The Grimer Gas Engine

The huge gas engines in the Anson collection are so spectacular on startup, the principle just had to be copied however pathetically. Just watch my short video and imagine the gas explosion contained in an engine about 10ft tall. Those early designers were so clever.

Why Grimer? Back around 2013 we lived next door to a very special gentleman called John Grimer. A WW2 war hero and much liked school teacher, a really super guy with a wicked sense of humour who was never going to give in to his major war wounds. His incredible life story belongs elsewhere but we were so fortunate to have known him. John had a hydraulic lift to get into the bath and when he passed away I was given parts of this apparatus to utilise however I wished. And so this engine started. I felt it should be called ‘The Grimer’.

Had to give up using gas!

Since I happen to still have my notes, here they are…

Feb 2017 Grimer Gas Engine


  • Bicycle chain and free wheel
  • Gas taps
  • Ball bearings
  • Flywheel from compressor
  • Piston
  • Safe-de-speeder
  • Cast iron base from compressor
  • Eccentric shaft dia – throw – bearings – 35dia steel


6th Dec – Blocked cylinder bottom. Ignition principle test successful. Ordered eBay piston material.

7th Dec – Chain drilled and cut out the top plate profile. Engine named The Grimer.

8th Dec – Ordered freewheel and chain. Squared up top plate.

9th Dec – Piston material arrived, good size!

10th Dec – Shortened top plate and started main bearing housings. Watched video and my project looks increasingly difficult 😑

12th Dec – More work on the bearing housings. Found a couple of ball races 5/8 bore.

13th Dec – Machined piston and fitted rod. Cut square hole in top plate.

14th Dec – Fitted length stop inside cylinder. Machined top plate locating flange.

15th Dec – Recd pictures and info from Anson.

19th Dec – Tested – explosion!  Dangerous – piston hit ceiling.

1st Jan – Another test was spectacularly risky and the decision to run the engine on air was taken.

2nd Piston stop removed and full stroke test on air proved ok.

3rd Milling slot for chain rack.

4th Chain rack finished and fixed.

5th. Main bearing housings bored.

6th. Housings split and drilled/tapped.

7th. Gas inlet tap arm made. Actuating rod started together with top control arm.

9th. Air test failed. Needs further thought – magnet? Extra weight?

10th. Free wheel hub screwcut.

11th. Free wheel hub fitted to main shaft. Flywheel hub made. Ex-compressor flywheel test fitted.

12th. Flywheel hub fixed. Flywheel cleaned.

13th. Speed reducer fitted. Base stand cleaned and fitted.

15th. Made most of camshaft bearer frame clamp.

16th. Bearer frame clamp fitted. Camshaft bearing arms started. Speed reducer brake bracket in hand.

17th. Decided to use gas taps! Sprockets arrived.

19th. Made sprocket hubs. Made eccentrics. Fitted camshaft.

20th. Bored cam followers. Chain link arrived.

21st. Cam followers finished and temporarily fitted. Rose joints arrived.

22nd. Gas tap actuator arms in progress.

23rd. Test. Mods reqd.

24th. Success!! 😃 After tuning mods. Now needs tidying. Tried bigger chain driving sprocket but not much difference. Needs heavier flywheel. And more air. Flywheel pulley ordered. Tidy valve arms. New connecting rods. Bigger sprocket? Paint. Polish steel and varnish. Air vent on top.

25th. Valve arms shortened.

26th. Sprocket arrived. Top flange may be moving with piston contact.

29th. Top flange tightened. Realised exhaust needs to be worked from piston rod to avoid mis-timing.

30th. Tried this and it worked! Needs serious tidying but principle good. Flywheel pulley arrived and looks good.

3rd Feb. Flywheel pulley fitted. Exhaust modified and works well but still needs tidying. More air volume would be good. Larger compressor!

5th. Bought compressor. Ordered air connectors. Modifying exhaust linkage. Rose joint idea. Tidying inlet rods.

6th. Finished rose joint exhaust. Blocked redundant front tap but left operational. Fixed airline to wall ready for compressor connection.

8th. Compressor rigged and works the Grimer well. Fitted exhaust copper tubes. Painted base

Later – following a chance remark from a friend I have embarked on making my engines actually power something… a water pump for the steamer is first! A 1 ton jack provides basic materials but needs considerable modification…

… I think the above diary shows just how boring these progress reports get. Full marks to anyone reading past December! I promise never to do it again…

My version running on compressed air

A problem I never overcame was the fact that the propane gas I used was heavier than air and wouldn’t rise to fill the combustion chamber as it did on the real engines running on ‘lighter than air’ town gas. Well, that’s my excuse…

YouTube video links:

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