How long from cold before fright time?

[Chilliman]

Have been having varying discussions on this recently, with different views forthcoming. Personally, I like to see the temp gauge on the move before I drive off, and I don't exceed around 3k rpm until she's up to running temperature.. which sometimes isn't easy in -3 degrees. But then I only use a few revs when it's that cold anyway. Another school of thought is just a few minutes to allow the oil to fully circulate, then off you go. And then there's the 'like to see the gauge right up to running temp before I set off'.

Any thoughts on this chaps?

Chilli

[Alun450]

Logic tells me the engine should be warm internally pretty quickly, enough to drive within a minute or so, as you say Chilli I'd never rev any motor when cold or near cold! When I hear a youngster starting a little two stroke bike up and reving the thing I cringe! Water takes longer to show but as long as it's not frozen it's not what matters when cold, the engine isn't, that's my idea maybe it's wrong but I've had engines last because of my careful use when cold!

[seeby]

By the time I,ve started her up,then release the security bar on my lock up, then drive out and close the electric shutters, the temp gauge is just on the move.Generally I would then give a quick dust down and move straight off, only up to 3k for about 5miles, by which time the gauge is reading normal.Then its beans time.This weather the gauge doesn't reach normal so I give it about ten minutes at 1.5-2k to warm everything up quicker. Mine is not a daily driver and there are no houses near where its kept.

[ChimpofDarkness]

Coolant temps can be misleading, your coolant temp being up to normal has no bearing on weather your engine is ready to play.

Try to avoid letting the car idle to warm up, far better to drive away gently as soon as possible.

Revs aren't necessarily your enemy when warming up either, but labouring the engine is deadly.

Try and strike a nice balance between revs and engine load.

Oil temp is a way more important indicator of when it's safe to press on.

Assuming you've sorted the oil pressure sender & have reasonable accurate OP readings, you can actually use your oil pressure reading as a oil temp indicator.

Better still fit an oil temp gauge.

[Mr Plow]

ChimpofDarkness said:

Try to avoid letting the car idle to warm up, far better to drive away gently as soon as possible

Better still fit an oil temp gauge.

This is what I do

Any advice on fitting an oil temp gauge would be appreciated, I presume using the sump plug is a no no. Can you take a feed from the oil pump anywhere?

Any advice appreciated?

[Discopotatoes]

As has been said idle is not the was to warm an engine, get in it and drive it when the water is at operating temp the give it some beans but I normally wait a little longer before scaring my self

[Goaty Bill]

ChimpofDarkness said:

Coolant temps can be misleading, your coolant temp being up to normal has no bearing on weather your engine is ready to play.

Try to avoid letting the car idle to warm up, far better to drive away gently as soon as possible.

Revs aren't necessarily your enemy when warming up either, but labouring the engine is deadly.

Try and strike a nice balance between revs and engine load.

Oil temp is a way more important indicator of when it's safe to press on.

Assuming you've sorted the oil pressure sender & have reasonable accurate OP readings, you can actually use your oil pressure reading as a oil temp indicator.

Better still fit an oil temp gauge.

Agree, 100% there.
Having fitted water temp gauge, oil temp and oil pressure gauges to my MG years ago, I noticed immediately that the slight pressure drop of the oil being warm, exactly corresponded with it actually being warm according to the oil temp gauge. I can equally confirm from this experience, that water temp does not relate directly to internal temperature, and can in fact be quite misleading.

Warming an engine before driving off is for SAE30 mineral oil, and cars of the Ford Model T era.
Driving gently but not labouring the engine is, as stated above, the accepted wisdom.

[phazed]

Mr Plow said:

This is what I do

Any advice on fitting an oil temp gauge would be appreciated, I presume using the sump plug is a no no. Can you take a feed from the oil pump anywhere?

Any advice appreciated?

I have an oil cooler that is piped from an oil filter sandwich plate.

The temp sender is on the pipe to the cooler.

When oil started to circulate to the cooler, I get a reading.

