Practically Classics Forum

that sucks.

Would just using 2 gaskets do it?

I suspect you'll need a little more than five thou removed - allow for a little slap in the piston as the bearings wear! I doubt double gaskets would be a great idea - it may be OK with petrol/paraffin Fergies, but the compression ratio is slightly higher on a 135!

It's just a shame that, whoever did the last repair didn't put new liners in - or did they? Are the old pistons completely shot, or is it worth cleaning them up and seeing if they can be reused?

I hope the liners are good and tight, with no chance of hot spots welding them to the block! I know the A3 was different, but I did have one drop a liner when I was driving it - it makes an interesting knocking noise (a late 35X, the boss had a spare tractor in a shed - a grey/gold Ferguson 35 that had to be tow started most of the time! It wasn't too bad until a back tyre punctured and he had to put a smaller (grey Fergy) wheel and tyre on - from another of the tractors hidden in the shed!

When you say that the pistons are 5 thou too high do you mean the liners or the pistons are too high? I seem to remember that the liners are supposed to protrude by about 5thou. On Ford and Nuffield engines liners sinking in the block was an issue and they had to be shimmed to get the correct protrusion otherwise the head gasket wouldn't last 5 minutes. These engines had wet liners ,not dry ones as in Perkins engines. I have given my Perkins manuals to the local vintage tractor club so I haven't any specifications to help you. Try ringing Perkins technical support as I have found them extremely helpful in the past.

AD3 liners are flush to 0.004 below block face. The 4cylinder is flush to 0.004 above.

I have clocked the pistons they are 0.005 above the face but the new gasket is 0.040 and even the old gasket i took off is still 0.035.

So as long as the HG's fire rings are outside the edge of the liners on all three then, you'll get away with this nicely. Result!

Just been told on a 'tractor' forum that 0.004 is top limit. according to that it should be fine i'm not arguing over a thou.

have you got it running yet?