Panzer III and IV engines were technically very reliable and I don't think that they normally formed a constraint in the use of the tanks. Tiger and Panther were a different thing because the engines were too weak compared to the weight of the vehicle. Tracks and transmissions of Panzer III&IV were much more sensitive to damage. However, both in Africa and Russia engines suffered heavily from fine dust and many engines broke down before proper air filters could be installed. How many hours exactly the engines were expected to last in theory I don't remember for certain, but 2.500 hours seems to ring a bell.

Regards,

quote:

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Originally posted by Greg LG:
I don't think T-34s could go more than 1,200-1,500kms before needing their engines replaced. I've read that even the track shoes on Sherman tanks had a longer life than a T-34 engine

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T-35, 300, 150 engine hours
T-26, 400, 200
BT-7, 600, 200
BT-2, 450, 150 (BT-5 same)
T-26, 600, 150
T-27, 800, 200 (T-37 and T-38 same)

Capital repairs or servicing is done at central workshops or the factory.

War experience for the average work indicator for a tank before dispatch to capital repairs is: T-34 - 250-300 motor hours (1500-2400 km), IS - 200-250 motor hours (1200-2000 km). Average distance for one motor hour is 6-8 kilometers.

"Concerning "engine life between services", the minimum time between capital/medium services was 600/200 hours for the BT-7 and 600/150 for the T-26. These were entirely satisfactory indicators; for the T-34-85, the most reliable model in the T-34 family, the corresponding numbers in 1945 were 600/250 hours (3,500/1500km). According to Anfilov, BT and T-26 tanks were considered have limited time before next service when they had 75-100 hours remaining. In this regard, one should keep in mind that during combat operations the servicing standards for armored vehicles, relevant for managing their operation in times of efficient accounting, were considered to be only recomendations."

"In connection with this, it should be noted that in the end of 1940 the head of the Chief Vehicular and Armored Directorate [GABTU], Ya. N. Fedorenko, believed that "a mechanized corps in a breakthrough could not operate longer than 4-5 days, since it would expend 50 hours of engine time."

"The time between services for a T-34-85 was 250 hours, but the driver-mechanics pushed that to 320-350 during mobile operations."

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Originally posted by Starinov:
Can anybody give similar info about german tanks?

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- A French report from 1947 on the Panther states that average engine life was 1000km with some reaching 1500km. (Spielberger)
- A German report from April 1944 mentions that "new engines have a significantly longer lifespan than the first series" and mentions examples of engines running up to 1800km. (Jentz)
- A document dealing with the engine life of a wide range of vehicles in service with British forces in North Africa (and Italy?) has some figures on engine life (from Bovington, was posted on the G104 Yahoo Group May 5th, 2001.)

Sherman M4A2: 1400-3000 miles
Sherman M4A4: 518-642 miles
Churchill: 600-1000 miles ("rarely more than 1000 miles")
Grant: 400-2000 miles.

I dont know how the French report reached its conclusions, but the figures from Jentz is a single case of three tanks while the British figures are taken from many different reports, some of the figures qualified by "isolated case" or some specific cause like "oiling up" or "by constant plug changing". So they should not be taken as averages but rather as examples.

Serviceability of British Tanks
From (WO 169/952) 7 August 1941, message from Brigadier AFVs, Western Desert to GSIa, Middle East, regarding the average daily percentage of vehicles unserviceable during June and July 1941:
“I” Tanks 19%
Cruiser Tanks 28%
Light Tanks 26%
Armoured Cars 3.4%
Carriers 10%
Morris FWOs 8.1%
“B” Vehicles 9.5%

7 September 1941, message Brigadier AFVs, Western Desert to DCGS, regarding of serviceable and unserviceable cruiser types in Middle East (runners include those with schools and etc.) under repair/serviceable = percentage of total available unserviceable:
Mk I (A9) 10/38 = 20.8%
Mk II (A10) 9/33 = 21.4%
Mk IV (A13) 18/67 = 21.2%
MK VI (A15) 14/53 = 20.9%

25 September 1941, message Major General AFVs, Middle East to ?, at the end of June 1941 the following were under repair/serviceable in the Middle East:
Cruisers 27/113 = 19.3%
“I” Tanks 39/63 = 38.2%
as of 25 September the situation was:
Cruisers 69/387 = 15.1%
“I” Tanks 35/216 = 13.9%

From (WO 169/3861) message G(AFV) Middle East to ?, end of September 1942, regarding the Tank Overhaul Program:
Overhaul Mileage Limit:
Crusader – 1,200
Valentine – 2,500
Matilda – 1,000
Stuart – 3,500
Grant – 1,500
Annual Mileage Rate:
All – 3,000
Time in Workshop for Overhaul
All (except Stuart) – 8 weeks
Stuart – 4 weeks

Objective of the program was to maintain tank formations in the field above strength with a vehicle mileage limit of 250 miles per month.

