1.7 engine cylinder leak, diagnosis protocol Options

[Flat VW]

Well the Shaggy-mobile has been down since just after C-mas. (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

It seems to sound like a compression leak to me.

The sound started off quite faint but has become louder, kind of a "huffing" sound from the engine.

It starts ok, it runs ok, just very anemically (no power), but still seems smooth, both running and idling. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

BTW, I am paying close attention to the following thread- Compression Testing (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

The Shaggster is going to lash the valves this evening as to see what is up, then he will try to operate it again and if it does not operate well, he will then conduct a compression test. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

Does that sound right?

Anybody want to register any experienced or educated guesses as to this latest malady?

The engine was out of the car recently, and the valves we adjusted by the Shaggy MANY times.

Wish the lad luck, I am concerned he is gonna need it...... (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif)


John

P.S. (IMG:http://www.914world.com/bbs2/html/emoticons/wavey.gif)

[Jake Raby]

Sounds like a blown "Head gasket" to me... The 1.7 seldom does this, but it can happen.

You can easily find it with a LEAKDOWN TEST, not a compression test. The leakdown test wil clearly illustrate where the air is leaking from and it really helps with narrowing the possible causes of the issue a lot.

Valve adjustments are not cure alls.... A blown head gasket would never be effected by a valve adjustment.

You'll soon see why we remove the head gaskets.

[Flat VW]

QUOTE (Jake Raby @ Jan 10 2006, 04:30 PM)

Sounds like a blown "Head gasket" to me... The 1.7 seldom does this, but it can happen. You can easily find it with a LEAKDOWN TEST, not a compression test. The leakdown test wil clearly illustrate where the air is leaking from and it really helps with narrowing the possible causes of the issue a lot. Valve adjustments are not cure alls.... A blown head gasket would never be effected by a valve adjustment. You'll soon see why we remove the head gaskets.

I think I understand Jake, but is not a valve adjustment confirmation the place to start with a possible cylinder leak?

John (IMG:http://www.914world.com/bbs2/html/emoticons/wavey.gif)

[KaptKaos]

I had something similar a few months ago. The exhaust just needed to be tightened down just a bit. See if you can feel where its coming from.

[Flat VW]

QUOTE (KaptKaos @ Jan 10 2006, 04:44 PM)

I had something similar a few months ago. The exhaust just needed to be tightened down just a bit. See if you can feel where its coming from.

from your typed message to God's ear!

John (IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif)

[SLITS]

Mit der maschine gerunning....stuck a hose in your ear and pass it around the maschine von der bottom (not uber; der under)...wenn sie das sound heredit, you vill haf an idea von where it kommen frum.

[Flat VW]

QUOTE (SLITS @ Jan 10 2006, 05:07 PM)

Mit der maschine gerunning....stuck a hose in your ear and pass it around the maschine von der bottom (not uber; der under)...wenn sie das sound heredit, you vill haf an idea von where it kommen frum.

danka, Heir Shlitz


J

[Flat VW]

How does one perform a leakdown test? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)



John

P.S. I did the search thing, too many hits, none with the right info..........

[Dave_Darling]

Damn, I wanna use an ersatz-German accent like Herr Schlitz, but it's just too much work!

Anyway--

Step 1 : Get yourself a leak-down tester. If you don't have one, you may be able to sort-of fake one up.

Step 2 : Screw the leak-down tester into the spark plug hole. (You will, of course, need to remove the plug first!)

Step 3 : Set up that cylinder to TDC and lock the flywheel so it doesn't move.

Step 4 : Hook up compressed air to the other end of the tester.

Step 5 : Turn on the air. The two gauges on the tester should tell you what pressure is going in and what is staying there. (Or are they flow gauges, I forget?)

Step 6 : Listen for air leaking out. If you hear air at the tailpipe, the exhaust valve isn't sealing well. If you hear it at the intake snorkel, the intake valve isn't sealing. If you hear it at the oil filler, the rings aren't sealing. If you hear it around the cylinder itself, you know the problem is there...

Repeat 2-6 for each of the other cylinders.

If the readings aren't that important to you, you may be able to use an old spark plug to fake up a way to get compressed air into the cyilnder.

--DD

[Flat VW]

QUOTE (Dave_Darling @ Jan 10 2006, 06:00 PM)

Damn, I wanna use an ersatz-German accent like Herr Schlitz, but it's just too much work! Anyway-- Step 1 : Get yourself a leak-down tester. If you don't have one, you may be able to sort-of fake one up. Step 2 : Screw the leak-down tester into the spark plug hole. (You will, of course, need to remove the plug first!) Step 3 : Set up that cylinder to TDC and lock the flywheel so it doesn't move. Step 4 : Hook up compressed air to the other end of the tester. Step 5 : Turn on the air. The two gauges on the tester should tell you what pressure is going in and what is staying there. (Or are they flow gauges, I forget?) Step 6 : Listen for air leaking out. If you hear air at the tailpipe, the exhaust valve isn't sealing well. If you hear it at the intake snorkel, the intake valve isn't sealing. If you hear it at the oil filler, the rings aren't sealing. If you hear it around the cylinder itself, you know the problem is there... Repeat 2-6 for each of the other cylinders. If the readings aren't that important to you, you may be able to use an old spark plug to fake up a way to get compressed air into the cyilnder. --DD

Thanks Dave, the car is being driven into the garage right now.



