Ahubbard Posted February 11, 2013 Share Posted February 11, 2013 (edited) Dad just bought a 96 rd688s and I assumed it was going to be a v-mac ii with the econovance and all that jazz. When he got it home I see it is fully mechanical (with a pushrod from pedal to pump). Was this an option to get in 96 or is this motor put into the truck sometime along the way? I thought they were all electronic by that time. VIN is 1M2P267C4VM032876 if that is any help. Thank Youedit- maybe a 1997 i will check Edited February 11, 2013 by HubMackDM Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/ Share on other sites More sharing options...
Frmconcrete09 Posted February 11, 2013 Share Posted February 11, 2013 The first electronic engines in our rds start in 99 , the older ones even the 98 has a mechanical engine ... I like them better also 1 Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163720 Share on other sites More sharing options...
Ahubbard Posted February 11, 2013 Author Share Posted February 11, 2013 Okay thanks. My 99 has the etech. Find myself sometimes wishing it was the old mechanical style though. Its almost like that computer gives up sometimes on a hard pull.... I think he should be happy with this motor. Also while I am posting here what's the difference between a 688 and 690. I see there is a decoder for vin and model numbers on wiki but the model number decoder seems to lack how to decode an RD? I am just curious thank you Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163722 Share on other sites More sharing options...
Frmconcrete09 Posted February 11, 2013 Share Posted February 11, 2013 Here's what I came up with ... Lolhttp://www.bigmacktrucks.com/index.php?/topic/1760-rd688-vs-rd690/The two dm's in my avatar one a 96 the other a 99 , are what I drive at work, I would rather drive the 96 with the mech engine ,just seems you can feel the power more with the mechanical engine ... Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163725 Share on other sites More sharing options...
2stacksuperdog Posted February 11, 2013 Share Posted February 11, 2013 All the trucks I have seen after '94 have the wire going into the injection pump. Quote Matt Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163727 Share on other sites More sharing options...
Ahubbard Posted February 11, 2013 Author Share Posted February 11, 2013 Here's what I came up with ... Lolhttp://www.bigmacktrucks.com/index.php?/topic/1760-rd688-vs-rd690/The two dm's in my avatar one a 96 the other a 99 , are what I drive at work, I would rather drive the 96 with the mech engine ,just seems you can feel the power more with the mechanical engine ...Thanks again. Your dm's are sharp looking. I spent my first 10 years in a 1986 dm 285 with a 6 speed. Kinda will always have that warm fuzzy spot in my heart for an offset cab.All the trucks I have seen after '94 have the wire going into the injection pump.Same thing I was thinking, when dad said mechanical I did not believe him until I saw for myself. Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163732 Share on other sites More sharing options...
Bigdogtrucker Posted February 11, 2013 Share Posted February 11, 2013 My buddy bought one of the last mechanical RD's in "98,SO much better than the electronic engines from the late "90's early "00's. Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163734 Share on other sites More sharing options...
Ahubbard Posted February 12, 2013 Author Share Posted February 12, 2013 Told myself that if i ever have trouble with that 99 motor I will swap it out for mechanical. They are probably harder to come by now i would assume. Plus I dont know how that works with emmissions and all that. But I like to picture her all mechanical, puffing a bit of black on the shifts. Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163742 Share on other sites More sharing options...
rsb502 Posted February 12, 2013 Share Posted February 12, 2013 You could get the mechanical E7 or the VMAC E7 from 93 to 98 then they went to all ETECH in 99 I believe, I had a 93 VMAC CH, a 95 Mechanical E7 RD, 98 Mechanical E7 RD, 99 ETECH RD, 2000 ETECH RD, 2004 ASET Granite, 2006 ASET Granite, then the E9 trucks of course but those are Mechanical up to the last few with the Bosch VMAC pumps and they were few and far between here, more in AU. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163788 Share on other sites More sharing options...
dds92780 Posted February 12, 2013 Share Posted February 12, 2013 Ryan, did you notice a difference in fuel economy on the mechanical vs the computerized? Quote Slow and Steady Wins the Race! Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163911 Share on other sites More sharing options...
bts-4120 Posted February 12, 2013 Share Posted February 12, 2013 a rd 690 would have a 300 maxidyne and 5,6,7 or 8 speed trans. a 688 would be 350 or 400 ect. with a fuller or mack trans. 9, 10, 13 speeds 8ll ect. Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163967 Share on other sites More sharing options...
2stacksuperdog Posted February 12, 2013 Share Posted February 12, 2013 a rd 690 would have a 300 maxidyne and 5,6,7 or 8 speed trans. a 688 would be 350 or 400 ect. with a fuller or mack trans. 9, 10, 13 speeds 8ll ect.Ours is a RD-690 and it has a 350, 8LL Quote Matt Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163977 Share on other sites More sharing options...
rsb502 Posted February 12, 2013 Share Posted February 12, 2013 I know those numbers (688,690,etc.) are supposed to hold true but I have seen a bunch of RD's that were mixed around, I figured it changed when they got into the newer trucks.Dds, most were triaxle dumps so fuel mileage didn't mean as much, seems the vmac 400 CH is doing good, its still running stock and averages 6.8 pulling a dump trailer, the ETECH should get better mileage if you really ponder it being unit pumps instead of an inline pump/nozzle setup but I don't really know. Quote "Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin"If your gonna be STUPID, you gotta be TOUGH" "You cant always get what you want, but if you try sometimes you get what you need" Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-163992 Share on other sites More sharing options...
bts-4120 Posted February 14, 2013 Share Posted February 14, 2013 Ours is a RD-690 and it has a 350, 8LLgood chance it didn't leave the factory like thatetech is supose to get better milage than the old bosch pump, but I really can't say it does 427 avg 6.8 to 7.2, but I have had manual e7's do the same numbers Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-164409 Share on other sites More sharing options...
2stacksuperdog Posted February 14, 2013 Share Posted February 14, 2013 good chance it didn't leave the factory like thatWe bought it stock from the dealer brand new. Quote Matt Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-164411 Share on other sites More sharing options...
Lmackattack Posted February 15, 2013 Share Posted February 15, 2013 The mechanical will pull better easy to maintain. Electronic better on fuel. I would take a mechanical all day long. Quote Link to comment https://www.bigmacktrucks.com/topic/29904-96-rd688s-mechanical-motor/#findComment-164438 Share on other sites More sharing options...
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