staxx Posted August 17, 2012 Share Posted August 17, 2012 What years did they build the R686ST with a Hood scoop, this would b a road tractor daycab Square fuel tanks. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/ Share on other sites More sharing options...
Lmackattack Posted August 17, 2012 Share Posted August 17, 2012 Late 70's early80s...with 285 tip turbine Mack diesels. The went away with the introduction of the dual outlet air cleaner. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133724 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 anyone have an underhood picture of the ductwork for the hood scoop? lookin to see where it bolts to. im assuming on the radiator? i have seen the hood scoops twards the front and twards the back of the hood. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133726 Share on other sites More sharing options...
staxx Posted August 17, 2012 Author Share Posted August 17, 2012 This is the first time I have seen one with a hood scoop Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133727 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 neighbor of ours had two 70's R600's one had a 237 and 10 speed and the other had the hood scoop, a 300+ with hood scoop and a 10 speed and air starter. i remember that truck growin up. they both got beat to shit and never taken care of. eventually the one with the 300+ got sold when they went out of business and the engine got put in a DM with the cheap dual inlet air cleaner and not the badass hood scoop. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133732 Share on other sites More sharing options...
staxx Posted August 17, 2012 Author Share Posted August 17, 2012 It doesnt have any duc work left. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133734 Share on other sites More sharing options...
Lmackattack Posted August 17, 2012 Share Posted August 17, 2012 First truck I drove was a rs700l with a 285 and a hood scoop. If I recall there was a big can with a filter in it that was sitting to the side of the turbine. When the hood was shut the filter would draw air in from the scoop. It was in my opinion a cheep way to get the result and cluttered the engine. The scoop did look cool tho...rare to see them these days... Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133735 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 was a white R model with a blue frame and an exhaust unloader on the stack i assume for offloadin concrete? at Macungie last year. cant find a pic of it now tho. wish i had an underhood pic as i wanna put a hood scoop on the R model im buildin with a 300+. i have the scoop and ductwork, just dunno where to bolt it as my truck is a 66 and the truck it came off of i assume was a 78 or so , so the radiator was bigger. mine has the smaller b model sized radiator so id like a pic so i ana make a mount for the under hood filter and ductwork. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133738 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 found it. but not a pic of the driverside with the stack concrete unloader. i assume it was used for that, thats what Mr Fetterly said Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133741 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 forgot to mention this truck is a 1974 Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133742 Share on other sites More sharing options...
Lmackattack Posted August 17, 2012 Share Posted August 17, 2012 Someone posted pics of a underhood shot years back.. Can't recall what thread it was on tho.. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133743 Share on other sites More sharing options...
57 bcr Posted August 17, 2012 Share Posted August 17, 2012 The scoops started showing up around '73-'74 when the first 300 Series Maxidynes came out.I want to say it was '77 or so when they combined the 2 filters into the 2 -stage air cleaner (U.S. production). I had a '79 R612ST (Canadian production) that had the scoop for the tip-turbine filter.As they were using a single stage air cleaner yet,with an air-operated "foul weather" under hood intake valve to keep snow and rain out of the air cleaner(like the old cable-operated set-ups in the R's).I elimated the piping and that filter, for the 2-stage set-up.I have some pictures of the "engine room" that the previous owner had sent me.(showing the original set-up air cleaner)I will look for them.I see some guys are using a K & N style filter now for the tip turbine.It's not original,but it gets the job done! Quote IF YOU BOUGHT IT, A TRUCK BROUGHT IT..AND WHEN YOU'RE DONE WITH IT, A TRUCK WILL HAUL IT AWAY!!! Big John Trimble,WRVA Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133744 Share on other sites More sharing options...
staxx Posted August 17, 2012 Author Share Posted August 17, 2012 Heres the rest of the truck. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133748 Share on other sites More sharing options...
