ZT and ZA cylinder blocks

Jerry Grant · Apr 28, 2019

Are the cylinder blocks from a ZA (206ci) the same size as the cylinder blocks from a ZT (185ci)? I know the 206 had a 5" strike, and the 185 had a 4 1/2" stroke but same bore. The cylinder blocks seem exactly the same to me. I am restoring a 1937 ZTU. 1 cylinder block from the 37 is cracked and is toast but I have a couple cylinder blocks from a ZA parts tractor. Will these interchange OK?

ChrisQ · Apr 28, 2019

Yes. ZA, ZT, and R are all the same cylinder jug.

Alan K · Apr 29, 2019

Just to add, If you dont remove the ring groove at the top of the cylinder make sure to use two block to crankcase gaskets on each block. After you have everything assembled and snugged up good, turn the engine over by hand with the crank. In doing this you make sure that the pistons and rings dont hit the ring groove and break. This is what they used to do years ago when overhauling the R-Z engines when a ring groove tool was no longer available.

JOCCO · Apr 29, 2019

Tend to agree wirh Chris barring aside externally features. Would like to see pictures of the 37.

molinegb · Apr 29, 2019

All same blocks. Later one may have 10A number.

MMDEL · Apr 29, 2019

Correct, The only difference between the RE blocks and the !0A blocks was the !0A blocks had satellite valve seats in them.
MMDEL

Jerry Grant · Apr 29, 2019

Thanks for your responses. You guys on this forum have always been very helpful.

ZT and ZA cylinder blocks

Jerry Grant

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ChrisQ

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Alan K

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JOCCO

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molinegb

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MMDEL

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Jerry Grant

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