe and has a Roadranger so I'm.thinkin 300 plus.  Either way I'm not taking my triplex out.