tatra 813 new owner

[doghead]

Tatra, thanks for the pics! That is a seriously cool rig! I look forward to seeing more of it in the future. (please share more with us as time allows)
Bjorn, great comparisons of your 757 and the Tatra !
Both of you really have AWESOME Trucks!

 

[tatra813]

Thanks for the warm welcome guys.

Cranetruck, I like your 8x8 alot is that a rare truck, out of all the rigs I have seen I dont believe seing one of those before I have always liked cabovers and the more tires and the bigger the better in my opinion.

What do you plan on doing with your tire setup, 1600x20 would look nice on your rig!
I also like the fact it is a convertable, makes those summer nights a lot of fun, I used to have a duece and we had a lot of fun drives in the summer with the top off.

I think I actually did see a truck like yours the other day on a web page from some other country and they offered rides in there 8x8's they had one that looked like yours and they also had a tatra, maybe I can find it again.

just got finished gutting out the interior and I am prepping the floors etc so I can have it rhino coated, then I am putting new seats in and as soon as I get the one front wheel bearing changed out I will be driving it around. Ill update with new pics soon.

Dean

 

[cranetruck]

...
Cranetruck, I like your 8x8 alot is that a rare truck, out of all the rigs I have seen I dont believe seing one of those before I have always liked cabovers and the more tires and the bigger the better in my opinion.

What do you plan on doing with your tire setup, 1600x20 would look nice on your rig!

Dean, the tires were custom made for this vehicle and are low profile 16R20 on 12 inch wide rims. They are tubeless and designed to run on very low pressure. I'd like to find more of the same, have located a few, but not in the very best condition.
The truck may look like a cabover, but the cab is fixed, access to the engine is from the top. It is all waterproof (the cargo version has pressurized door seals) for fording/swimming....Well you can read more about the xm757 by doing a search, no point in repeating it all again.

I also like the open top, have had a bikini top on the deuce for years.

The M656/XM757/XM791 are pretty rare, only about 500 built (compare to 360,000 of the Tatras!). They were basically only used in Europe with the Pershing Missile system for about 15 years. Mine comes from the training battalion in Ft Sill, Oklahoma.
Hope to see some detail images of your new aquisition in the future.

 

[tatra813]

A couple more pics.

 

[cranetruck]

Does the cab tilt? Doesn't look like it, so access is similar to the xm757 engine.

 

[tatra813]

your are right cab does not tilt, I dont know how you could ever pull the motor.

 

[cranetruck]

Well, on the 757 you have to lift the cab tub off, which isn't really a big job according to the TM, lots of connectors and the mounts. Thought about doing it when I worked on the injection pump, because of poor access from the side.

So that V12 is aircooled then, what make and model is it?

 

[M1075]

I love the look of the crew cab. Looks like plenty of room.

 

[tatra813]

Ill have to look as to the model but Tatra made the motor and I have read lots of great reviews on the motor, although it is a very dirty diesel and very noisy, it is also very inefficient and doesn't have much power, but it does have tons of torque.

 

[ARMYMAN30YearsPlus]

That big Tatra motor looks like it is begging for headers, I think they would add some power to the beast especially if you hooked dual turbos to them I bet it would clean up the exhaust and really make that thing scream

 

[tatra813]

sounds like a good suggestion, I doubt anyone makes headers for that motor. As far as adding duel turbos, what kind of problems can you run into and how hard is it to size a turbo?

 

[OPCOM]

Blowing a head gasket comes to mind.. I'd do some real deep research before I started messing with it. Are the heads individual cylinders or groups of 2 or 3?

 

[cranetruck]

Individual, Patrick.
The Continental AVSI-6 is an equivalent 12-cylinder air cooled engine used in the M60 tank I believe. About 700 hp.

The cylinders are separated for cooling.

 

[tatra813]

The heads appear to be individual. The idea of adding or custom making headers sounds like a fun idea, adding turbos sounds like even more fun, the only problems that come to mind is the fact that when ordering parts it takes a while before you get them. I know they use these trucks alot in the Truck trial competitions in Europe, unfortunately with the language barrier its hard to communicate with the guys over there as to what kind of upgrades they have been doing, so as to eliminate experimenting on my part.

I do plan on taking the exhaust that now goes into one exhaust through a exhaust brake damper then exhausts under the truck. I am either going to keep the single exhaust (mainly so I can keep the exhaust brake) and run it up vertically, or I might do duel exhaust going up vertically. There is a muffler of sorts back there I'm wandering how much louder it would get if I eliminated the muffler? any ideas? The deuce I used to have didn't have a muffler and didn't seem to terrible?

anyway thanks for all the ideas guys !!

