revtothelimit - motorbike forum

mangocrazy wrote: Thu Nov 21, 2024 6:41 pm It was actually quite relaxing and liberating (in a weird way) bimbling along as the slowest thing on the road. Hard to explain, but there's no annoyance getting baulked by slower traffic, or people pulling out on you and then dawdling, because you are Captain Slow driving his milk float. The only thing on the road slower than you is a cyclist.

Like riding an old 350 classic.

KungFooBob wrote: Wed Nov 20, 2024 10:20 am No one cares about old people tho'

Oi! Some of us do care.

Mainly because we are old too.

Rockburner wrote: Thu Nov 21, 2024 7:54 pm

mangocrazy wrote: Thu Nov 21, 2024 6:41 pm It was actually quite relaxing and liberating (in a weird way) bimbling along as the slowest thing on the road. Hard to explain, but there's no annoyance getting baulked by slower traffic, or people pulling out on you and then dawdling, because you are Captain Slow driving his milk float. The only thing on the road slower than you is a cyclist.

Like riding an old 350 classic.

At least on the LC I can hide in my own smokescreen...

I've just been out to retrieve some stuff from the van (Renegade exhaust, see different thread) and while ther I thought I'd check the header tank after the system had cooled down overnight.

Blow me if the coolant level isn't at the 'Max' mark! So driving like a Granny on Valium does wonders when you have a blown head gasket on a turbo diesel. Take the turbo out of the equation and coolant consumption drops to zero (or very close).

mangocrazy wrote: Fri Nov 22, 2024 1:21 pm I've just been out to retrieve some stuff from the van (Renegade exhaust, see different thread) and while ther I thought I'd check the header tank after the system had cooled down overnight.

Blow me if the coolant level isn't at the 'Max' mark! So driving like a Granny on Valium does wonders when you have a blown head gasket on a turbo diesel. Take the turbo out of the equation and coolant consumption drops to zero (or very close).

Is there an intercooler and if so is it part of the main coolant system?

(I know nowt about diesels and turbos but that ^^^^ about the turbo brought a turbo intercooler circuit to mind....).

Count Steer wrote: Fri Nov 22, 2024 5:04 pm Is there an intercooler and if so is it part of the main coolant system?

(I know nowt about diesels and turbos but that ^^^^ about the turbo brought a turbo intercooler circuit to mind....).

There is an intercooler but I think it's there to cool the incoming charge, although that is pure guesswork on my part. You may very well be right...

Just found this on t'interwebs...

An intercooler is a device that helps to cool air as it passes through the engine of a car or truck. By cooling the air, the intercooler helps improve the engine’s performance and prevent overheating. There are two main types of intercoolers: air-to-air and air-to-water. Air-to-air intercoolers use air to cool the air passing through the engine, while air-to-water intercoolers use water to cool the air.

So I know I have an intercooler, but I don't know what type it is...

mangocrazy wrote: Fri Nov 22, 2024 5:15 pm

Count Steer wrote: Fri Nov 22, 2024 5:04 pm Is there an intercooler and if so is it part of the main coolant system?

(I know nowt about diesels and turbos but that ^^^^ about the turbo brought a turbo intercooler circuit to mind....).

There is an intercooler but I think it's there to cool the incoming charge, although that is pure guesswork on my part. You may very well be right...

Just found this on t'interwebs...

An intercooler is a device that helps to cool air as it passes through the engine of a car or truck. By cooling the air, the intercooler helps improve the engine’s performance and prevent overheating. There are two main types of intercoolers: air-to-air and air-to-water. Air-to-air intercoolers use air to cool the air passing through the engine, while air-to-water intercoolers use water to cool the air.

So I know I have an intercooler, but I don't know what type it is...

Well, it'd be a shame to replace the cylinder head and find it's air-to-water and it's the coolant circuit for the turbo that's the problem! It's v odd though that the coolant didn't drop if the turbo didn't kick in.

Turbo compresses the air, which heats it up, the intercooler cools it back down again. You might be surprised how hot it gets! Hot enough that you cam use 100°C water to cool it down....

I'd be pretty surprised if you've got an air/water intercooler. The pics I can find of VW van ones looks like air/air ones, cause they look like "normal" radiators. Air/water ones (sometimes called charge coolers) don't need to flow any outside cooling air through them, so they don't need all the little fins.

I was wondering the same as count about the Turbo itself...

