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Recessed Valve

Posted: 11 Jan 2010, 20:54
by tonysbus
Well after running problems and a low compression and a valve sticking up i have taken the head off and guess what first stud snapped, anyway the valve has recessed into the head and as this is a recon that is only two year's old and hasn't done much mileage at all and to be honest i have never really been happy with the power of the engine , what i am asking is why would this occur. :(

Tony

Re: Recessed Valve

Posted: 11 Jan 2010, 20:57
by VWCamperfan
Usually caused by incorrect ingition timing or fuel mixture. Causes things to run a lot hotter than they should and melts surrounding area of valve seat causing the problem you have.

Re: Recessed Valve

Posted: 11 Jan 2010, 21:13
by tonysbus
Hi mark timing and mixture bang on mate.

Tony

Re: Recessed Valve

Posted: 12 Jan 2010, 22:03
by Mr Bean
In my opinion the vave will not significantly recess into the seat under normal or even abnormal use. I believe it would leak excessivelly well before that stage. I would suggest that the reconditioner over cut the valve seat leaving a an excesive pocket before the valve seat began. This would lead to some power loss although not significant on one valve and in an extreem case could result in the valve sticking open. Thats what I think anyway
Cheers
Wolfie

Re: Recessed Valve

Posted: 13 Jan 2010, 09:31
by tonysbus
Wolfie that's my view as well ,as i was never happy with the power of the engine from day one but now i have a bigger problem a snapped head stud which will not come out, didn't expect to be getting any of this hassel from a 2year old engine.

Tony :(

Re: Recessed Valve

Posted: 13 Jan 2010, 09:48
by ghost123uk
What engine is it ?

Re: Recessed Valve

Posted: 13 Jan 2010, 12:53
by tonysbus
Hi it's a 1.9.dg i'm going to take the piston & liner out to get to the stud right at the bottom any tip's .

Thank's Tony

Re: Recessed Valve

Posted: 13 Jan 2010, 14:18
by ghost123uk
tonysbus wrote:Hi it's a 1.9.dg i'm going to take the piston & liner out to get to the stud right at the bottom any tip's .

Thank's Tony

Yup, my biggest tip is to read this entire thread here = https://club8090.co.uk/forum/viewtopic.p ... &p=7363668" onclick="window.open(this.href);return false;

It starts on a slightly different subject but the work Karl did is pretty much the same as what you are looking at.

It's a long thread but I really think you will benefit from reading it all.

Good luck :ok

Re: Recessed Valve

Posted: 14 Jan 2010, 08:59
by tonysbus
Thank's John that's a good link , although i can't open the first video link on Karl's page but can open the last one anyway i'm not rushing into it yet just building up the knowlegde at the mo.

Tony