Mack B Mike

Hey All, Well finally had some time to work on the Mack, got the 673 all back together. Sleeve pistons, rings, bearings, gaskets paint etc. Still waiting for ex manifold gaskets but couldnt wait to hear it run so bolted manifold on n hit the air valve two tanks of air were used to get it running, fuel system was primed w/hand pump, 50 psi oil pressure @ cold idle. 673 first run 07-11.wmv

Hey All, Just got the 673 for my B61 back together, new sleeve, pistons, rings, bearings, etc. down to the last thing before i can fire it up, the oil filter. It has the luber-finer bypass filter as typical, I cannot remember which port on the block is supply to the filer and which one is return from the filter. If anyone can help me out it would be appreciated Thx. Mike

Name: Reo M35 (1957) Date Added: 07 November 2008 - 04:25 PM Owner: Mack B Mike Short Description: The Deuce View Vehicle

Name: Mack B61LT (1958) Date Added: 07 November 2008 - 03:18 PM Owner: Mack B Mike Short Description: None Provided View Vehicle

Hey Jase You can get Felpro head gaskets, the number is 2813 i think, i got them for mine when i overhauled my 673 due to a cracked sleeve, pistons,rings and bearings and gaskets are avliable from Mack. i can get you more info if you would like Mike

Hey All, actually it was suprisingly round within .0015 - .002, checked top, middle and bottom of the bore 3,6,9 and 12 o'clock at all the positions after cleaning, the #2 cylinder was the only one that was bored .030 over, i think whoever overhauled the engine prior to me stuck the wrong sleeve in, thats the only think i can think of

update on the 673 cleaned and measured block today and found that the # 2 cylinder was bored ~ .030 over, assuming std bore being 5.0945 compared to the measurement of the #2 cyl being 5.1240, when this hole was bored whoever did the engine work put a std size sleeve in, they did not put a oversized sleeve in it which is most likely why it cracked, maximum clearance between block and sleeve should be .002 to achieve sufficient heat transfer and support, i think .030 is a bit out of tolerance. new correct size sleeve is on its way. Mike

Hey All, got a question about the 673, is there any major differences between the standard END673 and the END673C or the END673E, i can only see that the "C" and "E" have different heads 20 stud heads verses 18 studs for the END673 from the books i have The reason why im asking is that a gentleman in my area owned/operated a construction/fuel company years back and had about 20 B models on the road, now after selling/retiring he was kind enough to give me a set of new sleeves and good pistons and new rings/gaskets to overhaul my engine for my B for a few cases of beer...yes a few cases of beer!! i couldnt turn the deal down anyway there is one small difference in the new sleeves compared to the ones that are in my block, the ones i have when installed sit level with the deck until the ring that contacts the head, the new ones sit level with the deck at first but there is a small recess cut in prior to reaching the ring that contacts the head and seals the combustion chamber, was this change in the sleeve done to improve head gasket sealing? the difference between the two of them is almost not even noticable but they are different. The new sleeves that i have are pictured in the mack book for 673C and E, i dont have a diagram of the sleeves should look like for the regular 673, but he said that they would work fine not sure if i should take the chance or look further into the sleeve difference Mike

Hey all, pulled engine apart today found more than one issue, ran engine with the fenders off to get a better look before dissassembly, found the rear head gasket leaking blowing oil bubbles out where the head meets the block, pulled intake, ex, and heads, found that the #2 cylinder sleeve had a large crack almost the whole length of the sleeve, pulled piston and found a large chunk below the top compression ring was missing, also found that there are two different style heads on the engine the front head had 5/8" corner studs and the rear head has 3/4" corner studs. On a positive note, found that the bottom end was gone over some what recently the bearings look great, no scratches or copper showing through the babbet

