Chinese look a like Little-M block
08-25-2009, 07:21 AM
#71
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Posts: 1
Originally Posted by hink
I talk to Dick Boyer yesterday and I told him a block was being sent to me to probe it out and I would not post the the results on the forums but would email him my findings and to the shop that is sending the block.
And by his response he seemd very interested in what I find as far as loctions and lifter bore angles ETC.
And by his response he seemd very interested in what I find as far as loctions and lifter bore angles ETC.
If it were me,and I would encourage all the engine builders to do the same,I'd just tell 'em it's all wrong,kick it outdoors,and let it rust in the gutter. It's probably going to come about anyway,but I would at least make them work for it rather than just steal it.
That's just my knee-jerk reaction/opinion however-your mileage may vary.
08-25-2009, 09:34 AM
#72
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Join Date: Sep 2007
Posts: 58
Originally Posted by heshtesh
You know guy's i appreciate the way your looking at this but did'nt someone have to buy the first Dart block in order to gain it's reputation. Where i live a lot of the guy's use PBM parts in thier dirt cars some turning a little over 9 grand sometimes with no quality or durability issues. Life's full of chances and if this piece is what they say it is i think it might prove to be a more stout piece than the Dart. Being a Manufacturer myself i would'nt risk my reputation that i could put a part on market prematuely and i don't think PBM would either. You know if the piece doe's turn out to be what it is indicated to be it could be a hell of a bargain. I like that all 5 mains are 4 bolt and i like the steel main caps and the fact the cylinder walls are a little thicker as i'm building a super charged engine. Sometimes you have to take the leap of faith in life, here go's
08-26-2009, 07:02 AM
#73
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QUOTE from speedtalk
Originally Posted by Doug Kennedy
I just got done looking at the pbm block. All I will say is,i'm not impressed. It does look like the same block that Carl posted a picture of.
It tested under 15 on the rockwell C scale on my tester
It tested under 15 on the rockwell C scale on my tester
09-09-2009, 02:17 AM
#74
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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.
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.
09-09-2009, 02:58 AM
#75
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Posts: 4,137
I am just curious....I understand we are talking about a race type block. But how does this thing compare to a production Chevy block as far as being to print? Would the average 010 block do better, worse or about the same as this if you measured it the same way? I am not asking this to make an argument for using this block, I am asking to satisfy my own curiosity as to how close to "right" a factory block is. Nothing more.
09-09-2009, 06:47 AM
#77
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Originally Posted by Tod74
I am just curious....I understand we are talking about a race type block. But how does this thing compare to a production Chevy block as far as being to print? Would the average 010 block do better, worse or about the same as this if you measured it the same way? I am not asking this to make an argument for using this block, I am asking to satisfy my own curiosity as to how close to "right" a factory block is. Nothing more.
010 very from block to block as far as lifter bore and cylinder placement and cam tunnel placement.
