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I’ve been fighting a starting issue since I got this truck back together in 2023, of course I only drive it about 6 times a year so I haven’t pushed too hard to fix it. It would start easily but then run out of fuel and I would have to crank it for a few seconds to get it going again. Also the hand primer wouldn’t pick up fuel unless I poured fuel in the inlet line. I went through the fuel lines, check valves, and replaced the hand primer. Then a couple of weeks ago I was reading what other guys did to fix theirs, and one guy on here (now I can’t find the post) said the overflow valve would cause this problem. That is the return tee at the back of the injection pump. I never had any experience with those; I looked at my old fuel system repair manual and it said that valve could cause issues with starting and low power. The spec on mine is 15 psi; I tested it and it held less than 10 psi. The one for the 673 is 697GC15, but that is NLA. The number for the E6 is 697GC123 and it’s the same configuration (1/4 x 1/4 x 1/8 NPT) so I bought one from PAI (no. 801090, $100). I tested the new one and it holds 20 psi. I installed it and now the truck starts and runs correctly. It’s frustrating to dink around with something for so long but I’m glad it’s fixed!

You can't flow time that pump?

aint no big mike obama either!!!!

I think the E6 was a two valve. I thought they would be more compatible, but they were not that E6 was a running son of a bitch. Well, I finished the velvet adjustment. I was gonna set the timing, but I figured that’s enough for the day. It’s a lousy day with no sun.

I have an update. Today I went in and had the horsepower increased from 355/380 to 380/410 hp on my 2002 Mach CH613. I figured it would at the least take half a day to do this but the dealer got me right in and they were done with the truck in about 45 minutes and I was out the door with the bill paid in an hour and 15 minutes. The tech said that I probably would not notice anything special as far as super performance and to temper my expectations. It’s a truck not a race car “copy” I understand that but I find this kind of stuff interesting so let me recap as to what has happened so far. 1. Installed a boost gauge to keep track of changes. 2. Stock Maxicruse 355/380 boost 25psi max unloaded 3. Installed 900cc injectors 355/380 32 psi max unloaded 4. Increase horsepower program to 380/410 w/ 900cc injectors 35psi boost max unloaded. I will take the truck on an equipment run next week and let you know how it goes.

Did the truck have an off-set cab? I honestly can't imagine a full one part hood made of steel. DM or DMM or RD800 could have steel nose but the engine gets accessed through a baterfly hood shells. Unified fiberglass nose is a different story. And with super singles at the front it was the most probably DM or DMM model. But all this just my guesses.

E6-4V came into production in 1985 if I'm not wrong. And many were equipped with Ambac pumps, Robert Bosch took place closer to 89. Trucks with E6-350 4V were 688 trucks - R688, MR688 etc. Trucks with generally similar EM6-300 4V were 690 trucks - R690, DM690 and so on.

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The E6 2 valve is commonly regarded as a harder and tougher motor than the 4 valve As they say "she'll pull christ from the cross" or "she'll pull the ass outta the ocean" 2 valves were the very best motors of their era Paul

Yes but you need to move the engine 30+ degrees back then go forward to remove gear lash.. a little gear lash effects a long way... Got it ??? The engine runs clockwise...

You have to remove the front cover and the 4 bolts on the pump gear. Leave the gear meshed in the hole. The pump coupler will come out with the pump. When the pump is ready to install. You will use the light timer to make sure the pump is set before installation. then install the pump with 2 bolts secured in the pump gear. Then back it off 30+ degrees, and bring it up til the lights match, and check the degree mark on the flywheel. 1/2 degree early is ok. If it is on the mark, lock it down.. your done... There are a few others here who know this better than me. I expect one to chime in.. jojo

That's a 2 valve. Million mile engine...

The Antique Truck Club of America National Meet is in Macungie on Father’s Day Weekend. It is an all make show but Mack’s do represent. Mack Days is in Lititz PA the first Saturday in October. It is also an all makes show and is out on by the Central Pennsylvania Chapter of the ATCA. Both are great shows.

Yes, now I remember that dowel. That time I didn't reset/check the timing. Just needed to get the truck yard driving (actually to take it off the street into my property. One plunger got stuck and I couldn't get it free until took the pump off the engine.

