R Cubed Posted February 23, 2015 Share Posted February 23, 2015 I'm going to try the same I have done for my Halftrack with our GMC, using the Cummims engine and the GMC gearbox. It should fit straight in as my granddad put a Perkins P6 in his years ago and the Cummins is shorter than the Perkins engine. Im going to look into the header tank, there is obviously a lot more room under the Halftrack bonnet compared to the GMC. I dont see how you can get a Cummins 6BT in the engine bay of a GMC without cutting the firewall out, my cummins is only 3 inches back from the original rad just enough to get an electric fan in there and I have about 1 1/2 cylinders inside the cab :cool2: but good luck. Would love to see some pics of the p6 in the GMC ! Quote Link to comment Share on other sites More sharing options...
R Cubed Posted February 23, 2015 Share Posted February 23, 2015 Richard, Regular topping up is exactly my point. How often do you top your car up? Very rarely I'd imagine? Should be the same for a Cummins system, but only if you have a pressurised system with a header/expansion tank. Having a system with the potential to self-evacuate seems like a recipe for disaster to me... My old WLF was running the original rad and after a long journey there would be a stain of coolant running across the tops of both wings. At that time I hadn't done enough conversions to understand what the problem was. - MG I dont get the coolant constantly running out no matter how long the run in the truck is it always seems to go down by the same ammount just like the old engine use to I always top it up before every run so I know how much is in there. then before the next run I check it again and its about the same ammount. saves modding the rad and fitting another expansion tank. Quote Link to comment Share on other sites More sharing options...
Tony B Posted February 23, 2015 Share Posted February 23, 2015 I'd use an alternator fitted with a vacum pump. The only extra effort is to feed oil to the pump. I used a T pice from the oil pressure gauge switch then fed it back through the rocker shaft cover. Worked fine for many moons on an old IIa Landy fitted with a BMC disiel. One problem. The vacum the pump generated. The brakes became think stop and scrape yourself off the windscreen. Quote Link to comment Share on other sites More sharing options...
RMS Posted February 23, 2015 Share Posted February 23, 2015 (edited) Mike, any idea on where I can find a vacuum pump for this engine? something like this would work a treat http://www.ebay.co.uk/itm/VAUXHALL-ASTRA-G-CORSA-C-inc-VANS-1-7-TD-DTi-DIESEL-BRAND-NEW-ALTERNATOR-99-04-/281518693241?pt=LH_DefaultDomain_3&fits=Car+Make%3AVauxhall|Model%3AAstra&hash=item418bd25b79 I used a similar on my Bedford when i put the Nissan engine in, pulls plenty of vacuum for the Vacuum trailer brake actuator. Alternatively many modern cars use electric vacuum pumps http://www.ebay.co.uk/itm/Brand-new-electrical-12V-vacuum-brake-pump-/321650581243?pt=LH_DefaultDomain_3&hash=item4ae3de5efb Edited February 23, 2015 by RMS Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted February 24, 2015 Share Posted February 24, 2015 Richard, I recall seeing a P6 in a GMC a few years back and the vehicle had been modified to fit the engine. I don't recall if the bonnet and radiator had been moved forward or if the firewall had been moved back; I suspect the former as that's why it caught my eye and made me look/enquire. Vince Quote Link to comment Share on other sites More sharing options...
