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Thread: a rough estimate of your VW engine stroke.

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    Default a rough estimate of your VW engine stroke.

    Good day to all, I just watched a racing engine mechanic show how to find a estimate value of your engine stroke.

    With a thin straight rod of metal, slide it down the spark plug hole until it stops. Note what you are aligning with to make the mark on the rod. Remember this area as the next mark has to be at the same point of reference. IF lined with the tin shrouds, you can use this edge, just make sure same spot when marking the rod for the second time.

    Now I rotated CCW to BTDC mark, that put's #2 at TDC, and #1 down at the end of its travel, slide the rod down #1 cylinder and mark it. Now you can take the rod and measure the distance between marks, this gives you a rough estimate of what the stoke is. My 74 1600 DP, which I know was rebuilt at least once, measured 76.14 mm, checked the process twice and 2nd time was 76.46mm, so straight rod and same angle and reference mark is the key to accurate measurement.

    Now I will look up and see if one can have such a thing as a 76mm stroke, I read about 69mm and 84mm so far in other articles. Getting interesting.

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    Interesting ... but wouldn't a VW book tell you the stroke?

    Does the stroke vary much from 74 1600 DP to other 74 1600 DP's?

    I might be missing something.
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    Told ya so....

    Did not think it was going to be totally stock inside there.

    Stock stroke for 1300 (1966 year) until the last type 1 made was 69mm.

    There are some odd stroke cranks like 74.3 and such. Not very popular now a days.

    You can do 74 to 76 stroke crank with no real heavy machine work inside the case.

    Mine is 86mm and is far as you are going to be able to go without buying a billet drop cam race case.

    I thought I had all the stroke charts over in tech?

    1b6f67bc935d12bfda074c07aa20c85a.jpg

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    Get an eyeball on it and see if there are shims under the cylinders where they meet the case.

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    I did it because it was a simple proven way to get an idea about things with out cracking it open. Rex your video link actually allowed me to view it. There are six different ones to watch, all had educational value to them for me.

    I am glad it is the only engine I have to play with, trying to keep the info separated from American to VW would really lead to major errors for me, at least I think.

    Humm, so lay down under the engine so that I can see the cylinder heads, follow down from the valve covers to were the heads meat the case, a seam line should be present, correct.

    Now how does one see shim's, oh not round shims around the bolts, but a large shim that would cover the entire surface that the cylinder head and case have, were they mate together. Correct

    I will give it a look a see, all is up for IRS bushings replacement, among other things.

    Also learned that I did not perform the compression test accurately, a general idea, but still could be 10 to 20 or more off on true PSI reading. Just the same I learned about the leak down test, the proper way, and how to make sense of the data you get, so than one can get an idea about valve leakage and/or cylinder ring leakage. Very interesting, why am I doing this, because I had my timing off, some how, and the engine has run hot for a bit, enough to change the coloring of the chrome exhaust pipes. Yep, a real newbie screw up.
    Last edited by grandpanystrom61; 03-24-2018 at 08:41 AM. Reason: add more text

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    Default a pic is worth a thousand words

    I took a picture of what I thought might be the shim you mentioned.

    20180324_064751_001.jpg

    that wheelie bar is in the way a bit, another try.

    20180324_064723.jpg

    The the top are of the pic is of the cylinder head, as the push rod tube goes down to the case, at the bottom area of the photo you see that other tin I mentioned, just up a little that the shim ?

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    I got to draw an arrow pointing to what I think is the shim.

    20180324_064751_001_LI.jpg

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    It looks like you are at the head end of the cyl.

    I can not quite place where you are.

    But if it is shimmer at the head to cylinder joint you will not be able to see it.

    Under the cylinder to the case joint where the head studs screw into the block.

    I am at the shop working on an leaking oil hose on mine right now. Lemme see if I can get a pic. Mine has huge shims.

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    At the base of black cylinder.

    Hard to see as all painted black together.

    15219018207680.jpg

    15219018478261.jpg

    NOT the head end. Even though mine is shimmer. 050 there also.

    15219018675412.jpg

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    wow, a very clean engine, but did not expect less from you. I am sure at first this engine looked that clean, but now it has the layer of crude, oil and fine dirt, road grime. I will get it cleaned up so I can see better, and yes I was the wrong end again. So this does prove what another said, really get to know and understand the engine before rebuilding it, it will make all the difference in the end. I totally agree with this, off to the garage I go

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