Some good reading before the sleep. No kidding

I beleive the pump shop will have to set the timing on the bench. Key is not to rotate the pump when handling it.

Ok, no sun - no timing

That's the early style with three clamps bolted to the cab. Clamp is 4 ME 2258-P1. I believe it's the same for all the early L series cab mounted mufflers.

“So for 40 years, America has been the piggy bank of the world. We absorb all of the ridiculous trade practices and economic practices of friend and foe alike. For the first time in probably 40 years, we have an American president who’s saying, ‘No more,’ that it’s not going to work, that he’s not going to allow America to be taken advantage of anymore. This decision is going to cause incredible benefits for American workers. You’ve already seen a number of American manufacturers and a number of foreign manufacturers who are saying they’re going to build or expand plants in America. That means more workers with good middle-class jobs. That means more self-sufficiency in the United States of America. Again, it can’t happen unless you have a president who fights back against these ridiculous trade practices. Finally, we have a president who’s doing exactly that.” “It’s funny. You have countries who threaten to retaliate against President Trump standing up for American workers. And my response is, well, if tariffs are so terrible, then isn’t them raising their tariffs good for us? Because these people always say that any tariffs are bad. Well, all these other countries have applied tariffs to the United States and non-tariff barriers to the United States for a generation. If it was so terrible, why do these countries keep on doing it? If it’s so terrible, why are these countries calling us, lobbying us, begging us not to do this thing? It just doesn’t make any sense. What we know from experience is that a lot of countries have gotten rich by using the United States as a piggy bank. We know that President Trump stopping this makes these countries nervous, and the reason it makes them nervous is because they know what common sense tells us, which is that when they impose tariffs on us, it’s bad for American workers, and when we fight back, it’s good for American workers.” “Yeah, in a word, it’s nationalism. In our foreign policy and our economic policy, we have a president who’s going to put the interests of Americans first and that means in our economic policy, we’re going to fight back against ridiculous trade practices. In our foreign policy, we’re going to stop starting stupid wars. But we’re also going to ensure that America’s enemies respect America’s national interests and that means we need access to critical resources. That means that we need our allies and ourselves to have missile security, to have national security, to make our own weapons if God forbid a war would start. And so, these things are often connected. Economic security is connected to national security because, if God forbid, we had to go to war, we want our troops to go to war with the best equipment and equipment that’s made in the United States of America. The president mentioned this in his remarks today: that we’re in a situation where if we went to war against a country that made our pharmaceuticals, our kids wouldn’t have access to antibiotics. So this basic understanding of President Trump’s, which I think is very much common sense and I think most Americans get, is that we need to have more self-sufficiency. We need to make more of our own stuff. We need a foreign policy that puts the interest of our citizens first, and we need an economic policy that does the same.” Vice President JD Vance

It seems to me that all the news stations are in bed together, trying to scare us into beleiving prices are going to sky rocket. I would look into big business owners and controllers intentionally keeping prices high just to increase profits, even when there costs are low.

yup, it will be great when prices start to go down on imports. Canada has already announced it will lower all it's tariffs on exports to match the American import tariffs

Yeah, the 2 valve was much tougher. PLM pumps on the 4 valve kinda sucked too. APE pump was much better

I gotcha now!

maybe to blind man.

I modified one off of another truck to temporarily drive it, anybody have a part number for the original? I’d welcome any pics of the factory hanger arrangement.

Sounds like the truck had a six speed in it. You don't "split" shift them. With the 3 position lever in HI you'd shift the other 5 position lever as a 5 speed. The "low" position was for crawl'n around in soft stuff with the 5 position lever in first. When the 3 position lever was in "reverse" That was reverse and the 5 position lever allowed you to chose the speed you wanted to go backwards in. Very unlikely that truck had a Thermodyne in it. Maybe a 237 or 300 ???

I love it.. I dont "truck" but i would proudly drive that to the hardware store..

i bet they would sell like cold beers on a hot summer day.

