Thread: Opinions on Bore please

As long as it hasnt pitted the bore it should hone out, i would loosen the rust with diesel or similar penetrant before trying to remove it.

Thanks for that, now never having had one of these engines apart before does it look like is has had a cylinder bore previously due to the piston having .020 stamped on it or is that std, plus they look rather clean, I would have expected them to be a bit blacker considering the age of the engine

+.020 is 20thou oversize.
The pistons look like they haven't been in a running engine. They look like they've just been cleaned.
Are all like this?

Yes they are all like this, also the head did come off rather easy no sticking just slid off when I removed the last bolt the gasket looks in very good order, but looking at the head itself the valves are filthy

Try some molasses on the bore, it will take the rust away and you will be able to see if the bore is pitted. If it is it might pay to fit a new liner, or bore out the rusty liner and put another oversize piston in, +0.030, all oversize pistons weigh the same as standard, but a 10thou. overbore will raise the compression on that cylinder a touch, which could be corrected with a light die grinder touch on the corresponding combustion chamber in the head.
If you have the cash get "Top Hat" liners fitted and bored to suit your 20thou. over pistons, Regards Frank.

Originally Posted by Tank

Try some molasses on the bore, it will take the rust away and you will be able to see if the bore is pitted. If it is it might pay to fit a new liner, or bore out the rusty liner and put another oversize piston in, +0.030, all oversize pistons weigh the same as standard, but a 10thou. overbore will raise the compression on that cylinder a touch, which could be corrected with a light die grinder touch on the corresponding combustion chamber in the head.
If you have the cash get "Top Hat" liners fitted and bored to suit your 20thou. over pistons, Regards Frank.

Thanks Tank, when you say molasses just the stuff you buy from the supermarket you put on your toast or is there a more concentrated stuff.

+1 on the molasses. Works a treat and will only remove the rust allowing you to get a good look at the bore. Be warned that it will stink a bit though as it does the rust munching... Be wary of it running down the bores into the crankcase/sump though.

Yep, normal, everday, supermarket molasses

If you can get one (ideally borrow, as not cheap), a Flexhone is a great way to de-glaze the bore afterwards and plateau hone at the same time ready for new rings.

Good luck.

Thank for that, I was going to send it away for a hone and block test at the same time, been reading about diy honing and not confident enough to do it myself

Will the molasses do anything to the piston top if I move it to the bottom of the cylinder then temp seal it and then fill it with the mix.