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Wobba
23-03-2009, 17:53
Can I get a brief guide on doing my own compression test with a compression tester? Going to buy one tonight and do it.

MAXIBOY
23-03-2009, 17:59
remove plugs..
screw tester in a cylinder.
hold throttle wide open and crank engine over for a few turns.
do all cylinders..
then add a few drops of oil and redo any cylinders that are low.
see if the readings increase.
most important is all cylinders are very close.
then the figures.

should tell you a few things..if all are fine and close engines ok.
all low but similar engines worn. if a rise once retested with oil added rings more than likely worn. if not valve seat might need work..if only one or two cylinders low could be a head gasket single valve damage etc

at this point a cylinder leakage test become invaluable..

Wobba
23-03-2009, 18:04
Thanks mate. Do I unplug the fuel pump? Dont want to flood it!

Will this fit?

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_19 9553_langId_-1_categoryId_165557

MAXIBOY
23-03-2009, 18:09
no as it will alter the compression ratio..will just crank out..won't flood it as the plugs aren't in it.

should be fine.

Wobba
23-03-2009, 18:13
When you say plugs you mean spark plugs or injectors. Surely, if injector plugs are in the powered they will shoot fuel in them and flood it eventually?

Sorry, I may be being a bit of a newbie today as my brain has seized.

MAXIBOY
23-03-2009, 18:18
leave the injectors alone remove the spark plugs..

flooding occurs when the spark plugs get flooded by fuel..can't happen if there removed..

Brealbags
23-03-2009, 18:19
yes disconnect the injectors in some way!!! :shock:

Either remove fuel pump fuze or relay or disconnect injector wiring. First de pressureize the fuel system by trying to run the car with no fuel pump relay in

Damage to cat

MAXIBOY
23-03-2009, 18:25
i never do..running a few cylinders of unburnt fuel will not damage the cat..

i do cover the remaining plug holes to stop fuel getting every where though.

never had a problem with this method been doing it oner 20 years now..

Brealbags
23-03-2009, 18:27
fair enough just telling how it should be done to the book. Make sure throttle is wide open though when your cranking the engine so it can take in as much air as poss.

Your looking at the difference in readings accross the cylinders rather than trying to get to a setpoint reading.

Wobba
23-03-2009, 18:28
I was going to say, covering the holes may be wise hehe. Also, would it be safer to remove the king lead from dizzy or is the spark from the HT leads safe without the plugs in to just dangle about...

MAXIBOY
23-03-2009, 18:32
yes mate but i usually just pull the leads away..

but remove king lead and cover holes..

fuel never been an issue..cant remove it from carb engines as easily..

never had an issue..no ones worry when they crank and engine that won't start..this is similar if for a shorter time in all reality ..

each to there own..

can't edit my first post now... :evil:

Wobba
24-03-2009, 12:31
I'm going to do this when I get home from work! Let's see what, if anything, is up with the old girl eh? I suspect slight HG failure personally.

Daz.
24-03-2009, 14:22
I thought you covered the holes and blew really hard through a straw? :shock:

No wonder mine was fine! :roll:

Wobba
24-03-2009, 15:42
I thought you covered the holes and blew really hard through a straw? :shock:

No wonder mine was fine! :roll:

lol. Noob :D

Wobba
24-03-2009, 19:48
AND THE RESULTS ARE IN!

Compression test carried out 24.03.09

No. 1: 160 PSI
No. 2: 159 PSI
No. 3: 160 PSI
No. 4: 158 PSI

So...the only thing I can gather here is WTF is causing my coolant loss unless the HG has only gone from a waterway to outside the block.

Also, seems there is nothing yet to worry about with regards the engine unless something in the BE is upset.

So next up, replace tappets, but first double check it's not clogged/shagged/unhappy injectors.

Still sounds like a Subaru Impreza though, but did stop tapping for about 1 minute on way home.

queegan
24-03-2009, 19:54
that would say too me a very healthy engine u got there dude nice 1! :D

Wobba
24-03-2009, 19:57
Yea! Hurrah!

One less thing to worry about!

bbaazz-08
24-03-2009, 20:30
deposits of water may only be leaking into cylinders when left overnight


when you start in the morning deos it run kinda shitty for about a minute??

Wobba
25-03-2009, 10:24
deposits of water may only be leaking into cylinders when left overnight


when you start in the morning deos it run kinda shitty for about a minute??

No, never. Starts perfectly always when cold. When hot it can be shit though for about 10 seconds sometimes.

bbaazz-08
25-03-2009, 17:59
best thing to do is to get a sniff test done by a local garage and this will tel for definiate if your hg is gone

Wobba
25-03-2009, 18:15
What the hell is a sniff test?

MAXIBOY
25-03-2009, 19:11
gas analyser smells the antifreeze iirc..

Wobba
25-03-2009, 22:35
gas analyser smells the antifreeze iirc..

Cool! Well, the warble type tone and poor running vanish when the apparent tappet noise subsides. I think if it's just tappets and not HG then they must be seriously stuck on more than one...

LEIGH-ANNE
26-03-2009, 10:26
How much to do a compression test on mine wobba??? :D

Wobba
26-03-2009, 12:01
How much to do a compression test on mine wobba??? :D

3 cups of tea or coffee and a sticky bun to you!!! $$$

LEIGH-ANNE
26-03-2009, 16:43
Name the date Dr wobba! :wink:

rob_887
27-03-2009, 23:05
AND THE RESULTS ARE IN!

Compression test carried out 24.03.09

No. 1: 160 PSI
No. 2: 159 PSI
No. 3: 160 PSI
No. 4: 158 PSI

So...the only thing I can gather here is WTF is causing my coolant loss unless the HG has only gone from a waterway to outside the block.

Also, seems there is nothing yet to worry about with regards the engine unless something in the BE is upset.

So next up, replace tappets, but first double check it's not clogged/shagged/unhappy injectors.

Still sounds like a Subaru Impreza though, but did stop tapping for about 1 minute on way home.

I'm not 100% sure about the water galleries on a F7R engine but wouldn't it be a maze to get to the out side of the block with out going into a oil gallery