info Zetor engine displacement increase studies

I am a fan of inline 5 cylinder engines, because they run so good in my Volvo (Volkswagen 2.5 TDI) and many other automotive applications like the legendary Audi Quattro, or the Mercedes diesels. I have expressed my preference for an inline five, over the 170hp four cylinder models sold by Valtra and MF in the past here on this forum... But now i just found a harmonic balance study of what the harmonic vibrations of a five cylinder setup would mean with the geometrical layout of the Zetor engine.


This is in Czech, and aside of that, its a bit complicated when youre not familiar with the matter so Google translate makes a mess of it so i havent read it all, but its interesting to see that they have already explored the feasibility of a 5 cylinder engine in the UR3 engine family...

The Zetor engine is a bit small compared to the 4.9 liter AgcoPower engine in the big Valtra and MF four cylinder models, and Deutz has just introduced a TCD 5.0 four cylinder to complement their TCD 4.1 which is a bit small compared to the competition that counts anywhere between 4.4 to 4.9 liter.

Downsizing is really the trend, but Zetor cant build a new engine for every liter of displacement like Deutz does. Also, in the current era of emission legislation it doesnt make sense to offer both a 4 and a six cylinder variant within the same model range, because both would need an individual homologation. So, an inline 5 engine based on the existing Zetor design would make sense, with the current power level it would be capable of 170hp, or 183hp if you compare it to the 147hp Forterra 150HD...

...Which means both Forterra HD and Crystal models could be united into a mid range with an inline 5 engine ranging from 130 to 170hp, replacing both 4 and 6 cylinder models, with only one homologation... Then later the Maxterra (or perhaps Super, like the original heavy Zetor of 1954) could pick up at 160-240hp with inline sixes...

This study is off course 7 years old, and there is no indication that this idea is still hot at Zetor... But who knows...


....And here is a more recent study (of 2016) to explore the possibilities of increasing the UR3 engine displacement..


An increase of the bore and stroke from 105/120 to 115/136 is the biggest size explored, however it would need extensive redesign because the block walls between the cylinders would be too thick to accomodate the big bore liners, and the crankshaft throw would be so big that it hits the counterbalance shafts. (modifying that, would mean beginning from scratch)

Also, stuffing cylinders too close together (like the Ford 112x112mm rebore of the original Major engine, beginning with the Ford 4000 3 cylinder modification although the problem was most evident in the early 1980s four cylinder engines: The three and six cylinder engines had a different balance that didnt propagate this problem as much) will remove too much stiffness from the block, which resulted in the "porous block problem" which was simply a matter of block cavitation because the natural frequency of the block was changed because of this bore increase. The solution was later, an anticavitation coolant addition, and external reinforcement ribs on the 4 cylinder block, to regain the required stiffness. Also the Perkins a6.354 turbocharged, cracked its heads because there wasnt enough heat sink mass.. This very engine is the reason MF changed to Valmet engines for their 150hp and bigger models... The Perkins A6.354 by the way, was as long as a 8011 engine and therefor offered by Motokov UK as a six cylinder alternative to the 10011, fitting under the Zetor 4 cylinder hood... The gap between cab and hood only increased an inch or so with this retrofit..

The most feasible modification to the existing engine is the variant with 110mm bore (alike the Crystal, though the Crystal had 150mm bore spacing and the Forterra has 136mm) and the 126mm stroke, which would increas the four cylinder displacement from 4.156 liter to 4.790 liter (allmost the UR4 engine, which had 110/128mm bore/stroke)


Anyways, i very much prefer the 5 cylinder 5.2 liter variant. No risk of boring away the stiffness of a block and getting Ford cavitation problems, and only one emission homologation for the entire midrange 130-170hp series...

Always thought ford blocks went porous as they were using poor material in the casting process and so there was a lot of swarf floating around in the coolant jacket and at a certain rev the coolant jacket would resonant causing the swarf to vibrate and eat away so the filter was just taking the swarf out of the system.
At the time the ford foundry was one of the biggest in Europe and so the unions were in a good position and maybe quality control suffered a little.
Five cylinder they have the staff but I wonder do the have the financial recourses but maybe there would be enough units sales to recover the investment. I buy one Best part in a Zetor is the Engine and A five cylinder would perform far better then those 4 cylinders on steroids.

The Ford problem occurred when the 4 cylinder was bored out to 112mm and cured when external webbing was used to reinforce the blocks. These were parent bore blocks so less limitations on how close they could put two cylinder walls together. Six cylinder engines cast from the same material and the same cylinder spacing, had a different natural frequency so they didnt have this problem... Cavitation is caused by imploding vapour bubbles, which rip steel out of the wall... Very common in hydraulic pumps, thats why all earthmovers put turbo pressure on the hydraulic tank, to prevent a vacuum in the pump suction line.

