Right quick story.

Engine has been sat unrun for about 2-3 months over crimbo. (Engine ran faultless before going away for christmas)

I decided to do a compression test just out of interest.

and found that Number 4 has 7bar of pressure, 5 bar below all the other 3.

I've done a wet compression test, and this didnt change the result so i think thats rules out a stuck piston ring.

After speak to diva, he said he has had it before where a tappet has become solid and doesnt allow the valve to shut properly. COuld this be the case. I've tried putting a feeling gauge under the cam/tappet area and alot of them i cant feed the gauge in (all 4 on the number 4) some i can move up and down slightly with my fingers but other i cant. (obviously i move the cams/belt round so the lobes are at dwell.

Could this have bent or chipped my valve?

Any other test to do or suggestions before i take the head off

 

Be worth doing a leakdown test before speculating on possible damage

 

Do a leak down test with the cams loosened off..

Edited to say..Beaten to it by a few seconds

 

right being a bit of a novice what is needed for a leak down test? as obviously the car is now static

 

rocker cover is already off and so is inlet as these were already being changed at the time.

If that makes life easier, or does it make it impossilbe to do a leak down with these off?

 

You will need a leak down tester and a compressor, if you don't have the facilities maybe a local place might be able to do it. I can but I'm hardly local!!

 

Leak down test is basically putting a threaded extension (bit like your compression tester) into the spark plug hole and then pressuring the cylinder with compressed air from your handy household compressor

(Not sure if you have access to an airline or not)

The leakdown test will basically show how much of a measured pressure is lost.

You can listen to where the air is escaping by listening either at the inlet or at the exhaust tailpipe - or through the oil filler cap if you have serious issues

 

that rules that out then

 

is there anything i can do with you average tool? i.e no compressor.

i.e test tappets/clearances etc etc

 

remove the cams and belt and then do a compression test, althoguh the figures will be low, they should all be near equal

 

what will this prove mark? i.e above cranking it normally, i.e obviously valves wont open, but if there not shutting properly in the 1st place its not changing anything? or you mean it will illiminate the HG?

sorry to sounds like a tit

 

if your lifters are staying open i.e they have jacked, then this will keep the valve open no matter what the cam does, by removing the cams it will free off the lifters to do what they want !

although the readings will be low, as to build compression you need to get air into the cylinders, without the cams the valves should stay shut, so on a good engine the figure will be low, but equal.

a leak doen is the easiest way tbh, but if you havent got one !

 

Ryan

I bet now you are cursing yourself now for doing a comp test for no reason mate. If nothing was wrong the last time you switched it off then how could anything major happen?

 

i know mate, your telling me.

mark yeah i might give that a go tonight.

 

Get out there and do it now ! atleast you will stop worrying.

 

right off to the garage now.

back in 20 mins with the results

and possibly the bad or good news.

 

Will you should be here by now, the film starts in 26mins and we need to que for ice cream.

 

Nicole hogging the kitchen Stu or you at the cinema?

What ya gone to see mate?

Sure everything will be fine Ryan, stop worrying!

 

right just done what mark suggested and now i'm even more worried

Measured in BAR

1 = 7.8
2 = 6.5
3 = 4.0
4 = 3.0

here's the weird thing, No 3 is very low and when i did the comp test normally, No 3 was the highest reading

Here are the normal comp test readings:

1 = 12.0
2 = 11.5
3 = 12.5
4 = 7.5

 

Its going somewhere mate

Cams are fully out I take it ?

 

yes cams are out mate, there sat on the bench, tappets are still in but im sure the weight of a tappet isnt going to affect anything.

i really do wonder why i started

 

what about getting it running again,taking it for a little run etc....and getting it checked out.

was it running ok etc....before.

 

Dont get to disheartend until its checked by an expert Ryan.

These tests are quite sensitive to the way in which they are carried out and if this is the first time you have done them there is no telling if you are doing them 100% correctly.

 

dont know euan, pretty sure im doing it right.

im loosing the will to live with this fucking 3dr, nothing is ever simple with it, it was easier building my old one, think its trying to tell me something

 

Break it

 

ryan if you have a compressor, i will overnight you my leak down tester tomorrow, so you can see where the leak is....

 

cheers for the offer, but i dont have a compressor

 

If it was running cool why did you check it and start all this worry

 

a stone cold engine will give unusual results, the amount of oil in the lifters & how the engine internals expand with heat will affect the results.
get it running then check again

 

ryan

just run it and do the test after if it was ok before then it should be ok

 

What make of gauge are you useing ? is the battery full charged up when doing the test ?

Also got to ask with the cams out where does the air come from to be compressed Ie no inlet cam to open the valve ?

 

thats why the reading are very low with the cams out.......

but they should still be even

 

battery was fully charged.

think the gauge is a halford/motor factors item, cant remember the name off hand.

 

Had one of my customers with a Low comp reading he moaned and moaned about the piston i has supplyed him, turned out to be the gauge.

Would try another gauge if i was you

 

yeah thats what i think im going to do tommorrow.

jsut to be on the safe side.

I've got a grpA head gasket and bolts coming tomorrow, but its obviously the last thing i want to be doing, but its not the end of the world

fucking feels like it though

 

are you cranking it over the same amount of time each time,stupid question i know but seen this give different readings if cranking it over more on some cylinders

 

yes mate, i do it till the needle on the gauge stops jumping.

Anymore suggestions?

 

Try that test again, I reckon number 1 will be lower now

 

chip, is that just common sense mate? or is there something that would make it have a high reading?

 

Try it mate, and see if its any lower now.