I don't know of any engines (except very old ones) that specify a hot
clearance. When materials became consistent enough that cold settings
could translate reliably to hot behaviour, setting at cold became
standard.
A frighteningly long time ago, I adjusted tappets on a 1954 Chevy.
("Blue Flame" six!) Specs were for a hot engine and the method that I
learned from my reference mechanic was to warm up the engine, slip a
feeler in (with the engine still running) and adjust until the feeler
wouldn't move easily, then back off slightly. Worked a treat.
Recognise that the feeler can only move when the tappet is on the
base circle of the cam; so you can't move it all the time, but the
time comes 'round pretty regularly when you can move it.
The hydraulic tappet Chebbys with spritzers at the top of the pressed
steel rocker gear were a different story -- while dodging the squirt,
loosen till the gear rattled, then tighten (1-1/4 turn?) a specified
amount. Until some genius came out with the little oil deflector
clips, it could be messy if the lifters were getting tired.
The only other valve gear I messed (made a mess) with was a
seventy-something Mazda-rottie. The timing chain sprayed lube oil all
over the inside of my garage -- only garage for miles around with a
racing stripe on the inside!
Donald.
> From: <ralemen@cableone.net>
> Date: Thu, 22 Aug 2002 09:07:35 -0700
>
> I'll second that, although according to my friend, his MGB (he is looking at
>replacing it with a TR6 now) is supposed to be adjusted when hot.
>
> Alan
>
> -----Original Message-----
> From: "spitfires-owner@autox.team.net" <spitfires-owner@autox.team.net> on
>behalf of "Jeff McNeal" <jmcneal@ohms.com>
> Sent: Thu, 22 Aug 2002 08:32:48 -0700
> To: "Nolan Penney" <npenney@mde.state.md.us>, "spitfires@autox.team.net"
><spitfires@autox.team.net>
> Subject: Re: tappets
>
> Nolan,
>
> Just curious. What manual gives the hot valve adjustment specs for Spitfire
> engines? I have Bentley and Haynes, but have yet to see anything that advises
> other than to adjust valves .010 while cold. If it isn't in the shop manual,
> written for professional mechanics, then where would this info be found?
>
> Take care,
>
> Jeff McNeal (San Diego)
>
> '68 Spitfire Mk3 frame off, bare metal project, aka "Mrs. Jones"
> '70 GT6+ "Accidental", eventual restoration project
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