From an engineering point of view, the only thing you change with a 5 pot is the balance. When increasing bore and stroke you change the combustion process too...

They would need 4 blocks and 3 heads: 3 cylinder for the Minor and Major, 4 cylinder for proxima and Forterra, 5 cylinder for the Forterra HD / Crystal, and a six cylinder block with two 3 cylinder heads for the Super.

I translated the final conclusion of the five cylinder study:

The conclusion is that a five cylinder engine needs a torsional vibration damper per say.... My Volvo (VW 2.5 TDI) indeed has a crankshaft torsional damper... John Deere 6 cylinder engines have torsional dampers...

...In fact, 90% of todays automotive diesels have torsional vibration dampers, because of torsional vibrations caused by the multiple injections per cylinder of todays Euro 5 diesels.. ZF even wants a torsional vibration analysis on their Ergopower transmissions for TIER 3 and higher engines, because thats where drivetrain resonance issues surfaced... Even the Paus small wheel loader had a cab resonance issue, after a common rail TIER 3 engine was fitted, even though it ran smoother at idle than the previous mechanical engine...

The author is sceptical: He says: I am not an economist but i wonder if it makes sense to construct a five cylinder (that needs the added expense of a torsional vibration damper) if you can derate a six cylinder ?


....That was a very valid point in the 80s and 90s, and the reason the 5 cylinder disappeared and was replaced by the turbo 4, in the Fiat 880-5, Same Leopard, the Deutz DX85 and DX90, and the Deutz inline 5 in the Eder/Caterpillar excavator.

But then: What makes more sense for Zetor, add a 5th cylinder unit to an existing design to gain 25% displacement and adding a torsional vibration damper a Common Rail engine would need anyway, or change the entire production line to increase the swept volume of the 4 cylinder by 15% ??

Deutz introduced a 5 liter 4 cylinder lately, next to their 4.1 liter 4, and 6.1 liter six... Because with all the emissions stuff, engines need to put out sufficently hot exhaust gases, even when too small engines in heavy applications dont last, or cant provide the transient response...

The turbo 4 replaced the naturally aspirated 90-100hp 5 cylinder in the tractor, while in automotive, the 5 cylinder engine became popular especially at the end of the 80s, early 90s. Fiat Marea, Volvo 850, VW Transporter, Mercedes E250, Mercedes Sprinter, all used inline 5 engines. Even in America, Chevy sells an inline 5.

If Zetor wants to compete in he 4.5 to 5 liter displacement, 150-170hp, against the Agco 4.9 and the Deutz TCD 5.0, and JD 4.5 and New Holland 4.5, i would still prefer to add another cylinder and offer something with character, for lowest development cost than to add a 4.7 liter 4 cylinder that needs a lot of development due to the different combustion chamber shape...

The Volvo 850 was nicknamed "the rumble" for its distinguished engine sound...

Also, hear this heavily tuned Mercedes OM 605 (2.5 liter inline 5, pre-chamber mechanically injected) roar...

Or more practical, a Sprinter with an OM 605 at 300hp

And here a direct injected row 5 diesel:

And here Volvo 850 "the rumble" (even though the rumble changes into a growl at racing rpm )

Then to the offroad engines, here a Fiat 880/5

And here a Deutz DX90 F5L912

And a Same Leopard 95: With not too much silencing, it does sound a bit like the Mercedes OM605 and the VW TDI at low rpm

And a Tiger 100, with the same 105x120mm bore and stroke as the Zetor engine:


...A 5 cylinder doesnt sound as cheap as a 4 cylinder... People are suspicious about the 170hp four cylinders... And manufacturers have to offer both a 4 and a 6 cylinder model to statisfy either group of buyers, and homologate an engine and exhaust aftertreatment set twice in the 130-170hp class...

I would simply replace both the Forterra HD and the Crystal by a 5 cylinder tractor of 140-155-170hp and sell only three models within one homologation in this power range, instead of five models in 2 homologations...

Lets face it: Zetor is left with an odd customer base. They will like it anyway, as long as it is a genuine Zetor engine. Maybe some potential customers (that now use different brands) will dislike the unique engine, (maybe 5%) but most will embrace the brand even stronger when its a little different

I agree renze 100%,us Zetor users r considered odd,But definately would prefer to be driving a Zetor that is a Zetor not some other manufacturers engine and maybe even another companies transmission put together with only thing Zetor is the bonnet,....of all things in a Zetor I could never fault their engine,have a 8145 with est.17000 hrs(clock stopped at 6k hrs)and engine never touched,likewise a 7320 with 12k-13khrs engine never touched,....I think there would be a massive interest in a 5cyl none common rail engine in the 140-180hp bracket for ordinary farmers like me who don't want expensive repair bills associated with common rail engines when u pile on the hrs or keep running them for 20-30 yrs,leaving aside the by now well documented flaws of the new crystal,all of which r mainly cosmetic and relative easy fixes,the will(or finances) doesn't seem to be there to do anything about it or listen to what customers want at management/company level

