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Topic Review (Newest First)

  • 10-07-2009, 05:57 AM
    fireboat607
    Just asking, who's name is on these Chinese blocks?

    Anyone can pedal a bicycle, can you pedal a flat?????
  • 10-04-2009, 06:07 PM
    MSCobalt220
    Quote Originally Posted by CNC BLOCKS View Post
    GM OEM blocks seem to all over the place as far as cylinder place, lifter placement, cam tunnels and decks and most GM blocks seem to be under 9.025 on the decks.

    Now once and a while I do get a GM block that is pretty good as far as locations go.

    On the GM blocks if you measure from the datum point (Front to rear) which is the center of the front head to block dowel hole they are pretty much right on the money.

    Yhe chinese block the front of the block needed to be machined .020 to be in spec and the would also make the cam go back further in the block to match the lifter bores.

    Using a flat tappet cam it would not last 5 minutes having the lobes riding over the edge of the lobes.

    99% of the OEM mainlines are with in spec as the chinese one needed .003 line honed out before it could be used and the cam tunnel is .002 tight on the first 4 journals and .003 on the rear one.

    Hope I have answered your questions.
    Quote Originally Posted by flat screwd View Post
    Yep.
    It appears that you would be getting "flat screwd" if you happen to buy this POS .
  • 10-01-2009, 04:41 PM
    flat screwd
    Yep.
  • 09-30-2009, 06:59 PM
    CNC BLOCKS
    Quote Originally Posted by flat screwd View Post
    I dont see any mention of stock gm numbers in post three, theoretical numbers maybe but then again , how does the inconsistency of stock gm hold up against the lookalikes. Not trying to bust any chops here ,just curious.
    GM OEM blocks seem to all over the place as far as cylinder place, lifter placement, cam tunnels and decks and most GM blocks seem to be under 9.025 on the decks.

    Now once and a while I do get a GM block that is pretty good as far as locations go.

    On the GM blocks if you measure from the datum point (Front to rear) which is the center of the front head to block dowel hole they are pretty much right on the money.

    Yhe chinese block the front of the block needed to be machined .020 to be in spec and the would also make the cam go back further in the block to match the lifter bores.

    Using a flat tappet cam it would not last 5 minutes having the lobes riding over the edge of the lobes.

    99% of the OEM mainlines are with in spec as the chinese one needed .003 line honed out before it could be used and the cam tunnel is .002 tight on the first 4 journals and .003 on the rear one.

    Hope I have answered your questions.
  • 09-30-2009, 05:02 PM
    flat screwd
    I dont see any mention of stock gm numbers in post three, theoretical numbers maybe but then again , how does the inconsistency of stock gm hold up against the lookalikes. Not trying to bust any chops here ,just curious.
  • 09-30-2009, 04:31 AM
    CNC BLOCKS
    Quote Originally Posted by flat screwd View Post
    Just for the sake of asking , with all the dimensions of the reproduction look alike blocks how do they compare to stock GM .I am not so concerned with the cosmetics but rather the blueprint dimensions.
    Post number 3 has all the info your looking for.
  • 09-29-2009, 08:06 PM
    flat screwd
    Just for the sake of asking , with all the dimensions of the reproduction look alike blocks how do they compare to stock GM .I am not so concerned with the cosmetics but rather the blueprint dimensions.
  • 09-28-2009, 09:50 PM
    Boat 405
    Quote Originally Posted by CNC BLOCKS View Post
    If you have a lot of time to read here is a link I did on the Chinese block.
    http://speedtalk.com/forum/viewtopic.php?t=17747
    Thanks Carl, that is some great info. I'll let you know the details after I test with the new motor.
  • 09-28-2009, 09:06 PM
    CNC BLOCKS
    If you have a lot of time to read here is a link I did on the Chinese block.
    http://speedtalk.com/forum/viewtopic.php?t=17747
  • 09-28-2009, 08:22 PM
    Woods 017
    Quote Originally Posted by CNC BLOCKS View Post
    Here is a quote from another site where I posted my findings of the Chinese block.
    Thanks for the info and welcome to performance boats.
  • 09-28-2009, 08:20 PM
    Woods 017
    Quote Originally Posted by Hydroguy View Post
    Why not the same deal on big M blocks?
    Because the block is a knock off of a Dart that is being cast and machined in china.
  • 09-28-2009, 07:25 PM
    sleekcrafter
    Quote Originally Posted by CNC BLOCKS View Post
    Here is a quote from another site where I posted my findings of the Chinese block.

