Full Floater

Ya this is the style of box that I have. The switch between floor and def is definite, and there is no lingering air movement in the opposite position as to what is selected.

Both pipes are hot. The engine also will run up to operating temps no problem. The blower motor is good. Just need more during the colder times, of both heat and blower volume. R model defrost vents are not the best to begin with, so the far reaches of the windshield always fog up etc.

The cowl vent makes next to no difference in air flow in my trucks.. I've had the boxes apart and confirmed no blockages or debris. The heater does fine, until maybe 10 below Celsius. Just looking for something better as I do spend a good portion of the year below those temps

HAHAHAHAHAH

This is the kind of stuff I was hoping to hear. My heaters in my trucks (all 70's vintage) are sub par at best. For both heat and blower force.

https://wattstruckcenter.com/shop/heater-ac-unit-for-r-rw-cabs?search=heater Has anyone run these? I'm looking at upgrading my factory 70's R heater in one way or another. I was thinking of either installing an aux heater somewhere, or installing this box. Does anyone know if the heater output is greater than the stock units? I don't run a/c, its strictly the heater that im after.

To only adjust when temps are below 100? Is that what you're saying?

While on the topic of valve adj. Does it make much of a difference doing it hot vs cold? I've always done it cold, due to the engine being apart at the time of, or not getting into it while the engine is still hot, etc.... But is it worth while intentionally doing it when hot? I've got an E6 that was last adjusted when cold, and once the engine is warmed up, there is a bit of valvetrain noise...but nothing at all when cold. Is this telling me the clearances are tighter when adjusting cold?

Probably going to end up buying one of these boxes from you. I need better heat/better flow out of the heater box in 2 of my 70's R models. Either wanting to go with an aux heater mounted somewhere in the cab, probably under the existing heater box, or upgrade to a better heater box if there is one available. Do these boxes heat/blow any better than the factory ones?

Air intrusion, and lack of consistent lift pump/supply pressure and lack of fuel lubricity is also a problem on the idi's that can prematurely wear out the injection pumps

Sounds like a poor quality rebuild. Yes the contraction of the housing is what makes it build pressure and start again, when cold water is poured on a heat soaked pump. There are lots of Ebay "rebuilt" pumps out there that aren't much more than cleaned up and sent back out the door at a fraction of the price of a quality builder. Theres a handful of good DB2 pump builders on this continent, and many that are not good. The DB2's are not a lifetime pump like some inline pumps can sometimes be. Generally they are worn out at 200,000miles. But they are also much cheaper to properly overhaul then most inline pumps.

I may be a rookie when it comes to old Macks and I find myself here asking for help and I get it! But im very familiar with the 7.3 powerstroke and the 6.9/7.3idi. I have several of each and run them everyday for work and for play. The 7.3 psd is capable of mileage and engine hours that aren't seen on many other medium duty engine. If it wants it straight piped, it won't hurt it....it sounds "good" for a while, then he'll grow up after a couple years of it. They are a HUEI engine, which is fine....just a little different to figure out when there's problems and they do not tolerate dirty oil for long periods of time. He's gotta keep his oil changed on time. Keep the EGT's in check. I could go on and on. ECM tuning goes a LONG ways for performance. I only run a mild tune on them....im not out to win races....cause it won't. But a mild tune wakes it up just enough for me. Drive accordingly. Keep it maintained, and be happy and make money. Yes, the 7.3psd has a handful of idiosyncrasies that can cause a fella to pull his hair out trying to figure out runability issues. But once they are understood and the quirks are dealt with, they are very good.

Oh they are around, no doubt. Don't see em everyday...but they're out there.

Yes.....not to many Mack guys in these parts. I feel like a lone wolf. OR.....a lone bull dog! Hahahah

Oh ya. Perhaps I should have an extra cup of coffee one day and pull off the head in question. Which apparently is the drivers side rear

Old post, but I have an 866-375hp that can be up for grabs very reasonably, if someone needs one (located in BC Canada). It's a "running" engine with what was diagnosed as a valve train knock. Not sure what exactly is going on as I have not looked very far into it.

Maybe it is an off breed axle. Never specified as such on the build sheet and everything else is Mack so I had just assumed Mack. But yes, all my other Macks have Mack looking axles, this one is different. Also heavier.

The new king pin set is now installed. Took me all day, but i don't care. The tool that I was interested in buying would have been useless for this job. The pins and the draw keys all pounded out just fine. I drilled out one of the draw keys as it was seized. The new pins went in fine, just a little bit of a chore to line everything up. I managed to get 1 extra shim in place over what was in there, just 1. Thanks for the suggestion Paul. The brass bushings that were in there, pounded out just fine once I got a bite on them. The new split poly or whatever they are bushings, went in like nothing. The grease holes lined up but I drilled them out anyways. All is good. Again, many thanks for all the tips and tricks gents. This is the kind of support that keeps these old trucks rolling for years to come!

Seems like my other 4 Macks (all lighter spec axles) have a different style of front knuckle/king pin design. Probably the tapered style. Maybe this style is more specific to the heavier spec axles?

They have the 2 "draw keys" which are tapered at one end. That I would assume get pounded out and in. That act as a key way into the 2 slots on the king pin. Is that what you mean? There is no nut of any kind on mine, far as I can see so far

Thank you very much for the detailed reply. As for reaming the bushings? Are we talking the ones that appear to by nylon/plastic in this particular kit?

Turns out mine are not tapered. Is that a bad thing? Here is a pic of what my new kit looks like. Looks straight forward. But I guess i'll soon find out. Will be starting this job in the morning. https://www.meritorpartsxpress.com/webapp/wcs/stores/servlet/en/meritor-na/r200168

Is anyone needing a complete "running" (with what has been diagnosed as a valve train knock/tick) 866, 375hp? 1978 as I recall. I will be parting out a re-powering a R700 with one, in BC Canada, and will offer this 866 to someone for any reasonable offer.

Yes. In this particular case, I am really trying to leave the axle in place, in the truck. When the truck was getting resurrected (I should have done the king pins then) I would have pulled the axle at that time and done it in a press, which I have. But it's now in service and am trying to do it in the most time efficient way. Plus i've just put new leaf springs in it and all that jazz and would like to leave all that alone. Again, I should have done the king pins at that time.

Did I ever! I'm now leaning towards tackling the king pin job without the Tiger Tool or equivalent.... still thinkin about it...