Stupid HG question

it sounds like you have the wrong gasket, change it or it will just burn away. cleaning the head faces can be safely done using a flat steel block and wet and dry paper, obviously don't scrape away in one area for too long.

Mrcheerful

In the relative warmth of our back room I got thinking out it and figured the same thing. Oh well, kiss good bye to another weekend then and anther £20+. The kit appears to be correct as it includes all the correct seals and gaskets for all other components. Everything about the gasket is the same as the other gasket, but looks like it's been pressed about 0.5 mm out to the right. Probably should return it to Fiat, but I've put it on now so they're probably not going to be happy about that.

The really annoying thing is after all this effort, because of the bubbly paint that's formed on the roof and your advice in a previous post. I'm only going to part-ex the damn thing anyway within a couple of months of getting it running. Fresh service (albeit done by me), MOT (with flying colours), new pads, tyres, HG, valve stem seals, brake fluid, shims not worn, valve look OK, cam bearing showing a little fatigue (according to the picture in Haynes). Gutted. But in saying that, I noticed a 1mm long by 0.5mm deep (not very wide, but certainly well stands out to the human eye) grove in the head matting surface around cylinder 1 (cylinder with the issue). I've put a dab of gasket paste on it, but all this could be academic if I need a new head anyway. I don't know how much a skim takes off, but I wouldn't have thought as much as this. Perhaps I should just leave it and drive it straight to part-ex eh?

Thanks for the cleaning tip. I used an extra wide wall paper stripper. Looked like most of the metal gasket scrappers I'd seen and was wide and blunt enough to reduce risk of digging in. The sanding paper sounds like a better route. Any cleaning agents suitable for shifting contaminates (e.g. oil) off the matting faces? Or isn't it an issue if you've run a rag over it?

Regards,

Tim

I would usually clean with brake cleaner last. petrol would be ok.

Mrcheerful

and yes, a skim would be a very good idea

As Mrcheerful said. It's probably the wrong gasket. Better to replace it than take a chance by leaving it.

Personally I find a blunt 1" wood chisel ideal. If you're thinking of a solvent for the crud, I don't know of one, but as far as washing is concerned, there's very few domestic type solvents that'll harm the head or block. White spirit, parrafin, petrol, cellulose thinners if you have any. Almost anything will do. I use a cheap bench parts washer with a pump, (£38.69 inc from Screwfix) and filled with about 3 galls of parrafin. Mike.

Only £12+VAT for a new HG from the local parts place, so not a big issue. Fingers crossed it will be a little warmer this weekend, or at the very least no wind and rain.

Thanks for the advise, I'll look into a head skim if it fails again shortly.

Regards,

Tim

In message , Tim writes

I would skim it *before* it fails again.

Definitely.

Mrcheerful

I use nice green Scotchbrite for this sort of thing (as for everything else) Works a treat, easy to hold, doesn't disintegrate, and available in cheap packets of 10 from Screwfix - ideal for padding other orders to get free delivery!

Ian

I would advise checking the head for straightness before possibly having it machined uneccessarily. Not all head gasket faiures result in a warped head. Mike.

IIUC a properly done skim checks for warping at the same time, by taking a minimum amount of metal which shows up any faults, then you take a suitable amount more. If it has overheated there will be warping, the OP says there is damage, therefore it needs a skim.

Mrcheerful

Quite possibly, but unless the warping is outside recommended tolerances, it doesn't need machining. It's a waste of money to set it up on a grinder or mill just to find out if it does, and even if it doesn't, the machinist will skim it anyway, which the customer will have to pay for. Could save money to do an easy check it on the bench with a straight edge and feelers. 'Then' decide if it needs skimming.

the OP says there

If the damage is as severe as the OP states, 1mm long by 0,5mm deep, to remove 0,5mm or 20 thou is more than a skim IMO. And is it necessary? If it is right on the edge, a careful peening to raise the the edge might be a better way of treating it.

I checked the head on a 1.8 Galant that had blown the head gasket about a year ago. 3 thou bow on length, otherwise OK. Was refitted with new gasket, and has since done around 10k without any problems. Mike.

The car never properly over heated. As it started to develop a misfire I kept an eye on the temperature gauge. It started to overheat at the last traffic lights 0.5 miles before home (i.e. started to rapidly go above middle, but didn't get into the red). So I simply turned off the engine, it didn't move above middle again until I got home. Think I caught it before any damage was done.

The damage might be less than 0.5mm deep. I think you've got about

10thou that you can skim off. I must admit I have no idea what 10/20thou looks like, or even what unit of measurement (inches I'm guessing). However the damage is in an area covered by the metal rings within the HG. I guess this is a critical area and probably does most of the sealing.

What's a skim, about £35inc VAT? Maybe I should find somewhere and see what they can do. On the other hand I'm just going to flog it ASAP on account of the bubbling paint on the roof. Shame that, I liked this car, always gave me something to do every 6k miles. All my other cars just worked :D

Regards,

Tim

For the extra 30 - 40 quid I would recommend a skim, the extra labour and gaskets would far exceed that if you have to do it all again, not to mention the extra inconvenience.

Mrcheerful