wingman Posted April 21, 2015 Share Posted April 21, 2015 A question for the folks who are in the know about the 673 series of Mack engines. I have both END673 and ENDT673 engines and I am wondering if the engines are identical except for the turbo charger. Are the pistons the same (compression ratio), pump settings? Can I take the turbo setup off one engine and put on the other? Thanks Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted April 21, 2015 Share Posted April 21, 2015 there have been many discussions on this topic. on the older late 50's early 60's end673T motor they were the same except for the setting on the pump I think.. the later 60's they came out with the endt673 b and endt673c motors which had oil cooled pistons and fire rings and the Maxidyne style head gasket instead of the old copper one.. the older version without the piston squirters and fire rings on the heads were troublesome when they turboed them. Quote Link to comment Share on other sites More sharing options...
wingman Posted April 23, 2015 Author Share Posted April 23, 2015 Thanks for the reply. I was considering swapping the turbo from one to the other. The turbo'ed engine has some blowby but runs well. The other engine has no blowby but will pull a trailer to shows, and could use a little more giddyup. Quote Link to comment Share on other sites More sharing options...
57 bcr Posted April 23, 2015 Share Posted April 23, 2015 Bob,Have an END673D (200hp) w/turbo added. According to stock specs,it has the same compression ratio as an ENDT673B(225hp) motor,so I just figured(hope) mine is putting out 225hp on a good day! I know the ENDT673C (250hp) has a lower comp. ratio than mine,if that helps any? Changed out the old Schwitzer to a newer Garrett off of a 237,gained 10-12lbs of boost! Good luck. Al Quote IF YOU BOUGHT IT, A TRUCK BROUGHT IT..AND WHEN YOU'RE DONE WITH IT, A TRUCK WILL HAUL IT AWAY!!! Big John Trimble,WRVA Link to comment Share on other sites More sharing options...
Bigdogtrucker Posted April 23, 2015 Share Posted April 23, 2015 I was told the early 205HP engines are the same as the END's internally, just different pump settings. I was asking some questions to a few older Mack mechanic's recently as I was thinking about adding a turbo to mine as well. They said don't over fuel it and beat the hell out of it and I'd be fine. I'm still on the fence about it... Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted April 23, 2015 Share Posted April 23, 2015 been toying with the idea of putting a turbo on my END707 (same as a 711 but mine had the maxidyne gaskets an fire rings and is 200hp instead of 211) but id have to ditch my split intake setup and don't really know what turbo to put on. I have a few complete turbo setups off 237's but dunno if they'd work. Quote Link to comment Share on other sites More sharing options...
wingman Posted April 24, 2015 Author Share Posted April 24, 2015 Lots of things to think about. The B61 that has the ENDT 673 is a tow truck, and when I get it basically cosmetically restored, it will go to shows close by under it's own power. It won't be used for any work. The engine runs good but is tired. My other B61 is a tractor and runs great and no blowby. It may pull lowboy with other stuff to shows. If it becomes to much of a hassle to change it the B's will all ride on the lowboy pulled by either of the other antique tractors I have with air ride and A/C (Pete, KW, Marmon). I'm getting to old to get beat to death! 1 Quote Link to comment Share on other sites More sharing options...
dougthegeologist Posted April 14, 2023 Share Posted April 14, 2023 It's 2023 and I'm reading this and still have the same question. I have a 673NA in my 1961 B67T. I need 1 good head to complete the build on my motor - I have 3 heads with cracks in the injectors that can't be repaired again. My motor is non-turbo with 18 bolt heads. I seem to be able to buy turbo heads. Will those heads fit on my 673NA? Is there also an option to turn my motor into a turbo, and if so, will it fit under the hood? Thank you. Doug Quote Link to comment Share on other sites More sharing options...
Freightrain Posted April 19, 2023 Share Posted April 19, 2023 Plenty of guys put turbos on early 673s. I don't think they do much beyond cleaning up the smoke a touch. I'm curious as to the stock 673T for boost? 5-10#? My 237 has 15#(love to have 20#). I remember going through the same thoughts for my NA 673 20 yrs ago. Glad I found a 237. I didn't want the chance of hurting my good running 673. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
terry Posted April 19, 2023 Share Posted April 19, 2023 12 hours ago, Freightrain said: Plenty of guys put turbos on early 673s. I don't think they do much beyond cleaning up the smoke a touch. I'm curious as to the stock 673T for boost? 5-10#? My 237 has 15#(love to have 20#). I remember going through the same thoughts for my NA 673 20 yrs ago. Glad I found a 237. I didn't want the chance of hurting my good running 673. I believe the biggest problem of putting turbos on the early engines was head gasket leaks, no fire rings. terry 1 Quote Link to comment Share on other sites More sharing options...
