Any guides to stripping/rebuilding a VR6 head?

[Jim Bowen 1]

Are there any decent guides to look at? Not something i've looked into before, but thinking of stripping my old head and then deciding if i fancy trying to rebuild it.

 

Any special tools i need? Have worked out that i need a valve spring compressor, thats as far as i've got.

[aide 0]

you need a valve spring compressor with longish reach, shortish ones won't achieve access. also long nose pliers for pulling stem seals off/ apart. magnetic screwdrivers also handy for attracting/ removing the collets.

 

you should be able to strip everything, but i'd suggest valve guides are removed by an engine shop. seats can be reground by hand if you have the patience for it...

 

if i was you remove caps, cams, valve train and stem seals, bag and label it all accurately. get an engine shop to remove/ reinstall guides, reseat valves, skim and clean up.

 

you then rebuild valve train back up using new stem seals and tappets, check and clean eveything else.

 

its not rocket science, just get stuck in.

[Stonejag 10]

Yeah, it's easy to get it all apart once you have the right tool :) I got this one by Sealey:

 

Once you have it in roughly the right place you wind the valve springs down until you can see the whole of the split cotters that fit into the three grooves in the top of the valve stems. Then wobble the compressor slightly and it'll make a hollow popping noise as the cotters come out of the coned indent in the retainer. They're steel so I just magnetised a long screwdriver and extracted them with that - just try not to dig around too much to avoid scratching the valve stem.

 

Once the cotters are out you can release pressure on the valve springs - the valve will then drop free of the bottom (you'll have to help it through the stem seal, just pull) and you can remove the twin springs and the retainer. Then just get the stem seals out - grip around the outside with the pliers and pull while wiggling them. If you try and grip through the middle you'll either gouge the valve guide or tear the stem seal, neither is good as they're in at least three parts and it's a devil to get the little bits of rubber out if they disintegrate!

 

Then just bag everything up per valve or per cylinder - per cylinder is fine as the exhaust and intake valves are different sizes and the valve springs/cotters/retainers are all identical. Number them up so you know which valve goes in which hole and you're golden!

 

I recommend getting an ultrasonic bath to clean the bits with - Maplin have their smallest model on special at the moment for £23 - I get excellent results with a bath of hot water, a dash of washing-up liquid and a glug of white vinegar. The valves may need multiple (read: many) cycles but they come up beautifully and you don't need to risk harming the surface as when you wire-brush them! The springs/retainers/cotters only need ten minutes or so. Before and after pic:

 

 

Have fun, it's really rewarding :)

 

Stone

[Jim Bowen 1]

Thanks for that, very helpful post. (nearly forgot i had made this thread)

 

Its all starting to make more sense now i've started taking bits aparts and seen what's what.

 

Even though i'm starting to lose interest in the car i think i may as well rebuild the old head

[Jim Bowen 1]

Got the valve tool today. Alot bigger than I had thought but never seen one before.

 

Going to try it out in a while

[beastie4126 0]

Get a magnetic screwdriver to help grabbing the valve retainers.

[Jim Bowen 1]

Got one set out for now, the smaller valve looks a bit messy to me

 

 

 

 

 

Is that valve ok? seems a bit worn where the black ring is, i've tried cleaning it up with a wire brush and some light sanded, but didn't want to do too much to it.

 

Will an ultrasonic cleaner clean the crap off the bottom of the valves? Is really solid stuff.

[aide 0]

you need to check valve stem wear with a micrometer, visually they look fine, but its stem thickness that should be checked before reusing. exhaust side wear worse than inlet.

 

can't see why an ultra sonic wouldn't work the carbon build up off.

[Jim Bowen 1]

Should get my ultrasonic cleaner sometime this week.

 

Have decided i will replace the exhaust valves and the guides.

 

Where is the best place to buy them from? Missed out on some that were being sold on ebay, set of 6 was £78.

 

Not sure what to send off to get done at a specialist and what to do myself, is there much machine to be done apart from skimming the head, are the valve guide best left to someone else?

 

Is lapping the valves something i can do? Does anything need doing to valve seats?

 

Am wondering if the VR6 engine book i've seen is worth buying and reading as i'm learning all this as i go.

[Jim 1]

Yeah - if you're on about the Peter Russek VR6 book I'd say it looks fairly essential if you're doing rebuild work like what you're doing!

[aide 0]

Where is the best place to buy them from? Missed out on some that were being sold on ebay, set of 6 was £78.

 

Not sure what to send off to get done at a specialist and what to do myself, is there much machine to be done apart from skimming the head, are the valve guide best left to someone else?

 

Is lapping the valves something i can do? Does anything need doing to valve seats?

 

I got my guides from ECP, my valves were fine so reused them.

 

See second post for what i'd suggest you do and what you get a machine shop to do.

 

lapping valves by hand is possible but will likely take an age, get a machine shop to do them.

[Jim Bowen 1]

Is it worth getting new springs? i see there are HD ones available, but quite expensive and may have to import from american.

 

Am considering putting the 263 cams in (not sure yet, might just sell them)

[aide 0]

i actually don't know how to test springs, i guess its a recovery test of some sort!

 

uprated springs probably a question for guys who have taken the vr6 further tuning wise, certainly i looked at them too and solid lifters, but I don't think valve float is an issue usually, but then i guess they make them for a reason, imo i though money was best spent on other things.

 

get those 263's in!

[Stonejag 10]

Don't forget to inspect the head side of the block for pitting - for no apparent reason the block has larger coolant channels than the head, so the head gets worn away by coolant cavitation where there's head material but no block material. If it's more than ~1mm deep then you probably want to get it welded up before skimming the head, otherwise you're relying on the head gasket to adjust for it, which may be asking a bit much of it. Mine was approx 3mm deep at its worst so badly needed doing! Welding up the head face and the coolant flange on the side (same problem) cost me £45, skimming both faces cost £40 (quoted £20 for just the block mating face, so don't do the thermostat flange side unless you need to, mine was really bad!)

 

Vapour blasting is worth the outlay, it hardens the outer surfaces and makes them look fresher than the day they were cast! Just be sure to thoroughly clean all the glass grit out before you reinstall everything, you don't want it in your engine - I recommend using an airline, then vacuuming, then airlining again. Blasting it before it's machined is a good idea as the machining process loosens any remaining grit, I tilted mine after skimming and a load of sand and swarf fell out! Getting everything scrupulously clean beforehand is definitely worthwhile - if you install any studs or bolts and it feel gritty then back them out and clean it again.

 

Vapour blasting: before

 

After:

 

You can see the pitting in this one, it was before I got it welded and skimmed. Now there are only a couple of tiny bubbles from where the weld wasn't perfect.

 

You don't need solid lifters or uprated springs unless you're running silly power and/or have altered your ECU's rev limiter. For n/a you'll be fine with the stock items.

 

Stone

[Jim Bowen 1]

Would it best to get it blasted and then send it off for any skimming or would the skimming people have ways of cleaning things up etc, i really need to find a local place i can trust.

 

Valves are all out now, ran them through the ultrasonic cleaner loads of times, think i need to renew the exhaust ones for sure. Have not measured anything but can feel lips on them with my finger.