Tester suspect? Am I missin' something?

[ally260]

Got 4 nic motors.
Motor # 1, 99hrs, good comp leak down 5 ta 6%
Motor # 2, 20hrs, good comp leak down 5 ta 6%
Motor #3, 30 min. good comp leak down 5 ta 6% This motor had tha most perfect holes (ALL rings were a loose 12 thou. thank you Mr. Ghor) of any we have EVER seen with everything in it new...........
Motor #4, 0hrs good comp leak down 5 ta 6%

All 4 were 2 ta 3 pounds difference in compression on each one, ie: #1 151 ta 149, #3 163 ta 165 etc...

For some reason I have never checked leak down on a motor when everything is new. Only after its got so time on it. I know I should have but what tha hell, if everything checks out and it runs good from tha git go it never entered my feeble mind ta do so. Just gettin' to old ta really give a **** I guess. Just havin' a hard time buyin' these numbers???? More so on #3 than any of tha other ones...............

TIME for a new one or am I missing something????

NONE of tha ring gap on any of 'em were more tha 14thou. All pistons were new or excellant condition.......

 

[ally260]

Guage went south...................

 

[allimax]

Those #'s do seem highly unlikely. Maybe you could try one with the threaded insert loose in one cylinder to create a slight leakage and see what you get?

 

[ally260]

Its tha guage no doubt. Anything we put it on got tha same type numbers. Even a wore out, scared up, beat up, way under 80lbs of comp on 5 of 6 with probably a zillion hours '79 2.0 motor! Needless ta say, got a new tester on tha way.......

 

[ssv1761982]

Could you just put a couple of new gauges on the old tester?

 

[1-fastone]

Single or double ring pistons

 

[ally260]

Could you just put a couple of new gauges on the old tester?

Guages (single) are more expensive than tha whole thing (good one, not harbor freight)

Single or double ring pistons

All two ring top pinned ('cept tha '99, #1, still side pin I think, never opened) Merc with gold rings...............................

 

[ally260]

All is well now. New, liquid filled guages testor showing ALL under 3% on tha '99 and 2.5% on tha 20 something hour motor. Tha other 2 were way less as they should be............