New ENGINE

[Abrs]

Jesus you've spent some time tinkering with that truck! BTW Why did you need to take the box apart? I do agree. there's nothing lightweight in the Tatra drivetrain, but then again there isn't likely to be in a truck that was designed to haul upto 100 tonnes!

You wouldn't need to change the injection pump in order to benefit from adding a turbo/s, but I would recommend changing the injector tips to make better use of the additional charge. But anyway that's all academic if you're not keeping that engine. If you're gonna change it does it have to be a Tatra lump you put back in? Over here the big old Deutz engines go for little money these days and to be fair they're a lot better engine, a friend of mine breaks lorries for export, he was telling me that he only gets £1200 for those big V8s in good order.

[duncan]

The gearbox, actually the second gearbox with splitter, high/low gearing and inter-axle differential (you know, the one INSIDE the driveline, not the 5 speed box you can remove easily in 30 minutes)...

Before a trip I changed the transfer gearbox oil and refilled to "check" level, and the next day drove off. Took 200km, then a little gearboxy-oily-smell came which "must be from just filling it recently", and another 10 km later a big bang, all gears dead. Gearbox inside the tube got so hot the paint burned off, the gears and bearings melted, the balls inside the bearings are funky shaped... properly broken.

I made a foobar when changing the oil. The oil fill/check plug is on the gearbox itself, but the oil flows everywhere between 2nd and 3rd axle, because the tube is full of gears and bearings. The old oil was some un-doped eastern europe gunk, this almost completely blocked the little gap between the gearbox part and the high/low & differential part. So you see, I filled to check level, but it took a while before the oil distributed itself... but by then I already closed the check hole and forgot about it.

Long story short: No oil is bad. Always fill to check hole, wait for hour, and check again.

Cost me an expensive tow home, a lot of effort to get the parts, 3 months of waiting for said parts, and around 3 days of actual work.

For the new engine... its in the following order of importance: Aircooled Diesel, V12, Tatra, at least 17.6 liters. I didn't buy the truck for fuel economy or anything, I bought it because its the coolest life-size toy car you can find, and being able to say youre running a 15+ liter V12 is a big part of the fun ;) If I can change engines to something equally or more crazy, I will, and if it increases fuel/oil economy, thats even better.
If I wanted something sensible, I shouldnt have gotten this thing in the first place

[paulob1]

duncan, where are you getting the tatra engine from...I need to get me this new engine and the reason i was going for a non turbo option was that I had been questioned on the drive train not being strong enough...but to be honest i dont believe that either...with this trucks off road efforts most people fit a turbo to the 813 stcd engine upping power to well over 300 bhp anyway and that means it must be strong enough to me...

I have therefore decided to buy a new 815 engine instead of the 813 engine and include in it the twin turbos...

[duncan]

Will write some truck part dealers in Czech, starting with the people at ATH, since they have always been very helpful. Planning on swapping the engines somewhere this winter or coming summer, depending on budget. Could ask for a good price if we get 2 at the same time Have no clue if the engine even fits though, there is no information about swapping the t930 engine for a t3-930, except for the occasional forum where people ask wheter it can be done So I figure, it's time to create said experience first hand

[Abrs]

The gearbox, actually the second gearbox with splitter, high/low gearing and inter-axle differential (you know, the one INSIDE the driveline, not the 5 speed box you can remove easily in 30 minutes)...

Before a trip I changed the transfer gearbox oil and refilled to "check" level, and the next day drove off. Took 200km, then a little gearboxy-oily-smell came which "must be from just filling it recently", and another 10 km later a big bang, all gears dead. Gearbox inside the tube got so hot the paint burned off, the gears and bearings melted, the balls inside the bearings are funky shaped... properly broken.

I made a foobar when changing the oil. The oil fill/check plug is on the gearbox itself, but the oil flows everywhere between 2nd and 3rd axle, because the tube is full of gears and bearings. The old oil was some un-doped eastern europe gunk, this almost completely blocked the little gap between the gearbox part and the high/low & differential part. So you see, I filled to check level, but it took a while before the oil distributed itself... but by then I already closed the check hole and forgot about it.

Long story short: No oil is bad. Always fill to check hole, wait for hour, and check again.

Cost me an expensive tow home, a lot of effort to get the parts, 3 months of waiting for said parts, and around 3 days of actual work.