The French garagiste made the observation that when he was testing for the presence of exhaust gases in the header tank, that the gas bubbles only really showed up when turbo boost was being applied. I largely disregarded this at the time, but it now seems to make a lot of sense. Diesels run at very high compression ratios anyway; some can go as high as 23:1, whereas a petrol engine CR is in the range of 8:1 to 12:1. It's logical to assume that when the turbo is in full effect the compression ratio is at its highest, so running the engine at RPMs/throttle openings that avoid calling for turbo boost will mean the engine runs at a lower CR and less combustion gases escape from the cylinder to force coolant to go where it shouldn't.

That's a fairly unscientific prognosis, but one that fits with what I've observed.

And yes, I'm pretty sure the intercooler on a VW 2.5 TDi ACV engine is of the air/air type.

Count Steer wrote: Fri Nov 22, 2024 6:56 pm Well, it'd be a shame to replace the cylinder head and find it's air-to-water and it's the coolant circuit for the turbo that's the problem!

A cam down the glowplug holes will soon tell, just look for the clean piston, mind ewe, getting glow plugs out can be a job in itself.

The intercooler is front and centre in the engine bay. If there was any water/coolant leak in that area it would be very, very obvious. I'm 99% certain that the intercooler is of the air/air variety. My first thought when the low coolant alarms registered back in September was 'what if it's the head gasket' and I'm now convinced that my initial concern/diagnosis was correct.

One way or the other, we'll find out in mid December.

It's only normally stuff like mad Subarus and super charged Astons that have charge coolers.

Air 2 Air intercooler and oil cooled turbo......get them spanners out!

Sadlonelygit wrote: Fri Nov 29, 2024 6:07 pm Air 2 Air intercooler and oil cooled turbo......get them spanners out!

Those aren't the spanners you're looking for...

The spanners in question will be weilded by Keith at AW Engineering in Darwen, who will be fitting a fully reconditioned head, new gasket and head bolts and anything else that needs renewing/replacing. As it happens the turbo will be replaced with a brand new item that I bought thinking that mine was duff (when it wasn't). It might as well go on as I've tried selling it and can't and it has to be better than the 260k mile item that's currently fitted.

mangocrazy wrote: Fri Nov 29, 2024 6:24 pm it has to be better than the 260k mile item that's currently fitted.

There was always the legend that BMW used really old engines for their F1 efforts in the 80s. The 1.5 litre turbo stuff was a straight 4, derived from a road car (with alot of modification).

The story goes, they'd buy old scrappers with hundreds of k on them and nab the engine, just to get a block which was really old and had been through loads of heat cycles, the theory being it would have been thoroughly stress relieved and generally proven solid.

Not sure I believe it myself

Mr. Dazzle wrote: Sat Nov 30, 2024 12:02 pm

mangocrazy wrote: Fri Nov 29, 2024 6:24 pm it has to be better than the 260k mile item that's currently fitted.

There was always the legend that BMW used really old engines for their F1 efforts in the 80s. The 1.5 litre turbo stuff was a straight 4, derived from a road car (with alot of modification).

The story goes, they'd buy old scrappers with hundreds of k on them and nab the engine, just to get a block which was really old and had been through loads of heat cycles, the theory being it would have been thoroughly stress relieved and generally proven solid.

Not sure I believe it myself

There's also the story about leaving then outside in the winter and the staff pissing on them.

Ford did something similar with model t blocks.....

Mr. Dazzle wrote: Sat Nov 30, 2024 12:02 pm

mangocrazy wrote: Fri Nov 29, 2024 6:24 pm it has to be better than the 260k mile item that's currently fitted.

There was always the legend that BMW used really old engines for their F1 efforts in the 80s. The 1.5 litre turbo stuff was a straight 4, derived from a road car (with alot of modification).

The story goes, they'd buy old scrappers with hundreds of k on them and nab the engine, just to get a block which was really old and had been through loads of heat cycles, the theory being it would have been thoroughly stress relieved and generally proven solid.

Not sure I believe it myself

I'd read that Brembo went through a period of having lots of returns on their discs, due to the blanks (big long circular ingots of steel) not being left out in the elements to 'rest' for long enough after emerging from the steel mills. Apparently the blanks need time for the internal molecular structure to align itself optimally (or words to that effect).

Don't think it applies to turbos though...

Sort of. There's definitely a lot of stress relieving and recrysalisation and aging required when working with metal.

Typically it's more scientific that leaving it out in the rain though

I'd say there are probably advantages to leaving the blanks outside. Being outside it/they would go through cycles of heating and cooling whereas inside a building the temperature tends to be constant. Rain wouldn't really be a problem, as the outer surface would be machined off anyway.