rustexpert Posted June 5, 2013 Share Posted June 5, 2013 Has any body got any suggestions on a diesel conversion engine for a Mack NM6? There is one going around with a Scania. I don't know about modern motors but I believe the Mack has a standard bell housing arrangement/design and a straight fit is not too much to hope for. Can anybody who has done such a conversion advise? Mack petrol is 180 h.p. should I be looking for 200 h.p. or would less be o.k.? Quote Link to comment Share on other sites More sharing options...
paulbrook Posted June 6, 2013 Share Posted June 6, 2013 Has any body got any suggestions on a diesel conversion engine for a Mack NM6? There is one going around with a Scania. I don't know about modern motors but I believe the Mack has a standard bell housing arrangement/design and a straight fit is not too much to hope for. Can anybody who has done such a conversion advise? Mack petrol is 180 h.p. should I be looking for 200 h.p. or would less be o.k.? Lots of options I suspect. The bellhousings and clutch plates are indeed standard SAE, but that is actually a range of standard sizes rather than a single one. Having put a Mack engine in a Mack I can say that it is not as easy as it should be but do-able all the same. It might even be worth considering a whole engine/gearbox swap (although I cannot remember the transfer box set up on a NM) I bet a Leyland 680 would go in though. As for HP about the same is best. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted June 7, 2013 Share Posted June 7, 2013 I know someone with a NM6 which has a 6-71 Detroit in it, and it performs well off road as well as on. Quote Link to comment Share on other sites More sharing options...
Brooky Posted June 7, 2013 Share Posted June 7, 2013 Yes there is one with a Scania engine, it was fairly straightforward and performs well PM me and I will let you have details of the owner Quote Link to comment Share on other sites More sharing options...
General Lee Posted June 7, 2013 Share Posted June 7, 2013 I know someone with a NM6 which has a 6-71 Detroit in it, and it performs well off road as well as on. Not this one thats for sale? http://www.gumtree.com.au/s-ad/st-clair/heavy-farming-agriculture-equipment/mack-nm6-1944-6x6/1020628282 Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted June 7, 2013 Share Posted June 7, 2013 Not this one thats for sale?http://www.gumtree.com.au/s-ad/st-clair/heavy-farming-agriculture-equipment/mack-nm6-1944-6x6/1020628282 Note the 'would suit house mover, farmer, logger....' :n00b: Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted June 7, 2013 Share Posted June 7, 2013 Not this one thats for sale?http://www.gumtree.com.au/s-ad/st-clair/heavy-farming-agriculture-equipment/mack-nm6-1944-6x6/1020628282 Yes, that's the one. Mark has taken it to Corowa a number of times Quote Link to comment Share on other sites More sharing options...
cosrec Posted June 7, 2013 Share Posted June 7, 2013 (edited) Like said any engine would be doable. Scania engine would be my choice though as they were fairly high reving i did a couple conversions to Big Ben trucks and kept same road speed. Turbos mounted mid way down not on top so no bonnet clearance problems. Only snag they are bad to find (Rough fourwheeler bald tyres rotton cab delivered to docks £4 to 5K so nobody seems to want to take engines out anymore) Thats the problem now with all the older engines if in a truck and start they are fetching good money for export. Edited June 7, 2013 by cosrec Quote Link to comment Share on other sites More sharing options...
paulbrook Posted June 7, 2013 Share Posted June 7, 2013 This is just a general observation and absolutley not a comment about the specific request here - as far as I am concerned owners are entirely at liberty to do what the heck they like with their own possessions and long may that remain so. But unless the gas motor is completely kaput I wonder what the advantages are of fitting a diesel? The obvious (or is it?) answer is MPG, but is it? With more expensive fuel and the cost of the conversion as well as the originality question I am unsure what I would say to anyone who came along and said that they wanted a diesel in their old truck, especially one that only does a relatively low mileage. I have, though, often wondered about offering gas conversions - maybe I should look again. So what do folks think? Just remember though that this is not any sort of comment on what owners want to do - that as I say is definitely up to them! PS I am a 100% certifiable petrol head..................and I mean petrol!! Quote Link to comment Share on other sites More sharing options...
cosrec Posted June 7, 2013 Share Posted June 7, 2013 This is just a general observation and absolutley not a comment about the specific request here - as far as I am concerned owners are entirely at liberty to do what the heck they like with their own possessions and long may that remain so. But unless the gas motor is completely kaput I wonder what the advantages are of fitting a diesel? The obvious (or is it?) answer is MPG, but is it? With more expensive fuel and the cost of the conversion as well as the originality question I am unsure what I would say to anyone who came along and said that they wanted a diesel in their old truck, especially one that only does a relatively low mileage. I have, though, often wondered about offering gas conversions - maybe I should look again. So what do folks think? Just remember though that this is not any sort of comment on what owners want to do - that as I say is definitely up to them! PS I am a 100% certifiable petrol head..................and I mean petrol!! i am 100 per cent behind you on that one if its there and running whats the point in ripping it out and putting 3.5k of diesel conversion by the time u add in labour to end up saving £200 over a season maybe Quote Link to comment Share on other sites More sharing options...