kscarbel Posted August 17, 2012 Share Posted August 17, 2012 For the record, the early "cool power" 300's with the hood scoop and tip turbine were the strongest running of all 300s. Just ask anyone that operated one. Interestingly, after the passing of the tip turbine in the US domestic market, they were still produced for export. I recall often seeing them at the Howard Sober yard (new truck forwarder) for delivery to South America. Those trucks were also ordered without heaters, leaving newfound space under the instrument panel. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133749 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 poor truck, would look better with the 300+ back under the hood and the hood back on. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133751 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 the RS612LST52368 i got my 300+ and 10 speed RR out of had the 2 stage air cleaner. i believe the truck was a 1980 and a western. had the ridge down the center of the hood like some of the late R700's had. somone hacked it off and made it a single axle with a pete rear end. the guy drove the whole truck to the junkyyard and got a whole $1800 for it.the cab was shot. we bought the engine and tranny out of it for a grand. come to find out it was a fresh rebuilt 300+. we put it in a 66 R600. had to make mounts for the transmission and use to old R600 radiator as the one out of the R612 was the long western radiator and had different mounts and spring hangers. i would like to put a single outlet air cleaner on it and a hood scoop as the big 2 stage air cleaner just doesnt look right on the cab to me. i like the looks of the old school small oil bath 1966 air cleaner but i assume the 300+ would suck the oil right out of the air cleaner pan so im up in the air about the hood scoop/air cleaner decision. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133753 Share on other sites More sharing options...
staxx Posted August 17, 2012 Author Share Posted August 17, 2012 Heres the engine that goes with it come out of a mixer Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133756 Share on other sites More sharing options...
Lmackattack Posted August 17, 2012 Share Posted August 17, 2012 Yea I wish I had the 300+ in my RS. those engines just loved to pull. On paper they had less TQ than a maxidyne but they out pulled them. 1400-1800 rpm shifting that turbo and turbine just kept screaming... Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133759 Share on other sites More sharing options...
umodelnut Posted August 17, 2012 Share Posted August 17, 2012 Up here the Lewis County NY Town Barn has 2 matching DM tandem dumps. (most likely sisters) I dont know about the other one, but one of the DMs was doing a job by my house and it had a hood scoop. Most likely a tip turbine then? I actually dont know where the other one went. Havent seen the hood scoop one in awhile now though. That red R model you posted staxx is awesome. Hope something gets done too it. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133796 Share on other sites More sharing options...
Popular Post MACKS Posted August 17, 2012 Popular Post Share Posted August 17, 2012 This was my 83 RD with the hood scoop,it had the 300+ with 12 speed,an awesome work truck... 5 Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133798 Share on other sites More sharing options...
staxx Posted August 17, 2012 Author Share Posted August 17, 2012 I will let you Know more on Sunday think i have a new project ...... Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133803 Share on other sites More sharing options...
Lmackattack Posted August 17, 2012 Share Posted August 17, 2012 ok here is a question while on topic of the tip turbines....Why was it that some 285's only had the air charge cooler and others had the air/water charge cooler? My truck is air only but have seen other 285s with the air and water set up?I thought that the 285 was air only and the 300+ was both air and water?what does it take to convert a 285 to a 300+ Is it as simple as a charge cooler and pump setting change? im putting in the 12 speed soon and have a water/air cooler. It would be cool to convert it over to a 300+ if its not much trouble. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133804 Share on other sites More sharing options...
umodelnut Posted August 17, 2012 Share Posted August 17, 2012 This was my 83 RD with the hood scoop,it had the 300+ with 12 speed,an awesome work truck...That is nice. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133808 Share on other sites More sharing options...
Maddog13407 Posted August 17, 2012 Share Posted August 17, 2012 boy is that a tough ass lookin RD with a hood scoop and the angled bumper. always liked the angled bumpers on the RD's and the Superdogs, just made them look tougher. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133839 Share on other sites More sharing options...
MACKS Posted August 17, 2012 Share Posted August 17, 2012 ok here is a question while on topic of the tip turbines....Why was it that some 285's only had the air charge cooler and others had the air/water charge cooler? My truck is air only but have seen other 285s with the air and water set up?I thought that the 285 was air only and the 300+ was both air and water?what does it take to convert a 285 to a 300+ Is it as simple as a charge cooler and pump setting change? im putting in the 12 speed soon and have a water/air cooler. It would be cool to convert it over to a 300+ if its not much trouble.I can't answer your question but my 300+ was air only no water,I was told the water setup was way more efficient at lowering air temps. Quote Link to comment https://www.bigmacktrucks.com/topic/26833-r686st-with-hood-scoop/#findComment-133840 Share on other sites More sharing options...
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