[spend]

Best place to fit an oil temp sensor (on serp timing covers) is to swap the pressure sensor to the side bung and mount the temp sensor in its place. You score treble ways doing that, it gets the expensive pressure sender away from st & heat under the engine, and the temp measures what its at after the oil pump has squashed your oil up ready to push into the important bits.

Ignore all the bits about special fittings, they only apply if you wish to block the internal gallery to divert oil to an external oil cooler (no stat feature in timing cover), any tapped bung that seals against the cover is fine. The bung & adapter (pressure sensor you have) are interchangeable, I'd just drill & tap the bung you have for the NPT sensor then swap the bungs or sensors around.

[Phoenixcat]

Is there anything wrong with using idle to warm the engine up? I usually let my car idle for 3-4 mins until the temp gauge gets to 50 degrees then drive off.

[Bassfiend229hp]

As I understand it the oil flow to the cam can be poor if left idling ...

I generally try to move off fairly soon after starting (I don't leave her "warming up" unless someone wants to hear her) and keep the revs down (<3,000 rpm) for a couple of minutes.

[spend]

Bassfiend229hp said:

As I understand it the oil flow to the cam can be poor if left idling ...

I think thats pretty much waffle, idling and overcareful limitimg of rpm during warm up is not very different at all. My reasoning:

The followers are first in the oil system and bleed straight onto the cam lobes (just as the cam bearings get oil before the main bearings). The real dangerous areas are the little ends. Oil gets to followers (straight to cam bearings off that big gallery), then off down tracts to the main bearings, a couple of galleries run up the rockers in the heads ( but as soon as you have good pressure most folks are concerned with restricting the oil spraying out under the rocker covers!). At the main bearings oil also enters inside the crank and 'hopefully' gets pushed, shaken, stirred, centrifuged up inside the throws to the little ends... This is not really a pumping action as the crank only picks up the oil across half the rotation ~ and then only at a couple of high pressure points where the wedge forms and is pushing rather than pulling (I like to think of the crank bearing a bit like the serp oil pump it can start pulling in oil at the start of the wedge & pushing it out at the tail of the wedge).

Mucho revs means greater oil flow..., ensuring you get it round quickly and get that crank floating on a pressure wedge not only means the crank has (to use a boating term) got up on plane rather than sliding on the oil means the pumping to the little ends will happen more quickly. It's essential that you get to the rpms that get the pressure and temp (locally at the main bearing) to get that wedge working properly ~ hence the boat getting on plane analogy.

Most important issue to grasp with cams is the simplified concept that low rpm wears the lobes and high rpm wears the base circle (I know which I'd rather wear out).

Keeping the engine over 2500rpm is far more sensible IMHO than not exceeding any revs (bursts of 5000+ rpm aren't going to any harm IMO and are likely to quickly promote formation of an oil wedge at the bearings which is good). I'm convinced there is far more damage to TVR engines caused by idling & under-revving than treating them very aggressively.

[Meths]

ChimpofDarkness said:

Coolant temps can be misleading, your coolant temp being up to normal has no bearing on weather your engine is ready to play.

Try to avoid letting the car idle to warm up, far better to drive away gently as soon as possible.

Revs aren't necessarily your enemy when warming up either, but labouring the engine is deadly.

Try and strike a nice balance between revs and engine load.

Oil temp is a way more important indicator of when it's safe to press on.

Assuming you've sorted the oil pressure sender & have reasonable accurate OP readings, you can actually use your oil pressure reading as a oil temp indicator.

Better still fit an oil temp gauge.

I agree!

I just drive it normally until it warms up, Just like you would do when you go to the shops in your fiesta. In fact, it's good to do this on all cars you use.

[Alun450]

Spend that was bloody ace. Thanks I will remember that everytime I fire the old girl up.

[Malcster]

ChimpOfDarkness said:

Assuming you've sorted the oil pressure sender

I haven't! Was there an issue with these from the factory?

Was it rectified in later models?

Edited by Malcster on Sunday 10th February 19:07