Porsche Enthusiasts Club Forum

thanks for your reply i will probably lift the engine out myself in the spring, to cold out in the garage right now, and go from there. probably have the head off at the same time.keep me posted.the rebore plus liners might well be the way to go bill

I'm with Paul on this one. If you can get away with nothing do nothing. There is alot of different people that have made alot of mistakes when reboring or lining these engines. I have been looking at refreshing my engine too and have read all I can on every website I can find. From what I can tell it is best to go to someone who has rebuilt alot of these engines, so Jon Mitchell or Hartech or alike. And I think everyone I've spoken to has said do as little as possible because Porsche did it well the first time arround.

I was planning to strip my engine down and if it was all in spec then fit new rings and that is it. If it need a bit more then maybe a bit of Honing and then probably the file fit piston rings from Lindsey racing in the States. Anymore than this looks like it will be expensive so before a rebore or liners (which I think I'd only use Darton sleeves) I'd think about a new engine with less wear......................... or an LS transplant for about the same sort of price!

As Dave will confirm I have just spent the last year rebuilding my 44's engine, it had covered 188k and the bores where very badly worn, you are quite correct regarding sourceing oversize pistons and rings, after several weeks of telephoning around I located a new set of .5mm oversize pistons from Hartech unfortunately they came without rings so serveral more phone calls later I located a full set of new .5 oversize rings from Bert Gear combined these cost me £500 and a further £200 to have the block rebored and coated, Porsche do sell and still have stocks of these on the shelf but I was quoted £1500 + VAT for a set, has it been sucsesssful, that I can't answer just yet as I have not fired her up yet, but I am keeping everything crossed.

Who did the rebore & honing?

Hi Jim,

The work was carried out for me by a company called Headshop based in Warrington, John Holland from Unit 11 Porsche sends all his machining work to them and it was John that put me onto them, I was a bit unsure at first as so many people told me it could not be done or would not last, but when I took the block and pistons to him and told him it was for a 944 he explained about the block being made up from Aluminium Silicone Carbide and explained the need to hone and polish after the rebore with an acid based compound to bring the silicone particles to the surface so preventing the rings picking up the particles of aluminium and eventually sizeing the pistons in the bores, I would recomend them as they have done a fantastic job, also in the price they balanced the crank too!
After I had the work done I found an offical Porsche document explaining how to carry out the process and seeing as Porsche themselves can supply oversize pistons and rings then I thought I'll give it ago, lets hope all those people who told me it was not possible to rebore the 944's block are wrong otherwise there will lots of "I told you so" heading my way.

I knew it was possible but lots get it wrong! I know one of the guys on Titanic had a block trashed through it not being treated correctly.
Very relevant to me as I'll have an S2 lump to be dealt with later when I rebuild it.