> (very bizarre explanation of horsepower using spheres &
> horses deleted) ds
> Granted, horses come in different shapes, sizes and strength. But does this
> explanation seem reasonable?
It may seem reasonable, but it is not true anyway. The spheres were an
attempt to demonstrate the strength of atmospheric pressure, and the
demonstration was quite effective. The horse-power experiment was quite another
involving some block & tackle, a large weight, and a quite large and strong
draft horse. The horse was worked pretty hard for it, too - the horsepower
unit that resulted is quite high for most horses.
--
---
John R. Lupien
lupienj@hpwarq.hp.com
>From I.know.art@barstow.pa.dec.com,
sfisher@wsl.dec.com Fri Sep 14 16:38:38 2001
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To: paisley@cme.nist.gov (Scotty Paisley)
Cc: british-cars@hoosier, sfisher@Pa.dec.com
Subject: Re: Head Gaskets
In-Reply-To: Your message of Fri, 01 May 92 09:19:29 -0400.
<9205011319.AA00880@lobotomy.cme.nist.gov>
Date: Fri, 01 May 92 13:19:19 PDT
From: I.know.art@barstow.pa.dec.com,
but I don't know what I like <sfisher@wsl.dec.com>
I was sworking *a ton* the peddler the other night. (a ton, pronouced
2000 pounds, is when you overwork yourself while swearing at your car.
:-) (Isn't it amazing how we come up with names for our cars? ;-)
One of the things I did to the peddler was retorque the head. I was
tempted to loosen all the nuts before retightening, but I didn't want
to risk losing the seat the head already had on the gasket.
You should loosen the nuts just a quarter-turn or so, just enough to
relieve the pressure on the studs. Then "sneak up on" the torque; I
start 10 or 15 lb-ft below my final value and then make three or four
separate runs at the nuts till they get the right torque values. Then
for good measure I go around the head in the proper sequence once or
twice more with the wrench still set at the final value, till I see
no more motion on the head nuts when I reach the proper torque. The
reason for this is that as you compress the head, it can sometimes
take a set at a very very slight angle when you compress the first
nuts (even starting in the middle), so that by the time you do the
last nuts, some of the early ones might now be loose due to head tilt.
Going over the nuts one final time makes sure that any of these nuts
which are now at reduced torque values due to angling (or maybe compression)
of the head are in fact at the correct value. This is a good thing
to do with bearing cap bolts too.
Actually I didn't notice it until I was out on a
bright sunny day, and saw a shiny line right along where the head
meets the block. I ran my finger down the line and got a small trace
of oil on my finger.
Oh, that. BMC engines are particularly bad at that; the four-cylinder
Big Healey engines "all do that" to some extent, and most MGB engines
do. Even my race engine, which I assembled and have torqued as I
describe above, has a tiny bit of coolant/oil weeping from between
the #2 and #3 spark plugs. It's not cause for alarm until you notice
other problems (oil in the coolant, for instance, or rusted spark plugs).
I've always heard to *never* put anything on a head
gasket, but the next time I pull a head on a TR6, I'd be tempted to
try a *thin* film of something on the outer edge to try and solve this
problem. Comments? BTW, I used the upper gasket set from TRF.
Here's a tip from an MG shop: Silver spray-paint. No, really. Apparently
there's something about the metal flakes used to make silver spray paint
that works just right. The trick is to spray the gasket with a coat of
silver the instant before you slap it on the block so that it's still wet
when the head lands on it a few seconds later. This shop tried a number
of different sealing compounds, head preparation techniques, and other
cures, and the silver spray paint actually works the best. Considering
that the engine they built is the only MGB engine I've ever seen that
didn't have even a faint track between the plugs, I would tend to
believe them.
--Scott "Prattling poodles putter around a puddle of piddle" Fisher
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