237 or 250?

[Bigdogtrucker]

This engine is in a "68(or so)R600 with a quadbox.Wondering if this would be a 673/250 or a 237?Truck is about 2 hours away.Thanks

[220cummins]

Its looks like a maxidyne 237 because of the spin on oil filters and oil cooler but the water neck throws me. The 237 has a spin on water filter where this does not. This engine has a maxidyne oil filler neck where as a thermodyne does not.

[57 bcr]

Check on top of the auxillary drive,toward the front of the block,should be stamped right on the top ahead of the injection pump.Or was that just on the Thermodynes,I can't remember?

[terry]

Check on top of the auxillary drive,toward the front of the block,should be stamped right on the top ahead of the injection pump.Or was that just on the Thermodynes,I can't remember?

All conventional engines are stamped there, cabovers were stamped on backside of motor next to firewall, right below headgasket. terry

[57 bcr]

All conventional engines are stamped there, cabovers were stamped on backside of motor next to firewall, right below headgasket. terry

Ah,yes! Thanks,Terry!

[220cummins]

All conventional engines are stamped there, cabovers were stamped on backside of motor next to firewall, right below headgasket. terry

That works 90% unless he numbers were grinded off like on my B model or his situation where the truck is 2 hours away

[Bigdogtrucker]

Can you tell by the turbo?

[220cummins]

I've seen that turbo used on 673T ON 711's and 237's. A B61sx I had for parts had a 711 with a turbo kit on it had the same one likewise a 237 I pulled from a CF600 had the same looking turbo too. I don't know the part number but I remember what they look like.

[fullfuel01]

250 have air to air on front. 237 don't. it's a 237.. also 250 don't have this type of manifold. I don't remember any piping like that near the thermostat.. might just be 'older version'

[2stacksuperdog]

They didn't start using air to air till mid '80s

[Lmackattack]

in that vintage a 250 was a thermodyne. Without intercooling. Often used with 10 or more speeds.

Looks like a 237 but many people swapped over basic parts to convert an old engine into a more user friendly design..I.e spin on filters..

[220cummins]

in that vintage a 250 was a thermodyne. Without intercooling. Often used with 10 or more speeds.

Looks like a 237 but many people swapped over basic parts to convert an old engine into a more user friendly design..I.e spin on filters..

That's where I was kinda leaning.

[daveigou]

That engine looks like a 237 because of the fabricated intake manifold. The 673 turbo'd (ENDT 673) had a top 250 hp rating, but used a different style intake manifold. Like others said, over the years guys did mix and match parts, they used Maxidyne pistons in their turned up 673's. The engine model should be stamped in the edge of the timing cover, it was around the introduction of the "300"s that they started to put a data plate on the engine block, right behind the lines off the injector pump

[jeffbyrne]

All Mack 6cyl. engines had spin on filters after, say, 1972, that's when the 'ESI' engines came out. ESI stands for 'Extended Sevice Interval'. Part of ESI programme was spin on filters. It does'nt matter if it is an END673E, an ENDT673C or an ENDT675, they will all have spin ons after 1972. But an ESI engine should have a spin on water conditioner element. this engine has the earlier style of water connections to the radiator. But as has been said, over the years things get changed. You can't always go by things like turbo(not by appearance anyway, you need the#), inlet manifold or water and oil connections or set ups because things get changed. The tin inlet manifold was used on the 'P' motor, the 'C' motor, the '237' and the END673'E'. The Turbo looks like a Switzer to me, could be a 237 or a 'C' motor. The oil filler is just a Mack 6cyl. oil filler neck for an 'R' model. You need the # from the side of the fuel pump, the engine # from either the front of the engine near where the fuel pump drive is, or the rear of the block if the engine was originally fitted to an F series,(don't know how you will get that if thats where it is located) The # on the turbo could possibly tell you what turbo it is, i.e. what engine it is for.

Why was the engine painted gold? Was it to fool people in to thinking it was a '237' or is it really a '237'?

But it looks like an ENDT675, a '237'

[theakerstwo]

All Mack 6cyl. engines had spin on filters after, say, 1972, that's when the 'ESI' engines came out. ESI stands for 'Extended Sevice Interval'. Part of ESI programme was spin on filters. It does'nt matter if it is an END673E, an ENDT673C or an ENDT675, they will all have spin ons after 1972. But an ESI engine should have a spin on water conditioner element. this engine has the earlier style of water connections to the radiator. But as has been said, over the years things get changed. You can't always go by things like turbo(not by appearance anyway, you need the#), inlet manifold or water and oil connections or set ups because things get changed. The tin inlet manifold was used on the 'P' motor, the 'C' motor, the '237' and the END673'E'. The Turbo looks like a Switzer to me, could be a 237 or a 'C' motor. The oil filler is just a Mack 6cyl. oil filler neck for an 'R' model. You need the # from the side of the fuel pump, the engine # from either the front of the engine near where the fuel pump drive is, or the rear of the block if the engine was originally fitted to an F series,(don't know how you will get that if thats where it is located) The # on the turbo could possibly tell you what turbo it is, i.e. what engine it is for.

