Cylinder Head Storage

[dobboy 231 2 Cars]

Can someone tell me...., if a cylinder head has been removed and just sat in storage is there any fear of warping?

 

if so, is that something a typical skim you would get when doing a new HG skim would cure?

[allanallen 528 2 Cars]

No it won't warp in storage! Unless you're storing it in an oven??

[dobboy 231 2 Cars]

Cheers AA, also, you know when the 16V head is in pinned position, would all the valves be in the 100% closed?

 

If so, would you be able to visually see anything obvious to be able to determine the likelihood of it being a tapper? (like a valve not seated quite correctly etc?)

[welshpug 1,657]

no, some will be partially open, you will bend them if you place the head face down.

[allanallen 528 2 Cars]

You can look for piston/valve collision marks on the valves and that's about it really.

 

Other than that you want to be looking at how much it's been skimmed (if at all), any marks on faces, also check the carriers are the matching ones for the heads, There's at least one specialst that thinks carriers are interchangeable.....

Edited March 18, 2015 by allanallen

[dobboy 231 2 Cars]

Thanks both of you.

[dobboy 231 2 Cars]

Just took the head off a scrap engine i have, very straight forward to my surprise.

 

16 bent valves I assume as 4 marks on each piston.

 

So i then decided to strip further to see what a hydraulic lifter looked like, and to my surprise again they all slipped/fell out.

 

Was going to tackle taking a valve out but i assume there is a fancy tool for doing it?

[jackherer 543]

There should be four cutouts for the valves, is that what you're seeing?

 

e.g. http://www.aussiefrogs.com/forum/attachments/parts-sale-wanted/5921d1126921125-306-gti-6-standard-pistons-wanted-s16_piston.jpg

 

If there are extra marks then that's a pretty sure sign of bent valves.

[dobboy 231 2 Cars]

Yeah Jack! I thought they were imprints from colliding with the valves! Lol

 

All the smaller silvery coloured valves still have shiney impact marks and i don't think they closed correctly when i turned the cams over.

[dobboy 231 2 Cars]

[dobboy 231 2 Cars]

[welshpug 1,657]

that looks like 16 bent valves and a non original gasket.

[dobboy 231 2 Cars]

Cool. I think the problem may have occurred at the water pump, the belt hardly had any teeth on it and it had a rubber birds nest behind the cover, and also lots of water marks. Who knows.

[dobboy 231 2 Cars]

Wonder if someone can give me an experience opinion please.

 

I've got the chance of a fairly cheap head, it's been in storage for a while, (i'm thinking if it looks sound i could clean it up, get it skimmed, then one weekend when i have time do a swap for my tapper head, or alternatively if i have time get my own tapper one machined and get them to rob the valves from this other one to replace anything knacked on mine).

 

This heads supposed to have come off a good engine, (which i find a wee bit odd). The head itself isn't particularly pretty, even worse looking than my scrap head, and i'm wondering if it came off a HG failure engine? and if so would/could that be detrimental to the head?

 

Here's a few pics of the valves, do they look ok? or anything odd in the pics?

 

 

 

Also, if i had to put a head into a machine/engine shop, what should i be asking them to do?

 

Skim and provide a suitable gasket?, do i need/request anything else?, is there anything that doesn't cost the earth that should be replaced whilst the heads off?

 

TIA

 

Or should i forget buying another head and just break up my spare known good engine and know exactly what i have. Advice please!

[petert 586]

Given the labour and other costs involved in fitting a cylinder head, I can't see the point in installing anything but a fully reco'd item. The steps (in order):

 

strip

clean

weld if required

skim

repair guides (you can't cut concentric seats unless you have round guides!)

cut seats

face valves

measure spring heights

test springs

re-assemble, shimming springs as required

[welshpug 1,657]

that looks to have a fair bit of corrosion and not a standard MLS gasket so may have been off before, or not even a gti6 head.

