VR6 Compression Test Results (Head Damage Pictures!)

[VRTrickster 0]

As some of you may know Ive had a few running problems with my vr ,which I think Ive almost got to the bottom of now. Although yesterday I decided to give it a compression test and heres the results.

 

 

1)13 bar 3)12ish bar 5)9.5 bar!

 

 

2)12.5ish bar 4)12 bar 6)12.5 bar

 

The thing that concerns me is the cylinder 5 ! The rest are very good ,in the Bentley it states 11-13 for a new engine and 7.5 minimum wear limit.

Maximum permissable difference between all cylinders is 3 bar.

Im I worrying about nothing as apart from the number 5 its got pretty good compression?

Please someone put my mind at rest !

[Supercharged 2]

Did you test it again?

[VRTrickster 0]

No but I have been advised so I shall carry out the test again this week, fingers crossed!

[Kevin Bacon 5]

Cyl 5 is within tolerance so I wouldn't worry about it too much personally...

[andy 0]

Are you testing it with the engine warm? You need to...

[VRTrickster 0]

Yes the test was carried out by the book. kevHaywire, yeah I was thinking that, its just I wanted to know if it would make a noticeable difference to the running? I want the car to be running sweet for the remap as I don't want to travel all that way for Vince to say there's a problem!

[2corrados 0]

Rather than fanny about with a compression test, you need to do a full leak down test. This will tell you what the problem is, rather than just low compression. My vr6 has low compression on 5 and is booked for full leak down test next week. Will tell you if head / valves are knackered, and if you remove cams, and rotate engine, it will even tell you if the bore is suspect lower down, or just at the top.

Just an Idea

[VRTrickster 0]

Right I brought myself a comp tester today and retested number 5. It measured the same result of 9.5 ! One thing I did notice is when turning the engine whilst testing the engine was making a chirping noise that was quite loud! This noise but quieter also happens when I switch off the ignition after driving. I was just wondering if this could be the sound of air coming back up through the intake ?

[VRTrickster 0]

Right the heads coming off tomorrow ,get to see whats up with number 5!

Hopefully the damage isnt to bad as I want to get it rebuilt, cant wait for it to get back either, should be a top job!

 

Ill post up pics of my findings.

[NickVR6 0]

Interesting thread this mate, i hope its good news bud.

 

Some choice mods your making, cant wait to see what the results are when you've got it and the map sorted !!

[NickVR6 0]

oh, and you will probably come past me on your way there and back, so feel free to make a pit stop in either direction!

[andy 0]

Right I brought myself a comp tester today and retested number 5. It measured the same result of 9.5 ! One thing I did notice is when turning the engine whilst testing the engine was making a chirping noise that was quite loud! This noise but quieter also happens when I switch off the ignition after driving. I was just wondering if this could be the sound of air coming back up through the intake ?

 

Mine used to do that, only used to notice it when switching off. About a fortnight later the water pump failed. I changed the pump and the 'chirp' vanished too. Just a thought!

[andy 0]

Right I brought myself a comp tester today and retested number 5. It measured the same result of 9.5 ! One thing I did notice is when turning the engine whilst testing the engine was making a chirping noise that was quite loud! This noise but quieter also happens when I switch off the ignition after driving. I was just wondering if this could be the sound of air coming back up through the intake ?

 

Mine used to do that, only used to notice it when switching off. About a fortnight later the water pump failed. I changed the pump and the 'chirp' vanished too. Just a thought!

[VRTrickster 0]

Right Ive stripped the head and found a burnt inlet valve seat on number 5!

The valve didnt look that bad but Ill find out for sure when its inspected and rebuilt. Does anyone think that it might no be able to be re-seated as I know the seats cant be replaced on these heads?

Didnt really come across any problems when stripping apart from Im going to need a new cam sprocket bolt and coil pack bolts, along with the gaskets and seals etc.

Im probably going to go for new bronze stems, exhaust valves, multi angled seats and port polish/gas flow. He has asked me to send the lower inlet mani for port matching plus all the old gaskets for guides for porting I suppose.

The fella is based in south Ireland and will be picking in up from the ANC depot on the 24th to carry out the work and send it back. I really cant wait to slap it back on!

[2corrados 0]

i know the feeling. My engine looks like yours at the mo.

I had the bores checked as well, just precautionary whilst the head was off.

I had been advised that sometimes the block "relaxes" after the head is removed.

Glad I did, as it needs rebore too.

Get it checked whilst your in this position

Good luck and let us know how you get on

Dic

[VRTrickster 0]

It did have a brand new block and pistons with new bearings about 35,000 ago so I would think its fine. It looks fine anyway!