They check the engine temperature to make sure it is within a proper range,
and they have temperature correction factors. (at least they did on mine)
When people build a certain engine combination that goes right to the
maximum cubic inch break, I don't think that that they compensate for the
engine being hot, nor should they. Engine specs apply to the temperature
that the engine is when you build it, (which sounds like it might be pretty
cold from some of the postings I have seen here). You measure your bore and
stroke when you assemble the engine, and thats the numbers you go by. I
don't see that anybody gets an unfair advantage since everybodies engine
gets "warm" during the run. I think the point is to have the engine measure
the same as at the time when it was assembled. If someone is cutting it so
close that temperature makes the difference between legal and not, they are
just creating more problems for themselves. Does that last quarte of a cubic
inch really make all the difference in the world? It sure is a lot easier to
be able to "pump" than to pull the head off.
David (gave away 17 ENTIRE cubic inches in C class, and loved every minute
of it)
-----Original Message-----
From: Lawrence E. & Cathy R. Mayfield [mailto:lemay@hiwaay.net]
Sent: Monday, February 14, 2000 8:30 PM
To: FastmetalBDF@aol.com; dwarner@electrorent.com; lemay@hiwaay.net;
land-speed@autox.team.net
Subject: Re: CHECKING CUBES
I suspect that the temperature being checked before the measurement is the
ambient air temperature and not the engine. I have never witnessed this so
I am talking through my hat here. But the point I was shooting for was the
cheating of the system by not measuring at ambient temperature. This is
cheating, pure and simple. Hell, why not heat the bore gage or micrometer
until it is so hot that it has to be handled with gloves? Same thing, not a
TRUE measurement of the dimension. Plain cheating the system. Any records
set using a method like this should be voided. Measurements should be taken
only after both the tool and the thing being measured have reached the same
temperature after a soaking period.
my $0.02 and worth every penny...
mayf
At 03:37 PM 2/15/00 EST, FastmetalBDF@aol.com wrote:
> Dan, Mayf, list , Just a thought here ........ At every
>engine displacement
>check ( usually as the result of a protest ) I have been present at
,
>both at
>the drag strip and the stock car ovals here in the Northeast , where the
>method
>is the " pumping " one , often referred to as " P and G - ing "
the
> motor ,
>the cylinder TEMPERATURE was measured immediately prior to the
attachment
>of the air pump , and the resultant temperature reading was factored in ,
>with a
>correction chart , to give a reading with a higher degree of accuracy .
>Some of these motors were crackling hot , after a 100 lap feature race
,
>plus some
>yellow flag laps in between , on a hot summer afternoon or evening .
>While
>it is more accurate to use the mikes right in the engine , " where the
>ACTION is ",
>most competitors don' t wish to pull a head off , especially at midnight
or
>later
>at some dusty outside pit area location , and will generally agree to
the
>pump
>method as the final say on the engine' s legality . IF the
>displacement can
>be checked with a high degree of accuracy , UTILIZING the temp
correction
>factor , then it seems this would preclude such somewhat extreme measures
>as cooling down the motor with DRY ICE . We used to cool engines
>between rounds with ice from our coolers , and I have never seen one
iced
>down for measurement purposes , but this just proves my observation that
no
>matter what our racing experience , or how lengthy , we can ALL learn
>MANY
>things here on this list ! I can see where the dry ice would sure
>hasten up the
>normalization of the engine' s specs . Many years ago , the boys and
I
>put
>an axle bearing on the axle , when no press was available , by sticking
>the axle
>in a snowbank ( really ) and the bearing in the kitchen oven ( BRIEFLY
>), and
>it did the job . Backyard engineering saved the day , or as my Dad
>always
>told me ----- Necessity is the Mother of Invention .
> Bruce on sunny warmer Connecticut shoreline -----
>
>
>
L.E. Mayfield
124 Maximillion Drive
Madison, Al. 35758-8171
ph: 1-256-837-1051
http://home.hiwaay.net/~lemayf
lemay@hiwaay.net
Sunbeam Tiger, B9471136
Sunbeam Alpine Bonneville Land Speed Racer,
'66 Hydroplane Drag Boat (390 FE)
|