jamie meachin Posted February 24, 2015 Author Share Posted February 24, 2015 Richard, I'm using 24 volt start and 12 volt electrics. The fuel filter on the front at the top of the engine is something the bus company dose. I'm guessing lack of space in the engine bay? I will be moving it once I get it in the chassis. I can get you some pictures of the Perkins P6 engine in a GMC. Jamie Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted February 24, 2015 Share Posted February 24, 2015 Alternatively many modern cars use electric vacuum pumps http://www.ebay.co.uk/itm/Brand-new-electrical-12V-vacuum-brake-pump-/321650581243?pt=LH_DefaultDomain_3&hash=item4ae3de5efb Power the vacuum pump with a relay which is switched on with the brake switch. So, touch the brake pedal, vacuum pump is switched on and vacuum is available!!! Does anyone foresee a slight problem here?? Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted February 24, 2015 Share Posted February 24, 2015 Power the vacuum pump with a relay which is switched on with the brake switch.So, touch the brake pedal, vacuum pump is switched on and vacuum is available!!! Does anyone foresee a slight problem here?? I believe this is a common system in USA with brakes on those jumbo pickup trailers? But I'm not sure it is a system which is approved for use in UK? Maybe due to inherent delay in application? Though that may not be significant enough to cause an issue and can be eliminated by use of a small reservoir always maintained at vacuum. Can anyone enlighten us further? Also I'm sure only rad is pushed forward on P6 GMC conversion - bonnet remains same length. My dad used them, he also had one or more with a Gardner 4LK or LW - snails at best but would slog across wet fields for ever :-D (Sorry for thread hijack Jamie!). Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted February 24, 2015 Share Posted February 24, 2015 I believe this is a common system in USA with brakes on those jumbo pickup trailers? But I'm not sure it is a system which is approved for use in UK? Maybe due to inherent delay in application? Though that may not be significant enough to cause an issue and can be eliminated by use of a small reservoir always maintained at vacuum. Can anyone enlighten us further? Also I'm sure only rad is pushed forward on P6 GMC conversion - bonnet remains same length. My dad used them, he also had one or more with a Gardner 4LK or LW - snails at best but would slog across wet fields for ever :-D (Sorry for thread hijack Jamie!). The seller was suggesting only running the pump when the brakes are applied, there would be a huge delay while the pressure dropped, the equivalent of only running the compressor on an air braked vehicle when pressing the brake pedal with no air in the tanks. The vacuum pump would have to be connected with the keyswitch in the running position to provide a vacuum at all times when the vehicle was being driven. Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted February 24, 2015 Share Posted February 24, 2015 (edited) Any reason for not going either full 12v or full 24V? Normally the fuel filter on Darts is on the LH side of the head, on the underside of the inlet chamber and is integral to the head. This system works absolutely fine for up to 180hp engines. This location appears to be clear on your engine so I wonder why they used that front mounted jobby? It would be a very easy job to change yours to the more conventional spec. and would save you having to find anywhere else for a filter housing. FYI on higher-powered engines this location is not used and a separate filter assembly is bolted onto the side a bit further back using two of the inlet cover bolts. I presume the reason is that the higher powered engines require a greater fuel flow than the original design allowed for. - MG Richard, I'm using 24 volt start and 12 volt electrics. The fuel filter on the front at the top of the engine is something the bus company dose. I'm guessing lack of space in the engine bay? I will be moving it once I get it in the chassis. I can get you some pictures of the Perkins P6 engine in a GMC. Jamie Edited February 24, 2015 by TooTallMike Quote Link to comment Share on other sites More sharing options...
Zuffen Posted February 25, 2015 Share Posted February 25, 2015 We run an electric vacuum pump on our Lancia 037. The supercharger discharges into the throttle body so it's like a diesel, no vacuum to use. It runs with the ignition on and has a Hobbs switch so it only runs when needed. We have a small reservoir so a few quick brake applications won't run it out of vacuum. It's reliable, effective and quiet. We couldn't fit an alternator in with a vacuum pump as there just isn't enough room. Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted February 25, 2015 Share Posted February 25, 2015 . This location appears to be clear on your engine so I wonder why they used that front mounted jobby? - MG Mike, think of the layout in a Dart. When you open the bonnet (at the rear of the bus for those not familiar with busses), the front of the engine is staring at you. Having the filter on the front of the engine is probably to improve accessibility for servicing as you wont have to get underneath the vehicle to change the filter. Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted February 25, 2015 Share Posted February 25, 2015 (edited) Thanks Vince, That does make sense but it must have been a mod by the bus company, or a special order. - MG Mike, think of the layout in a Dart. When you open the bonnet (at the rear of the bus for those not familiar with busses), the front of the engine is staring at you. Having the filter on the front of the engine is probably to improve accessibility for servicing as you wont have to get underneath the vehicle to change the filter. Edited February 25, 2015 by TooTallMike deleting random spare words Quote Link to comment Share on other sites More sharing options...
datadawg Posted February 27, 2015 Share Posted February 27, 2015 For anyone interested, I am aware of refurbished HT motors, still in crates. They are about 3,850 Euros. Check Sandorf website, ask for Stef. Quote Link to comment Share on other sites More sharing options...
jamie meachin Posted March 9, 2015 Author Share Posted March 9, 2015 Finally got the engine blocked up and say in the chassis this weekend. I'm surprised how small this engine is compared to the original. Next step is to modify the engine mounts. Quote Link to comment Share on other sites More sharing options...