I read Ron Borsboom, former CEO, chief of the board of directors at DAF, now advisor at Tatra say in an interview: " a manager said they quit taking orders because they were afraid production wouldnt be able to keep up. I told him if he worked at DAF and i was still chairman of the board, he would have his arse sacked immediately... The Communist market mindset is still around in the company, apparently a mindset is hard to erase"

That is crazy indeed,....look what's happening at John Deere,rightly or wrongly the market leader in most countries,they consulted a lot of there big contractor customers across Europe to develop the 6230R and 6250R,and I even see in farming press today that they r offering a 5 pillar cab on the R series to "meet customer demand" who didn't like the big single piece door,so if a company as big as Deere feel they must listen where r Zetor heading

They even explored the possibilities of a two cylinder engine with balancing shafts... which is a bridge too far, only 3rd world countries would buy it.

And American style bar axles:

This type of axle is used on all big tractors because the big clamp is less prone to fatigue than a thin flange

Does anyone else have blackened text and pictures in that file or is it just my phone ? If not, we might see parts of this soon on new Crystals

Here an analysis of a six cylinder crankshaft. They say the six pot also needs a torsional vibration damper... Did the 12045 have one ? Or were these old engines so much heavier so that they had a different torsional inertia ?

I even see in farming press today that they r offering a 5 pillar cab on the R series to "meet customer demand" who didn't like the big single piece door,

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Same reason why MF stopped making those big doors on the successors of the 500 and 2005 series... The same still applies. Side visibility may be improved but ergonomics is less: its a huge surface to pull close, in windy weather, the inertia is bigger so you cant rush in and out of the cab, and it sticks way out besides the tractor. Especially with this large glass area, they are just too fragile. Even when the glass comes from Zetors new supplier
Next to that, roll a Fendt and a 12045 downhill and see the survivability rate of the driver in each cab.. Seeing how flat those Fendt cab get, even with six pillars, and working on ROPS frames for wheel loader cabs, make me a bit scary of driving a thin 4 pillar cab at 50kmh.... ???

About five cylinder engines, Deutz is making 2.2/2.9/3.6/4.1/5/6.1/7.8/9/12/16 liter engines these days. Especially around the mainstream 4 cylinder, the 4.1, Deutz is decreasing the displacement stagger by adding a 3.6 below and a 5.0 above, in order to get an optimum approach between exhaust gas temperature for a given load collective (so that the exhaust aftertreatment will function properly) and engine displacement to get short transient response times.. They promote them as fitting in the same envelope as the 4.1.... because the 4.1 appears to just not cut it in heavy applications at high power...

Cummins is already engineering to delete EGR, and go back to a simple waste gated turbo, for reliability on all kinds of fuel quality. So for Zetor, if they want to embrace the inline injection pump as part of a high reliability philosophy, a 5.2 five cylinder engine of 130-150-170hp that does the job reliable and responsive without variable turbos will certainly make sense, especiallyy if it gets to replace both the Forterra HD 4 cylinder, and Crystal small 6 cylinder range.. The emission regulations make it a different game than in the 80s when 5 cylinder engines were popular because of poor transient response of the turbo 4 of that era... In fact, its the very same reason they have a chance again, because of the power increase of the 4 cylinder engines these days...

Just for teasers, here the "best sounding 5 cylinder engines in the world"

Deere has dumped too much money in EGR technology to come back from it. First they yelled "diesel only" for TIER 4 interim whilst doubling on their EGR related reliability issues, then came TIER 4 final and they had to admit "well we only meant diesel only for TIER 4 interim, because SCR technology wasnt reliable enough yet" while EGR technology doubled the service and repair costs of their engines as well as the price... E13.000 for a 185hp TIER 3A engine, 22.000 for a TIER 4F engine with SCR and DPF and several air flow restrictors in both intake and exhaust to force EGR back into the engine (which increases pumping losses and isnt reliable)

About a year after i spoke with Deere salespeople about how they disadvantaged themself with this technology that doesnt work with hired operators (regenerations overruled by the rental customer because of rental by the hour causing soot filters to breakdown) they introduced a 100-140hp DPF-less engine for the rental market... I might have some crazy ideas and convictions sometimes, but sometimes time proves me right... Thats because the best game wardens used to be once a poacher too

The biggest disadvantage with the current engine block of the zetor engine is that the size of the cooling channels is marginal on the two cylinders thats closest to the cab, a slight oil spill and dust collecting in it will be enough to get the two cylinders to overheat and seize up. it has happened on numerous occasions here in norway, its also a problem with the operators that starts up in the morning and gives full throttle and dont let the engine get enough warm up time, and at the same time when they are done they just pull the stop button without letting the engine cool down enough.

