Head skimming

Mostly: they would remove the head and have an engineering firm skim it, then the garage would refit as necessary.

mrcheerful

Well, they only need to skim the head under normal circumstances - so thye whip it off and send it to a local engineering shop.

like the other replies, most garages use an outside engineering company due to the tools and expertise involved in skimming, a straight forward skim isn't to much of a problem, its when you have a severe gasket blow, then a pressure test would be required.

Normally, you can do it with a suitably large linishing machine (giant belt sander )

A cast iron head would most probably be refaced with a plough grinder. That's a grinder with a horizontal cupped grinding wheel that grinds the whole face in one pass. Ally heads can be done using the same machine, but ally doesn't lend itself to easy grinding. A vertical milling machine with a similar horizontal cutter or single point fly cutter, might be used instead.

They only need to take the head off. A local garage is highly unlikely to have machinery capable of doing the job, so yes, it would be sub-contracted to another engineering Co. Mike.

May be a silly question, but here goes:

How far do you have to strip the head down to send it for skimming ? ie. do all the valves have to come out & studs removed so its completely bare?

I have to do a gasket job on my old Rover 100 1.4 K series soon. It runs OK but it has almost as much oil in the header tank as in the sump!

The message from Skokiaan contains these words:

Generally yes. No so much because they can't do it with the valves in place but because they have to wash it very thoroughly after use and can't get any abrasive swarf out if it's not bare.

If it's any help, I know of at least two vehicles whose owners have put oil in the cooling system instead of water. That way any mixing is immaterial. Also you don't need antifreeze!

Rob Graham

I have had k series skimmed with the valves in without problems, just get them to run it through the overnight wash sequence and use an air line to blow out everywhere afterwards. mind you, if you have the time removing the valves, grinding or recutting the valves and seats and replace the stem seals is a nice idea if you have the time. Preferably get the valves refaced and the seats recut by the engineering firm that does the skim. But bear in mind that all this is worth more than the car if you have to pay for labour, and borderline if labour is free.

mrcheerful

Yes it does work, but not for long, as the rubber hoses soon soften and burst...

Tim..

Find out whether it needs skimming first.

On something thats prone to HG issues, or has been more than slightly over heated, a light skim is essential, else you'll be doing the gasket again soon after!

Tim..

How?

mrcheerful

Well, I know these vehicles ran for at least a couple of years without needing new hoses - maybe more. And is the effect of oil in the water less damaging?

Rob

If it's an alloy head, skim it regardless (it will probably need it). For the cost of the job it's not worth cutting corners. Considering that if you don't, and it turns out to need skimming, then you will pay more than the cost of a skim in time and more new gaskets!

Something tells me that's a bad idea, oddly I can't think why.

For your replies...

Good stuff, gents.

In that case, if you can get your hands on such machinery, its easy money around xmas time.

Heres one

Arthur :)

Earth calling rob, earth calling rob...................are you receiving rob..............