#1: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Fri Feb 10, 2012 3:26 pm ---- Hi everyone!
I've been searching the forums for a while for help when needed and it's always been brilliant but this is the first time I haven't found an answer so here goes!
Recently the head gasket on my 1.4 8v SOHC Pug206 failed, so after twelve hours of good old fashion car-DIY, the head gasket and timing belt have been replaced and the car filled with fresh oil.
Unfortunately there is a significant tapping/clicking noise coming from the head. My first thought was the timing was out of sync but with the timing belt in place, I'm still able to lock the flywheel and camshaft pulley at the same time, so I don't think it's that. Oil starvation also occurred to me, but I've done two oil changes today so I doubt it's that either.
On the forum, deanparkr is having the same noise problem currently in the thread Lack of power after head gasket repair. I posted a new thread in case the title of this thread caught someone’s eye. deanparkr was also good enough to post some videos, which match my car completely.
I am really stumped as to why this is occurring? Has anyone else experienced this? More importantly cured it? I really don’t want to go to a garage, in my experience they extort you for either making things worse or replacing everything that works fine!
I did screw up once during the rebuild, I read the 2.0DOHC torque settings for the head bolts which resulted in me over tightening them in the final stage by approximately 50degrees, I don't think this is enough to cause an interference but I'm not 100% certain?
Any help much appreciated!!
Thanks, Renks
#2: Re: Tapping noise after new head gasket Author: Lee, Location: EnglandPosted: Fri Feb 10, 2012 3:30 pm ---- www.gunstar.co.uk/Anti...20277.aspx
#3: Re: Tapping noise after new head gasket Author: kandlbarrett, Location: SwindonPosted: Fri Feb 10, 2012 6:33 pm ---- 1.4 8V?
#4: Re: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Sat Feb 11, 2012 4:16 am ----
kandlbarrett wrote:
1.4 8V?
Certainly is, 1.4 8v SOHC.
#5: Re: Tapping noise after new head gasket Author: gixxerkev, Location: wiltshirePosted: Sat Feb 11, 2012 4:27 am ---- Have you tried adjusting the valve clearences? If so, did you do them in the correct order ie: are you sure you've indentified No 1 cylinder at the correct side of the engine? Ive also read somewhere that the thickness of the new head gasket can have an effect on the valve head clearences to the top of the pistons, but dont quote me on that.
#6: Re: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Sat Feb 11, 2012 7:57 am ----
gixxerkev wrote:
Have you tried adjusting the valve clearences? If so, did you do them in the correct order ie: are you sure you've indentified No 1 cylinder at the correct side of the engine? Ive also read somewhere that the thickness of the new head gasket can have an effect on the valve head clearences to the top of the pistons, but dont quote me on that.
I'm about to check the clearances, although the Haynes manual isn't exactly clear on the process! :S
#7: Re: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Sat Feb 11, 2012 8:09 am ---- Am I doing it wrong because my valve clearances seem to be about 3mm currently??
#8: Re: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Sat Feb 11, 2012 10:58 am ----
Renks26 wrote:
Am I doing it wrong because my valve clearances seem to be about 3mm currently??
I was doing it wrong lol.
Valve clearance adjustment has significantly improved the noise, a bit of fine tuning and I'm positive it will be gone completely!
#9: Re: Tapping noise after new head gasket Author: gixxerkev, Location: wiltshirePosted: Sat Feb 11, 2012 12:05 pm ---- 3mm is a bit excessive, no wonder it was making a noise. Haynes aren't the best but if it's read 3 times it makes sense. Another success with a bit of patience, well done.
#10: Re: Tapping noise after new head gasket Author: deanparkr, Location: United KingdomPosted: Sat Feb 11, 2012 12:07 pm ---- Interesting. What should the clearances be set to?
#11: Re: Tapping noise after new head gasket Author: Renks26, Location: CheshirePosted: Sun Feb 12, 2012 6:36 am ----
deanparkr wrote:
Interesting. What should the clearances be set to?
When I read 3mm I was looking at the wrong gap, oops!
Inlet 0.2mm, exhaust, 0.4mm, +/- 0.05mm.
Some of mine were off slightly, I only adjusted two of the inlet valves and one exhaust valve and reduced the noise about 80%. So just going to let the cylinder head relax over a couple of weeks of normal running then re-check them all.
Deanparkr, could be worth asking to have your valve clearances set rather than giving some plonker a problem solving exercise?
#12: Re: Tapping noise after new head gasket Author: deanparkr, Location: United KingdomPosted: Sun Feb 12, 2012 9:32 am ---- Sure will. I'm going in on Wednesday and will explicitly ask for valve clearances to be checked.
Will report back on Wednesday!
#13: Re: Tapping noise after new head gasket Author: kandlbarrett, Location: SwindonPosted: Sun Feb 12, 2012 1:19 pm ---- 3mm is huge! I am so old I still struggle to visualise fraction of mm. But was expectecting somewhere between 6 thou and 12 thou. Well .2mm = 8 thou and .4 = 16 thou. 0.4mm is relatively large but if that is what the manufacturer specifies that is what you should adjust to.
Just to show how big the gap was a 3mm gap equals 120 thou of an inch. The correct settings are, as above, 8 thou and 12 thou so at 3mm it was between 10 and 15 times the clearance you should have set. I bet it was tappety! Scale it up - it's like setting a 10 metre gap instead of a 1 metre gap!
When setting the clearances there should be a very slight drag on the feeler gauge when you pull it from between the cam and follower.
A good check is that the gap should be too small for the next larger size feller gauge so a 0.3mm shouldn't fit in the 0.2 setting and a 0.5 shouln't fit in the 0.4 gap.
Also the next size down should be quite loose with no drag so a 0.1 should be loose in the 0.2 and a 0.3 should be loose in the 0.4.
When setting clearances I usually have three feeler gauges in my hand. The exact size, the size bigger and the size smaller. It's then easy to check that you are very close to the setting. You really don't have to play around too much so long as the clearance is between the higher and lower value either side of the exact setting.
So when setting the 0.2 have a 0.1, 0.2 and 0.3 to hand and when setting the 0.4 have a 0.3, 0.4 and 0.5 ready.
Do NOT get the clearances confused. The greater clearance is for the exhaust valves because these get hotter and expand more than the inlets so that 0.4 clearance is essential for the exhaust valves and is soon taken up. If you set the exhaust at 0.2 then when the engine is hot the valves won't fully close and before you know it you will have burnt a valve seat, that valve won't seal and that's a head off to re-seat it.
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