Also, I am guessing that Tapage first comments on size of plungers is probably right on the mark. In the factory manual for the 2h/12HT the start up cc's are about the same for both engines which leads me to suspect they use the same plungers (elements).
such an impresive 2H-T
- Thread starter Tapage
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but they dont... 12ht has bigger elements and you should be able to confirm it just be checking the serials on pump..
Ok Blis, then that is really good new actually. I will check the manual now for rack movement in mm compared with cc's fuel....
And even if I check the serials, I dont know how to get the information I need from that point....
Post up the serial #'s off the tag, the plunger diameter is in there.
If i remember right the serial should look like ND-PS6Axxyyyyy or something like that, those two numbers after A means element size, 7mm for 2h and 9mm for 12ht...
Well, I pulled out one element and the verdict is....
10mm stroke
9mm element
Great, so the elements are quite big and someone knows what they are talking about - blis!
I didnt read the last post before I took it apart.
So...blis do you know what they can be tuned up to flow?
10mm stroke
9mm element
Great, so the elements are quite big and someone knows what they are talking about - blis!
I didnt read the last post before I took it apart.
So...blis do you know what they can be tuned up to flow?
Got no hands on experience but since you can get 160cc with 8.5mm elements i'd guess its good for around 180cc or so, maybe more... might be there are even bigger elements around for it which would mean a ridiculous amount of diesel injected...
oh, while browsing the net i found interesting french site, they make marine motors that use 4.2 straight-six out of hdj80 as base and produce decent 320hp/3600rpms, so 400hp 12ht might not be so far fetched idea :E
heres the link too...
http://www.nannifigaro.com/EXTRANET%20SUPPORT%20FILES/ENGINES%20PAGES/LEAFLET/francais/IN%20LINE/Feuillet%20commercial%206.420%20TDI%20FR.pdf
Isuzu A type pumps (similar to toyota A type pumps) have been measured at 180cc /1000 for 9.5mm elements.
However, this is maximum pump flow, your governor may not have enough stroke to let the pump deliver that much.
To burn that cleanly, you're talking 30-40psi boost and decent intercooling.
Should we start a sweepstake for guessing which parts will break first and second?
Dougal, c'mon 30-40psi, that is surely a big concession for you 
180cc would need at least 45psi to burn cleanly and probably a bit more. Last time I ran up the calcs I would like to have 40psi with 135cc @ 4000rpm. That should be good for 300rwhp.
As for breakages, it just comes down to r&d since no-one on this or any other site (that I have read) has conclusive info. The video that started this thread is the closest I have seen, and while the engine did expire, oil consumption probably means at least one piston picked up which is not the first thing that I would have expected - a leg out of bed was..... Hardly suprising a piston picked up; with no intercooler, no oil squirters, not high enough boost (crazy egts) and no additional cooling mods to the head (steam bleeds etc).
Regarding the 12ht strength compared to 2H, you cant compare directly. The ignition event in a DI with single stage injectors is very harsh (which is why the top ring land flogs out so quickly). IDI is relatively soft and while much less efficient, may be the reason so many IDI enges are able to make so much power without breaking when modded. Of course, it may be such a small difference in practice that it is irrelevant. Bear in mind that a DI engine has a greater surface area that a DI piston and the combustion event takes place in/on the piston so it absorbs alot more heat and probably (a guess) has a greater need for oil squirters than the 2H.
So, who will be the first to test? There will be a 30psi intercooled VNT 12ht in perth soon (not the one I am building),...... 40psi I am not sure.......
As for fuel pumps, 9mm elements are big enough for the fuel I would want. Except, bigger elements could mean shorter injection periods which may be beneficial when the pump is pumping in 2.5-3 times more fuel than std.
Cylinder walls are very thick, head has good size bolts, crank can obviously take it, rods.....seem weaker compared to 1HD but who has ever broken a 1HD rod from torque?
Anyone know if the tension needed to open the rack changes with fuel flow and rpm?
180cc would need at least 45psi to burn cleanly and probably a bit more. Last time I ran up the calcs I would like to have 40psi with 135cc @ 4000rpm. That should be good for 300rwhp.As for breakages, it just comes down to r&d since no-one on this or any other site (that I have read) has conclusive info. The video that started this thread is the closest I have seen, and while the engine did expire, oil consumption probably means at least one piston picked up which is not the first thing that I would have expected - a leg out of bed was..... Hardly suprising a piston picked up; with no intercooler, no oil squirters, not high enough boost (crazy egts) and no additional cooling mods to the head (steam bleeds etc).
Regarding the 12ht strength compared to 2H, you cant compare directly. The ignition event in a DI with single stage injectors is very harsh (which is why the top ring land flogs out so quickly). IDI is relatively soft and while much less efficient, may be the reason so many IDI enges are able to make so much power without breaking when modded. Of course, it may be such a small difference in practice that it is irrelevant. Bear in mind that a DI engine has a greater surface area that a DI piston and the combustion event takes place in/on the piston so it absorbs alot more heat and probably (a guess) has a greater need for oil squirters than the 2H.
So, who will be the first to test? There will be a 30psi intercooled VNT 12ht in perth soon (not the one I am building),...... 40psi I am not sure.......
As for fuel pumps, 9mm elements are big enough for the fuel I would want. Except, bigger elements could mean shorter injection periods which may be beneficial when the pump is pumping in 2.5-3 times more fuel than std.