    Great info
  • 09-28-2009, 07:20 PM
    Hydroguy
    Why not the same deal on big M blocks?
  • 09-28-2009, 07:09 PM
    CNC BLOCKS
    Here is a quote from another site where I posted my findings of the Chinese block.
    Quote Originally Posted by CNC BLOCKS
    Finally did the final probling of the Brand X block
    Block datum points in the CNC machine are the cam and crank center line, center line of the bar through the mains and the center of the head dowel on the front of the drivers side block.
    Also the block uses the same dowel holes under the fuel pump and starter area which I would say means the blocks are being machined on a track system which is used in high production machining.
    One of the biggest problems with the block is from the center of the dowel pin which is the datum point, From there out to the front of the block the demension is suppose to be .845 and on this block its .865 which will move the cam a head in the block .020 and on a flat tappet cam the lobe will not last long riding on the edge of the lobe.
    Now if you are using a BHJ lifter bore fixture which referances of the front of the block and going to an lifter .875 lifter bore it will leave a shadow on the rear of each lifter bore which means every lifter bore will need to be bushed even to run a .875 lifter.
    The cylinders on the both sides were with in .003 front to rear.
    On the even side left to right or intake to exhaust or I call this Y-axis the best was .001 worst was .0038
    On the odd side in Y-axis best was .0018 the worst was .0077
    Deck heights were on the even side were
    low was 9.028
    High was 9.038
    Deck heights on the odd side were
    Low was 9.029
    High was 9.032
    On the lifter bores we check the angles on all four corners only which should be 41 degrees.
    Front lifter bore cylinder one was 40.937
    Rear on cylinder seven was 41.026
    Front lifter bore cylinder two was 41.020
    Rear on cylinder eight was 41.014
    I also used a .8425 cutter and machined down appox. .200 down on all four corners
    And on cylinder one first lifter bore the cutter cut appox.006 at about 8 O'clock looking from the left side of the block which means the lifter bore was to far back and to far to the inside of the block
    On cylinder 7 the rear lifter bore cut only at 12 O'clock looking from the left side of the block meaning the lifter bore was to far to the out side of the block appox. .006
    On cylinder number 2 front lifter bore and cylinder number 8 rear lifter bore the cutter was only cutting at 12 O'Clock looking from the left side of the block which means the lifter bore was towards the inside of the block to much appox. .004
    Running a roller cam your are dealing with direct center lines and having lifter bores of that far will change your seat to seat timing events.
    The other problem I mentioned earlier was the hole through the lifter bore front to rear to and on the front lifter bore even side was the with in .003 of the Dart block but the rear of the hole dropped .0024
    Looking at the 2 blocks side by side the hole in the Brand X block looks like the oil hole is 3/16 closer to the bottom of the lifter bore compared to the Dart blocks, The problem being is there is not enough material under the bottom side of the lifter bore or cam tunnel area as I measured from the cam bearing journal to the casting and its .200 different then the Dart block. Which means there maybe a chance of the lifters oil band being exposed when the lifter is on the base cirlce of the cam and more so a bigger problem with a small base circle camshaft.
    From here the block is going to an other shop to have a brennel test done.
    At this piont I am not going to waste my time check the cam tunnel for its locations as I have spent to much time all ready.
    From my findings this block needs a lot of work before it could be used and if its a soft as I think it is there is no cure for that.
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