I guess that means not enough heat sink mass on top, just like the Cummins 5.9BTA had, at 180hp in excavators... On wheel loaders i've replaced cracked heads with 17.000hrs on it (175hp configuration) so with those hours quite acceptable, but it was a weakness nonetheless...

Anyways, that means increasing the cylinder displacement with the current heads is out of the question...


But please explain, how do external oil spill and dust buildup have to do with internal coolant passages ? Its not an air cooled Deutz isnt it ? Or is the oil spill just a sign of a head gasket giving way ?

I guess that means not enough heat sink mass on top, just like the Cummins 5.9BTA had, at 180hp in excavators... On wheel loaders i've replaced cracked heads with 17.000hrs on it (175hp configuration) so with those hours quite acceptable, but it was a weakness nonetheless...

Anyways, that means increasing the cylinder displacement with the current heads is out of the question...


But please explain, how do external oil spill and dust buildup have to do with internal coolant passages ? Its not an air cooled Deutz isnt it ? Or is the oil spill just a sign of a head gasket giving way ?

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The spillage creates a layer that is just enough that the engine will not give away heat to the surrounding air, but instead it insulates the heat inside the block making the temperature in those part of the engine overheat because the cooling passages are already marginal.

That makes sense. On the 5245 it was also the cylinder farthest away from the fan that started sweating..

I guess this is an issue with the new 16v head ?

That makes sense. On the 5245 it was also the cylinder farthest away from the fan that started sweating..

I guess this is an issue with the new 16v head ?

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no strangely enough its the 8v engines that gives this problem, from the introduction of the forterra to about 2005 ish.

no strangely enough its the 8v engines that gives this problem, from the introduction of the forterra to about 2005 ish.

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...phew... I was afraid they still had a pain in the ass haunting them... So this problem is solved on the new models (including the turbo lag, overheating, and exploding glass doors on the 11441 which the new generations dont have anymore)

...Thats a relief to me. If they still had a nasty issue like this, they'd better quit and go home... They have a long way to recover from the damage to their reliable name which the 11441 generation has done...


Was the problem solved in 2005, or do only pre 2005 tractors have enough age and hours on them for this problem to occur ?

no strangely enough its the 8v engines that gives this problem, from the introduction of the forterra to about 2005 ish.

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...phew... I was afraid they still had a pain in the ass haunting them... So this problem is solved on the new models (including the turbo lag, overheating, and exploding glass doors on the 11441 which the new generations dont have anymore)

...Thats a relief to me. If they still had a nasty issue like this, they'd better quit and go home... They have a long way to recover from the damage to their reliable name which the 11441 generation has done...


Was the problem solved in 2005, or do only pre 2005 tractors have enough age and hours on them for this problem to occur ?

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I dont know of any issues with the newer 16v engines, or other after 2005. i know of one engine seizing up due to a faulty visco fan clutch. other than that the engines seem to function perfectly, have 2000 hrs soon on 140 and no major flaws has presented it self exept the shitty quality of mitas tires and three heat registrys from webasto thats sprung aleak. oil sela on propshaft and a seal in the bellhousing when new.

Hmm i have thought this over, but it doesnt have anything to do with the heads: its about the insufficient capacity of the cooling system of the TIER 2 forterras. I know two or three of them with overheating issues. The constant high temperature is what kills the head gasket furthest away from the fan.

Hmm i have thought this over, but it doesnt have anything to do with the heads: its about the insufficient capacity of the cooling system of the TIER 2 forterras. I know two or three of them with overheating issues. The constant high temperature is what kills the head gasket furthest away from the fan.

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yes my 11441 blew 2 headgaskets and seized the back piston once. along with shitty load charactheristics im glad i got rid of it, it didnt feel like a zetor more like a Perkins engine dead in the water.

That series wasnt Zetors finest hour. In my area a 9641 bought new, is replaced by a 2nd hand New Holland and a 11441 with 2300hrs is replaced by an 8000hr Maxxum MX135. (They had two Ursus bought new, with 13.000hrs without major repairs)

Then another 11441 is at a customer that is rebuilding it a 2nd time because of overheating. His Proxima is making the most hours on the farm, even more than the Fendts.

That, together with the change of importer (to a wholesaler that offered no dealership backup) have hurt Zetor sales badly here. Customers are afraid that new Zetors are still as poor as the 11441 and dealers are afraid that Zetor CZ lets them down another time.
The Zetor import is back in trusted hands, but you cant win trust by just a signature on a contract...

What i read in Zetor writings is that the Crystal is just an appetizer while they work out all customer comments in its successor... Thats a good thing but if they made some minor ergonomic changes, on things that are the same points of critique as on the Forterra, they would have been taken a lot more serious.