Milwaukee Midget

[Milwaukee Midget]

Ah yes – my sodium level is now in check.  Couldn’t stay for the duration, but tech day and Wednesday were glorious at World Finals.  All hail Britannia – all it took was some American know-how to push a Triumph GT into the halls of doorslammer mythology.

To the project at hand – Fordboy has the head, and today I ordered up a new valve, guide, seal and tappet, along with a replacement rocker for good measure for the intake on the 1-hole. 

Here’s the issue – the valve stuck in the guide.  I called APT and talked to Phil, who did the machine work, which he had blueprinted.  The valve and guide were within the specs that they build to.  Well, okay, but Fordboy said it best – “clearly the valve and the guide had different ideas”.  I’ll chalk this one up as the “it’s your turn for it to break on you” aspect of chaos theory, but we’re not putting it together the same as last time.  At this point, I just want to assure myself that they won’t weld themselves together again.

Dema Elgin called checking up on progress, and guys, keep that in mind – the cam grinder called out of the blue to inquire why I wasn’t running at World Finals.  The guy clearly wants us to succeed with his products.  I related my tale of woe, and he suggested knurled guides, which kept the guide to a close spec but still let oil get in and around.  Conversely, Fordboy’s experience with F2 and Cosworths has me leaning in the direction of simply opening up the guides a scoach.  If it were an engine that needed to run for an entire season in vintage racing, Dema’s approach is probably the one I think I’d choose, but the guides I have are a bronze alloy which doesn’t take a knurling very well, and I’m not driving that far, or for that long.

Harland Sharp will be sending out a replacement for the rocker - it's not damaged, but it did undergo a pretty sever shock.  They're between production queues for this part, but Keith says it should be in the mail in a week and a half – that’s fine – I’ve got other work to do – which might include some home repairs at Fordboy Acres – I owe him a favor or two. 

[manta22]

MM;

Could part of the problem with the valve be a less-than-ideal combination of metals between the valve stem and the guide? You said that the guides are a bronze alloy; what is the valve stem material? Is this the ideal combination?

Perhaps even flash-chroming the stems might help. You might also add some zinc dithiosulfate (in a "high- zinc" oil) which is an anti-scuffing agent.

Number Six

[aussievetteracer]

Hi MM from Oz- when I was circut racing a Cooper S 40 years ago, I had a problem with sticking exhaust valves: solved it by running a whisker more clearance than MR MOWOG recommended, no seals, and by running a UNC tap through the guide, to encourage oil flow. Good luck in solving the problem- even though I play with a vette and sbc's these days, I still have a (twisted) affection for midgets, bricks, and that brilliant little donk.
                                                                                                                                          Denis

[generatorshovel]

MM, In relation to Broaching the guides (internal knurling), I have a mate who races an 'ol shovel, and had a similar problem with sticky valves. He got onto a guy who made super hard valve guides for HD's, who also recommended "Broaching", and ZERO clearance !
Against better judgement, my mate tried his suggestion,and the worked, so well, in fact, after chasing 150 mph on lake G for several years, managed 152 the last time he run.
Upon the post event tear down, the valve stems showed no sign of anything untoward , and with a 4 5/8" stroke, 7000 rpm for as long as a bottle of Nos lasted, things were more then a little stressed (the head gaskets failed)

[Dr Goggles]

Chris:

You should make a pass thru Colorado and pick up some of this beer: http://blogs.denverpost.com/beer/2012/10/01/joke-wynkoop-brews-rocky-mountain-oyster-stout/6330/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+dp-blogs+(Denver+Post%3A+Blogs)
 
Mike

I've sampled some pretty weird brews in my time, but this one appears to be the 'weirdest' possibility.   What would be the side effects, if any?   If the side effects are like Viagra..........count me in for a sixer.........

Guess I shouldn't sample that "Lobotomy Bock" I picked up in NOLA........
 
F/B

last time I ate a dozen oysters and had two pints of Guinness it did some evil things inside me, evil things...tasted good but.

[manta22]

MM;

What matters most is the valve-to-guide clearance when everything is HOT. Which expands more from cold to hot-- the valve stem or the guide in the head? The clearances need to be set accordingly.

"What you need is information."

Regards, Neil  Tucson, AZ   (#6)

[Tman]

Different type of Oysters Goggles. 

[Glen]

Different type of Oysters Goggles. 

Mercury infested

[manta22]

Mountain oysters?

[Milwaukee Midget]

MM;

What matters most is the valve-to-guide clearance when everything is HOT. Which expands more from cold to hot-- the valve stem or the guide in the head? The clearances need to be set accordingly.

"What you need is information."

Regards, Neil  Tucson, AZ   (#6)

#6, that's a concern of mine, and for a few reasons not mentioned.

The valves are stainless, I understand the guides to be a bronze-silicon alloy.

First off, the valves have a three angle grind on them, which minimizes the head's ability to dissipate heat from the valve head.  Additionally, running too loose in the guide also stores heat in the valve, which is more easily carried away into the head with a somewhat tighter clearance.  But both of these issues are more related to exhaust valves than intake valves.

G'shovel, that's a fascinating idea, and I'm glad it worked on your droog's bike, but I don't know how a HD head dissipates heat compared to a BMC head, especially with a shared exhaust port in the center and an exhaust system not exposed to the elements.   It's an experiment I'd be a little queasy to try - this is the last possible hurrah for this head, as extensively as it's been chopped, and I don't want to potentially compromise it any further.

I'm running the Brad Penn hi zinc oil with Lucas zinc additive (that would be the other Lucas), but the teflon seals do a marvelous job of wiping the stem clean.  I am running a leaded racing gasoline, although I don't know if that helps stems as much as it helps seats.

Right now, the plan is to open 'em up a smidge.

Going from memory - it's been over a week - I want to say the #2 intake was at .0006, the # 1, of course, a post-operative press fit.

[Dean Los Angeles]

Hmm . . . a smidge. Is that close to an iota, scintilla, shred, smidgen, smidgeon, smidgin, tittle, or whit?

I'm absolutely sure it's bigger than a CH. Microns can be measured with an RCH. 

[Milwaukee Midget]

Hmm . . . a smidge. Is that close to an iota, scintilla, shred, smidgen, smidgeon, smidgin, tittle, or whit?

I'm absolutely sure it's bigger than a CH. Microns can be measured with an RCH. 

Well, I'm getting my hair cut tomorrow, and I know they do body waxing there, so I'll talk to Stephanie and see if they have any Pubigage I can borrow . . .

[Kiwi Paul]

If you get some, PLEASE don`t post any pics...(shudder.....)

[aussievetteracer]

Dean L/A One of my favourites is "Just a whisker- about a foreskin of a fly's d**k"

[manta22]

Dean;

"Smidge" is equivalent to 1 RCH.

Regards, Neil  Tucson, AZ