M30 Valve spring compressors? (and other issues with my head.)

[DanH]

Anyone have a good valve spring compressing technique that they would care to share? what kind of tool works best for this?

I was thinking about doing my own valve job on my head since it is already apart and doesnt look too bad. (All the disassembly and testing was done at a machine shop.) It seems like the spring compressing will be the most difficult part of re-assembling the head.

What kind of compound would work best for grinding the valve edges?

I will still need to bring it into another machine shop to get the bottom resurfaced.

Thanks,

[Rory535i]

do you not have a valve spring compressor? as for the valves; go into an auto suppliers and ask for valve lapping paste.

[632 Regal]

you will have to tap the retainers to crack them loose then get a spring compressor. ummm grinding valve angles is completely different than lapping the valves. If your going to lapp the valves there is usually 2 kinds, use the grittier stuff first.

[Rory535i]

i lapped the valves on my head when i put a new cam in it and polished the base of them along with the combustion chamber. made the engine seem to run smoother and obviously gave the valves a great seal on the head. my spring compressor only just did the job, had to put a socket over the springs otherwise it wouldn't reach! take your time with the valves, it pays off in the end.

[DanH]

Sorry for slaughtering the terminology. (I've never done this before so thats why I'm asking.)

Also my valves have some carbon build up on them, is it better to scrape it off or soak them in some kind of solvent?

[Rory535i]

Sorry for slaughtering the terminology. (I've never done this before so thats why I'm asking.)

Also my valves have some carbon build up on them, is it better to scrape it off or soak them in some kind of solvent?

get a can of carb cleaner and with a bit of perseverance with a cloth you should be able to get it off. might need a few cans. that's what i did anyway but then i polished them aswell.

[winfred]

i buff the carbon off the valves on a bench grinder with a wire wheel, i use a regular c clamp type compressor to install the valve springs, mines a old blue point but any decent good sized unit should work. i remove the valve springs with a hammer and socket but that's best left to the pros :D

[DanH]

Thanks for the tip winfred... I just bought a wire wheel for my grinder recently. Wasn't sure if it would scratch the valves though.

Couple more questions:
The machine shop said my exhaust valve guide need replacing too... What is the spec for amount of play in the valve stems? I can feel them very slightly move side to side with both the exhaust and intake guides. Although, I dont have a gauge small enough to measure the movement.

Will new valve guide seals be enough to stop most oil flow?

Thanks,

[winfred]

they will probably be ok with just the new seals unless something weird happened and totally screwed the guides

[genphreak]

New guides are real cheap- like $5 each, so I would replace them as you probably will never do it again... are you going to grind the cam? If it takes the grind down so much you cano no longer get the valve adjustment right, there are little caps that can be fitted to the tops of the spring retainers which will make up for it... they are expensive as they are very rare- some smart bimmer shops have them- as well as titanium retainers and the like. I think they cost about the same as the guides... :) what fun you'll be having! :) GP

[DanH]

I know the guides are cheap, but I dont know how I would be able to change them out. The labor is what would cost something, or would it be possible to do myself without any special tools?

I won't be grinding the cam, i'd buy a new reground cam before grinding the old one.


New guides are real cheap- like $5 each, so I would replace them as you probably will never do it again... are you going to grind the cam? If it takes the grind down so much you cano no longer get the valve adjustment right, there are little caps that can be fitted to the tops of the spring retainers which will make up for it... they are expensive as they are very rare- some smart bimmer shops have them- as well as titanium retainers and the like. I think they cost about the same as the guides... :) what fun you'll be having! :) GP

[JonE]

No, you likely would have to have the guides installed by a machine shop. Even then the fit with the valve might not be "perfect", and would need some extra boring... Like Winfred said, just consider putting it all back together after cleaning, replaning the head and dressing your valve seats and faces. Unless you have other big plans for the engine with that many miles on it, then you'd have to consider having it all done by a shop. I can't remember the spec on valve stems, maybe 1 or 2 thousandths?, but after you get the springs off then check your play again.

[632 Regal]

michine shop bait: Yes sir guides are only 5 bucks each. (you) does that include all hidden charges? (them) yes sir guides are only 5 bux each. you go there and get a bill for 3000 dollars...your like WTF? the guides are 5 bux each pressing old ones out are 30 bux each pressing in new ones are 45 each and the valve job each is 50 bux a hole. multiply that by the amount of valves you have. This is why I have way to many tools in my hands.

[DanH]

I figured a machine shop would be required for the guides.

Btw, The springs are already off, and the head is totally disassembled. I don't think the play is too much but I dont know the difference between a thousandth or two by feeling the movement and also do not have fine measurement tools.

At the moment, I'm thinking about just lapping the valves and putting new seals in with all of the other old parts. Also, I'll be getting a replaning. Its probably got too many miles on it to make any major part replacement worthwhile.


No, you likely would have to have the guides installed by a machine shop. Even then the fit with the valve might not be "perfect", and would need some extra boring... Like Winfred said, just consider putting it all back together after cleaning, replaning the head and dressing your valve seats and faces. Unless you have other big plans for the engine with that many miles on it, then you'd have to consider having it all done by a shop. I can't remember the spec on valve stems, maybe 1 or 2 thousandths?, but after you get the springs off then check your play again.

[632 Regal]

if the guides are trashed they will move about the width of a paperclip, anything less and you should be fine...hope that helps some.

[DanH]

Ok, I'll try getting a paperclip between the valve and guide.

Thanks for the info.


if the guides are trashed they will move about the width of a paperclip, anything less and you should be fine...hope that helps some.

[632 Regal]

not between the guide and valve! I mean the movement in the valve head when pulled out about 3/8" have to eyeball the play and guess without guages.

[DanH]

Oh, that makes more sense! I was thinking that would have to be a large gap. :p


not between the guide and valve! I mean the movement in the valve head when pulled out about 3/8" have to eyeball the play and guess without guages.