Board index Flathead Power-Technical Questions, Answers, and Suggestions Indians Chief porting

Chief porting

Moderators: Curt!, Pa

Post Sun Jul 29, 2001 4:55 pm

Posts: 582
Location: meridian, id. usa
(It heps if you have a book on porting and polishing to guide you like pro engine blueprinting or flathead related speed books
not essintial but well worth the monet for the info)
first remove all valve related parts,
bead blast the crud off until its clean metal
in through the ports
may as well do the whole outside surface area
while your at it.
get your handy dremal and burr set along with
sanding drums and alot of those little drums
start on cleaning all the casting flash out of all the ports until the intakes surfaces are smooth from the intake spigot to the bottom of the valve set all the way around.
smooth not polished.
do the same on the exhaust but make it shine
and that should just about do it.
you dont have to make the diameter larger u just need to make the transistions smooth

[This message has been edited by dotman (edited 29 July 2001).]

Post Sun Jul 29, 2001 5:17 pm

Posts: 1028
Location: Ojo Caliente,NM,USA
All of the normal port work helps but the best inprovement unless you already have it is the change to popup Bonneyville type pistons or better yet change to 80 wheels and pistons which give the same popup. you will have to raise the combustion chamber to use these pistons (leave about .026 head clearance) witch increases the opening into the cylinder.

Post Fri Aug 03, 2001 4:12 am

Posts: 1028
Location: Ojo Caliente,NM,USA
The releaving was to direct more flow of mixture to the cylinder the second greatest problem of a flathead is the restriction caused by squish area over most of the piston. Although Indians popup pistons and raised squish area wheren't as good as the last KRs it was very good and easy to do.
The major problem with flathead combustion chambers was the tendacy to detonate because of the long shallow chamber the squish area was to shorten the chamber while combustion was going on. And this would allow higher compression.
Pop me your email addr. and I'll send a copy of Tuning The Flathead I think most of the old timers on the list have a copy from the severall times I've sent them out.
Have your heads already had the Bonneyville treatment? Are you building a 74 or 80? What year? Have you found the Virtual Indian site and list yet?

[This message has been edited by Dusty-Dave (edited 03 August 2001).]

Post Fri Aug 03, 2001 11:06 pm

Dave - can I get a copy? I don't think I've seen this.. Thanks!

Click here to see my Pages-O-Tech-Stuff

Post Sat Aug 04, 2001 11:14 pm

Posts: 896
Location: Bixby,OK, USA
Dave, Any chance I could get a copy of that also?

Post Sun Aug 05, 2001 2:46 am

Posts: 3134
Location: Central Illinois, USA
gosh, Dave, I guess I need one too!

Post Sun Aug 05, 2001 6:20 am

Posts: 6
Location: bel air md. usa
Hey dave....count me in , i would like ta have a copy also !

Post Tue Aug 07, 2001 2:02 am

Posts: 108
Location: San Diego
Copy for me too, please.

Post Tue Aug 07, 2001 2:12 pm

Posts: 896
Location: Bixby,OK, USA
Thanks Dave!

Post Wed Aug 08, 2001 2:46 am

Posts: 3134
Location: Central Illinois, USA
Thanks from me, too, although the volume overloaded my server for an hour! I've been offline on my Outlook E. until I saved it to my harddrive.
Now if I can just figure out how to read it...

Post Wed Aug 08, 2001 3:06 am

Posts: 1028
Location: Ojo Caliente,NM,USA
Open the files one at a time with Kodak Photo preview or Kodak Photo Editor (on the win 98 disk or free on line) then print them. Or even use Internet explorer to open and print them, just type the path to where they are in your confuser on the address bar. They took almost an hour to upload If this is a real problem for anyone I can break them up into eight messages with two each. But don't have them in that format anymore so would have to make them again.
Dusty Dave

Post Fri Aug 10, 2001 2:44 am

Posts: 1028
Location: Ojo Caliente,NM,USA
If it's working properly the iron pump is fine.
The thermal barriers are an excellent idea. All of the larger suppliers will stock the Bonney pistons. Be sure to measure your paticular engine before having the heads cut And be sure to allow for the brand of gaskets you will be useing. I prefer Hastings rings. If you use anything else assemble the piston with just the oil ring into a well oiled cylinder and measure pull required to move the piston. If more than about 3 lbs. carefully adjust the expander ring with a pair of needle nose pliars.

Post Fri Aug 10, 2001 4:46 am

Posts: 1028
Location: Ojo Caliente,NM,USA
Would you check the email addr. that you posted MSM sent a bounce notice but they didn't give a reason. If it isn't an addr. problem I'll try smaller attachment size.
Dusty Dave

Post Fri Aug 10, 2001 4:54 am

Posts: 1319
Location: State College, Pa.

Nice bit of info on the oil rings. Where did ya get that from? Just makes me want to spend a little bit more time testing ring tensions. I usually paint my piston skirts and crowns with a molybdenum compound and bake it on. Makes the skirt slippery and acts as a thermal barrier on the crown.


Post Fri Aug 10, 2001 4:12 pm

Posts: 1050
Location: Greenbackville, Virginia, USA
Moly on the skirts is a lot better than the old way of knurling the skirt to hold oil. G

Post Tue Aug 14, 2001 7:25 pm

Posts: 1
Location: Alton, IL
I have started modifying Indian heads the way the KR's were done. Seems to work well. The big restriction on flathead breathing is generally the area around and above the intake valve, which is why the KR's were relieved there. This is also why raising the compression on a flatty is a mixed bag


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