datadawg Posted March 18, 2015 Share Posted March 18, 2015 I might have missed it, but how does the power/torque of the Cummins compare to the original motor? Is the HT going to be a speed demon? Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted March 18, 2015 Share Posted March 18, 2015 Having been lucky enough to have driven both original and 6BT powered halftracks, you wont be changing down gears quite as much with the Cummins. On the speed front I don't think that there will be much of a difference; I don't think that the rev range of the petrol is too much different to the Cummins. Older petrol engines tend to have a longer stroke than more modern high-revving petrol engines. The big difference will be the higher noise level of the diesel engine in an armoured vehicle. I thought that of the WW2 petrol engined vehicles I have driven, the Halftrack (petrol) motor was nicely matched to the vehicle much in the same was as a Dodge WC52 and engine seem in good balance with regard to weight and power/torque. The Ward LaFrance trucks of the same vintage are hideously underpowered by any standard! Vince Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted March 18, 2015 Share Posted March 18, 2015 I might have missed it, but how does the power/torque of the Cummins compare to the original motor? Is the HT going to be a speed demon? As Vince says, the rev range will be almost the same so speed will be similar but with the greater torque it'll spend much more time in the higher gears and will probably therefore actually seem faster. It will be louder although the turbo should help reduce that. The big wins are on economy (think 8- to 10-fold improvement in consumption) and reliability (starts first turn every time and no more churning over on damp mornings). Petrol engines will never catch on... - MG Quote Link to comment Share on other sites More sharing options...
R Cubed Posted March 24, 2015 Share Posted March 24, 2015 Jamie, I run a non-turbo 6B in a heavily laden Bedford MJR and would not hesitate to use the same in a GMC. They are a lively responsive little engine giving out 130hp even without a hair dryer, and unless you plan to tow a gigantic piece of WW2 arsenal around I see no necessity for a turbo. But the more pics of the R36BZF conversion I see the more I like it! yea, I think the non turbo 6B's were about 130 HP but when DAF started producing the 10 Ton tipper for the ground workers they needed a bit more so stuffed a small turbo on them which generates about 10 psi and boosts the HP to about 150 HP, which is what I have in my GMC, also it does not have any waste gate presumably it cant build any more pressure due to design... I seem to recall comparing a 6b against a P6 and ruling it out for a GMC, but I might just have to measure up again if you are confident. I'm sometimes not too good with tape measures..... :-) I will get some pics of the engine in my truck I recon you would have to do what I have done as the engine is as far forward as I could get it and still have about 1 1/2 cylinders in the cab! I think the P6 required the rad to be moved forward? Which may be the only reason I ruled the 6B out? Perkins supplied a complete kit with all stuff required for the GMC conversion including a special flywheel housing to mate with the box and I believe brackets for the radiator move? Great work on the adapter rings! Tony Quote Link to comment Share on other sites More sharing options...
R Cubed Posted March 24, 2015 Share Posted March 24, 2015 Richard, I'm using 24 volt start and 12 volt electrics. The fuel filter on the front at the top of the engine is something the bus company dose. I'm guessing lack of space in the engine bay? I will be moving it once I get it in the chassis. I can get you some pictures of the Perkins P6 engine in a GMC. Jamie Jamie Do you have any idea of what the HP rating is of your 6BT ? will probably be in Kw on the rating plate on the side of the timing gear cover. Quote Link to comment Share on other sites More sharing options...
jamie meachin Posted March 24, 2015 Author Share Posted March 24, 2015 (edited) Hello Richard, I will have a look this weekend for you and let you know. I have a feeling the guy I know at the bus company said they are around the 160 HP mark. Jamie Edited March 24, 2015 by jamie meachin Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted March 24, 2015 Share Posted March 24, 2015 Hello Richard, I will have a look this weekend for you and let you know. I have a feeling the guy I know at the bus company said they are around the 160 HP mark. Jamie Dart engine should be 180hp. - MG Quote Link to comment Share on other sites More sharing options...
R Cubed Posted November 22, 2015 Share Posted November 22, 2015 Any more pics need more pics..... Quote Link to comment Share on other sites More sharing options...
DoctorCheney223 Posted January 8, 2016 Share Posted January 8, 2016 I apologize for dragging up an older post but did the conversion every go through as planned and get on the road? V/R Ron Quote Link to comment Share on other sites More sharing options...
Corbs Posted January 8, 2016 Share Posted January 8, 2016 I hope Jamie doesn't mind me posting up a pic of where he was at last month... Tracks fitted and out for a test drive Quote Link to comment Share on other sites More sharing options...
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