NOTES ON KMZ “DNEPR” ENGINE EVOLUTION POST MODEL MT-10
This information pertains to modifications made to the design of the cam followers* (*sometimes incorrectly referred to as “tappets” which are actually the valve lift actuators [rocker arms] located in the cylinder heads), different pushrods (length ???), and even different engine crankcases (part numbers. drawings???) used on some later model KMZ Dnepr overhead-valve 650cc engines, i.e. MT-11. Read on.
Definition: In mechanical engineering a camshaft follower is a specialized mechanical part designed to follow the cam lobe profile (lobe ramping), and is part of the engine’s valve timing mechanism. The cam followers lift transmits to the pushrod that activates the inlet and exhaust valves in the cylinder heads.
There are two types of Dnepr camshaft followers, 2 types of pushrods, and different crankcases!.
Let’s just call these cam followers Type 1 (early) and Type 2 (later). The two types are not interchangeable with each other (see below).
There are four cam followers and pushrods per engine. They are interchangeable with each other but must be all either of the Type 1 or Type 2 design and used in their appropriate engine crankcase).
Please study and read this article in full and look closely at the parts diagrams!
Type 1: Part number MT801411 is a one-piece cam follower for mass produced models “Dnepr” K-650, MT-9, MT-10
Type 2: for some models of “Dnepr” MT-11 (and MT-16), described below, is a spring assisted cam follower which consists of four (4) separate parts that make up the cam follower as follows:
- Part number KMZ-8.152014-6 Tappet
- Part Number KMZ-8.15201412 Tappet guide
- Part number KMZ-8.15201413 Spring
- Part numver KMZ-8.15201414 Circlip
There are two cam follower styles (here referred to as “tappets”) for MT11/MT16 engines, one is the regular single piece and the other two piece (plus the spring and circlip). They’re not interchangeable however, because a different crankcase is required for the retaining circlip rings! Theses two-piece tappets along with spring and circlip are super rare and are hard to find these days however they are a better design as there is less moving mass and you can replace the sleeve without wearing out the engine crankcase itself. There is one conversion that people (like myself) have done which is to adapt the modern Ural tappets, which are also two piece round design to the Dnepr crankcase, however they are longer and require the pushrods to be shortened I’ve been doing a deep study into variants of the Dnepr MT11 build and encourage others to have a look, notice for example that there are several part numbers listed in that drawing for pushrods, this is because the cylinder height (which sets the compression) varies between different variants of an MT11. There are lots of subtelties like that, all fascinating and infuriating. Thank you, I’ve noted the information and will retain for future use if anyone asks. I’ve got one case with these 2-piece style tappets and I’ve been searching for these tappets for a long time on the used market, 5 found so far, only 2 usable. You can buy them new from oldtimergarage, but they’re £40 each there, possibly they manufacture them newly from raw material p.s. if you read this far, could you let me know the dimensions of the springs? I’ve been trying to find that out for a while Thank you Igor.
from Igor Turner via the Cossack Owners Club:
Thanks for the info, thought already that they are very rare😄 spring dimensions, height 20, diam. 24 thick 2.5 I ordered springs on Ali, because I was missing one! The tension is a bit too much compared with the old ones, so thickness can be less, 2.0 or 2.2 will be better!
reply from John
*** NEED MORE INFORMATION, MEASUREMENTS, PHOTOS DIFFERENT “DNEPR” MT-11-16 CRANKCASES PUSHROD ASSY ***
sorry for the poor quality image (from MT-16 owners manual) showing a Type 2 cam follower, showing pushrod (left) and camshaft (right) 17 & 18 circlip and spring (proper description of parts???) 19 Bottom half of follower (proper description of part???) 20 Top cam follower (proper description of part???) DIFFERENT “DNEPR” MT-11 PUSHRODS MT8014-5 MT-9, MT-10 MT8014-5-01* PUSHROD ASSY (proper description of paer???) MT8014-5-02** PUSHROD ASSY (proper description of paer???) NEED MORE INFORMATION, MEASUREMENTS, PHOTOS How many MT-11 were made? The answer is probably, a lot. Any contributions are welcomed if you have any pjotos or further information to add here, send it in! That’s the story so far, we’ll add to this page if possible. Compiled by Cat and JD Additional sources: Igor Turner, various parts manuals