Compression test

[petegardner_901]

Hi all

Checked the compressions on the GT6 just now.

1,2,3 and 5 all showed 133 psi

4 was 125

5 was 128

Should this be a concern? Engine is running fine - could these lower numbers be due to tapped clearance or should I just forget it.

thanks as always -  all your advice is invaluable

pete

 

[Pete Lewis]

was this with throttles OPEN  ?  

think i would say ok for those results  for now   recheck later see if theres a reducing trend   or   not 

Pete

[NonMember]

If you want to check your tappet clearances then it probably wouldn't do any harm, but I don't think I'd worry too much about those pressures. As Pete says, check again in a while to see if it's getting worse.

[Nick Jones]

Compression tests should be done warm with all plugs out and the throttle wide open. I generally allow 5 compression strokes per pot.

Absolute results are a bit lower than might be expected, but the compression gauge is an uncalibrated device. They are nice and even though, so if it’s running well and not breathing heavily or burning oil, I reckon it’s likely fine 

Nick

[daverclasper]

4 hours ago, Nick Jones said:

breathing heavily

Hi. How do you determine this/the symptoms.

Dave

[dougbgt6]

Dave,

Pete has a whole section on heavy breathing on the "other" site.

I don't think you have anything to worry about with those figures, just try it again in a couple of months.

Doug

[daverclasper]

Hi Doug. It was Pete's original enquiry. Just interested if "heavy breathing" is part of my life?.

 

[dougbgt6]

Oh, sorry Dave it's the heat, and I haven't recovered from my trip to Duxford, I can't believe the GT6 used to be my everyday car, how did I put up with it?!! 4 stone lighter perhaps?

db

[Iain T]

21 minutes ago, dougbgt6 said:

I can't believe the GT6 used to be my everyday car, how did I put up with it?!! 4 stone lighter perhaps?

Doug,

You were 4 stone lighter because you sweated a gallon a day in a GT6🥵

I meant to find you at Duxford and put another face to the name.....but forgot. 

Iain

 

[Badwolf]

1 hour ago, dougbgt6 said:

Pete has a whole section on heavy breathing on the "other" site.

When it comes to heavy breathing and the other web site, all that comes to mind these days.....

...is the web site of a certain stair lift company.....and we live in a bungalow!!!

[dougbgt6]

12 hours ago, Iain T said:

I meant to find you at Duxford and put another face to the name.....but forgot. 

Yeh, me too! I did shout at a gnarled beardy with a rolling gate "Are you Dick Twichin?" And he was! Turns out a jolly nice chap.

Doug 

[johny]

15 hours ago, daverclasper said:

Hi Doug. It was Pete's original enquiry. Just interested if "heavy breathing" is part of my life?.

 

Believe its related to how much pressure you can feel with the oil filler cap removed. If the rings/bores are worn there will be more leakage to the crankcase which, up to a certain flow, will be drawn into the carbs by the PCV. However Im not sure if its necessary to block off the PCV to test this...