Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: JamesV6CDX on 10 July 2007, 14:19:01
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Just having a look at Haynes, part of me is tempted to have a shot at the head rebuild process...
reading it, the only thing I would be concerned about doing, is valve guides. Now, I've noticed, that some of the valves on this head, have a "side to side" movement.. does this mean valve guides are shagged?
I'll probably still come running to Mark, but it can't hurt to look ;D ;D
Maybe I could even do some dismantling and cleaning in preparation...
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Would THIS be sufficient for removing/refitting valves on the 1,8 Veccy...
http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10151&productId=216847&categoryId=71557
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Looking at the head, the valve seat appears to be OK
Presumably then, the parts I need will be:
New valves - definately
New stem seals - Definately
New springs?
New Valve guides?
I will service the followers...
Now feel fairly confident about grinding, and changing valves, and stem seals - only big concern, is if I need new guides, as I'm not sure I could fit those :-/
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I think your in unchartered territory here James with only a select few Gods and Demi Gods being able to advise on this one ( Such as Mr DTM etc)
....the rest of us are eager to learn from this project :) ;)
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as i understand it as a noob if theres any slop on the valves the guides are shagged not an easy job to do really tbh ofc i stand to be corrected and i will eat my hat
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It really doesen't seem that hard... the only bit I'm unsure about, is defining whether or not the guides are knackered
Having said that, maybe when I get the cams out, and the valves are all tight against the seats, might be a better test?
The car burns no oil...
Other than that, I'm ALMOST happy to have a go at this job ;D ;D
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I'm not sure that valve spring compressor would have enough reach to go down into the bores where the hydraulic tappets live. I have one that would that you're welcome to borrow though. I (hope I) won't need it for some time!
Side to side movement is not good. It's probably best to assess this after you've removed the valve springs and colletts. Drop the valve back into the guide without the spring and see if it has significant movement side to side.
I wouldn't normally worry about changing the valve springs however the engine has done a good few miles so maybe they should be checked. Depends also on the cost of replacement versus your plans for the car vis a vis selling it on or running it yourself for another 100K! Stem seals will come in a head set anyway. I'd probably change all the exhaust valves if I were you. Inlets will probably be OK as they run much cooler but change them if the stems have worn.
Jobs like changing the valve guides can be done by a local engine workshop. Little jobs like that are very reasonable if you bring the bits in to them ready to go and they don't have to do all the time consuming disassembly, cleaning, reassembly, etc. They should also be able to advise on the condition of all the components and measure them accurately where required. I came across a very helpful local workshop when I last trod this path. He also supplied replacement bits at very good prices.
I'd lap all the valves back in on reassembly, obviously. After that mileage they'll need it.
What does the bottom end look like? Bores OK? Compression looked good on the Ok cylinders so I guess it's probably in fine fettle still.
Have fun!
Kevin
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I'm not sure that valve spring compressor would have enough reach to go down into the bores where the hydraulic tappets live. I have one that would that you're welcome to borrow though. I (hope I) won't need it for some time!
Side to side movement is not good. It's probably best to assess this after you've removed the valve springs and colletts. Drop the valve back into the guide without the spring and see if it has significant movement side to side.
I wouldn't normally worry about changing the valve springs however the engine has done a good few miles so maybe they should be checked. Depends also on the cost of replacement versus your plans for the car vis a vis selling it on or running it yourself for another 100K! Stem seals will come in a head set anyway. I'd probably change all the exhaust valves if I were you. Inlets will probably be OK as they run much cooler but change them if the stems have worn.
Jobs like changing the valve guides can be done by a local engine workshop. Little jobs like that are very reasonable if you bring the bits in to them ready to go and they don't have to do all the time consuming disassembly, cleaning, reassembly, etc. They should also be able to advise on the condition of all the components and measure them accurately where required. I came across a very helpful local workshop when I last trod this path. He also supplied replacement bits at very good prices.
I'd lap all the valves back in on reassembly, obviously. After that mileage they'll need it.
What does the bottom end look like? Bores OK? Compression looked good on the Ok cylinders so I guess it's probably in fine fettle still.
Have fun!
Kevin
The bores look like new, believe it or not! I was planning on changing ALL the valves - but if you think there's no need to change inlets - then I'm open to ideas.
If I was just selling the car for a fast buck, then I wouldn't go to the trouble of doing a big head rebuild.. however I'm thinking I might keep it, and it's a good excuse to take the head to bits!!!!
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What do you mean by lap the valves Kevin - grind them in?
Excuse my ignorance in this area, I've never removed a valve!!
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To be honest, vx valves, seats, springs, guides and heads dont realy wear at all.
I would definately fit new exhaust valves and it looks like it might have been running slightly weak on gas to in order to melt the valve like that.
Valve guide slop has been covered, not seen it yet on a Vx engine though and particularly not on a multivalve so guides should be fine which is a good job because if changed they should be reamed and the seat re-cut to get the alignment correct.