rustexpert Posted June 11, 2013 Author Share Posted June 11, 2013 Thanks for the interest. Apologies for not commenting further sooner. Situation is I would sell the truck, you'd think a basically unmolested WW2 prime mover which has been dry stored for 20 years but never the less needs general resto/cab sorting would be quite sought after but only offers/interest is from t?@@'#s who want it for less than scrap money and timewasters who don't even do that. There is basically nothing wrong with the petrol engine but perhaps some of the posters don't realise the insatiable thirst of a 11.6 mack. To illustrate if you go to start it up armed with a red gallon can; drop the pipe into the can pump the juice up to the carb and fire her up, get her running on the choke; wow what music man! Warming up now running with no choke: NICE! Sputter, cough. That's it folks. So this means you'd be using 10 gallons to go to a local rally. My source of contam petrol isn't that reliable especially now everybody and their dog is after it too. That which I get is used in other ways so is not to spare anyway. As I am an engineer a diesel conversion would "cost" around £1500 and I would hope to return 10 m.p.g. and the resulting truck after a not to exhaustive make over and a few events; would be a bit more saleable. You might say that I just can't afford to run this truck end of but I think money spent on the conversion wouldn't be like chucking it on the big bonfire and it's better to convert something than cut it up. Quote Link to comment Share on other sites More sharing options...
paulbrook Posted June 11, 2013 Share Posted June 11, 2013 I do - realise the thirst that is......... Would it really do 10 MPG with a diesel? Even my (modern) Iveco recovery truck only just about into double figures when it is working a little. I know what you mean about cost though. Even my much more modest toys can slurp it a bit. I put a thermoswine gas engine in a chaindrive Mack a while ago and completely recognise the can scenario. That said I am doing an Antar (diesel) at the moment that has a fetish for whole jerrycans of diesel at a time for little forward/backwards progress Just out of interest what did you have it advertised for? Quote Link to comment Share on other sites More sharing options...
rustexpert Posted June 11, 2013 Author Share Posted June 11, 2013 I find modern heavy vehicles slurp the diesel a bit enthusiastically too. My engineering education leads me to think that this is solely due to the higher travelling speeds involved and associated generally heavier demands for acceleration. If modern 40 ton lorries were running around at 20m.p.h. with Gardner 6LX's they would be a good deal more economical on fuel but I don't think that would be a step forward really! I would still hope that a converted heavy like Mack NM6 should return 10 m.p.g. running about light at 30 - 35 m.p.h. Would anyone who has done such a conversion comment please? Quote Link to comment Share on other sites More sharing options...
gritineye Posted June 11, 2013 Share Posted June 11, 2013 (edited) I find modern heavy vehicles slurp the diesel a bit enthusiastically too. My engineering education leads me to think that this is solely due to the higher travelling speeds involved and associated generally heavier demands for acceleration. If modern 40 ton lorries were running around at 20m.p.h. with Gardner 6LX's they would be a good deal more economical on fuel but I don't think that would be a step forward really! I would still hope that a converted heavy like Mack NM6 should return 10 m.p.g. running about light at 30 - 35 m.p.h. Would anyone who has done such a conversion comment please? My Scammell Explorer fitted with a 290hp Cummins L10 diesel is doing at least 10 mpg by my rough reckoning, I haven't done a brim to brim test as this would take 148 galls...:sweat: Due to the low gearing and excess power, only a very light foot is ever needed... A Diesel conversion does not always have to be expensive, buying a donor vehicle, keeping the bits you need and parting out the rest of it, selling your old engine and any spares you have can keep costs down. If you do the work yourself then you are quids in, after doing mine I was out of pocket around £120 ish..:-D Edited June 11, 2013 by gritineye Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted June 19, 2013 Share Posted June 19, 2013 I find modern heavy vehicles slurp the diesel a bit enthusiastically too. My engineering education leads me to think that this is solely due to the higher travelling speeds involved and associated generally heavier demands for acceleration. If modern 40 ton lorries were running around at 20m.p.h. with Gardner 6LX's they would be a good deal more economical on fuel but I don't think that would be a step forward really! I would still hope that a converted heavy like Mack NM6 should return 10 m.p.g. running about light at 30 - 35 m.p.h. Would anyone who has done such a conversion comment please? Hi, Having completed 3 diesel conversions to Ward laFrances (14 tonnes) and being in the final stages of the 4th I can categorically state that it is perfectly viable to do this kind of work, and it can change a previously underpowered, unreliable and thirsty truck into something that will start every time and will return 13mpg (calculated) all day at 35 - 40mph. My conversions will pay for themselves in fuel savings in only 3 show seasons. I would rather see an originally petrol vehicle fitted with a diesel engine than see it relegated to the shed or broken up because it's too expensive to run. - MG Quote Link to comment Share on other sites More sharing options...
Dave Posted June 21, 2013 Share Posted June 21, 2013 We all wish our vehicles would do a bit more MPG But if they did every one would have a big truck or there would be more blue subaru`s with gold wheels My Diamond T returns 5mpg at best, i love driving the truck so i put up with the consumption. Quote Link to comment Share on other sites More sharing options...
kw573 Posted July 12, 2013 Share Posted July 12, 2013 Hi all, I am building a Diamond T 969 which I plan to rally for decades. For the type of person I am, feeding that beast at 3-4mpg is prohibitive. I really feel the cash-out-of-pocket each week but am more comfortable with bigger investments. Also I am very much a do it myself man. So, the 969 will be getting a Cummins 6bt which I hope will return at least 10mpg. The whole conversion should cost around AU$3000-3500 (app.USD3000). As I hope to do many thousands of kms, I expect to be well ahead financially before real long. I also have a Kenworth M1A1 that will eventually get a Cummins (thanks for the inspiration, Mike!), as the current Leyland 600 is almost undriveable due to low power and revs. It suits me. Everyone is different. Have a nice day. Sam. Quote Link to comment Share on other sites More sharing options...
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