Hey Mark, Yeah i got one off of a Freightliner temporarily until I was able to get the correct B model one and brackets. Matt Pfahl brought me a B model tank to Gerharts show in 08, didnt get to put it on yet though other troubles had come up, rear, engine etc... Thanks for checkin though. Mike

hey all, opened the drain plug in the pan after work today, no coolant present, oil came out, was hoping this was the issue, of course not, i did run the engine for a bit, to check the smoke out again, took a while its a whopping 16ºF up here, i did notice a billow of smoke on combustion strokes comming out of the oil fill cap in the valve cover not a steady stream and also noticed that the exhaust manifold was not as hot at #4 cylinder as the remainder of the cylinders im going to assume that this is the trouble one, i will open the injector lines at each cylinder to make sure that it is #4 as HK trucking had suggested as well, thanks everyone for the help and ideas Mike

hey all engine is a ENDL 673, im gonna check all the easier stuff prior to pulling it apart i dont feel that it would be a coolant issue because of the smell of the smoke, antifreeze has a distinct smell when it is heated and the smoke dont smell like that plus the oil is normal color if there was coolant in it, it would be circulated by the oil pump and make the oil look like a chocolate milkshake, but i will check all the ideas that everyone has offered, i also was reading about the head gaskets and if the head gasket is leaking at an oil galley the combustion pressure/exhaust could virtually get forced back down to the crankcase which would cause some blow by, but to the extent that this one does im going to assume the worst, the engine does have some oil seepage where the heads meet the block, thanks everyone for the imput, ill keep everyone updated with the progress, plus if i have to pull it apart it will force me to clean everything and paint it up nice before reassembly thanks all Mike

that was one of my thoughts actually thought one had cracked gonna pull the heads off next weekend and check it out thx Mike

I have JC Taylor for my trucks as well, combined about 160 bucks a year for the 57 REO M35 and the 58 B Model, they are located near Philly PA

thats a good idea, i have done somewhat the same thing on small engine valve seats that would pop out, it worked great, ill have to remember that for next time, if there is one, so far the JB weld held it in without a problem thx Mike

Hey All, more troubles again, now i got the issues worked out with the rear, which is working perfect something else had to happen, took the truck out for a ride a few days ago after about 20 miles i was going up a relatively large hill, engine almost at governed speed ~2kRPM the cab started to fill up with smoke not exhaust though, i nursed it back to my garage with a large cloud of smoke following me found smoke comming out of every possible opening to the crankcase; breather, oil fill in the valve cover and the road draft tube, small amount of oil at the breather filter and none at the draft tube, this engine did have a small amout of blowby since i have owned it but this is just insane with the oil cap off engine running the smoke would just billow out, engine temp ~ 160ºF oil pressure was 20 lbs@ idle and ~60@ governed speed hot, the engine starts in ~ 5 seconds of cranking when air temp is ~25º at 1/4 throttle no ether and almost the instant i hit the air valve when hot, i let the truck sit for a few hrs and ran it again, about 5 miles down the road started doing it again, let me know if yall got any ideas, any help would be appreciated thx Mike

Hey Rustydog, i have an extra air starter but it is a Start Aire starter, i put the IR starter that i had on my truck, the starter does work it started the truck fine, but it does need a drive gear, both starters work on the 673 if you have or could find a starting gear(bendix assembly) from an IR starter it will work on the "Start Aire" starter, Mike

of course as things go it could not have been a quick fix to replace the bearing/race. I found that the race for the inner pinion bearing had spun in the housing and also the inner pinion bearing spun and welded itself to the pinion. the removel of the old bearing was interesting had to use the hot wrench and carefully cut it off found some small gouges and high spots on the pinion, cleaned it up in the lathe and installed the new bearing all good there, now the pinion housing, the new race just dropped into the housing, this was not good so i cut down all the rough spots in the housing so the race would sit level there was some side to side play ~.0005 of an inch, two choices either bore the housing and install a bushing around the race to be able to press fit the parts or JB weld the new race in, i took the easier of the two... JB welded the race in, assembled pinioin/bearings to center the race and allowed to dry, installed pinion assembly this morning, filled with GO-J and were back on the road.... see pic of pinion housing where the race spun

Hey All, pulled center section apart today i found that it was the inner pinion bearing that failed, the cage that holds the roller bearings in place got shredded somehow and a few of the rollers got out, it appears that 4 were missing and were getting chewed up, found two rollers and alot of metal shavings in the bottom of the carrier, fortuneatly all the gears are intact with the exception of one that has a small chip out of it hopefully i can just replace the bearings/races and get back on the road Mike