 

[vtunimog]

The heads appear to be individual. The idea of adding or custom making headers sounds like a fun idea, adding turbos sounds like even more fun, the only problems that come to mind is the fact that when ordering parts it takes a while before you get them. I know they use these trucks alot in the Truck trial competitions in Europe, unfortunately with the language barrier its hard to communicate with the guys over there as to what kind of upgrades they have been doing, so as to eliminate experimenting on my part.

I do plan on taking the exhaust that now goes into one exhaust through a exhaust brake damper then exhausts under the truck. I am either going to keep the single exhaust (mainly so I can keep the exhaust brake) and run it up vertically, or I might do duel exhaust going up vertically. There is a muffler of sorts back there I'm wandering how much louder it would get if I eliminated the muffler? any ideas? The deuce I used to have didn't have a muffler and didn't seem to terrible? anyway thanks for all the ideas guys !!

hey Dean - glad to see you are thinking of making improvements to performance. Most of the guys who use the 813 in Truck Trials are using them pretty much stock. To get a few more horses out of the engine will put in bigger Jikov injectors or turn the timing up a bit. But you get a fair amount of black smoke. Most of the smoke you see in the Truck Trial vids is for effect only and is done by running the truck with the Cold Start lever on.

As for Turbos, before you do that I would suggest you swap the engine out for a T930 engine which is the V8 with Dual turbos. The 813 motor just wasnt' built for a turbo and you will run into serious issues with cooling. I have spoken with quite a few air cooled tatra drivers over the past 5 years and they talk about how absolutely durable these engines are and well engineered. Tatra was making 6x6 offroad trucks long before anyone else was really just prototyping and testing. In fact Tatra designers built the first early VW bettle style car, which their young designer/engineer ran back to Germany with and later built his own car the VW, which would be Dr. Porsche.

One thing you may wish to consider is putting rear raised intakes on if you plan to drive offroad and encounter fording operations. Besides it frees up space under the "hood" so to speak for a larger oil cooler.

Chris M

 

[vtunimog]

Ooops Correction ! The T930 Motor is in the 813 and the later T813 Motor which is 3 Liters bigger (19L) and puts out 350hp or so. The Later 815 models (like th ATC Wildlands Ultra XT fire fighting vehicle that the BLM uses). had a variety of engines to begin with ranging from the T813-12 19L V12, to a smaller V8 (12L) but I think both were twin turbos. When I first starting looking there was talk of putting on twin turbos but the reduced engine life wasn't worth it. There was a company in Holland that built a few special 813 support vehicles for the Paris-Dakkar rally years ago and they had modified the heads somehow and put in larger injectors. I am not sure what they used but my guess is something off from a KHD/MAN or Deutz air cooled engine. It bumped the power up to somewhere in the 340 hp and torque to 1100 lbs. I am guess the amount of smoke was incredible. If you watch the Kamaz trucks in the Paris Dakkar rallies their engines are putting out something like 900 - 1200 hp but the smoke is incredible. Ok if you in the middle of the desert but not so great in downtown USA.

 

[tatra813]

Great info Chris, thanks for the update, I think I will just leave the engine stock so as to not risk problems.

thanks for the input

 

[pa.rich]

I just want to say welcome here to this site. We all love the pictures of each others projects. Your Tatra is an exciting addition to the group. I will look forward to seeing more pictures and words of progress. Have fun and good hearing from you. Rich.

 

[rmgill]

Dual turbos, under that engine access cover...ouch, makes my ears ring just thinking about it.

 

[tatra813]

Can anyone help me out with some of these oil requirments. My manual calls for these types of oils I assume they may make sense in Europe? any help with us equivilents would be appreciated.

t-nh2
gearboxes call for pp80
engine oil oa-m6ad
bearings t-nh2
winch housing pp-90h
power steering ON-1 Hydraulic fluid

brake fluid syntol 190 HD
clutch hydraulic oa-m6ad

Im assuming the gearboxes are standard 80 weight oil. Im sure 15w40 in the engine would be fine, I wanted to make sure on the power steering and clutch fluid. and brake fluid

for the air filter it calls for a mixture of oa-m6ad and petrol 2:1
I assume thats engine oil and diesel?
thanks again guys.