Why was the engine painted gold? Was it to fool people in to thinking it was a '237' or is it really a '237'?

But it looks like an ENDT675, a '237'

That is the way i remenber it.

[umodelnut]

Looks like a 237 to me because of the intake manifold. And some other little things here and there. That thing looks cherry, all that nice gold, is that original engine paint on that? What's the trucks model number? You could tell what it had for a motor from the factory from the model number.

[jeffbyrne]

A Mack 6 is a Mack 6, you need to look closer, i.e. at the numbers, to accuratley tell what engine it is.

[skip grandjean]

I am sure it is an endt675 I have one in my 69 r model same filters turbo oil fill and lack of water filter mine is original from build sheet. hope this helps

[220cummins]

All Mack 6cyl. engines had spin on filters after, say, 1972, that's when the 'ESI' engines came out. ESI stands for 'Extended Sevice Interval'. Part of ESI programme was spin on filters. It does'nt matter if it is an END673E, an ENDT673C or an ENDT675, they will all have spin ons after 1972. But an ESI engine should have a spin on water conditioner element. this engine has the earlier style of water connections to the radiator. But as has been said, over the years things get changed. You can't always go by things like turbo(not by appearance anyway, you need the#), inlet manifold or water and oil connections or set ups because things get changed. The tin inlet manifold was used on the 'P' motor, the 'C' motor, the '237' and the END673'E'. The Turbo looks like a Switzer to me, could be a 237 or a 'C' motor. The oil filler is just a Mack 6cyl. oil filler neck for an 'R' model. You need the # from the side of the fuel pump, the engine # from either the front of the engine near where the fuel pump drive is, or the rear of the block if the engine was originally fitted to an F series,(don't know how you will get that if thats where it is located) The # on the turbo could possibly tell you what turbo it is, i.e. what engine it is for.

Why was the engine painted gold? Was it to fool people in to thinking it was a '237' or is it really a '237'?

But it looks like an ENDT675, a '237'

Again the problem is it's two hours away from the guy so numbers at this point doesn't matter. Likewise the identification is great when the numbers are there and aren't scratched or grinded off. I had to order a few set of head gaskets for the 673c in my B61 before I got the correct ones. The numbers on the front housing were ground off. The pump number was 673t the turbo number was the same as a 237. That engine has 3 hairline cracked pistons which the numbers can't be out. Numbers are great when they are there but when they are not out comes the old TS442 and B-model manuals. The oil fill neck from a ENDT675 I parted out will not fit the supposed 673c currently in my B61. The bolt pattern was different. I converted to spin on filters (water and oil) by changing the oil cooler, the water pump, and cross drilled the block for oil flow. Then added the water filter manifold. My point is over 40 years a lot can change or be converted on a truck.

[Maddog13407]

i have seen the tin intake manifold used on 673's, the tin one on 237 has the smaller inlet tube for the turbo. regular 673 tin one has a 4'' tube for direct to the air cleaner. looks like a 673c motor to me with the old style 711/673 manifold but as others have said things change. could be a 237 with the old water manifold or a endt673c with a spin on filter kit.

[jeffbyrne]

All we have to go on is two pics of an engine around 40 years old. The engine in the pics has ESI oil system with pre-ESI water system. So it's a guess without the #'s. It looks like a 237. Sometimes you have to delve deeper.

[220cummins]

Isn't that what were doing here?

[Bigdogtrucker]

OK,got the vin R685ST1601 .Truck was a tandem,turned into a single axle.I was told it has a quadbox,but who knows?Here's a pic of the truck

[jeffbyrne]

Bigdogtrucker,

The chassis number puts this truck in the 1967 period, could be 68, as stated.

The number is for a 237 tandem, but would not have been a Quad. It would more than likely have been a 5 speed Maxitorque.

[umodelnut]

OK,got the vin R685ST1601 .Truck was a tandem,turned into a single axle.I was told it has a quadbox,but who knows?Here's a pic of the truck

That thing is beast. R685 means it had a 237 from the factory.