Welcome aboard bud sorry to hear about your Kenworth. Most of us are fans of those also especially the W 900 good luck on your search

Found number on the front axle and they match up with my build sheet. FA 600

haha thanks for that,,,,didnt do anything today but yes that steering box is next and one axle seal,for now,,,i might have to swap trans soon since i have it kinda sitting in the way where it is,,,,and thanks for the happy cheers vlad,and yes steel dash,,,ive been a big fan since riding with my pop in a 1970 U model at 14 ,,bob

Damn, I was going to ask how could you get the engine into the cab?? Ok, I also have a DM but probably have never taken the dog house away. Nice thing about your truck is it's steel dash. At least it's on my taste and I just forgot the fact. And I don't feel guilty now for not paying attention to the thread for a while, read all the pages I missed in the last couple of months. So wishes of good luck on the progress whatever it will be the hood, tranny, steering gear... And sure pictures

haha me and the mrs had quite our share of bourbon last night

Clearly that's the motivation you need Bob Time for the cook to inspire you ha ha ha ha Paul

Don't worry about stuff falling in the motor, thats what the oil filter is for 😁😁 You Im pulling.yah leg and been silly The older we get the harder it is to get motivated, especially when hot, doesn't get cold here But just turn the T.V. off and start seems to work, I think working for myself most of my life I have had to go out and do as no one else is here to do it Because I care I have a helper for you A different Mrs Mack than normal ha ha ha Paul

No thanks for that. I think I heard somebody mention that in a previous post I will definitely check that. I can’t figure out why there wouldn’t be a pointer on it. Not sure if I motor manual mentions that or not but I didn’t completely comb thru it I do recall it mentioning the flywheel I’ll crawl under there in the morning and take a look

Boy..does that sound familiar. Plus i'm into my fourth year of "covid long haul". Some people say"no such thing- I say bullshit. It just effects people in different ways. As for me, lack of strength, tiredness, brain fog.."where is that XX?"..right where I just looked five minutes ago! Last year I started bitching to my PC doc about how this was dragging on. He looks at me and says..."But you are 80 years old"! I said yeah and two years ago I was 78 and I was doing stuff a lot of 58 year olds could not do. Case in point I was having troubling starting my Stihl 036 saw. finally I'm searching on line and find some gal who works on saws..subject was hard starting..and she says..." now you guys who have these big Stihl and Husky saws, it takes a lot of snap to start these""🤔I ended swapping it to my son for his smaller saw.

Bob. I am somewhat in the same position.. After retirement my motivation level went way down.. After them morning news I like to check my emails and truck sites, THEN I have to force my self to get off the computer and do something.

My 2 cents on the hinge arrangements. In my efforts to bring my L cab back, I found about eight different hinge arrangements for the doors. Most had, and early production, two hinges and no vent window. About '48 (might be earlier) they added the vent window. X versions and late production (B73,75,77, C600) had the three hinge arrangement. LM's and off road versions had four or more hinges. Spacing of the hinges can vary even more, but this is usually only on the very heavy off road versions. LT's had two hinges. If it has three, it's usually a cab swap or replacement late production cab. On the lock side of the door there are two dovetails and the lock centered in between. The jamb side has the female receivers to support the door when closed. Lock and inside door handle arrangements are numerous over the production run. I attached pictures of the NOS LJX driver's door I located and used on my B73. Very early door with the single window and three hinge arrangement. It only needed one modification to accept the vent window setup and that was removing the forward glass channel. I'll also say take all of that with a grain of salt. The factory did a lot of stuff to satisfy it's customer's, so custom or one-off versions are always possible. Variations on the production line are out there.

Very cool truck. Definitely Looks like it was set up for a heavy spec. Those are older mack rear axles with newer style top load differentials. Never knew you could interchange them. If the stamped ratio is correct, that's a 7.00 ratio. You can check by lifting the rear up rotate drive shaft and count how many times the shaft turns to get the wheel to do 1 full rotation. Obviously all those aftermarket air assist steering and filter housings etc are add ons. It definitely has character and somebody enjoyed improving it thru the years.

It would be a Robert Bosch pump of that era. The easiest way to tell is where you screw your injector line on. The Robert Bosch pump has a extremely fine spline barrel nut that takes a special socket to remove the barrel and replace pump washers. The American Bosch pump was way more low profile where the injector lines screwed on. The fine tuning of the pumps were not done at the dealerships. This was a pump shop type of repair/adjustment. However like some people said I remember removing the top cover marking the position of the sliding rail with a punch and moving it forward and test driving. I’ll see if I have any information on it in my old manuals at work

I think the chimp has more brains (and ability) than some of the guys in trucks now.