I wouldn't fit new inlet valves unless they came in the head set (which I note some do have).
That spring compressor will not do the job, its designed for push rod style power plants. I use one with a home made tool to allow it to reach into the valve recesses. Its this sort you need
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_202285_langId_-1_CarSelectorCatalogId__CarSelectorGroupId__varient__categoryId_71557_crumb__parentcategoryrn_71557
My approach is to strip the head and if all new valves are being fitted then its easier because if you do re-use them then you need to push them through a bit of marked up card so you know where to re-fit them.
If valves are being re-used, I put them in a drill mounted in a vice and use some wet emery to remove the carbon deposits and get them shiney again whilst being careful not to damage the seats......this is where you can also tell if they are bent or not!
Then I clean the springs, spring cups, collets and spring bases (if fitted) in a good engine cleaner solution.
Next onto the head, first off a real good wash down with traffic film remover and then a blast with the pressure washer. This is then followed by a real detailed clean with paint stripper to remove any nastier deposits and carbon build up......this is followed by another traffic film clean and blast with the pressure washer.
Then I blow all the ports, tapped holes and oil ways etc out with the air line.
Then I take each valve and lap them in using a fine paste only (you dont realy need to use the coarse stuff these days on modern engines) and place them in a piece of marked up card as I finish each one.
Then its time to fit the valve bases (if fitted) followed by the new stem seals (10mm deep socket) and then in with each valve, applying a dab of oil on each one and refitting the valve caps and collets (grease on the colllet helps it stick as does using a small screwdriver with a magnetised end).
Then the quick check of stricking the top of each valve with a soft mallet to ensure the collets are sat correctly.
Carry out the parafin test to check the valves for leaks.
Fit any head studs etc and jobs a good un.
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What do you mean by lap the valves Kevin - grind them in?
Yes, exactly. A little grinding paste and a stick with a sucker on the end.
Excuse my ignorance in this area, I've never removed a valve!!
Go for it! Follow Mark's procedure and you won't find anything difficult in rebuilding a head after the jobs you've tackled in the past. It's one of the more satisfying car jobs, in my opinion, too.
Kevin
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Does this mean you want me to look for my paste? - I don't have the stick and my compressor is for push rod heads.
That kit at £99 is good - so buy it
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I have stick, spring compressor and paste if you need it.
That kit at £99 is good - so buy it
Yep, FAI if the pic is to be believed so ought to be reasonable.
Kevin
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It really doesen't seem that hard... the only bit I'm unsure about, is defining whether or not the guides are knackered
Having said that, maybe when I get the cams out, and the valves are all tight against the seats, might be a better test?
The car burns no oil...
Other than that, I'm ALMOST happy to have a go at this job ;D ;D
Ummm it does! I did tell you about 2k miles to a litre of oil
If your changing all the valves and seals then this might fix it.....as i suspect its the valve seals.
And note to Mark.....i mentioned to James that my neglect to fix the petrol injector on no3 may have been the cause of the valve failing......or is coincedence....petrol injector on that cylinder not working for about 6 months and then a valve fails......it wouldnt have had any lubrication from petrol when starting it.
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It doesn't look like a lube problem....it looks a bit more of a hot problem....and knowing how crap these LPG controllers are!
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It doesn't look like a lube problem....it looks a bit more of a hot problem....and knowing how crap these LPG controllers are!
Oh ok....just thought it worth a mention...
I agree about the 'add on' lpg ecu's.....tho 'factory fit' ecu's seem more involved to me.....ie they have a hell of lot more wires going to them......ive been trying to find a wiring diagram for a 'factory fit' system....but been unsuccessful so far :(
If James has sussed which the lpg ecu is yet.....he will be able to confirm, looks just like engine ecu with same two multiconnectors plugged into it.
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It doesn't look like a lube problem....it looks a bit more of a hot problem....and knowing how crap these LPG controllers are!
Oh ok....just thought it worth a mention...
I agree about the 'add on' lpg ecu's.....tho 'factory fit' ecu's seem more involved to me.....ie they have a hell of lot more wires going to them......ive been trying to find a wiring diagram for a 'factory fit' system....but been unsuccessful so far :(
If James has sussed which the lpg ecu is yet.....he will be able to confirm, looks just like engine ecu with same two multiconnectors plugged into it.
Oh, I know the one..
It's sat on Maria's mantlepeice - along with the 4 x LPG injectors, and the petrol injectors+ rail!
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LOL.......looks just like the engine ecu, dont it.
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LOL.......looks just like the engine ecu, dont it.
Indeed... you have PM... can I pop up tonight, and pick up my Elite? Just checking train times...
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LOL.......looks just like the engine ecu, dont it.
Indeed... you have PM... can I pop up tonight, and pick up my Elite? Just checking train times...
PM replied.....was wondering when you were going to pick that up.....was just about to shove an add in the for sale section......abandoned green elite for sale ;D