250 2v XY

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I spoke with crow about their cams, and they suggested the one above it (63666) if you are doing a lot of driving or high way driving if I remember correctly. However they appear to be relatively close....
 
yeah i was thinking that one but i want a rough idle and i will be doing alot of highway and lots of driving, so its a hard decision. I will be going to straight gas soon, so fuel consumption wont be a mssive deal, as long as its still cheaper than petrol.

Do you think there would be much difference between the 2?
 
i tried to measure it, how does this sound?
The height from top of block to top of piston is 1.2mm
and
the height from top of block to dished section of the piston is 4.05mm

I will try to get a better measuremnt tomorow, but i forgot to get the diameter of the dished section. which will be hard to measure since the dished section is a parabolla.
 
also dad just said that he has a feeling the pistons in it might be from a crossflow, and the conrods have been reconditioned so they are smaller, which would explain the big measurement of the deck height.

So maybe i need to shave the head a fair bit.
 
47 thou deck height. Dish sounds fairly small - maybe 8CC?

I'm getting a CR about 9.4 to 9.5, but that's with a LOT of assumptions. It tallies with the practical experience of A7M's number.
 
tomxy":ycysm1qd said:
yeah i was thinking that one but i want a rough idle and i will be doing alot of highway and lots of driving, so its a hard decision. I will be going to straight gas soon, so fuel consumption wont be a mssive deal, as long as its still cheaper than petrol.

Do you think there would be much difference between the 2?

you dont want to go too big on the cam with gas mate or you will loose vacuum and the car will be doughy as anything off the line
stick with the cam stated above the 63666 i use this and it is a fantastic cam with a nice exhaust note, if you want a lumpy rough idle go and put a solid in an 8. sorry just my 2 cents
 
ok ive ordered the crow cam 63666 with increased midrange power, good fuel economy and quality idle, i also got springs, lifters and timing set.

With the head i was thinking of getting the exhaust faced, the head shaved about 60 thou, hardened exhaust seats, because apparently you dont need them for the inlet. and valves faced and tipped.

How will this go?
 
tomxy":29d321kd said:
ok ive ordered the crow cam 63666 with increased midrange power, good fuel economy and quality idle, i also got springs, lifters and timing set.

With the head i was thinking of getting the exhaust faced, the head shaved about 60 thou, hardened exhaust seats, because apparently you dont need them for the inlet. and valves faced and tipped.

How will this go?

i would think 60thou off the head would bump the comp too high
especially if the blcok is zero decked.

zero deck the block first and then cc the head before shaving anything off. check and recheck your CR before shaving the head. You can always take some off but you cannot put any back on without big cost.
 
thanks for that, i will measure the cc and cr again, and make sure and see what the machinist has to say as well as you guys.

Will the cam im getting be good for straight gas?
 
Ok i got my cam, just want to know if i should advance my timing, what would it acheive?
 
Cam timing? Have a read of the Big Block Six Forum thread with a name like "figures".

Bill moves the timing back and forwards on a standard cam - the effects will be similar (proportionally).
 
i think for the mild nature of your engine tom and your also your abit inexperienced like me i would just line your cam timing marks up on your timing set dot to dot.
you could dial in your cam but you will need to go and invest in a dial guage and also someone with the knowledge of how to use this properly.

i beleve for a hyro camed street engine like yours and mine the dot to dot is just fine.
 
We've had one here, where the cam was 11 degrees off where it was supposed to be. Admittedly, not a Crow grind - but it makes you pretty wary.
 
Today i got my head back from the machinist, $350 for lpg exhaust seats, exhaust stems, faced and tipped exhaust valves, shaved the exhaust manifold 3mm to get it flat, shaved the head 40 thou to get out a warp, and now i have to try face and tip the inlet valves and seat them and we are ready!

Hows this sound, did I end up getting the right stuff done for the right price?
 
yep all of it was done for $350, at a local machinest, if i went to canberra it would of cost $700, so i am very happy. Cant wait to put it together today, with all the new parts.

Just hope it will go quicker than a VL or VS. lol
 
Hey Tom,

Do the machinist a favour and let us all know where you went? Nothing better than word of mouth, especially if he did a good job for you.

Where are you located as well? I am in Penrith area.

Dan
 
Gunner_Boone":zfvuqtyi said:
Hey Tom,

Do the machinist a favour and let us all know where you went? Nothing better than word of mouth, especially if he did a good job for you.

Where are you located as well? I am in Penrith area.

Dan

hey Dan,

I live on the south coast of NSW near batemans bay, i went to a guy just past moruya, not sure if anyone knows where abouts i am but if you want more details tell me.
 
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