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Model specific boards => Golf mk2 => Topic started by: golfmk4owner on 22 October 2011, 16:12
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After failing to turn my engine over properly due to wrong timing, i suspected id damaged a few valves. I've took the head off and thought i'd see something obvious but with the cams off all the valves are closed fine and straight from what i can see. When the head was on the car the cams were really hard to turn by hand, but now im thinking maybe it was the cams that were the problem... could overtightening the caps have been the problem perhaps?
I dont want to struggle getting the valves out if i dont have to, so heres a typical pic of the valves for your opinions:
(http://img838.imageshack.us/img838/8002/img1068z.jpg) (http://imageshack.us/photo/my-images/838/img1068z.jpg/)
Uploaded with ImageShack.us (http://imageshack.us)
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Ok i'll be simpler - Do these valves look ok? If so, why might the head be difficult to turn?
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If they'd hit your pistons at all you'd see little crescent shaped dents on the piston crowns, are there any marks on the pistons ?
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No chance you mixed the cam caps when refitting :undecided:
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Im sure i put the caps back in numbered order. I didnt torque them i admit, and when it came to removing them again, one of the caps was really stuck on hard. I was just expecting to see valve damage but now im thinking theyre fine and the cams were just too stiff?
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They look fine nothing a bit of honning on them to clean them up!
Sounds like they could be sticking????
:undecided:
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Hmm what would cause them to stick mate? Carbon and such is it? would your advice be to get them out and cleaned up?
Also, my haynes says not to grind the valves on a 16valver, why is this?
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I reckon you should strip the valves out now that you have the head off. They may look ok but a slight bend would be enough. Check each slides easily in its guide once you have the springs off.
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Yes i agree they need to come out, im just ready to order a tool to get em out!
I'll only be using it the once, so dont want to spend mega money, but havnt used one before. Does this tool look suitable for it?
http://www.ebay.co.uk/itm/Clarke-CHT462-OHV-Valve-Spring-Compressor-Tool-/150654846213?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D4%26po%3DLVI%26ps%3D63%26clkid%3D3708805610206216923
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Pretty sure you need one that can get to deep valves, that looks more suited to rocker actuated valves rather than cam on bucket style. The one in the link seems pretty good value to me and should have the depth to get in there (I have always end up making special extensions for my cheapy sealey as one size definately doesnt fit all lol).
http://www.ebay.co.uk/itm/9pc-Valve-Spring-Compressor-Set-/220871295655?pt=UK_Hand_Tools_Equipment&hash=item336cf482a7
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Yes i agree they need to come out, im just ready to order a tool to get em out!
I'll only be using it the once, so dont want to spend mega money, but havnt used one before. Does this tool look suitable for it?
http://www.ebay.co.uk/itm/Clarke-CHT462-OHV-Valve-Spring-Compressor-Tool-/150654846213?_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D4%26po%3DLVI%26ps%3D63%26clkid%3D3708805610206216923
I have a snap-on one like this ive never used it but friends of mine are mechanics and they only use ones like these as you dont need to tighten and loosen for hours very good piece of kit
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Hmm what would cause them to stick mate? Carbon and such is it? would your advice be to get them out and cleaned up?
Also, my haynes says not to grind the valves on a 16valver, why is this?
It could be carbon, but more likely to be a bent valve causing friction.
The only way I know to determine a bent valve is to do a compression first before strip down to determine if the pressure is all over the place or no pressure at all? Then I would proceed to strip our valves, springs and piston rings to see if I can see the culprit. (in between do a wet compression test with light oil to see if it goes past the rings)
But generally I clean up carbonised parts with "OVEN CLEANER" All I do is mark them up so I remember the order they go in or get plastic bags mark them one to four then spray oven cleaner foam into the bags then leave them over night. By morning you will be shocked how clean they have become after the Oven Gnomes have done their job! :wink:
Honning is for any scratch marks on the crown bores the valves sit in (proberly due to bent valves).
Valves are cleaned via chemicals! using abrassive material on the valves could cause damage hence chemical clean. Some people just polish them up afterwards with a very soft buffer pad nothing that will take material away from the valves as the valves clearance is specific and to the micron!
A clean valve is easier to inspect for damage than a carbonised one! Worst case you buy a new set if the carbon was holding them together. Remember the valves are sodium filled so if they break that stuff is not nice LOL!
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Some nice cleaning tips there! As soon as the compression tool comes ill try getting them out and ill try cleaning them without friction as you've suggested ;)
Ill let you know how i get on!
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most likely to be the cam being to tight i would of thought , not torqued down to the right torque will cause the cam to bind maybe evenseize completely after time , it happed to a mates vauxhall and snapped the cambelt tensioner
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Out of interest, did you buy the compressor you posted or the one I suggested as I took a look at a 16V head I have in the garage today and Im doubly sure the one you posted wont work :undecided:.
Secondly, check the inlet cam cap at the flywheel end to check its on the right way up. It should have the audi markings at the top when looking from the inlet side (guess who has just realised why the ABF in the garage's cams wouldnt turn lol).
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Just a tip: I check for bent valves by leaving the plugs in, turn cam til both/all four valves are shut, pour petrol onto head chambers. If the fluid remains, they're sealing fine. If it leaks, the valves are bent or need decoking etc.
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i ther turnthem to to TDC valvs shut on that cyl and connect and airline to where the plug was, you'll soon hear a bent valve, or it just take the cams out