Pipes to viper 780

1: No
2: 98 octane. But our 98 means 93 in us. We have different way to measure. for example cm/inc
3: Dont know what to say about that ;)
 
1.)ok, well we are close to a fix, do you know how to cc a head? its easy and you can do it right there on your workbench. if you need me to, i can explain it.

2.)do you have access to a machine shop, a shop with a mill?
 
1: Yes but dont have a cc pipe to fill with water, but maybe you have a idea?

2: No access but know people who can do it for me
 
find a large syringe, ( a shot), this will be in cc increments, works great.
 
ok, great.

put in just 1 layer of the headgaket, .010" layer. Clean it well with brake clean etc, then give it a dusting of copper coat spray gaslet sealer, do both sides and let it dry good. Then install the new venom heads, this will give you .061" squish, which is a little big for my liking but will be better then the .070" you had before.

if you want to make it really good, youd need to machine the flat surface of the domes .004-.005", and also the head shells. i do realize not everyone has the luxury of being able to whip something into the mill like I have. Its not going to be worth 10hp but just makes the engine alot closer as far as head set up. If you dont have a buddy who can do it just run it with 1 layer and we will go from there, its an improvement to it no matter what, the squish will be better, the cooling will be almost 2 times better so its a no lose situation using that venom head over the stock one.
 
kinda tuff to say how much power gain,but it will most definitely run better then with .070" squish.

since you have the head off you can take a digital caliper, use the end and measure the exh. port heigth to the top of the cylinder, because this will give me an idea of the compression ratio youll be set up with, it will also give me some insight as to what spec the cylinders , to make good power hopefully its right around 29.5-30mm from the top of the cylinder.

lastly, what jetting is in it as of now, pilots, needles pos. and mains?
 
Wich port height do you mean? Exhaust? Intake? The jetting is no problem. I have run it in a dyno so I know I have to have 1230F exhaust temp to make it down to 0.62-0.65 bfsc
 
I believe the measurement that Don is interested in would be from the top of the cylinder to the top of the exhaust port. This measurement would indicate what RPM and how aggressive the porting was..."Mild" or "Wild".
 
yes, Bob is right its the main exh port, just go from top edge of cylinder to top of port.
 
Mrviper700... you are a good guy!
This thread is very impressive, and the amount of help you are providing to a stranger (assuming) is incredible.

Kudos to you!
This is the kind of thing that makes this site so successful!
 
well viperhauck, you just found out why it doesnt make big power, between the exh port and the head set up is why your low on power. If it were me at this point, I would pull the cylinders and open up/raise the main exh ports, thats way too low for a 780 with pipes. 29.5-30mm minimum, theres LOTS of power to be had there yet.

for referance: 30.5mm is a stock viper cylinder, so thats where your likely at and its easier to measure with cylinder off.

maybe remove the cylinders and take some pics of the ports,some measurements and I can maybe help ya out on some more power.
 
Thanks for all the help. Hauck has presumably just bored it out and replated and nothing more. Is it difficult to port this myself? Havent done it before and I know it must be done right so I dont mess up the nicasil.
 
Hauck has had the tendency to bore out cylinders in his big bores, and do absolutely zero porting on them, resulting in lower than stock port heights from the increased bore size. I've seen it a few times on his cylinders. Hopefully that is not the case for you.
 
mrviper700 said:
well viperhauck, you just found out why it doesnt make big power, between the exh port and the head set up is why your low on power. If it were me at this point, I would pull the cylinders and open up/raise the main exh ports, thats way too low for a 780 with pipes. 29.5-30mm minimum, theres LOTS of power to be had there yet.

for referance: 30.5mm is a stock viper cylinder, so thats where your likely at and its easier to measure with cylinder off.

maybe remove the cylinders and take some pics of the ports,some measurements and I can maybe help ya out on some more power.
Click to expand...

JM.02c

The port may have ended up at 31mm because of the down angle of the exhaust port...when they bored the cylinder and did not raise the exhaust port they would have actually moved the exhaust port down slightly!
If it were me I would get these cylinders ported properly for a 780 by someone that knows these BB engines well...

Like MrViper

As I said before great posts and expert info!
 
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