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leak down test

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lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#21900
Hey there,just had a service done on my beetle 1300sp and they did a leak down test,hmmmm interesting 1. 25% 2. 70% 3. 30% 4. 20%.What do you reckon will it hang together long enough to do a run on the dyno,should i wear a flac jacket and helmet or should i just stay home and sulk.🙁

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#21926
ummm.... how does it run?

Does if feel bad?

Just bring it!
Futue te ipsum!!!

KruizinKombi Seriously Obsessed Cyber Dubber

3,493 posts · joined Aug 2002 ·

#21927
I assume you're talking about a compression test? Are those readings the percentages lost or the percentages remaining? Do you have the actual pressure readings?

With that kind of variation in pressures, you'll be looking at a rebuild fairly soon - it's way outside tolerances. Engines can often continue running that way for a LONG time, but they use heaps of fuel and lose a lot of power, and sometimes crap themselves quite quickly.
Kruizin Kol

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#22008
It still runs OK starts easily idles perfectly and gets 26-30mpg or 10.7-9.4 lp100k.But on the downside uses 1 litre per 1000km of oil.This is not a compression test i had a compression test done 13100km ago and got 125psi on all cylinders and the percentages are what is leaking out not whats left,thanks guys see you at the dyno day.

KruizinKombi Seriously Obsessed Cyber Dubber

3,493 posts · joined Aug 2002 ·

#22054
Is it burning it or leaking it?
Kruizin Kol

speedster356 Plastic not Classic Racing

1,624 posts · joined Aug 2002 ·

#22107
Some info that might be of interest....

Leakdown Test is different to a compression test

Leakdown test tips

In the aviation world, we run the engines to get them hot (only accurate way for a leakdown) and put nothing in the cylinders to alter the test (such as oil) .

At TDC, apply air pressure (about 100psi)via a differential pressure tester and note the reading. I'm not sure what "normal" leakage is for a type 1, but in my experiences you should be maintaining somewhere in the area of 90% of what you put in for a nice "tight" cylinder. More importantly, all cylinders should be within 5% of each other.

When rotating a cylinder to TDC, don't go past TDC and then back. If the rings are not seated against the bottom of the lands, your readings will be low. It was common during aircraft tests to rotate the piston slightly back from TDC (with air pressure applied) and then back to TDC to ensure proper seating. Often times this would "fix" what initially appeared to be a leaking cylinder.

If you have excessive leakage, use your aural indicator (ear) to locate the cause. Pop the oil cap off and listen for a hiss (blowby from rings or worse), next listen at the exhaust pipe (exhaust valve) and finally at the intake with the butterfly open (intake valve). This will isolate your problem and direct you to the proper corrective action.

bring it along.......it sounds just like the Speedsters engine!
I must put that new 1916 in sometime.
Spyder-WISD 07-09-05 11.6s @ 125 MPH

Speedster-WISD Nats 05 14.4s @ 89 MPH

Jet cruiser-Coogee 22-09-05 900 deg C @ 110,000 rpm

Weaseling out of things is what separates us from the animals....................Except the Weasel.

Doug Sweetman Nil Bastardo Carborundum

2,128 posts · joined Sep 2002 ·

#22123
Thanks for the explanation speedster - I have learnt more from your one post than I have from many other discussions I have had.

Keep up the good work 🙂

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#22126
Its burning it and blowby is coming out my oil filled standard airfilter.

vw54 Administrator Always Waiting 4 Friday

16,723 posts · joined Aug 2002 ·

#22160
I wouldnt worry about it too much, the reading of 125psi is that about the same on all 4 cyclinders.

As long as its not 125 or # 2 and say 50psi on # 3 then i would have something to worry about,

Drive it steady n check the oil regulary and it might last a few more years.

My Smoothiee burns oil pretty heavy ( does not leak ) but it does not rattle and runs quite when warm
I read it on FACEBOOK so it must be true


http://forums.aussieveedubbers.com/viewtopic.php?tid=91278&page=1#pid848630


http://forums.aussieveedubbers.com/viewtopic.php?tid=63561&page=1#pid624099


http://forums.aussieveedubbers.com/viewtopic.php?tid=4832&page=1#pid452603


http://forums.aussieveedubbers.com/viewtopic.php?tid=60650&page=1#pid574409

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#22245
Im as curious as hell now,can anybody tell me if they have done leakage tests and there results,theres an article at Kens Buggy Barn and it says 10% is a good engine,20% is a worn engine 30% is an engine rebuild or valve job and that 90% indicates serious damage such as a badly burned valve,holed piston or the like,come on how bout it pros and racers give us the lowdown spill the beans please,please come on grovelling sincerely.Mick.

geodon Wolfsburg Wizard

478 posts · joined Aug 2002 ·

#22309
In the aviation world, the standards have to be very tight or else planes will be falling out of the sky. I always remember the story Bob Ansett tells of when Budget Rent-a-car bought a heap of Holden Camiras with disasterous results. After hearing GMH's explanations, Bob said "It's just as well my company is not Budget Rent-a-Plane!".
Seriously, if your 1300 is performing as you say, just keep driving it. If you're worried, post an ad for "wanted to buy" & see if you can get a spare engine- then if your current one karks it you can swap it over & fix your original. I think you may be applying too stringent mechanical specs that are really only relevant to a fairly new car.

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#22423
Geodon yes your right i am applying stringent standards i have this habit of going overboard on things,i think i may have Obsessive Compulsive Disorder.Mick.🙁

KruizinKombi Seriously Obsessed Cyber Dubber

3,493 posts · joined Aug 2002 ·

#22441
There could be no better way to display such a disorder than through your Volkswagen!! 😀:thumb

I'm glad this post came up, I've learnt something. I've never heard of a leakdown test before, probably because I live in the sticks where even my compression tester is regarded as 'state-of-the-art'!!😉
Kruizin Kol

70AutoStik Insano Dub Head

730 posts · joined Aug 2002 ·

#22969
Leak-down is more commonly used by race-engine builders. The figures quoted would probably cause a top-fuel engine builder to make some adjustments... but I wouldn't be too concerned myself if the compression figures are good. The 1.2% figure seems a little low, though - are you running Total Seal rings?

lugnuts Custom Title Time!

1,070 posts · joined Aug 2002 ·

#23022
Dont know if it has Total Seals or not would think not,ive had this car for 2 1/2 yrs now when i got it it had 111728mls original, 2 owners the dad and his son his son is 70.I think this engine is untouched maybe just the heads freshened.I dont like things that leak,i dont care what it leaks oil or compression whatever if there is a way i can maximize its efficiency im going for it,thats just me though,yes maybe i am a little loopy or just eccentric.😀