SXGT

what the real problem is when running cold is the metal expanding...the block and pistons expand at different rates (being of different mass, and sometimes different metals as with iron blocks and aluminum pistons, etc). if you put too much strain on the engine when cold (45 seconds is not enough time to get everything up to temp) you risk making the pistons expand faster than the block does, and tolerances will be off and wear will be much more pronounced.




is that correct or just jargon ?

67mustang302

Partly true. Different metals expand at different rates. Running cold means pistons and rings aren't totally expanded so you get increased blow-by. Also the metal alloys are designed to have certain wear characteristics within a given temperature range, so when the engine is cold the alloys will wear more quickly when outside the optimum temperature range. Also if the oil is cold it doesn't flow as well, which is especially important for cylinder walls since they're just splash oiled from what's thrown out of the rod bearings, so if the oil isn't up to temp it won't flow properly and you can get increased wear from a lack of proper lubrication.

Andy13186

+1 on the oil needing a few minutes to get up to temperature

i let mine fully warm up before going wot or over like 3500-4000 rpms

Jfsram

I drive EVERYTHING with ease when it's first fired up. I totally do not believe in idling to warm it up either. Start it and drive it gently until the water temperature is at normal.

Driving it with ease means keep it deep into vacuum, keep the rpms low and just tip the pedal enough to make the car move.

Aside from the metals warming up. It's the oil pressure and the transmission fluid you should also be concerned for.

ChalknCover

You shouldn't have an issue, at least not where I run, even if your engine is cold from sitting in the pits, by the time you pull into the lanes, wait for your turn, get up to the staging area, your car should be warm, mine usually is. I do keep it off in the lanes to keep the underhood temps down, but usually by burnout time I am at operating temps. Of course I am taking for granted we are talking about legal drag racing on a track, not on a street.

GreyStang

Its' not just engine oil needs to warm up. ALL the fluids including stuff like transmission and power steering fluid needs to get up to temp before it behaves normally

SXGT

my ET was a LOT faster with a cooled engine.

Mustang Boy

ok this is going to be hard to understand on your part but it makes sense in my head lets see if i can get it into words

with the
rings and pistons not being up to temp the dont settle in correctly till everything is up to operating temps, combine that with less oil on the cylinder walls from the oil still being cold it causes the rings to expand and retract slightly which causes a washboarding affect on the cylinder walls. ive seen the end result of this from motors that got built then put directly on the dyno and run WOT for 3 runs at a time and probably around 20 runs in 3 weeks before being torn down and there was a definite washboarding of the cylinder walls but it didnt matter in this circumstance because it was at a school and the motors were torn down and rebuilt and the cylinders honed every 3 weeks anyways

PNYXPRESS

This had nothing to do with you engine being cooled. It has to do with the fact that the intake was cool and not heating up the incoming air. Also, the underhood temps hat up the fuel rail and incoming fuel. Best thing to do is wrap your fuel lines/rail in a insulating wrap and pack dry ice around the intake before your runs.

You want your oil at operating temp and your incoming air/fuel as cold as you can get them.

SideSwipe

Good thing i dont go above 2500 rpms until at normal running temp