For the new engine... its in the following order of importance: Aircooled Diesel, V12, Tatra, at least 17.6 liters. I didn't buy the truck for fuel economy or anything, I bought it because its the coolest life-size toy car you can find, and being able to say youre running a 15+ liter V12 is a big part of the fun ;) If I can change engines to something equally or more crazy, I will, and if it increases fuel/oil economy, thats even better.
If I wanted something sensible, I shouldnt have gotten this thing in the first place

Bet you won't do that again!

Did you manage to get hold of new OEM gearbox parts or were they S/H - or manufactured to order?

Ok, for the engine may I suggest the air cooled 19L V12 Deutz, model BF12....something or other. I was looking at one a while ago for my truck, it's twin turbo & rated at around 480hp! Would make the Tatra almost a pleasure to drive I reckon The engine I looked at was fitted to an old crusher but I believe they are also in a few lorries. Physically the lump itself doesn't look all that much bigger than the old Tatra engine so it should fit in the chassis ok, however it's fitted with two massive oil coolers either side of the cooling fan which stick out a fair way, as do the two turbos on the back, also the intercooler sits on top of the engine making it quite tall, you'd have to do some light fabrication work on the engine covers to get it in but it would be well worth it I think .....Wish I'd bought that one I saw now thinking about it

[duncan]

Did you manage to get hold of new OEM gearbox parts or were they S/H - or manufactured to order?

Got a new OEM part in crate, pre-assembled, replacing everything between 2nd and 3rd axle: Differential, high/low gear, transfer gearbox, pneumatic splitter & neutral, handbrake, winch drive.... the lot. Just slide into place and re-fit the rear axles, really a piece of cake.

Ok, for the engine may I suggest the air cooled 19L V12 Deutz, model BF12....something or other. I was looking at one a while ago for my truck, it's twin turbo & rated at around 480hp! Would make the Tatra almost a pleasure to drive I reckon The engine I looked at was fitted to an old crusher but I believe they are also in a few lorries. Physically the lump itself doesn't look all that much bigger than the old Tatra engine so it should fit in the chassis ok, however it's fitted with two massive oil coolers either side of the cooling fan which stick out a fair way, as do the two turbos on the back, also the intercooler sits on top of the engine making it quite tall, you'd have to do some light fabrication work on the engine covers to get it in but it would be well worth it I think .....Wish I'd bought that one I saw now thinking about it

Like this? Seems like a lot of work to fit! Any ideas of the related figures, power & fuel consumption?

[Abrs]

Aye, that looks very similar if not the same as the engine I'd looked at, I think perhaps though the manifolds and oil coolers were slightly different but that probably just depends what the engine is fitted into. I don't really know a great deal about the specs other than what I had been told which is; they rev to about 2600Rpm and produce about 480hp, I have no idea what the fuel consumption would be like, probably not great I imagine but then again the Tatr engine isn't exactly efficient anyway so it probably wouldn't be too much worse.

Yea, you're probably right, it would be a fair amount of work, but as you were changing engines anyway why not go the extra mile and have yourself a real beast!! More power than a Man Kat! Which BTW also use an air cooled Deutz motor, albeit a smaller one As did some of the Urals I noticed - Besides the work wouldn't be a patch on what you've already done to that truck

BTW - Are those gearbox units NOS or are they still being manufactured, I was told certain drive line components are getting hard to obtain, is this really the case?

[duncan]

You're making a string point for this engine, whats your percentage on the sale ? I will see about getting some more information on it.

BTW - Are those gearbox units NOS or are they still being manufactured, I was told certain drive line components are getting hard to obtain, is this really the case?

The gearbox was NOS, had the original paper on it with production numbers, inspection date (somewhere in the 80's), and a bunch of signatures and stamps. It was filled with preservation-oil and all holes plugged or covered. It came in transportation cage made to fit, and from the marks on the cage its obvious they have been stacked somewhere, so I'm guessing there is plenty more where they came from.

Out of all the spares and replacements I've ordered, the only things really "not available anymore" are things like the mudguards, toolboxes, parts for the heater, etcetera. On other parts it often happens the specific bit I need is not available, but then I can always get the "complete" replacement, i.e. I needed a little valve for the overpressure system, but I got the complete unit with valve, pressure regulator, manometer and mounting bracket instead, for roughly the same price.

