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Suffolk Punch 98G14 1A exhaust removal issue

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v8alex

I have the pleasure of restoring a 17" Suffolk Punch Professional and have run across an issue with the exhaust.  When stripping down the engine, the exhaust box disintegrated upon removal, leaving the engine block like the attached image with part of the exhaust in place that I need to remove.  The exhaust was a square style box unit.  In the literature I have searched for, I can only find diagrams for the 75cc engine with a different style of exhaust.

So my question is - how is the exhaust attached and any ideas on how to remove the remainder without damaging anything?

Forums

Mowing Wurzel Sun, 15/06/2025

The exhaust pipe, the bit broken off has a BSP thread (as I recall) male thread, tapped into the engine block.

I would first advise to secure the block,  and use stillson's or other grips to give good purchase..... to grip around the exhaust, and naturally see if it will move in anticlockwise direction.

You could also get a large nut and drill out the centre, then weld over the broken exhaust pipe to give better grip than stillsons, which slip if not used correctly.

90% of cases the exhaust won't move and  it needs the block area heated to expand the casting, and spray with rust penetrant.

 

 

v8alex Sun, 15/06/2025

Thanks for the advice - much appreciated.  You can see some marks where I have already tried some stillsons, but I hadn't used much force or any heat.

So time to try a bit harder, now that I know it's threaded into the block.

Mowing Wurzel Sun, 15/06/2025

If you have more time.  Tilt the engine on its side,  wire brush where the exhaust goes into the block and then squirt some rust penetrant around it.

This is one of the problems with old machinery,   the fear of breaking components which haven't been apart for years.

As I say heating around the block,  but not the exhaust itself, as heating this would cause expansion in the thread, would certainly help.

 

v8alex Tue, 17/06/2025

I have more time as it's not shifting yet. Welding a nut round it didn't work either, though I confess to not drilling it out and sleeving the exhaust - I just tack welded it on the end.

I have some PB Blaster expected tomorrow and some freeze spray and a big pair of stilsons, so plan to soak in PB first for a few days, then heat the block etc and try again.

I've also thought of tapping a LH thread inside the exhaust and screwing in a bolt.

Also thought of accepting it's not coming out, so cutting off flush with the block, then drilling out and re-tapping and making my own exhaust pipe to fit. Or just tapping it and making a shorter exhaust to fit.

v8alex Wed, 18/06/2025

Success! 

Used PB Blaster, big stilsons and held the engine in the vice.  Exhaust finally gave up the fight and came free.  Didn't use heat in the end, but I had done previously. 

Threads look fine too, but I'll probably chase the them out in the block.

Many thanks for the good guidance.

 

Mowing Wurzel Wed, 18/06/2025

Good to hear this is resolved without any breakages.

The old Suffolk Mowers are all British construction and are very well built and turned out ... Quality like what they made is only found in high end professional Mowers now!