Hi all,

I have a mf 35 4 cylinder engine rebuilt pistons liners rings little ends
valve seats recut new valves head skimed it used to start up on 3 cylinders then the 4th cylinder come in we have had the injectors and injector pump serviced now it takes up to 4 atemps to start even in hot weather, if it was cold don’ go there because it won’t start. Heater plug is working only got 1.

I suppose it must be something to do with the injection timing. Did you have a look at the timing chain and tensioner and also the backlash on the injection pump drive gear?

Hi steve
No we didn’t look at the timing chain or the tensioner or the backlash of the injection pump, one thing we did do is to check the compression 120 psi when dry and 190 psi when wet,do you know what the compression should be please. Many thanks, Phil butler

I’ve been searching for the compression test data which I knew I had somewhere but just couldn’t find. Anyway I’ve found it now.

The data I have is that the dry test should be 380PSI and then the wet test no more than about 10% above this. I would think that anything above 350PSI would be acceptable.

The dry figure I have is considerably higher than yours, but you have had new pistons, liners and rings. Did you fit the rings yourself? Were rings 2 and 3 fitted with the tapered periphery of these rings towards the crown of the piston?

The good news is that there is a difference between your two tests so that eliminates the cause of your problems been with the head gasket or valves.

However, the difference between your dry and wet tests is quite a lot, which all points towards a problem with either the liners or the pistons/rings.

Did you do the compression test on all 4 cylinders? and observe similar results.

I believe your compression test is very low, so I would think this is probably the cause of your starting problems.

Just a thought. Have you connected your tester through the injector fitting with a clear passage from the cylinder to the guague? Did you turn the engine over so the test gauge gave 5-6 readings before taking the reading?

I haven’t tested lots of the 23C engines myself, so I haven’t got any data of my own to compare with your test results. The 380PSI I quoted was a ‘text book figure’ I once wrote down, but I think it is about right.

120PSI is certainly low.