John

[SLITS]

Und furder, iffin sie gepressurizes das zylinder mit compresses luft, folgen Damp Daves insrucktions, ohne guage, sie can schtill hearin verfromen das leak ist occurin.

Anyway...setting the cylinder at tdc and pressurizing the cylinder to 125 psig...you can listen at the exhaust pipe, intake TB and the oil filler...if you hear hissing, in their respective order...exhaust valve, intake valve and rings. Or mit der hose, you can hear it if it is leaking from the head/cylinder sealing surface...not perfect, but.....

If you need an engine...give me a call John.

SnapOn Leak Down Tester Just $300

[Flat VW]

QUOTE (SLITS @ Jan 10 2006, 06:20 PM)

If you need an engine...give me a call John.

Geez, I hope not, this one has less than six or seven thousand on a new top end after I ruined the last one with a roll of paper towels......

John (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

[Flat VW]

RESULTS:

The valves were adjusted just fine....


Compression test results

#1=90

#2=115

#3=140

#4=10

(IMG:http://www.914world.com/bbs2/html/emoticons/WTF.gif)

What is the next step fellas?

Is there really any point in doing a leakdown test before dropping this motor, yet AGAIN? (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

If the answer is no, then is a visual inspection of the "head gasket area" next?

Is there any reason in checking head torque values?



John

P.S. We do not own a leakdown test tool ............ , yet.............. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

[bd1308]

Im in the exact same boat.

but i dont own a compression tester....

head bolts might loosen (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)
those little gasket things might have broken or leaked (IMG:http://www.914world.com/bbs2/html/emoticons/WTF.gif)

i dunno.

b

[r_towle]

go old school.

Take the hose off your compression tester and rig it up to your air compressor hose...

Fill the cylinder to 125 PSI and listen with short piece of garden hose connected to your ear...

This is a poor mans leak down tester...

This was stated above, Im just saying it without the sarcasm...

BEFORE you take the engine apart...find the leak.

It could be alot of things...
head gasket
valve seat
bent valve
blown ring
hole in piston

You name it...

follow the leak...

If you dont hear it all around the head to cylinder joints....listen inside the intake and exhaust ports..

If its not there...listen insde the oil filler neck...

Do you see the pattern..follow the air...its getting out somewhere and you need to find it...

Rich

[Flat VW]

QUOTE (r_towle @ Jan 10 2006, 08:57 PM)

go old school. Take the hose off your compression tester and rig it up to your air compressor hose... Fill the cylinder to 125 PSI and listen with short piece of garden hose connected to your ear... This is a poor mans leak down tester... This was stated above, Im just saying it without the sarcasm... BEFORE you take the engine apart...find the leak. It could be alot of things... head gasket valve seat bent valve blown ring hole in piston You name it... follow the leak... If you dont hear it all around the head to cylinder joints....listen inside the intake and exhaust ports.. If its not there...listen insde the oil filler neck... Do you see the pattern..follow the air...its getting out somewhere and you need to find it... Rich

Each cylinder beginning with the worst, I guess.

A project for another day, I 'spose, persons here still have homework to complete tonight.......

THX,

John

[Jake Raby]

Tear it down..
With only 10 PSI the issue will slap you dead in the face really quickly.

Judging by those numbers I'd have to say that engine was ran out of tune, more than likely it was lean or had an intake leak.

It takes a lot to blow a head gasket on a 1.7- they seal better than any other engine.....

If you need help- you have my number.

[TravisNeff]

Sounds like you have a big hole somewhere. Dropped valve guide or busted rings.

[DJsRepS]

I just did a valve job on an OEM motor first time out and found no kind of seal on the cylinder to the head. I expected to see a ring crush seal of some kind. My seal kit had no such rings for the head. I was told to clean and lap the cylinder to the head.

[Flat VW]

QUOTE (Jake Raby @ Jan 10 2006, 09:25 PM)

Tear it down.. With only 10 PSI the issue will slap you dead in the face really quickly. Judging by those numbers I'd have to say that engine was ran out of tune, more than likely it was lean or had an intake leak. It takes a lot to blow a head gasket on a 1.7- they seal better than any other engine..... If you need help- you have my number.

Thanks,


John (IMG:http://www.914world.com/bbs2/html/emoticons/wavey.gif)