Want to check out our tractor maintenance videos? Click here to see what we've got!

We have written before about the benefits of enlarging the entrance to the pre-combustion chamber on the Standard 23C engine as fitted to the Ferguson FE35 tractor.

One of our fellow FE35 owners (Neil) had completed a full rebuild of his engine but the starting performance was disappointing.  Neil ordered Vintage Tractor Engineers’s DVD so see if there was anything he had overlooked, and the only thing hd could see different to his own job was that the engine in the DVD had had the entrance to the pre-combustion chambers enlarged.

Neil removed the cylinder head, loaded it up and took it along to Park Engineers (that’s who Vintage Tractor Engineer uses, and John at Parks knows his job inside out).   The grinding was done while Neil waited and then the engine was re-assembled as before.

And the result…

Much improved starting performance.

Here’s what Neil said…


You may recall I emailed you earlier this month regarding difficult starting of my 23c engine. Working back to front I had overhauled the engine, experienced difficult starting, then purchased your DVD, which confirmed I had done most things correctly except I was not aware of the need to enlarge the combustion chambers.

You made me aware of two companies who are experienced in this procedure, one in Ireland and Park Engineering, North Yorkshire.

I contacted John at Park Engineering, he could not have been more helpful, the work was carried out whilst I waited. My tractor now starts satisfactory (no easy start!).

Thanks for your help in this matter.


Neil H.

Was this the only alteration to the engine?

Vintage Tractor Engineer asked Neil if this was the only alteration that was made to the engine – was everything else just as before. Neil replied…


Thanks for your response. You ask, “is that the only change you have made”? Yes, just re-fitted cylinder head with a new head gasket.

Remarkable the difference, runs very smooth, will give it some work soon to settle everything down.

Once again, many thanks.


Neil H.


Vintage Tractor Engineer has never rebuilt a 23C without having these ports enlarged, so it has been good to get the feedback from Neil. It would seem that this modification makes all the difference.

If an engine is just experiencing poor starting performance and presuming that everything else is OK, then this modification is something well worth considering.

Steve and Ian Ridsdale


One More Thing

Whilst doing an internet search on this subject, VTE found ‘The Tractor Lad’ website by Ben Phillips.  Ben restores vintage tractors and has written a nice article on enlarging the pre-combustion chambers, with some photos of ‘before’ and ‘after’.