[dobboy 231 2 Cars]

Given the labour and other costs involved in fitting a cylinder head, I can't see the point in installing anything but a fully reco'd item. The steps (in order):

 

strip

clean

weld if required

skim

repair guides (you can't cut concentric seats unless you have round guides!)

cut seats

face valves

measure spring heights

test springs

re-assemble, shimming springs as required

 

Thanks PeterT. (ignoring the heads in the pics above as i thought it looked a bit scabby and with what WP's said about maybe being skimmed and corrorded i'll just use my spare head).

 

My timing belt, water pump etc is all new, and i have spare new gaskets etc

I'll take the head off myself and refit the replacement (probably with engine out).

 

I've previously done a leak down test on this particular head and everything was 89/91% iirc, therefore would just a skim and gasket, not suffice?

or would it suffice but just not be as good as it could be?

 

I really don't know enough about engines/heads to decide what i need or make sure i don't get ripped off.

 

I got a price from a local place who said they'd skim it, face the valves, and (i think) provide a gasket for £200....... but in the same conversation he said he charges £65/hr which i though was excessive. I don't mind paying £200 if i get £200 worth of work done, but i do mind paying £200 if i only get £100 worth of work done.

[dobboy 231 2 Cars]

Just had another price

 

Skim £30

Valve cut and face £3 each

 

They'll check everything else is within tolerances (never got a price)

 

If i drop the head off it will be ready the next day unless they find something that needs replaced.

[Kane 34]

Jack, if I can offer any advice it would be to get everything at least checked over, especially valve guides! I had valves and seats re-done initally but as you may know my guides were goosed which has meant not only do guides need replacing but also the seats re-cut. More money down the pan!

 

Best to follow Pete's advice and get everything done at once, that way you won't have any doubt a little further down the line.

[dobboy 231 2 Cars]

Jack, if I can offer any advice it would be to get everything at least checked over, especially valve guides! I had valves and seats re-done initally but as you may know my guides were goosed which has meant not only do guides need replacing but also the seats re-cut. More money down the pan!

 

Best to follow Pete's advice and get everything done at once, that way you won't have any doubt a little further down the line.

 

Yeah i'll get everything checked and if there is anything fooked i'll get it replaced.

 

But i'm not doing a head/engine rebuild either, all i want is my decent spare head, prepared to go on my car, so that i know it's not likely to go bang 100 miles from home lol and a new HG is a bonus.

[welshpug 1,657]

prepared means rebuild!

[dobboy 231 2 Cars]

So does a HG change necessitate rebuild, or is that what you anticipate when they check everything over?

[dobboy 231 2 Cars]

Can somebody advise please?

 

I've taken the head off my good spare engine and found a place who'll skim, check springs, do valve seats and faces, and give it a general once over.

 

Does this look like original gasket/never been skimmed? The gasket is 3 metal layers and looks a bit deteriorated, the layers have split and a bit of corrosion here and there.

 

Is there anything else i need to tell them? Gasket type to provide/thickness etc? And should i request they replace anything else (that won't break the bank) while it's in bits? Seals/cam seals etc?

 

 

 

 

 

 

Thanks

Edited March 27, 2015 by dobboy

[welshpug 1,657]

you need to measure it to ascertain if its ever had a skim, 137mm +/- 0.05mm is standard, 136.8mm is max skim.

 

looks a fair bit of corrosion there, that may be an issue, if they need to skim a full 0.2mm off then it will be wise to use a 1.4mm repair gasket not the standard 1.2mm ones, looks like that gasket, if it hadnt gone, wass very close to going quite badly.

 

Its normal for the MLS gaskets to not be stuck together, they have a very thin layer of sealant of some kind on them as well as the raised rings, so the surface finish has to be very high standard.

[dobboy 231 2 Cars]

Thanks WP,

 

Where do i measure from/to for the 137mm? And do i just do it with digi calipers?

 

Yeah glad i took head off rather than use engine, so i get a new HG.

 

Will they tell me how much they've taken off when skimming and that will determine what gasket i buy?

 

Thanks