ET: Engine (Twin) Fogging for Mosquitos; Valve Guide Issues and Solutions

vibrac

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Those barrels will have to come off unless you have real gear the only way is grinding the one thing to watch is to keep the paste off the short vertical head face in itself difficult . Not my favourite job I must admit
 

ClassicBiker

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After searching through all the usual books and searching here on the forum I couldn't find any reference to the angle between the valves. Obviously I'll indicate it in, but I was curious to see how close it actually is. I've got my rotary table with a decent angle plate attached set up square on the mill. I've also laid out and drilled four hold bolt holes and made two hollow dowels to locate the head to the angle plate. Photos to follow.
Steven
 

oexing

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Steven,
what is your plan, tidying up the valve guide bores ? Sorry for you, that will be a quite lengthy setup , when really a reamer with pilots would do it in minutes. Maybe you could find a GOOD reamer , best with uneven spaced blades for avoiding chatter effects. That might be upgraded with a sort of pilot replacing one nut on it. Once again the Hunger company in Munich has all sorts of handy tools that don´t require a machine. -- Like on big ship engines, you cannot possibly use a machine for head and valve jobs. So they came up with manual tools for same jobs - for perfect results in a fraction of time . In my photo is one of these piloted reamers that locates with its taper face in the 45 degree seat ring and you can ream the bore from the spring side down. When you set up the head on a machine you will be challenged to stay concentric from seat ring to lower guide to upper guide. No question I did that only with Hunger tools , no mill near . Same idea for line reaming bushes in girder forks, no other ways to do that in reasonable time . So maybe you´d like to find a GOOD adjustable reamer , best with uneven spaced blades to avoid chatter effects, and add a sort of pilot on it by replacing one nut with an extension. While trying to remember, I think I used the upper guide as datum for locating the taper of the reamer and have another taper sitting in the seat ring. Between them I reamed the guide bore - or so . . .

Vic

P1060461.JPG


some more types of Hunger reamers for engine jobs etc .

P1040021.JPG
 

ClassicBiker

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"The valves are inclined to each other at 65°, the pushrods at the same angle" P.E.I., M.P.H.329 and in "Forty Years On"

Thank you Chankly, I read that in "Forty Years On" and thought he was referring to pre-war Comets only as there was mention of 90° and 100° in the same paragraph. I messed about briefly with a level on the face of the valve cap and an adjustable draftsman's triangle under the head's face and got 57° and thought "no, you're messed up there." Thanks for clearing that up.

Valve angle on big port heads is 32º / 64º included.
Thanks Litnman, I read that on the data bases here and also in "FYO" and thought it referred to the angle of the valve face for sealing.

Steven,
what is your plan, tidying up the valve guide bores ? Sorry for you, that will be a quite lengthy setup , when really a reamer with pilots would do it in minutes. Maybe you could find a GOOD reamer , best with uneven spaced blades for avoiding chatter effects. That might be upgraded with a sort of pilot replacing one nut on it. Once again the Hunger company in Munich has all sorts of handy tools that don´t require a machine. -- Like on big ship engines, you cannot possibly use a machine for head and valve jobs. So they came up with manual tools for same jobs - for perfect results in a fraction of time . In my photo is one of these piloted reamers that locates with its taper face in the 45 degree seat ring and you can ream the bore from the spring side down. When you set up the head on a machine you will be challenged to stay concentric from seat ring to lower guide to upper guide. No question I did that only with Hunger tools , no mill near . Same idea for line reaming bushes in girder forks, no other ways to do that in reasonable time . So maybe you´d like to find a GOOD adjustable reamer , best with uneven spaced blades to avoid chatter effects, and add a sort of pilot on it by replacing one nut with an extension. While trying to remember, I think I used the upper guide as datum for locating the taper of the reamer and have another taper sitting in the seat ring. Between them I reamed the guide bore - or so . . .

Vic

View attachment 27294

some more types of Hunger reamers for engine jobs etc .

View attachment 27295
Vic, not just cleaning up the valve guide bores but the threaded portion of the head where the valve guide lock ring used to reside. It is complete chewed up. My plan is to clean up the bore where the forked end of the rocker operates all the way down to surface that the shoulder of the lower valve guide rests against. Then make a modified keeper that Timetraveller refers too. Once I've got that sorted then I have to address the guide bore to keep is concentric to the valve seat ring. Living just outside of Detroit there are plenty of tool suppliers to source reamers from. Thanks for the post it has given me some ideas.

Steven
 

A_HRD

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For the record, in a perfect world, the Series 'A' Valve Angle is 62 degrees.
Peter B
 

Cyborg

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Before folks start retching over this setup, it was only used to trim off the portion of the guide that was protruding into the port. It was beat up and mushroomed over slightly. Given there was no other damage, I assume some freak tried to beat the guide out without removing the lock ring. Unfortunately the photo does't show the jig that screws into the inspection cap hole and holds the head.
It sounds like you have it figured out, but I'm betting Dan Smith has a jig for holding the heads while truing up the head/barrel mating surface. I only know this by the look he gave me when I mentioned lapping the surfaces. Off topic sort of... but when trying to hold impossible things in the mill or the lathe, don't forget Cerrobend.

HRD Head.jpg
 

bmetcalf

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Likewise, Clev Trev.

Steve Hamel, also. I last saw it ~10 years ago, but i think it had several degrees of freedom, but could lock down concentric with a plug fixed against the upper guide seating that had been trued. Can't remember how that truing was done.

It sounds like you have it figured out, but I'm betting Dan Smith has a jig for holding the heads while truing up the head/barrel mating surface. I only know this by the look he gave me when I mentioned lapping the surfaces.
 
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