Chasing a slightly lumpy idle...still

[Laird Scooby]

Originally Posted by Stephen Edwin

It sounds as if mounting the spare amp on a spare heat sink is a very good idea thanks. Why defer doing the compound &c. to be done at the roadside? Make it good when preparing the spare heat sink. Be prepared.

Sorry your brown paper failed. You forgot the string and sealing wax!

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As the inner wing is effectively the heatsink, the amp still needs to be removed from said heatsink and fitted properly at a later date. It saves time in the long run, i've proved it countless times in the past.

[Stephen Edwin]

Originally Posted by Laird Scooby

As the inner wing is effectively the heatsink, the amp still needs to be removed from said heatsink and fitted properly at a later date. It saves time in the long run, i've proved it countless times in the past.

Well if the spare amp is fitted properly to the equally spare item designated as the heat sink, that does not need to be removed and fitted properly at a later date. That has already been done properly. Init. Cushti.

Is there some chalk and cheese here?

[Laird Scooby]

Originally Posted by Stephen Edwin

Well if the spare amp is fitted properly to the equally spare item designated as the heat sink, that does not need to be removed and fitted properly at a later date. That has already been done properly. Init. Cushti.

Is there some chalk and cheese here?

Where does the "spare" heatsink come from?

[Stephen Edwin]

From a donor car?

Cheers.

[Laird Scooby]

Originally Posted by Stephen Edwin

From a donor car?

Cheers.

Hmmmmm............. use a disc cutter to slice out a lump of the inner wing to get a heatsink, i still prefer my method!

[Stephen Edwin]

Originally Posted by Laird Scooby

Hmmmmm............. use a disc cutter to slice out a lump of the inner wing to get a heatsink, i still prefer my method!

Plain speaking Dave. Are you saying that on the 700 &c. cars the heat sink is integral to the wing? Welded, brazed, such like?

Remember that I inhabit upstairs in the 240 section. I referenced the 240 section in passing on the excellent recommendation. I'm guessing that you might have disclosed now a retrograde aspect of the 700 &c.

I suspected there was some chalk and cheese here....

[Laird Scooby]

As far as i'm aware the 7xx ignition amps bolt onto the inner wing, same as most other cars do. Can't remember the last 240 i changed an ignition amp on, was nearly 30 years ago now!

Most manufacturers will make use of the metal they have available and you don't get a much bigger heatsink than the car!

Even using an aluminium heatsink in between, it still needs securing to the car so the car, by extension, becomes the heatsink. Why waste money on the extra heatsink? It can in some cases cause more harm than good as sometimes the extra heatsink won't transfer the heat to the car effectively.

As such, it's not a retrograde aspect but a correct progression.

[Stephen Edwin]

Originally Posted by Laird Scooby

As far as i'm aware the 7xx ignition amps bolt onto the inner wing, same as most other cars do. Can't remember the last 240 i changed an ignition amp on, was nearly 30 years ago now!

Most manufacturers will make use of the metal they have available and you don't get a much bigger heatsink than the car!

Even using an aluminium heatsink in between, it still needs securing to the car so the car, by extension, becomes the heatsink. Why waste money on the extra heatsink? It can in some cases cause more harm than good as sometimes the extra heatsink won't transfer the heat to the car effectively.

As such, it's not a retrograde aspect but a correct progression.

Dave !!!

I'm guessing a spare heat sink for a 240 is cheap as inexpensive fried potatoes. And it means the amp can be mounted carefully in advance, be prepared.

Nobody is talking about an extra heat sink !!!

It does sound to me as if the 240 is different.

Pity if the 700 &c. retrograde removed that option. Correct progression, neat turn of phrase. I must remember and use that.

Dave. We seem to have have found one of the little differences in two models that have a lot shared. Cushti!

[Laird Scooby]

I did a bit of digging Stephen on the Volvopartswebstore and it appears the later 240s (from about 1988 on) had some sort of extra aluminium plate interposed between the ignition amp and the inner wing.

Judging from the diagram, this would be for heat transfer more than an actual heatsink - in other words, it's not capable of providing enough heat dissipation by itself and is only there to prevent electrolytic corrosion between the ignition amp module and the heatsink. The heatsink compound should also provide the same function, possibly why i don't recall seeing it on a 7xx although in fairness, it's a good 6 years since i last removed the ignition amp from a 7xx and should really remove my current one, clean it and re-paste it with fresh heatsink compound.

If i find it's different when i do that i'll let you know but either way, for the sake of two screws, why not do the job properly in the first place?

[Stephen Edwin]

Thank you for digging Dave.

I have just been to the car and lifted the bonnet. That's enough work for today thank you. The amp is screwed to a substantial heat sink. So it is worth having the spare amp ready mounted on a spare heat sink....doing the job properly being prepared.

Never having changed an amp heatsink I don't know about the screws holding the heat sink to the wing. They don't look easy to get at. Are they in to captive nuts which might fail? Is serious cleaning necessary before re-fitting a heat sink to the wing or do the job again later after a roadside fitment? Will it be raining or snowing at the roadside? Will plod be rushing one along to clear the highway? Is it worth debating?

The point relevant to the 240 is, it is worth having the spare amp mounted to a spare heat sink. Saves possibly polishing and applying paste at the roadside in possibly adverse conditions or circumstance. Have I said before, be prepared.

I am curious about the fitment of the heat sink to the wing now. Clifford Pope is one of life and Volvo owner good eggs. As indeed are you Dave. I'll pick his brains on this for my own preparedness.

Moto re this: there is more than one good proper way to skin a rabbit.


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