Transfer ports

[black]

When you guys do drag race porting, high exhaust and transfer port duration
do you hit the water jackets on the transfers and do you weld it up? The 86 jug when flattening the transfer roofs hit the water jacket pretty quick.

[Roostius_Maximus]

I've never hit water in any jug

Post a pic of where you did please.
How tall we're you making them?
I prefer to keep the port ceiling the same angle or a degree steeper than the piston dome angle.
I also haven't had to really hog them out really tall tho either. I found the velocity really drops off and they go turbulent so much that they flow less than stock, kinda defeats the purpose.

[cr500man]

If your dealing with really high numbers you should have raised the cylinder with a thicker base and decked the top of the cylinder to get the deck height back to normal. Lani at copper gaskets unlimited can make copper base gaskets in different thicknesses. The problem with high durations on the exhaust is the drop in torque, we never ran drag numbers cause the gain wasn't worth the sacrifice.

[black]

I send it for welding, my numbers was not high and was only asking about drag type porting because I hit the water jacket.
I flattened it a lot trying to regrinding the outside radius were it meets the roof and that's were the one transfer port opened.
I think it could be a casting problem on that specific jug.

[Roostius_Maximus]

while doing sleeve work i've seen some be perfect, usually their older jugs, the later ones have big porosity cavities in them behind the stock liner.

[coley13]

There is bloke down under that might be able to help. He is a member on the other site. If you want his details pm me.

His bike will do 1/4 mile high 9 sec low 10 depending on reaction time at 198km/h over 400 meters. His cylinder is heavily modified to the point you can see welding onthe outside of the cylinder.


Not sure if he will help you but I can point you in his direction if you like.