Macktruckman

I’ll see if I can post a picture of the liner

It had a broken liner. I pulled it. My mechanic friends there set up a dial indicator on the deck and the counter bore is not the same depth all the way around. They say that’s why the liner broke. They figure the new liner will crack like the old one sooner than later. Because it’s a dry liner it doesn’t put compression in the coolant. It dumps it in the crankcase. I personally do not know much about big diesels. But I have a good understanding of mechanics, and went to vocational school, loved hotrodding growing up and dad had a parts store and a truck and backhoe. But the two guys helping me I trust 100%. They are used to later model stuff though not antique Mack’s. Lol

If I had more time I could fix mine, but it was supposed to have a quick head gasket change and be out of his shop in a couple days. I’m pretty sure the counter bores need cut so I talked to the machine shop that is local (well 50 miles away, there’s nothing near me) anyway they are a month out. At the moment it’s gotta run soon and I figured I would find something to put in or even overhaul and have ready to swap out over a weekend. My plans seldom just work out. Lol.

Lol. Yeah I don’t imagine an E9 would ever be in my budget. I was looking at parts for them. Wow. Lol. I really do like the idea of an E7 though.

Where I live there’s not a whole lot of Mack’s. I saw an E9 in a superliner one time years ago and I sure did fall in love with that thing but I’ve only seen the one in person. a long time ago when I was a kid there was a local milk hauler that bought parts in my dads parts store and he had a superliner but it was a 8V92.

Yes I was curious if they have the same frame as the R ? would an E9 fit in an R you think?

Well the 4 valve engine is no longer an option. Friend of mine owns it and he’s decided to keep it. So I’m hunting an engine. Should have the parts to patch mine together and at least get it out of his shop. Maybe I can make a few bucks with it while I find something else to put in it. Out of pure curiosity are the frames wider or anything on the superliner to allow the E9 to fit or would an E9 theoretically fit in a R685??

Looked over the 4v E6 in the spare truck. 1988 year. Was EM6-250. Mack turned it to a 300 many years ago and stamped the engine plate 300. Looks very similar in most ways to my 2v. It definitely has a different injection pump than mine. The 4v pump has a sloped back or governor housing

Oh I almost forgot, looks like you have access to some talented help too jojo! Lol

Thank you guys! That 4 valve looks like a little different front mount than mine but it appears to bolt on identical to the crossmember. I’d like to know if I would see a noticeable increase in performance with a 4 valve over mine. As I do have access to a 4v E6. As far as making a mount for the E7 to work that’s doable for us too. Little fab work is no problem. Have piles of scrap metal and welders and cutters and access to mills and lathe and I’m one of the most fortunate people I know to have brothers that are absolute craftsmen and engineers. Lol. I’ve done a lot to this old thing the past few years with information and knowledge I gathered from you guys on this site and the talent and materials I have access to here. And it’s not lost on me I appreciate it all

It wears many hats. Lol

I don’t know for sure how much it weighs here but somewhere in the vicinity of 100k gross I’d guess.

I appreciate all the information and the part numbers very much. I have decided I’m going to slap a liner and head gaskets on this engine this week on the cheap. It needs out of the shop it’s in and on the job ASAP. I know it won’t last. I suspect the counter bore is off enough the new liner won’t last too long but I am aware of it and I am going to make a decision on what to do long term and start gathering parts for a new engine and get ready to just swap out one weekend. I’m still very much considering an E7 but also considering this 4 valve E6 in the parts wagon. I don’t really HAVE to have more power but man it would be nice. Lol. I was looking at its suspension today. (The parts truck) It’s a mixer truck. 12 yard drum I believe. 2 drop axles ahead of the drivers and a drag behind. I don’t know what the rears are other than Mack and HEAVY. LOL. walking beam and no spring at all. 6 spoke drives and steer. Thank you again jojo and vlad and everyone.

