Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles Knuckle valves and seats

Knuckle valves and seats

Moderators: Curt!, Pa

Post Fri May 08, 2009 6:35 am

Posts: 79
Location: No. Andover, Mass. USA
Hello. Got a couple knucklehead castings I'm working over to install on a 86" stroker. Both required some work, a little welding, and thread repair. That's all gone well and done. Now noticed that one intake seat has a larger ID than the other. This one is @ 1.700 ID x 1.875 OD for the installed seat. The other is stock like @ 1.562 x 1.875. I think there are two alternatives to have them match. Find OS intake valves and open up the stock seat to match the OS seat. Or, pull the OS seat and intall stock seat and stock valves. Assuming I can locate OS intake valves, would it be better to go that route to get more flow seeing it's a stroker and using a heartier Leineweber #2 cam? I have seen OS intakes at 1.875 from Flo Headworks and 1.94 elsewhere. That's 1.875 valve over a 1.700 seat so does that leave enough contact area for the seat? I've also seen posted oversized knuckle valves at .002 and .004 OS. Is this in reference to head diameter or the stem? I also have another abortion of a head that looked to have had 2.+++ car intake valve but it must have had to be cut down as the stem tip was mushroomed big time.

Any ideas where to find OS intake valves? I've looked at Manley and Rowe already plus Flo which I have to check out.

Any advise or comments are appreciated.

ricochet

Post Fri May 08, 2009 7:52 am

Posts: 639
Location: Wisconsin, USA
You can buy valves from Kibblewhite aka Precision Machining with O/S heads and unmachined stems. You have to cut to length and machine keeper grooves.

Post Fri May 22, 2009 11:05 am

Posts: 79
Location: No. Andover, Mass. USA
I found 1/8 oversized intake valves at a couple of places. KPMI (kibblewhite) has stock but I've found it very difficult to get to them because this valve is not listed in any distributors catelogs and once they do get at a price it's like $94. Something wrong there! V-twin has them and these fine folks here at S & S have them to at a more reasonable price although again it wasn't easy getting to order them and it's a min 4 pcs order. Still work to be done in the new Flathead Power offerings and part/price lists. Wonder who makes these? Another question please. What is considered the proper press fit for new guides in knuckle castings? Looked all over the manual and have the references to oversize guides but nowhere is it stated what the press fit tollerance is.

ricochet

Post Fri May 22, 2009 12:07 pm

Posts: 639
Location: Wisconsin, USA
I have a couple of the V-Twin O/S valves I'll make you a deal on if you are interested. They are imported. Guide fit should be .0015-.002 in a true round hole. (No taper or bell)

Post Tue May 26, 2009 1:31 pm

Posts: 79
Location: No. Andover, Mass. USA
Thanks,

I ended up ordering the valves from S & S. They're waiting on their delivery so it'll be a couple of weeks. Still wonder whose valves those are? Anyhow I ordered a couple of .644 plus pin gages to take the mistery out of sizing the guide holes. My measurements without pins indicate 3 holes at near .644 and one that reads about .646. They all look to be in good shape within the bore. I'll confirm with the pins but this says to me to use .646 on 3 guides and .648 on the single guide. Any of these pins are rather inexpensive if you want a go/no go gage. Got them from MSC. I've already got a few guides in .002 and .004 oversize.

ricochet

Post Thu Jun 11, 2009 11:50 am

Posts: 79
Location: No. Andover, Mass. USA
FYI, I ended up buying the 1.94 oversize intake valves fro S & S for the knuckle and they ended up being nice looking KPMI valves anyhow at a reasonable price. KPMI was etched into the valve stem.

ricochet


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