Porting cyls w/ racelogic template and 4mil short rod

[Atomic Monkey]

Hello all!

I have questions about a build I'm doing on my banshee.  

I just got it last year, and melted a piston recently due to a leaky head gasket that caused a over-heat cyl to piston weld problem.

Digging into it, I found out it came with a 4mil short rod stroker with a spacer under the cylinders.  

I want to delete the spacer and bought a cool head. I'm going to turn the domes to accept the 2mm pop-up, then redo the chambers to get the right cc. But that's getting ahead of myself because that'll happen after the cyls are finally on to get a deckheight measurement for the correct squish with the stock 0.20 base gaskets.

 

THE PROBLEM: I ordered stage III porting templates from Race Logic, and am trying to figure out how to line them up. Do I go off the top of the cylinder, or do I compensate for the raised piston height? And then at that rate, do I raise the transfers as well?

 

After many searches that had conflicting info, I'm not familiar with the right timing numbers for this type of build, but I do have a degree wheel and have no problem mapping it out. The templates sounded like the easy way to siamese the porting. 

 

Thanks in advance!

 

[lms1977]

first off before you even think of porting they cylinders you need to learn how to degree in your motor and figure out what type of rpm you want it to run or where the power needs to be..

 

the template might get you close but is not the true way to do it, it will probably be a good idea as far as the size or shape of the port possibly thou

[sheerider11]

All that thing is good for is the exhaust shape. Other then that, they don't do transfers. They intake one is huge and makes the bridge to skinny. I used one and it took a lot more to improve on them

[trickedcarbine]

Do not use those templates . The exhaust is the only thing that works. Do one with scribing over dykem after setting it up with a degree wheel. Then template that for the other if you are worried about symmetry

[trickedcarbine]

In fact ken O'conner has a you tube video of him doing a set with these.

[Young Guns Racing]

I've seen these before, and I've used a set a long time ago. I used their intake shaping similarities to a few templates of my own and found out what has already been discussed - they are way to large, no sense in hogging them out that large, the bridge becomes very weak. The exhaust shape is ok, its really wide, be careful not to go too far if this is your first set, take your time and cut small sections. Transfers will need work that there is no template for, shape the transfers themselves to be "economical" as far as flow is concerned, make sure all windows are the same size and shape. Choosing angles and duration will be all up to you as the porter. I don't remember these templates coming in 4 mil, only standard stroke so again you will need to refer to your degree wheel and knowledge you've obtained to set your cylinders up for what you want.

 

With a little research here on the forum you can obtain alot of basic information on what you are wanting to achieve.

 

This website is full of knowledge >> http://www.macdizzy.com/

 

That should help you out.

[registered user]

i never tried them templates but most likely they were designed to sit at the top cylinder deck and scribe your lines. but since your stroke is longer you cant simply put the template at the top deck. maybe they make a template for the added stroke. other wise your on your own with the degree wheel. maybe you could mark some timing heights from the wheel then use the template for the window shape

[Atomic Monkey]

I did put in a call to Racelogic a few days ago, and of course whoever said... yes, the templates work well with the 4 mil stroker. After some research, it really got me that there wasn't any other questions asked! Hope that wasn't just a case of "buy my product"

[lms1977]

Here is the issue with the templates for a 4 mil just say you put a 54 mm crank 110 mm rod port it to 192 deg exhaust will give you 27.5 mm roughly top of cyl to top of exhaust port

 

If you do a 58mm crank 110 rod same 27.5 mm will give you more like 201 degree if my calculations are right?

 

You absolutely need to know how to degree a motor in to port it other than that your wasting your time. IMO

 

You also need to know what numbers your shooting for when you degree it in.

[sleeper06]

Calcs are wrong long rod pistons compensate by moving pin so duration will be relatively close

[sleeper06]

Whoops didnt read your post close enouph on 4mil rite piston combo,25.90 is 201 degrees , but I agree unless you degree set up assembled it varies, I always port damn close to where I need then bore , then finish work

[sleeper06]

Lms you still have your shee larry was telling me you might sell it

[Deadbeat]

mike traded his beasty for...a...raptor

[Coupelx]

Porting starts with a book not a template.

[registered user]

i dont see a problem with new guys using templates. gives them a chance to practice without totally screwing up something. but the problem is the template was probly intended for stock stroke and bore. with the added stroke its gonna throw a curve ball in the situation. if you dont have the knowledge to sort it out i would get some help before you start cutting