KPMI C630 guides

acadian

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Top end rebuild is coming along well, but KPMI sent me C630 guides instead of the standard manganese bronze set I ordered. 6 week turnover on getting the correct ones, so I decided to install them, and come up with a solution to ream them with the tooling I have (I'm not spending $200+ on a carbide reamer that will barely fit in my mill). My goal was to get them sized a few thou under finished and concentric to the valve seats. Ended up machining a pilot, lots of lube, and it worked out well. Waiting to borrow a Sunnen stone hone to finish them off.

 
Very good.
Anti clockwise is new to me so guessing it is coming up the guide.
 
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I have the flex hones, but removing .107 out these guides with it would likely take forever, and end up bell mouthing them. The reaming took them to .3110, concentric. The final .0005 will be done with the Sunnen hone (he's offered to sell it to me, so I'm negotiating a price with him)
 
I used the flex hone on KPMI guides that fitted the valves fine loose but when installed in the head were a bit tight, so not removing .107" but .001 to .002, but guides should not be supplied so undersized anyway. More than the material was wrong, surprised you got a reamer that would go in without sending a drill down first to get it closer, normal reaming allowance is 10 to 15 thou not 107.
 
Interesting, I"m a bit confused though, the flexhones (the ones posted, and that I have anyway) are explicitly described as not intended for material removal, only for surface finishing and bore cleanup. That's one of the reasons I'm hesitant to use it for sizing. Anyway, Sunnen guide hone is on its way, so I'll give that a go, apparently it's a good piece of kit
 
John Healy recommends them over HSS reamers as they blunt so quickly on C630, the KPMI guides were a perfect fit on their valves before they were installed, after fitting to The head the valves dragged until the flex hone was used. Your .107 is 2.5mm a huge amount of material to be removed.
 
I love this sort of work but still wonder why the reamer looks to be being used in a counter clockwise rotation.
 
I love this sort of work but still wonder why the reamer looks to be being used in a counter clockwise rotation.

The only one I have in the correct size is a CCW rotation reamer.

Question for all, what are your thoughts on stem clearance? Service bulletins say .0027 IN - .0032 EX, whereas KPMI says .0008-.0012 IN and .0012-.0015 EX

I'm inclined to lean towards caution shoot closer to the factory specs, but is anyone running the KPMI clearances? Any issues?
 
A CCW reamer, I learned something. :thumbup
Generally it is 0.001" for inlets, 0.0015 for exhaust.

I used one of that brand flex hone yesterday but need to order one for the follower/tappet bores.
 
A CCW reamer, I learned something. :thumbup
Generally it is 0.001" for inlets, 0.0015 for exhaust.

I used one of that brand flex hone yesterday but need to order one for the follower/tappet bores.

It's the only .3110 reamer I found in a stash from my old man's tool chest, old snap-on stuff from the 50's...

Ok, thanks, contradicting advice over on the BB forum, Healey et al. recommending to not go that tight.
 
I had forgotten what Dan said when I got my KW pre unit parts but see they have a Tech page devoted to the subject and would be worth contacting being Triumph only specialists even if for a second opinion.

I see they have the usual information including the 0.0005" reduction on Triumph EX valves.

 
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