hard cider Posted November 4, 2013 Share Posted November 4, 2013 helloI am hoping someone can give a little help with a Mack I am looking to buy.The truck is a 1984 half cab log boom truck with the 8th vin is a Yfirst, I need help identifying the engine, what is it?Second, maybe a little insight on it's problem: the owner said it was driving fine and then started missing and stumbling. Had a mechanic come out who took off the valve covers and told him it was the cam.Did this engine have a problem with camshafts? Or is there another related issue common?Thanks in advance for any input Quote Link to comment Share on other sites More sharing options...
Doug Maney Posted November 4, 2013 Share Posted November 4, 2013 The Y is the weight class. You need the letter and 3 numbers prior to the Y. Quote Interested in Old Trucks? Check out: www.antiquetruckclubofamerica.org Link to comment Share on other sites More sharing options...
2stacksuperdog Posted November 4, 2013 Share Posted November 4, 2013 1 Quote Matt Link to comment Share on other sites More sharing options...
hard cider Posted November 4, 2013 Author Share Posted November 4, 2013 heh heh I will get some and post them since they are so important......why?The Y is the weight class. You need the letter and 3 numbers prior to the Y.ok I will get the rest of the VINI thought the digits would be the same as regular vehicles where the 8th is the engine codeit will be a few days before I can get them so hopefully you will still reply then. thanks Quote Link to comment Share on other sites More sharing options...
kscarbel Posted November 4, 2013 Share Posted November 4, 2013 helloI am hoping someone can give a little help with a Mack I am looking to buy.The truck is a 1984 half cab log boom truck with the 8th vin is a Yfirst, I need help identifying the engine, what is it?Second, maybe a little insight on it's problem: the owner said it was driving fine and then started missing and stumbling. Had a mechanic come out who took off the valve covers and told him it was the cam.Did this engine have a problem with camshafts? Or is there another related issue common?Thanks in advance for any input1984? The only "half cab" Mack produced was the HMM, from 1973 thru 1979. Located on the driver's door, what was the model number on the vehicle identification plate? Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 4, 2013 Author Share Posted November 4, 2013 kscarbelI will get all the other info for ya'll in a few days.It did say 1984 in the door tag, and i thought I was getting the engine with the 8thit is a half cab... I can say that for sure, but the rest will have to wait a few daysthanks for the reply Quote Link to comment Share on other sites More sharing options...
terry Posted November 5, 2013 Share Posted November 5, 2013 Some people call the DM and the U model half cabs. Quote Link to comment Share on other sites More sharing options...
Maddog13407 Posted November 5, 2013 Share Posted November 5, 2013 any older Mack engine could have a bad cam, could also be worn valve guides. have seen older 237's and 300's sound like they are skipping or the jake is stuck on from excessive Jake brake use and worn valve guides. Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 5, 2013 Author Share Posted November 5, 2013 any older Mack engine could have a bad cam, could also be worn valve guides. have seen older 237's and 300's sound like they are skipping or the jake is stuck on from excessive Jake brake use and worn valve guides.I was told by the driver that it was a sudden problem. Ran fine, going down the road, and somewhere on the way back it suddenly started missing Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 21, 2013 Author Share Posted November 21, 2013 okay guys,I have the vin and modeli have picturesas well in a few daysmodel: U686STV.I.N. : 1m2w133y0fa009824anyone know what I am dealing with for the engine? Quote Link to comment Share on other sites More sharing options...
blackdog2 Posted November 21, 2013 Share Posted November 21, 2013 Its 285 up 300 hp does it have a tip turbine or inter cooler it could be higher hp. Quote Ed Link to comment Share on other sites More sharing options...
hard cider Posted November 21, 2013 Author Share Posted November 21, 2013 I will be able to tell you as soon as the pictures come, they took a couple from under hood, so I will post them Quote Link to comment Share on other sites More sharing options...
220cummins Posted November 21, 2013 Share Posted November 21, 2013 pictures would be the best. you can't really tell from the vin all the time, transplants happen often Quote Link to comment Share on other sites More sharing options...
2stacksuperdog Posted November 21, 2013 Share Posted November 21, 2013 U686 means a 285 or 300 but like said there might have been a transplant at one time. Not a halfcab either. Offset cab, but still a full cab 1 Quote Matt Link to comment Share on other sites More sharing options...
hard cider Posted November 21, 2013 Author Share Posted November 21, 2013 ok thanks guys, I'll get the pics posted asap. also good to know about the halfcab, never knew there was a difference in the offset vs half Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 ok, got some photos Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 more 1 Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 more 1 Quote Link to comment Share on other sites More sharing options...
2stacksuperdog Posted November 22, 2013 Share Posted November 22, 2013 looks like 237. No tip turbine, and no air cooler in front of motor. Wait till Vinny sees this.... Quote Matt Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 my best guess is that it is air to air intercooled, wonder if the hp is 300?A friend looked up the vin at the mackshack and it should be the E6 300 2V engine with 5sp and 4.17 rearsane idea about the miss?he also mentioned this might be the engine which the faces of the lifters fell off and wiped the camalso maybe the mack eng brake stuck. can you tell from the pics if it has a brake at all ? I don't see any wiresthanks for all your advice Quote Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 in the first photo, what is the big pipe in the foreground?looks like a boost tube to me? Quote Link to comment Share on other sites More sharing options...
umodelnut Posted November 22, 2013 Share Posted November 22, 2013 Oh boy im a U model nut. Nice U! Where are you from? And the truck is a U686, the 86 in the serial number means it had a 300 from the factory. So you may have the tip turbine missing. Quote Link to comment Share on other sites More sharing options...
2stacksuperdog Posted November 22, 2013 Share Posted November 22, 2013 wait i just noticed theres a pipe going to in front of the radiator so it must be air to air. I was pretty sure they used tip turbines in DMs and Us until they made the hood longer. 1 Quote Matt Link to comment Share on other sites More sharing options...
j hancock Posted November 22, 2013 Share Posted November 22, 2013 Looks like the air pipe comes from the radiator area and then goes into the intake manifold.How long has the motor been open? The top of the motor looks plenty dry with no residual oil on anything. Looks like a lot of crap has gone into the head.Plus, there is a tree growing next to it. Quote JimIt doesn't cost anything to pay attention. Link to comment Share on other sites More sharing options...
hard cider Posted November 22, 2013 Author Share Posted November 22, 2013 It has been sitting like this since 2005 with the hood shut thoughI don't think any water got in it but if it did it went straight down and can be drainedso you are thinking maybe it has had the intercooler added?What exactly is the tip turbine? Quote Link to comment Share on other sites More sharing options...
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