Piston down (compression)

[RedRunner]

Stevo...

Stevo

I'm from Stockport originally. My parents still live there.

Do you work on surfs (as a profession), or are you just a really nice guy, that likes to help struggling new surfers?

do wanna fix the problem myself, though it would be nice to meet up with a fellow surfer, specially since your local, and i'm sure your advice would be invaluable.

[Sancho]

This is Stevo:

http://www.hiluxsurf.co.uk/members_p...evo/index.html

He is the king of surf engines, particularly whilst TonyN is too busy building a house.

Give him a call and he will give you advice. If it needs fixing, there is no-one better in the country.

[RedRunner]

compression readings..

Right... I did a compression test on all 6 cylinders earlier today.

I've definitely found which one is gone, and am pretty sure its a valve, as Stevo confirmed for me on the phone (cheers mate).

Heres the readings; (all pressures in bar)

Cylinder....................dr y...........wet
.....1........................ ..2..............2
.....2........................ ..7..............9
.....3........................ ..10............12
.....4........................ ..5..............6
.....5........................ ..8..............10
.....6........................ ..9..............12



I have no idea what a good pressure value should be, but as you can see, there's less variety in a pik'n'mix, so something is not right all over.

This also confirms EXACTLY what that guys funky tool told me.

I just need some guidance now, as what exactly i need to do to get it sorted.???

Should i just fork out 5-6 hundred pounds for a set of new heads, and replace them all??

If that would put my engine in tip top shape it'd be worth it right?????

off the topic, i wrecked two of my HT leads removing them (crap bosch ones), and toyota want £130!!!!

Managed to order

[Albannach]

Your guy's funky tool told you you were down on one cylinder, I could probably have told you that by listening to it. Your compression test shows you're down on at least 2 cylinders (1 & 4) with number 2 looking a bit iffy.

Still think the voltage thing is smoke and mirrors.

[RedRunner]

Your guy's funky tool told you you were down on one cylinder, I could probably have told you that by listening to it. Your compression test shows you're down on at least 2 cylinders (1 & 4) with number 2 looking a bit iffy.

Still think the voltage thing is smoke and mirrors.

Well, the graph produced by the said tool, gave me 1 cylinder down, and two at about 60 %. thats if we consider the best one to be performing at 100%.

But anyway, when i next go up there, as its in Bolton, and i'm not. I will get a full break down of this thing, and happily explain to all, even though i don't see why its hard to believe, its hardly impossible is it?!

If you could tell that a cylinder is down by listening to it, then surely a computer can tell you a just little bit more than that, which is all it did.

[RedRunner]

Albannach,

take a look at this, i think is a very similar sort of thing.

http://www.picotech.com/auto/wavefor...mpression.html

[Albannach]

Assuming 12barg is equal to 100%

Cylinder 1 - - 17%
Cylinder 2 - - 75%
Cylinder 3 - - 100%
Cylinder 4 - - 50%
Cylinder 5 - - 83%
Cylinder 6 - - 100%

The reason the funky tool will never work properly is that you have no base to work from. Who's to say that the cylinder with the highest compression is correct? Maybe it's low and the others lower still?

Looking at your figures, you have too big a spread on each bank; you need to be looking at both heads, not just one. Anything more than 1 or 2barg out from the others is not good. Also, 12barg is a bit too good, that's what I'd expect from a brand new engine, not something with almost 100k on the clock.

You can get as many graphs and printouts as you like, I'll still not be convinced.

The only reliable way to test an engine's compression is by using a quality compression gauge and comparing the results to the manufacturer's data. It is possible to check the power drop at each cylinder by dropping the spark at each one sequentially, are you sure this isn't what he did?

Lastly, a cylinder running at only 17% would be easily detectible aurally.

[Tiger]

If it helps at all in anyway, (probably not) i have a siezed v6 if you need any bits. Havent had time to open her up yet to see what the problem is though

[Sancho]

OK, in the V6 the cylinders are in two banks (obviously): 1, 3 and 5 and 2, 4 and 6 so you have problems on both sides. Compression should be between 10 and 12 bar with no more than 1 bar variation so.........you have problems on both sides. Big revelation there.

At a guess (which is all I can do), the LPG has caused the valve seats to regress, hence the lack of compression. You will need hardened valve seats fitted if you want to keep using the LPG.

[RedRunner]

Assuming 12barg is equal to 100%

The reason the funky tool will never work properly is that you have no base to work from. Who's to say that the cylinder with the highest compression is correct? Maybe it's low and the others lower still?
.

Well yes, the test was simply a reference test, whereby it assumed (or classes) the best performing one to be functioning at 100%, and judges the others with respect to that one.

But like i said, i'm defending something i dont fully understand, or someone i dont really know. and ive probably explained it all wrong.

but the link i posted works in the way ive just mentioned also does it not.

[RedRunner]

If it helps at all in anyway, (probably not) i have a siezed v6 if you need any bits. Havent had time to open her up yet to see what the problem is though

You actually might be able to help me.

how much would you want for the heads?

assuming ur willing to break it.

that way i could keep my car on the road whilst i sort the valves.

[Tiger]

Yes i would break the engine, wouldn't know about a price make me an offer.
cheers chris

[Vagrant No2]

My 5p worth is : Get heads from Tiger and get them stripped and fitted with new hardened valve seats and new valves and the genuine upgraded head gaskets . Then strip out your heads and fit the rebuilt ones . Then back on the road with good heads and piece of mind .

[Sancho]

My 5p worth is : Get heads from Tiger and get them stripped and fitted with new hardened valve seats and new valves and the genuine upgraded head gaskets . Then strip out your heads and fit the rebuilt ones . Then back on the road with good heads and piece of mind .

Wise words IMHO. It still runs how it is, so you might as well get new heads sorted whilst it's going and put them on when they're perfect. I imagine Stevo could sort it for you.

[RedRunner]

right then.

Cheers people, i think that sounds like the best option for me, bonus being i can keep her on the road and break something else, whilst i fix this little issue.

I had a quick word with Stevo, though i said id ring at a more convenient time (he was working i think). He did however mention to me that it was going to cost me ALOT of money!!!

Will have to get some more info when am next in Stockport.

Tiger..

I have no clue what heads cost in used condition. (meaning pre-refurbishment).

I'm only a poor student and all my money goes on LPG and insurance lol.

I honestly wouldn't know what to fairly offer you, especially considering i'm gonna have to pay to get it all re-furbed.

Is £100 round abouts a fair price, or would somebody be being ripped off??