Mean Green Posted April 19, 2023 Share Posted April 19, 2023 I put a turbo on my 673 last year I had to add some fuel cause it seemed like it had too much air it was actually running worse with it . Still waiting to see how the head gasket holds up hopefully I’ll have the boost gage and Pryo hooked up this year Quote If your going to be a bear be a grizzly Link to comment Share on other sites More sharing options...
Joey Mack Posted April 19, 2023 Share Posted April 19, 2023 I have a 673 in my shop.. I had to change the pistons when I added a turbo.. So END-to an- ENDT... I am not an E-6 Guru.. I just did some reading and asked a few people about the change over.. My new head gaskets have fire rings. I wish I knew a lot more about these engines.. and when I finish this one, I will have to make a jig to mount it in, so I can start it up. Thats going to be an effort.. 1 Quote Link to comment Share on other sites More sharing options...
terry Posted April 20, 2023 Share Posted April 20, 2023 17 hours ago, Joey Mack said: I have a 673 in my shop.. I had to change the pistons when I added a turbo.. So END-to an- ENDT... I am not an E-6 Guru.. I just did some reading and asked a few people about the change over.. My new head gaskets have fire rings. I wish I knew a lot more about these engines.. and when I finish this one, I will have to make a jig to mount it in, so I can start it up. Thats going to be an effort.. Does your liners have the ridges for fire rings? and are the heads scored for the rings? terry Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 20, 2023 Share Posted April 20, 2023 Yes My heads are correct.. it's not easy to find someone who knows how to cut the fire ring grooves in my area.. Quote Link to comment Share on other sites More sharing options...
terry Posted April 20, 2023 Share Posted April 20, 2023 7 hours ago, Joey Mack said: Yes My heads are correct.. it's not easy to find someone who knows how to cut the fire ring grooves in my area.. Does it have the fire ring liners? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 20, 2023 Share Posted April 20, 2023 yes 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 20, 2023 Share Posted April 20, 2023 Terry, I went back to the begining of this thread... I just saw that he has 18 bolt heads... I have to apologize.. I have a 20 bolt engine block, and 20 bolt heads.. So disregard my statements about liners and fire ring grooves... Truly sorry,,, Jojo 1 Quote Link to comment Share on other sites More sharing options...
terry Posted April 21, 2023 Share Posted April 21, 2023 So they don't have fire ring head gasket for the 20 bolt gasket? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 21, 2023 Share Posted April 21, 2023 Mine have fire rings.. if I remember, when I get home I will get a picture of them. They are still in the package. Quote Link to comment Share on other sites More sharing options...
mechohaulic Posted April 21, 2023 Share Posted April 21, 2023 On 4/20/2023 at 12:11 PM, Joey Mack said: Yes My heads are correct.. it's not easy to find someone who knows how to cut the fire ring grooves in my area.. don't think it's limited to only your area trying to find someone to cut rings. wide spread . have 15 mins before leaving for Dr appointment. knew I should have stayed off BMT. will be in Dr office racking brain cells trying to picture head gaskets of days gone by to see fire rings/ grooves. late now !! Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 22, 2023 Share Posted April 22, 2023 I have pictures.. There are fire rings, the white box has the part number. The other 2 boxes are the part numbers for the rest of the gasket sets. Quote Link to comment Share on other sites More sharing options...
Freightrain Posted April 23, 2023 Share Posted April 23, 2023 On 4/19/2023 at 6:22 PM, Joey Mack said: I have a 673 in my shop.. I had to change the pistons when I added a turbo.. So END-to an- ENDT... I am not an E-6 Guru.. I just did some reading and asked a few people about the change over.. My new head gaskets have fire rings. I wish I knew a lot more about these engines.. and when I finish this one, I will have to make a jig to mount it in, so I can start it up. Thats going to be an effort.. When I wanted to start my 237, I took some square tubing and welded plates to them to bolt to the front corners of the block, then a made similar stand for the lower two bolts of the bellhousing(allowed me to install flywheel). Worked great. You can see them in this video I made after I first started it up after having to pull the heads to get the mud daubers out of two cylinders. 1 1 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
Joey Mack Posted April 23, 2023 Share Posted April 23, 2023 Thats pretty cool.. I noticed the rear stand is narrow, and yet the engine ran smooth enough to not tip over, Impressive.. I have an E-Tech in my shop right now, but hope to finish the E-6 later this year.. Quote Link to comment Share on other sites More sharing options...
Freightrain Posted April 23, 2023 Share Posted April 23, 2023 The two front legs are wide,so the rear didn't need to be so wide. It was stable. My initial intent was to be able to drop the pan if need be. I didn't have to, luckily. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment Share on other sites More sharing options...
Joey Mack Posted April 23, 2023 Share Posted April 23, 2023 Still awesome!! Is it ok if I copy you? Quote Link to comment Share on other sites More sharing options...
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