first time portin...

Thank you fur the info input...I seen several vids on this part and it looks pretty straight forward...but I don't have a mic gauge...but hope to get one in the spring when I go back to work with a few other tools I would like too get....thank you...

 

The intake can be squared and lowered if needed to get that nick out. I've never seen a 372 family that can't be ran without the gasket. It will net about 15 lbs in compression. The exhaust port shape looks good. The upper transfers are where the big gains are. The blue coils from a 346 go to 14.1k rpm and work well for most ported 372 and 390s.

 

Thank you fur the input...so if I take out the nick and bevel the edge a bit...and polished the exhaust and intake with out doin anything else to it...it should improve performance a little...

 

You don't want to polish the intake all the way to 220. I go to 80 grit and that's it. The rougher it is the better fuel atomizes to vapor. You'll gain more with a muffler mod and gasket delete than just polishing the ports.

 

Thank you fur your input...I will rough up the intake more...I already did a muffler mod...what is a gasket delete?... Is it not usin the cylinder gasket...thank you...

 

Using a sealer for the base gasket to tighten squish. Motoseal, Yamabond, three bond, loctite 518 or permatex equivalent.

 

Thank you fur the input...but if I run with out the base gasket...won't I have to find out the sqish and change the timin...thank you...

 

Hi Mike!

 

It changes it 1 degree. I've not seen one too tight but it won't hurt to check. Yellow plastigauge can also be used.

 

Hey Carl

 

Thank you fur the input...I will try it...thank you...

 

If you have any more questions ask away.

 

How do you guys determine the numbers for opening and closing of the ports on a saw that you have never done before? I would suppose changing those numbers would be like changing a cam in a 4 stroke.

 

Top of exhaust and transfer openings and the bottom of the intake is where you read them. Then they can be turned into durations or left as 97° from TDC for exhaust and so on.

 

Is it mostly done when you cut the base and lower the cylinder to bring them back to where they were or is it more for duration and beneficial even if the base is left alone?

 

Some can be changed some without machine work. Most really need it after machine work though.

 

Ok thanks I had been wandering about what all factored in. Now what determines when it's time for finger ports?

 

Thank you fur the input...I do have a few more...as the jug sets right do you think I could put it on my saw and see a positive result after I remove the bur on the wall? What grit sand paper should I use to remove it with? At the bottom of the jug...at the transfer ports...would it be OK to clean that area up and polish them...what about the lip at the transfer ports...should I remove any of that or wait till I get the tools to measure the ports...thank you...

 

I only raise that window about 1/8" after dropping the jug. Look at the base gasket and you'll see where the case opens. You can smooth and blend the edges. Just hog the ducts out.