Compression test result

[JuNK512G]

Asked to do a compression test on a 1098cc Trav low on power & smoking a little & apparently uses oil, I was surprised to find the following results which seem higher than normal. I use a Gunson tester which I appreciate is not highly rated, however the many tests I have done on my 1300cc A+ has never shown above 190psi.
HOT/DRY HOT/WET
1) 230 1) 250
2) 210 2) 230
3) 205 3) 230
4) 220 4) 240
I would not expect high psi to produce low power, any comments please.

[ssnjimb]

those results are very high

is the timing correct.

Are the valves opening ?

could the exhaust be blocked

Jamie

[bmcecosse]

These are indeed exceptional results! Pretty much what I would expect on a full race engine !!! Can you try the gauge on another engine to see what it reads there??

[JuNK512G]

Thank you for the comments, my brief was just to do compression tests, I didn't investigate further but I will try & check out my tester again on my engine & a 1098cc.

[JuNK512G]

Carried out another test on my 1300cc A+. Results:- three cylinders at 170 & one at 172 Dry. Wet two at 190, one 191 & one 185, these figures are consistent with all my previous tests. Over the moon with these results from a 1275cc engine which I believe has target figures of 150 to 190 as healthy.
I have to wait now for a volunteer 1098cc so I can test the tester some more.
Although I did not delve into the problems with the engine in question, I did notice the plug noses were very white which may account for low power.

[alexmcguffie]

At least it sounds like your compression tester and engine are both good. As for the other engine.... I think 190 is the maximum I've seen on any engine.

[bmcecosse]

These results are also on the slightly high side - but the important thing is that all the readings on each engine are similar, so there is nothing seriously wrong internally. Low power then must be down to poor induction /poor exhaust or poor ignition timing (assuming camshaft is correctly timed in ). Have you tried without the air filter fitted - in case it is not flowing air as it should? What size is the carb - and is the throttle plate opening fully when you press the pedal to the floor ? And - is the carb piston free to rise and fall ??

[JuNK512G]

Thanks again for your help, I borrowed a newish 'Silverline' tester & did my engine again which shows my tester as being high by around 85psi so that's for the bin. The bottom line is that the original engine is healthy & mine not very good, however as BMC pointed out, the important fact is the differences between cylinders is tolerable. The owner of the first engine is watching this topic so will no doubt follow up BMC's advice.
Charlie.

[bmcecosse]

Oh dear - if you take 85 off all the results - then the first engine is 'ok' but the second engine is pretty much kaput....