Most people who read this forum are probably familiar with the assessment which the Aberdeen Proving Ground in Maryland did on a T-34 and a KV-1 in 1942. A recent article by Boris Kavalerchik about the assessment appeared in the Russian-language magazine Voenno-Istoricheskiy Arkhiv, issue No. 1, 2006. I found a couple of things striking. First of all, and this is not the striking part, Kavalerchik says that contrary to popular opinion in Russia which holds that the T-34s which were sent to the US and England were intentionally not of the highest quality, in the spring of 1942 five T-34s were specially prepared using the highest quality parts at the Ural Tank Factory (UTZ), which at that time produced the best T-34s in Russia. These five tanks were better than regular T-34s. One was sent to the U.S., one to England, two to the front, and one to the Peoples Commissariat for Tank Production and can now be found mounted on a pedestal in the yard of the Central Museum of the Armed Forces in Moscow.

The striking part of the article, to me at least, is this part, which comments on Aberdeen’s finding that the T-34 broke down beyond repair after 343 kilometers due to dirt getting into the engine’s cylinders. Apparently this was very good!

“There was nothing unusual about a tank breaking down after such a short period. At that time T-34 tanks were guaranteed not to break down for 1,000 kilometers, but in practice this number was unattainable. According to a report by the Scientific Institute for Armored Equipment (NIBT) to Ya. N. Fedorenko, the chief of the Red Army’s Auto-Armored Directorate, the average distance a T-34 traveled before requiring overhaul (capital repairs) did not exceed 200 kilometers. The Aberdeen T-34 exceeded this.

In 1942 the quality of Soviet tanks had significantly fallen for many understandable reasons. These included the difficulty of reestablishing production by the evacuated factories at new locations, factories switching over to new production, the loss of many supply lines and sources of raw materials, a sharp drop in the average qualification of workers due to losses among experienced workers and the hiring of many new, inexperienced workers including women and teenagers. These new workers worked tirelessly and did everything they could for the front, but they were not qualified. Producing the most tanks possible was the priority, which was understandable since the heavy losses of the initial part of the year had to be made up. Therefore the requirement for quality was reduced, and the military accepted any tank that was built. As a result, in 1942 some 34’s could only go 30-35 kilometers before needing an overhaul.

To a certain degree this was justified because tanks, as a rule, did not survive until the expiration of its overhaul life, short as that was. The life of a tank on the front line was not long – on average 4-10 days (not counting time spent in transit on rail road and being repaired), or from 1-3 attacks. In 1942 the average mileage before being put out of service due to combat was 66.7 kilometers, which was less than half the average mileage before needing an overhaul. The majority of tanks simply didn’t live long enough to break down.

The V-2 diesel engine which equipped T-34s and KV-1s was still suffering growing pains. At that time its designers were struggling to extend the diesel’s service life to 100 hours, but in reality it seldom lasted more than 60. The engine of the T-34 which was tested at Aberdeen broke down at 72.5 hours, of which 58.45 were under load and 14.05 were while idling. The KV’s diesel lasted 66.4 hours. One of the deficiencies of the B-2, besides a short guaranteed life, was an increased fuel consumption (12% above norm), and, especially, a completely unacceptable over-consumption of oil, which exceeded existing norms by 3-8 times! Therefore the range of a T-34 in 1942 was limited not by fuel, but by oil: according to the averages at that time from the technical department of the People’s Commissariat for Tank Production, a T-34 carried enough fuel for 200-220 kilometers, but oil for only 145. At the same time German and American tanks didn’t require any additional oil; it was simply changed every 2,000 kilometers.”

[This message has been edited by Gary Dickson (edited 02-04-2006).]