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Author Topic:   dumb question
mod777
Dirt Roller

Total posts: 19
posted September 11, 2002 09:46 PM
Steel expands when it gets hotter, right?
So when an engine warms up, do the cylinder bores get bigger or smaller?

smallrock98
Dirt Roller

Total posts: 19
posted September 17, 2002 09:36 PM
The bores I believe do get smaller but not by a lot.

Merlin
Dirt Full Roller

Total posts: 26
posted September 17, 2002 09:46 PM
The bores get BIGGER when the block is heated. Have you ever seen piston pins being pressed into rods? To properly do this the rod is heated to make the small end larger in inside diameter so the pin can easily be slid into place by hand. So the same happens when a block is heated. It isn't like the whole thing is inflating like a baloon. The entire block gets bigger in every dimension. As the bores get larger so do the pistons, but the pistons grow at a faster rate. So when your engine is at operating temperature the clearance between your cylinder walls and piston skirts are smaller than what they were machined to at the shop. Piston manufacturers and machinists know this. Strick attention has to be given to the piston "fitting" process to achieve the correct fit.
Any questions?

outlawstock17
Dirt Forum Champ
Total posts: 620
posted September 19, 2002 05:45 AM
i've been watching this thread for a while, waiting to see some replies. most guys were staying away from it like it was the track squirrel. LOL. merlin is correct and his rod heater comparison is right on. good post.

autoshop
Dirt Maniac

Total posts: 102
posted September 19, 2002 08:16 AM
the bores get bigger , Ever been cube checked they take the cylinder temp first so they can correct the sizing .I've been just alittle over hot but when it cools down I have them check it again and it comes back smaller...

mod777
Dirt Roller

Total posts: 19
posted September 19, 2002 01:29 PM
So has anything ever happened while trying to avoid the track squirrel? We don't have one at our track (at least not since I've been racing. 'course that may suggest there was one at one time and somthing *did* happen).

Merlin
Dirt Full Roller

Total posts: 26
posted September 19, 2002 09:19 PM
ok, machining stuff and engine building i know. but, could you please tell me what the definition is for the "track squirrel"

outlawstock17
Dirt Forum Champ
Total posts: 620
posted September 20, 2002 10:34 AM
let's see..........outlawstock17's racing dictionary says there are 2 species of this critter...........track squirrel (wreckumus alotomus) and (stepomus onomus dingdongomus alotomus)........the racer that you want to pass real quick and give plenty of room........LOL!


carscomefirst
Dirt Full Roller

Total posts: 45
posted September 20, 2002 08:51 PM
quote:
Originally posted by outlawstock17:
let's see..........outlawstock17's racing dictionary says there are 2 species of this critter...........track squirrel (wreckumus alotomus) and (stepomus onomus dingdongomus alotomus)........the racer that you want to pass real quick and give plenty of room........LOL!


Great definition!!


Merlin
Dirt Full Roller

Total posts: 26
posted September 20, 2002 09:49 PM
OK!!! That makes total sence now!!!!
LOL!!!!!
Thanks!

mod777
Dirt Roller

Total posts: 19
posted September 21, 2002 07:16 AM
How embarrassing! The whole time I thought we didn't have one, and then to find out, it's ME! Wondered why my dingdongomus was so sore on Sunday mornings.(sigh)

outlawstock17
Dirt Forum Champ
Total posts: 620
posted September 21, 2002 01:05 PM
mod 777, you're killing me! LMAO! we've all been that "track squirrel" at one time or another. i hope it's not my turn!

Wheels47
Dirt Maniac

Total posts: 127
posted September 22, 2002 08:27 AM
HMMM not sure about the track squirrels but we have a few sneaky snakes at our track..You must beware of the sneaky snakes.....

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