Warming up an old Saab Turbo?

[Lowtimer]

shalmaneser said:

Generally takes much longer than 5 minutes to warm up the oil in any car I've ever owned with an oil temperature gauge. 15 mins is about right.

Yep. Takes 15 minutes to get the oil up to temp on mine. 5 minutes for the water.
OP, others have said this but what I do with my old-school turbo is start it up and drive straight off but keep the revs down and off-boost until it's properly warmed through.

The shutdown thing depends on how you've been running it. If your last 10 minutes of a run is pootling gently around the suburbs at light throttle and no more than 2000 rpm, then I'd just let it idle for 30 secs so that the turbocharger actually stops before killing the ignition. It will already be cool.

On the other hand if I'd just thrashed it up a steep windy mountain pass using full everything, and wanted to stop for a look at the view at the top, I would let it idle for five minutes so that the turbocharger cools down while there is still oil passing through it. Otherwise they tend to cook the oil in the turbocharger bearings.

Edited by Lowtimer on Tuesday 24th March 18:22

[NiceCupOfTea]

MagicMike said:

From my experience of owning a 900 T16s, even when you did gun it hard, the car would not allow you to over rev, and would cut out .

Excellent choice of motor btw

It has a rev limiter and also a boost cutout (as long as it hasn't been disabled), plus the APC which will cut boost on knock.

[hman]

Up to you how long you leave it but I have never ruined an engine or a turbo by leaving it 5 mins absolute maximum before giving it major welly and I have taken some to galactic mileages without issue and without a lot of care for warm up or cool down.

The road near my house goes 30, 100 yards, 40, 100 yards, NSL for 4 miles then 30 limit again - thats as long as any car gets to warm up because the next section is a lovely flowing 15 miles of NSL and theres no way I'm going to be pussy footing it along there if theres no traffic.

Some people get really anal about warming cars up, without realising that the extended wear tests carried out on these engines prior to release are a million percent more demanding than anything they could manage even if the caned the engine from cold for a lifetime.

But if it makes you feel better then theres no harm in it, (and little benefit except on the MPG probably)

[Olivera]

spitsfire said:

The engine needs a bit of work anyway (valve guides are tired so it smokes like a mofo if left standing for a few days and then started) but I'm going to try to put that off for a while and get the interior and electrics all sorted first.

I'm just a bit more cautious with the turbo because it's an additional complication that I'm not too familiar with and expensive if it goes wrong!

I don't quite understand why you are so concerned with the turbo but not with worn valve guides. A refurbished, second hand or replacement turbo is likely to be much cheaper than your impending cylinder head rebuild.

[Benbay001]

I start my 80s Excel, set some music going (30 seconds max) and then drive off.
If i had a turbo id just use common sense, if its been driven hard then id wait for the turbo to cool for a minute (or drive slower for the last 5 minutes).

[spitsfire]

Olivera said:

I don't quite understand why you are so concerned with the turbo but not with worn valve guides. A refurbished, second hand or replacement turbo is likely to be much cheaper than your impending cylinder head rebuild.

I've already factored in the work needed to the head, and am planning to upgrade to a cylinder head from a 2.1 engine - here's some info on 900 turbo engine upgrades. I've already sourced one from a low mileage car!

The worn valve guides are a 'slow burn' issue, in that they won't cause the car to stop working tomorrow. Cooking the turbo bearings on the other hand...

I'm not sure how long I'll keep the car for, and the high mileage means that, even if I got it back to tip-top condition I'd not get big money for it. As such, I'm planning to improve the car where I can if it doesn't cost too much money, but keen to avoid additional expense/wear if at all possible.

Isn't it always better to be mechanically sympathetic and minimise unnecessary wear on engines?

[spitsfire]

For posters here and elsewhere saying idling an engine until it's warm is unnecessary, I'm a bit confused by this: I started my motoring life in old Triumphs, which suffer terribly from oil starvation, and used to sail boats with old-school Gardner diesel engines. I had it drilled into me at a young age (and this could be completely wrong) that putting a load on a cold engine increased wear because everything was 'tight' and lubricants more viscous, so reducing lubrication and increasing wear.