For the gearbox, the bearing and planetary gear wheel system that actually broke were just as expensive as getting a complete unit with these parts build in... in fact, I got a call asking if they could please send the complete unit instead of the parts I ordered, because it was "too much work to disassble the gearbox to get the required parts". Got to love it

[duncan]

Deutz BF12L513C

Code: Select all

Cylinder                            V12
Displacement                        19.144L
Automotive Power As Per ISO1585     386/2300
Max.Torque/Speed (N.M/rpm)          1900/1500
Min Fuel Consumption (g/kw.h)       205
Net Weight (kg)                     1300
Overall Diemension (LXWXH)(mm)      1590X1192X1087

DEUTZ BF12L513CP Diesel Engine For Vehicle Application

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Cylinder                            V12
Displacement                        19.144L
Automotive Power As Per ISO1585     411/2300
Max.Torque/Speed (N.M/rpm)          2200/1400
Min Fuel Consumption (g/kw.h)       200
Net Weight (kg)                     1520
Overall Diemension (LXWXH)(mm)      1590X1192X1112

Must find out maximum engine size for the 813.

Edit: Im not sure on this calculation, but 200 gram per kw per hour seems like a lot. With a weight for diesel of 820 gram per liter, and say at "half power" for driving 80kmh (wild guess, not based on facts) you would get:

Code: Select all

200 (gram per kwh) * 200 (kwh required to drive at 80kmh) / 820 (gram per liter diesel) = 49 liters per hour

If youre running said 80km/h... thats 50 liters for 80km, which is 62 liters / 100km. Figures ofcourse vary a bit when you alter the amount of power used to drive 80kmh, but I think 200kwh is about right, seeing as driving the tatra 813 with original (235kwh) engine at 80kmh means almost lead-foot.

[Abrs]

Hmm yea it does sound like it's a bit thirsty But I suppose it's not too bad given the power/torque it's delivering! To be honest I'd never given any consideration to the fuel consumption as mine only does local runs and it's using agricultural diesel anyway(reduced duty).

Was it much of a job fitting the box? I take it those axles/tubes come away quite easily once you've got it all jacked up and unbolted?

Ohh BTW have you had the main propsaft apart yet on yours? Mine's developed a clacking as it gets warm, from what I've read there's another splined shaft inside which I think's now slapping around inside for some reason.

[duncan]

Fitting the box was easier than removing. Basicly as follows:

• Before starting, make sure to safely block the truck from moving, since you will remove the handbrake and spend a lot of time underneath the truck and between the wheels.
• Drain oil in gearbox and transfer gearbox
• Remove primary gearbox through inspection hatch
• Remove the brake lines, overpressure piping and difflock piping going from the subframe to the rear 2 axles, and the gear shifting rods and valves on the transfer gearbox
• Remove the 8 bolts (yes, just 8) connecting the subframe to the supports on the rear 2 axles
• Jack up the rear bumper (attached to the subframe) so it comes lose from the rear 2 axles, but dont lift too high (couple of cm is enough)
• Remove bolts on the flange connecting the rear drivetrain to the transfer gearbox
• Roll back rear 2 weels for about 20 cm, be prepared for OIL EVERYWHERE... slide away the bush connecting the gearbox axle to the rear drivetrain axle
• The rear axles are now fully free from the truck, lift the rear bumper a bit higher to give you room to work, deflate the tires on the axles to make it lower and roll it away
• Disconnect the winch drive, remove it, and remove the handbrake drum
• The transfer gearbox now is free, connected to truck only by the flange towards the front at the 2nd axle. Put a hoist around it, remove the bolts on the flange, and prepare for OIL EVERYWHERE AGAIN
• Move the transfer gearbox towards the back of the truck about 50cm to get it off the spline and axle going to the front axles. This is a MAJOR PITA, because the whole 600 kilo box has to be moved perfectly straight, otherwise the spline on the axle will block inside the box and you cant move an inch. The manuals suggest some special "montage truck" for this, which I think is a trolley with lifting mechanism. We used a hoist, a lot of elbow grease, and many curse words.
• Lower the transfer gearbox on a pallet and remove from under truck... and done.

Reinstalling is the same but reverse, and a lot easier, because you just lift the transferbox up to the correct height, and when it aligns, it slides into place by itself. I recon if you have a proper crane (and required tools) ready, you can remove and replace the transfer gearbox with 2 people within 10 hours, including a 1 hr lunch break, and be mobile again end of the day.

[duncan]

HBTW have you had the main propsaft apart yet on yours? Mine's developed a clacking as it gets warm, from what I've read there's another splined shaft inside which I think's now slapping around inside for some reason.

The shaft from the engine to primary gearbox? Have not had it apart, but it is a driveshaft like any other, with a spline for length-adjustment.