Kwik

iTrader: (10)

I'm looking for some advice and possibly a guide on stripping and rebuilding a set of V4 heads taken from my Type R (Shim under bucket). But I have a few questions....

1. The head gaskets were not leaking, so will I still need to skim the head to block surface?. (New gaskets will be used)
2. If not what is the best way to clean the head surface?.
3. Do I just need to replace the valve seals? Or is there anything else that should be changed?.
4. Does anyone have the clearances?. Should these be set once torqued down to the block?.

Thanks in advance.
Al

pot1175

iTrader: (14)

Clean the head & block faces off & check for flatness,I used thinners & a razor scraper, to remove the remains of the old gasket, IMO i'd get a mahine shop to give them a light dust skim, that will clean them off & remove any imperfections, once you strip them, & lap in the valves, you will need to re-shim the buckets. I measured mine & worked out what amount of material needed to be removed & sent them to a machine shop to linish them.
0.20mm Inlet
0.25mm Exhaust
& i'm more than sure the tollerance is +/- .2mm.

edsel

iTrader: (2)

I've just had my heads rebuilt by www.finchmotorsport.co.uk far superior job to what I could ever achieve.
Valve seats recut to Pauls spec, new seals and guides. They look like new



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Kwik

iTrader: (10)

Thanks for the info chaps, what should I expect a light skim to cost?.
What did you pay for yours to be done professionally Edsel?

savage bulldogs

iTrader: (6)

I had a local engineer take 2 tho off both heads (and block faces just to be safe),check the valve guides, recut all the valves and then chuck the heads through his hot wash
cost me £100 for the work on the heads
I lapped the valves in and replaced the stem seals myself but, I did upgrade the inlet valve seals by using exhaust ones as the exhaust seals are the same dimensions and made from a higher grade Viton rubber to take the heat

Kwik

iTrader: (10)

Ah ok, that's a good price. I may have to do the same with the new seals.

edsel

iTrader: (2)

Drop Paul an email mate, proper nice bloke and will offer advice.
My fees were included in a build. The heads in the picture were breakers yard items that were resurrected

Kwik

iTrader: (10)

Kwik

iTrader: (10)

Does anyone know the best way to remove valve seals?.

Swedge

iTrader: (1)

long nose pliers

then use a socket to put the new ones on

Kwik

iTrader: (10)

Thanks, I tried to remove one gently but didn't want to get too rough (Even though I'm changing them). I'll try again tomorrow.

Swedge

iTrader: (1)

Just turn them as you try to get them out

Kwik

iTrader: (10)

Heads now skimmed. New Valve stem seals all ready. I've lapped the valves in using the finer grinding paste, but I didn't want to over do it.

Now to build the heads back up. I was thinking of cleaning each spring/collet etc with gunk, then spraying off with brake cleaner. Do I need to oil any parts up before putting them back in situ?







Also does anyone know if the blue seals are for the exhaust valves?

MOTORS S GT

iTrader: (2)

You need to completly strip the heads including all the oil gallery bungs & the 2 restrictors, where do you think the ally swarf can get to when skimmed, they also need a complete decoke, before you lap the valves, when clean build it all with oil or assembly lube, the latter if its going to stand about for a while.
Be carefull with Supertech seals, they have a tendency for the seal to part company with its metal outer, genuine Subaru Ex seals are a lot better fitted to all valves.

merlin24

iTrader: (1)

Before you go ahead and assemble anything, I would recommend removing the oil gallery plugs and the restrictor in each head and giving the oil gallerys a good flush through seeing the heads have been skimmed and to remove the years of tarnish and crud.

Mick

The above post beat me to it lol

Kwik

iTrader: (10)

Thanks for the advice. Where are the gallery plugs and restrictors? Are these the bolts on the side of each head?
Any advice on decoking?
Thanks

merlin24

iTrader: (1)

The photo shows a later restrictor from STi Version 5~6 heads but your heads will be similar and use a cylinderical restrictor.
Follow the oil feed from the head face and upwards on each head and this is where the restrictor is located.
The gallery bungs are a combination of 14mm headed bungs and 5mm allen key bungs - remove the 5mm allen key bungs ( 5 or 6 depending on version of heads) by warming the bungs up with a blow-torch to soften the locktite.
Using a long rod, tap out the restrictor from the opposite end of the gallery.
Remove all bungs if possible and you will be suprised by the amount of crud which comes out when flushed through with brake cleaner especially on the exhaust side oil gallerys.





Mick

Kwik

iTrader: (10)

Thanks Mick. I haven't got a decent 5mm hex socket at the moment, but did the 14mm sockets and they were pretty loose. Also, the rod needs to be long eh?

Is this imperative?

MOTORS S GT

iTrader: (2)

If you don't clean the galleries out, or any part of the engine, including new parts, you might as well flush your money invested in an engine down the loo, does'nt matter what you buy, billet cranks, rods forged pistons etc, if its not spotlessly clean it will be scrap.

edsel

iTrader: (2)

The oil ways (galleries) are drilled into the rough casting during manufacture. Because the drilling paths cross, the ends are plugged. Swarf during the machining process is a major issue. The car industry spends millions trying to reduce swarf from their processes.

Kwik

iTrader: (10)

OK, as per usual nothing is straight forward. I invested in a blow torch and 5mm allen socket and got all bar one out, as it has rounded!!!!
Any advice?. I'm thinking it's back to the machine shop to get it drilled out. Can you buy the plugs anywhere?

Kwik

iTrader: (10)

up

joe v3sti

iTrader: (8)

If be taking it to a machine shop mate, might cost you £20 tops. Drop it off, forget about it, collect it and carry on with your build. Nice and stress free.

Joe

Kwik

iTrader: (10)

Looks likely Joe, but it's finding the plugs for sale.

P.S. I'll get back to you about the alloys, I'll find out whether the v2 STI alloys will fit over 4pot/2pots and let you know.

MOTORS S GT

iTrader: (2)

If you want plugs there 1/8npt, should be able to get them locally, if stuck I have spares.

Kwik

iTrader: (10)

Thanks. I'll probably take you up on that offer .
If I manage to the original out.

Kwik

iTrader: (10)

I ran the head up to Southern rebore for them to have a look at the grub screw that is rounded and they advised not touching it. Instead they advised to clean out from the other side, and the grub screw about an inch away. They said as it is a tapered thread it would cause more problems.

They aren't a Subaru specialist so thought I'd see what is advised before I did anything else.

MOTORS S GT

iTrader: (2)

Which one can't you get out, is it on the exhaust port side ?

Kwik

iTrader: (10)

On the R/H bank, centrally at the end of the oil way. The exhaust one's came out surprisingly easy.




Rounded one is ..... above ^

MOTORS S GT

iTrader: (2)

Would'nt worry about that too much, as long as you get the main front to rear out, the 1 on the inlet side & exh 2.