All I can go on is personal experience here because I'm not a mechanical engineer, but I've managed to nurse worn Triumph engines for 50k+ without a rebuild (I've also never had to change a clutch!) so the advice I was given back in the day seems to have worked for me up to now. That's not to say it's right; merely an observation.

Any mechanical engineers care to comment?

Here's a pic of my car with an exceptionally rare and very tidy Mk1 Sunbeam Alpine

[SuperPav]

spitsfire said:

For posters here and elsewhere saying idling an engine until it's warm is unnecessary, I'm a bit confused by this: I started my motoring life in old Triumphs, which suffer terribly from oil starvation, and used to sail boats with old-school Gardner diesel engines. I had it drilled into me at a young age (and this could be completely wrong) that putting a load on a cold engine increased wear because everything was 'tight' and lubricants more viscous, so reducing lubrication and increasing wear.

All I can go on is personal experience here because I'm not a mechanical engineer, but I've managed to nurse worn Triumph engines for 50k+ without a rebuild (I've also never had to change a clutch!) so the advice I was given back in the day seems to have worked for me up to now. That's not to say it's right; merely an observation.

Any mechanical engineers care to comment?

Here's a pic of my car with an exceptionally rare and very tidy Mk1 Sunbeam Alpine

There's a balance. If you start a car in -30 and let it idle, it'll never get to temperature, and all it'll ever do is run ad infinitum while cold - and cold is increased wear.

Driving the car, as many posters here have said, in a calm manner, short after start, is the best way to get it up to temperature, without putting unnecessary stress on the engine. The 3k rpm rule is not bad, but remember, load is as much about your throttle (no full throttle) as it is about RPM. So just drive it gently, and after a few miles it'll have warmed up well.

One thing to try and avoid is the "rev the balls off while starting" approach. Ironically some new cars do this for sporty effect, and on some old cars you had to apply throttle while starting!


Re: cool down, driving off-boost and gently through your village/residential streets before parking up is enough to cool the turbo down without having to leave it idling. The one time I would leave it to idle a bit (one minute is plenty, none of this 10 minute turbo timer stuff) is if you've just pulled off the motorway into services or for fuel.

[spitsfire]

NiceCupOfTea said:

What year is it? Iirc the earlier cars had oil cooled garrets which needed a bit more care than the later smoother water cooled Mitsubishis. Either way, just drive gently until fluids are warm and a gentle last couple of minutes before switching off.

My 91 is on 190k on the original turbo.

Enjoy - pics?

A full write up is in progress; Part 1 here - Saab 900 Turbo Convertible

[aeropilot]

spitsfire said:

I'm not sure how long I'll keep the car for, and the high mileage means that, even if I got it back to tip-top condition I'd not get big money for it.

200k isn't high mileage for a C900

It's just about run-in

[spitsfire]

aeropilot said:

spitsfire said:

I'm not sure how long I'll keep the car for, and the high mileage means that, even if I got it back to tip-top condition I'd not get big money for it.

200k isn't high mileage for a C900

It's just about run-in

Mmmm.... dunno about that one... I'm finding quite a lot of wearing out bits are pretty tired

I've posted up the 'to do' list (first instalment) over on Readers' cars; I'd be grateful for any advice/words of warning from Saab owners

[DKS]

Mine says 233k. I just drive it 'normally' with the exception of counting to 10 before switching off. I certainly wouldn't idle it from cold for 5 mins! Think of the fuel along you must be wasting! If you're using good old 10/40 semi oil it'll be miles better than oil in a '50s Triumph! Everything is designed to work with the engine nice and hot, so you want to get it there a quick as reasonably possible.

Is your rear beam a mess? I'm just in the process of fitting a powder coated one with new bushes. Very satisfying.

[spitsfire]

DKS said:

Is your rear beam a mess? I'm just in the process of fitting a powder coated one with new bushes. Very satisfying.

I haven't looked at the rear beam yet, but I'd guess that it is original so probably needs an overhaul/rebush/replaced. My attempts to test the suspension with hard cornering have been pretty fruitless - it seems (although harder to tell with a rag-top) fairly neutral, and lets go quite progressively. I have been amazed by just how sticky the front is, even on mini roundabouts.

Are there any easy ways to check the health of the rear beam?