Cylinder walls are very thick, head has good size bolts, crank can obviously take it, rods.....seem weaker compared to 1HD but who has ever broken a 1HD rod from torque?
Anyone know if the tension needed to open the rack changes with fuel flow and rpm?
Dougal, c'mon 30-40psi, that is surely a big concession for you
Oops, It would take 30-40psi on my engine, but the 12HT has smaller cylinders so yes it needs more boost.
The problem I have is space for the turbos. I have a coil spring and shock tower right where you guys don't.
It's crank strength that is my first thought. Provided the tuner keeps it lean enough to not melt anything up top.
How big are the mains and big ends on a 12HT/2H?
The little end is 32mm, big end 55mm and I think mains are 58mm. Only a few mm different to the 1HDT.
I know I have said in the past that the 12HT crank looked weak. But that is compared to the 1HD/HZ series. I was dissapointed that the dual counter weights on each cylinder were not there and there was no full crank girdle.
Stronger than what would be the question....it only needs to be strong enough to do the job and I dont have the smarts or the time to work that out. The 1HD/HZ looks like a full racing crank, quite impressive. If someone said their 1Hx engine was happy at 5500rpm and 50psi, head gasket and rods not withstanding, I could believe them. So on that basis, perhaps the 12HT crank is strong enough for 900nm and 400hp. Actually the 12HT crank looks VERY similar to the Volvo Penta 3.6L engines that put out 260hp.
The big point of course is at the start of the thread - there is a 2h that didnt break the crank or rods with the torque and power levels we are talking about.
I know I have said in the past that the 12HT crank looked weak. But that is compared to the 1HD/HZ series. I was dissapointed that the dual counter weights on each cylinder were not there and there was no full crank girdle.
Stronger than what would be the question....it only needs to be strong enough to do the job and I dont have the smarts or the time to work that out. The 1HD/HZ looks like a full racing crank, quite impressive. If someone said their 1Hx engine was happy at 5500rpm and 50psi, head gasket and rods not withstanding, I could believe them. So on that basis, perhaps the 12HT crank is strong enough for 900nm and 400hp. Actually the 12HT crank looks VERY similar to the Volvo Penta 3.6L engines that put out 260hp.
The big point of course is at the start of the thread - there is a 2h that didnt break the crank or rods with the torque and power levels we are talking about.
I looked up the specs, I was out on the mains.
2H LE: 29mm, BE: 55mm Mains: 70mm.
12HT LE: 32mm, BE: 55mm Mains: 70mm.
2H LE: 29mm, BE: 55mm Mains: 70mm.
12HT LE: 32mm, BE: 55mm Mains: 70mm.
Just saw a thread where the H engines have the same problem on the top ring as the 12HT. That is really great news for the 12HT. The ring land issue in the 12HT bothered me alot.
How does that compare to the HD/HZ bottom end?
For reference an Isuzu 4BD1T is 35/64/80mm.
Does anyone know what did die on that 2H? Or are we just hypothesising from the video? I didn't see any reference to power levels, only fuel volumes. What is possible with a given fuel volume and what that engine acheived could be very very different.
I suggested the power - couldnt be too far out, surely making over 300hp from the fuel figures, not to mention the video.
I now hypothesise that the problem killing the engine was cylinder groove cause by top ring wear since the engine was apparrantly a very high km.
2H LE: 29mm, BE: 55mm Mains: 70mm.
12HT LE: 32mm, BE: 55mm Mains: 70mm.
1HZ: LE: 29mm, BE: 57mm, Main: 67mm
1HDT: LE: 33mm, BE: 57mm, Main: 67mm
1HZ/1HD series: 11mm between cylinders with stock bore.
2H/12HT series: 16mm between cylinders with stock bore (20mm between 3 and 4)
I now hypothesise that the problem killing the engine was cylinder groove cause by top ring wear since the engine was apparrantly a very high km.
2H LE: 29mm, BE: 55mm Mains: 70mm.
12HT LE: 32mm, BE: 55mm Mains: 70mm.
1HZ: LE: 29mm, BE: 57mm, Main: 67mm
1HDT: LE: 33mm, BE: 57mm, Main: 67mm
1HZ/1HD series: 11mm between cylinders with stock bore.
2H/12HT series: 16mm between cylinders with stock bore (20mm between 3 and 4)
The gent with the big 2H wrote that the engine was burning a heap of oil, but not leaking any extra. I assumed all rods were still inside the block and connected where they should be......
He actually said he blew up that engine? 'cos last time i checked in finnish offroad forum he sayed nothing about blown engines...
The top groove of piston is also fixable rather easily, just throw in mercedes pistons (need just a bit of machining) that have steel top groove, shouldnt be awfully expensive (couple hundred i presume) and it fixes the top groove problem for good...
He said that the turbo and fuel pump mods had "done it's job" and that he used 2 litres of oil driving 40km and that is blow ALOT of blue smoke.
Now he is putting in a 12HT in 3-4 weeks. I hope he checks the pistons first. I would like it to work really well and test the strength of the 12HT varient.
Now he is putting in a 12HT in 3-4 weeks. I hope he checks the pistons first. I would like it to work really well and test the strength of the 12HT varient.
OK, you mean the OM617. I guess if you use OM617 pistons and pins/circlips you just change the little end bush size. This of course assumes compatible compression height. GREAT idea....not for me though, I want the efficiency of the DI.