Thank you jojo. I would agree with the camelbacks in the soft ground from what experience I have. I was just thinking about my own back… haha. As far as the EM6, it is impressive at 11 liters I don’t disagree. Just everything I’ve read says the E7 is a much stronger block. I have almost zero experience in a E7. Lots of EM6 with 2 stick 6. Some 3406B and some C12 and a little in some C15’s. My 285 is probably in the neighborhood of 325-350hp and the cats and one lone N14 525 in a KW will lap me every few rounds. Lol. That said mine rolls through the soft ground and pits much easier than those Pete’s and that kw. Lol. I have access to a 88 R parts truck with a 4 valve EM6. That particular engine was a 250 and a mack dealer turned it up years ago and restamped the plate with 300. I never drove it but they all say it was the best running E6 on the place. It has an identical twin one serial number apart that was done by mack at the same time and it never ran as well. I don’t know anything about the 4 valve. Never driven one. Would it be an improvement over my 2 valve or a waste of time? Again I appreciate the knowledge here. I’m asking and learning.

Hahaha love that!

I appreciate that. It’s sure no show truck but it works for a living and it lives most of it’s life in the dirt. There are much nicer trucks but I’m sorta attached to this one. Lol

Thank you for the tip Joe! Since it’s in the shop I took that advice and crawled over and under with a light and I don’t see anything suspicious. I’ve been advised a few times to just patch this engine and sell the old thing and buy something later model and already spec’d to my needs. But I’ve had this old thing for many years and I’ve gradually spent lots of time and sweat and dollars on it making it like I want it so I’m not fixing to give up on it as long as the frame and such is solid. My dream truck has always been a super dog with an E9 but I don’t ever see that happening and I like this old thing. Where I live it gets lots of comments as there are not that many R models left and the ones still around are pretty rough and ragged. I’m reading everything I can find. Id like to find or put together an E7-454 and use a mechanical pump. I’m trying to get more power and keep it reliable. I already have a heavier clutch and Eaton 9LL that are fresh. I’ll throw a liner and head gaskets on this 285 for the time being but I’m on the hunt. I would like to get somewhere around 450-500hp. This truck sees mostly lowboy work and some site work and very local hauls. It gets very low mileage per year. Also considering a cut off because I’m ready for locking rears. Does anyone have an opinion about Rockwell 41-160’s on Hendrickson air ride?

Awesome information thanks so much to all of you. Yes Joe it’s single frame and all budd wheels. 38 camelbacks and I’ve got a bottom leaf broken and all the bushings need replaced too. So I’ve got some decisions to make concerning this old thing. I put a cab and hood on it a few years ago and painted it. Swapped the old 2 stick 6 for an Eaton 9LL and built air ride for the cab. All new interior and insulation. A/C and stereo and the works. Got lots of information here from all these good folks on this site at that time too

Oh worth mentioning maybe some of you can tell me if it’s an issue or not is the heads have a small crack from an injector over to an intake valve. I was told it’s not an issue but I don’t know. I appreciate everyone very much here

My 285 has a sorta full circle front mount that bolts together behind the balancer it looks like

To be clear I did the charge cooler and pump rebuild last summer along with injectors and new turbo. Recently it started over pressuring the radiator. Putting compression in the coolant. I figured head gasket after I checked the air compressor and it passed. So I pulled the heads and sure enough number 2 has been leaking to a coolant jacket. Then noticed the crack in 4 liner. I didn’t know how the liners would be to get out but when I barred the engine over some of the liners raised up out of the block when the piston started up. So I assume they will come out easy enough. Going to pull the pan tomorrow and the pistons. I’m pretty afraid I might have a counter bore problem that has caused the crack. Going to check it out. If the block has to come out of the truck I was curious about replacing it with an E7

Joe it’s an old 1978 R685ST. The engine in it is an EM6-285 that I believe is a 1980. At lest the pump shop said the pump is an 80 when they rebuilt and recalibrated it last year. It was tip turbine but I pulled it all off and fitted a air to air charge cooler in front of the radiator from an 88 R model. After pulling the heads I found I have a crack all the way down the side of number 4 liner. So I’m weighing options

Is the E7 longer than my current EM6?

The transmission is an Eaton RTO-14909MLL that I put in a few years ago when I swapped cabs out on the truck it was taken from a later model Mack mixer truck with an E7 so it bolted right in.

It’s a tractor that pulls an equipment trailer and also an end dump so some more power would be appreciated