Competition Diesel.Com -  Bringing The BEST Together

Competition Diesel.Com - Bringing The BEST Together (http://www.competitiondiesel.com/forums/index.php)
-   Extreme Engine Tech (http://www.competitiondiesel.com/forums/forumdisplay.php?f=232)
-   -   Cutting piston bowls (http://www.competitiondiesel.com/forums/showthread.php?t=199927)

mfsuper90 04-16-2018 11:25 AM

Cutting piston bowls
 
Getting ready to do a Reenterant delete to an engine I’m playing with.

The piston im working on has an offset bowl with a deep lip. My plan was to cut the lip straight down to the bottom radius of the bowl. Going to chuck it up in a four jaw chuck and center it to the offset bowl then cut the lip off. I’d love to post pictures, but photobucket screwed me and I haven’t taken the time to figure anything else out.

I know bowl geometry is a complicated design, so I’m not looking to totally redesign it. I just want to open the bowl up to keep from burning the lip off the piston when we run advanced timing.

Application is a 1006 perkins running a “Farm stock” class

mfsuper90 04-18-2018 11:04 PM

Well I finished them

https://uploads.tapatalk-cdn.com/201...1073c88c40.jpg

Before and after.
Before the bowl ID was 1.9, now it is 2.45”
Went from 45cc bowl to 60cc. Should put compression at 14.5:1. I think that’ll work fine for what we are doing

fatgraderman 04-18-2018 11:14 PM

Quote:

Originally Posted by mfsuper90 (Post 2664628)
Well I finished them

https://uploads.tapatalk-cdn.com/201...1073c88c40.jpg

Before and after.
Before the bowl ID was 1.9, now it is 2.45”
Went from 45cc bowl to 60cc. Should put compression at 14.5:1. I think that’ll work fine for what we are doing



Nice work!


Sent from my iPhone using Tapatalk Pro

Rich dzl 04-19-2018 07:54 AM

Looks good

mfsuper90 04-20-2018 08:09 AM

I’m open for Criticism. I’m sure there is some way I could improve them

Rich dzl 04-20-2018 06:18 PM

I wish now I haven't junked 30 sets of stock pistons now lol ..

mfsuper90 04-21-2018 01:32 PM

Interesting side note, just torqued the head down. Specs are 80ft lbs then plus 180 degrees if it’s a medium length bolt (different lengths get different degrees). After running them, I set my torque wrench to 150ft lb, and the bolt I tested didn’t even budge.

I’m not a big guy, I had to have a 3ft cheater pipe to get them torqued. That’s a lot of torque on a 1/2” bolt

TheBac 04-21-2018 08:40 PM

Quote:

Originally Posted by mfsuper90 (Post 2664871)
I’m open for Criticism. I’m sure there is some way I could improve them

You did good. Thats how shops cut Dmax pistons, for the same reasons you did. What size radius did you put on the edge?

mfsuper90 04-21-2018 11:25 PM

Quote:

Originally Posted by TheBac (Post 2665031)
You did good. Thats how shops cut Dmax pistons, for the same reasons you did. What size radius did you put on the edge?

I gave it the eye ball radius :lolly:

I’m no machinist by any means, but I’m slowly learning. The grinder I use has no degree marks so cut them by eye with the regular tool I was using. Then I cleaned them up with some rough sandpaper and finished them with some rough scotch brite (red pads?). I couldn’t get my tool to give me the surface finish I wanted, but it did the job. Need to upgrade my tooling

TheBac 04-22-2018 07:11 AM

I like it. :) I believe when Merchant cut mine, his machinist used a .25" radius. Yours look close to that.
I figured it lowered my comp ratio around .5 by doing so, too.

mfsuper90 04-22-2018 07:09 PM

Going from 45cc to 60 dropped mine 3 points roughly

TheBac 04-22-2018 07:52 PM

3 points? Yow.

mfsuper90 04-23-2018 06:57 AM

But I was going from 17.5 down to 14.5

odieub 04-23-2018 08:30 PM

Talked before i read.

Highwayman 04-23-2018 10:58 PM

I’m curious to see how the straight walls change things up.

mfsuper90 04-24-2018 05:31 AM

Quote:

Originally Posted by Highwayman (Post 2665266)
I’m curious to see how the straight walls change things up.

Abunch of things are changing at once, so I won’t have a good report of how it changed performance


All times are GMT -5. The time now is 01:03 PM.

Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2006 - 2024, CompetitionDiesel.com
all information found on this site is property of www.competitiondiesel.com