Home Porting

crammit442

crammit442

makin' legs
Location
here
If you have much in the way of case porting, you'll need to fill the area behind your stator also. That area gets paper thin when ported. Mine is in the oven curing as we speak.:biggrin:

Charles
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Yes.....there's two spots in the flywheel/stator area that need epoxy. I got that covered.
Cleanliness and a bit of sanding will go a long f'n way to ensure the epoxy stays on.
 
D-Roc

D-Roc

I forgot!
Location
Dirty River Rider
do you fill all the voids or just the ones on the intake side and how did you fill the two bolt holes? did you just put the bolft in covered in grease and turn it out after the epoxy was cured? i am doing mine today.
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Yup, I filled all of them.

As for what angle to grind the ports....you shouldn't be touching the port roof or bottom. You grind the sleeve to match the template. Then you angle the bigger opening in the sleeve back towards the casting.
I believe you want at least 1/2 inch long taper - I believe more is better.
 
crammit442

crammit442

makin' legs
Location
here
D-Roc said:
do you fill all the voids or just the ones on the intake side and how did you fill the two bolt holes? did you just put the bolft in covered in grease and turn it out after the epoxy was cured? i am doing mine today.
Click to expand...

Yes. Pull the bolts when epoxy is still green before it fully cures.:smile:

Charles
 
D-Roc

D-Roc

I forgot!
Location
Dirty River Rider
okay i did the intake side but don't see the point of doing the voids on the opposite side, am i missing something? i do have more jb weld but didn't want to waste it on voids that don't need it.
 
Whale

Whale

X
Location
New Zealand
Ok ive just had a closer look at your pics form earlier in the thread and it looks like im on the right track. so you pretty much leave the top and bottom of the ports flat but tidy them up a bit.

thanks for the time you put into this thread:arms:
 
M

mikey23

Location
the netherlands
Matt_E said:
Alright....some case porting info.
Please note that I have [limited] experience with 62T cases only. In fact, I am not sure how you would go about porting 61X cases - though I think Keith Head does it. I believe Slymo ran one of his 61X ported cases.

Tools and materials:
  • Rough grit sandpaper
  • Metal epoxy (Devcon, and the like)
  • Grinder, slim profile (Dremel for me)

The important thing first: You'll be porting only the top case half - the 62T part . The bottom part is the 6M6 case half, the same on all 650s, 701s, 760s.

First, you need to clean out all the voids on visible from the top. Clean them with paint thinner, or something - you want the gunk, grease, and chunks out.
Take sandpaper to the inside of the voids where you can, to rough it up.
Once those voids are clean and dry, you need to fill them up with metal epoxy. I used the two parts stuff that comes in sticks from Randy @ Watcon. Great guy, full of information, too.
Stuff it in there good, fill up those voids. Your goal is to fill them up to the top.

The case porting will grind right through some of the case walls. The epoxy keeps everything together - essentially, you're making everything much beefier, so that you can take material away during porting.
Look at the flywheel area - there are a few deep spots in there that need epoxy. Make sure the area is clean, grease-free and dry, then put epoxy on.
Let everything cure, and make sure the top of the case (base gasket mating surface) is smooth and even. Take some sandpaper to it to straighten it out if needed.

Now on to the porting: Basically, you need to grind channels into each top corner of each intake port, for a total of four tunnels. This channels fuel/air mixture right into the transfer ports. So, grind a tunnel from the intake to the transfers - it's not that hard, just look at the pictures for guidance.
Make sure the tunnels are evenly sized.



Next, take some sandpaper and rough up every surface inside the top case that will have fuel/air mix going through it. All of the intake port, the bottom bowls of the transfer ports, etc...(it's a good idea to do this to the transfer tunnels on the cylinder as well)
The rough surface will promote better flow characteristics than the stock smooth surface.

Last thing: Finger filling. Looking at the intake ports of the 62T case, you'll see the infamous fingers. You have two options: Leave them alone, or fill them with epoxy.
If you fill with epoxy, do it like before - sand, clean, degrease, dry, then put epoxy on. The goal is to make the divets in the fingers disappear and to create a smooth top surface at finger top height.
Essentially, this reduces the volume available to air in the intake tract. This leads to higher air velocities through the intake tract. The advantage is better throttle response, as any change in throttle will get to the engine quicker (through higher air speed).
This comes at a significant trade-off. Less volume for intake air/fuel leads to weaker bottom end power. Freestyle case porting often leaves the fingers unported, for this very reason.
That's all I've got.

The first two pics are my cases, the third is Mile's Able stroker from last year, and the last shows what epoxied fingers should look like.
Click to expand...

How can the fuel/air mixture get in to the transfer ports when de piston is going up and closes the transferports ????
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
Yes, you should have left the top of the sleeve alone. That overhang is normal and determines port timing. You might be able to make up for it with more compression and ignition timing
 
MikeyB

MikeyB

H2O-Addict®
Location
Michigan
This is a great thread. One question, what are the fingers in the case that you guys are referring to?
 
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