Valve Springs and head bolts....

[M12maniac]

Just taken the engine out of my M12 GTO 3 to have the diff replaced by the gearboxman....... and while it's sitting there Tuxman has encouraged me to fit a new valve spring kit and ARP headbolts. Good lad that he is!

Before I undertake this with my mechanic friend supervising, when I replace the springs what else will I need? .....obviously new head gaskets, and timing adjust (What should it be set at?) once it's done.....anything else???

Thanks as always.

[funkybmx1]

If you wanna do the full monty. All new valves are £100 inlet £100 exhaust. All lifters and that are only few quid each. And your cams about £100 a cam. Depending what you wanna do

[M12maniac]

I'm trying to be sensible......as the costs are rising! Are they improved valves your talking about or new standard ones?

[Gadgeroonie]

you can change the valve springs with the engine still assembled - there is a tool to do it

(it may actually be possbile to change them with the engine still in the car - with a modified tool)

if you do take the cylinder head off - it would be rude not to get the heads ported a set of cams and forged pistons fitted - you will have same spec engine as funky !!!!!

where are you getting the new springs from and how much do they cost

[TuxMan]

Hi Richard changing valves depends on there condition , you will know more when you get heads off , if the valves are in good order I would not worry !! Cams are only needed if you want more than 500 bhp again I would not modifie cams on STD cast pistons !!! Just make sure heads are in good order .

[andygtt]

M12maniac said:

I'm trying to be sensible......as the costs are rising! Are they improved valves your talking about or new standard ones?

I rebuilt my engine last year and refitted the original valves, one pair failed and destroyed the entire engine.
I highly recommend fitting new valves is you have the head apart!

[M12maniac]

Cheers guys....

It's so tempting to keep going with this stuff! I may regret it in the future but I think I'll just do the headbolts and springs for now. Give the valves a good look over.

What sort of horse power could I get with a standard de-cat pipe, standard turbos, and the new valve springs??? Bearing in mind that I've just had the 5-speed box shot peened etc, and new cerametalic clutch back from mardi-gras....

[M12maniac]

[quote=Gadgeroonie]you can change the valve springs with the engine still assembled - there is a tool to do it

Any idea what the tool is called/looks like? I've seen a clamp like contraption to squeeze the valve but that requires the head to come off....

[Gadgeroonie]

its called an overhead valve compression tool

this is one

http://cgi.ebay.co.uk/Universal-Overhead-Cam-Valve...

[Blu3R]

M12maniac said:

=Gadgeroonie]you can change the valve springs with the engine still assembled - there is a tool to do it

Any idea what the tool is called/looks like? I've seen a clamp like contraption to squeeze the valve but that requires the head to come off....

If you can fit an adapter into the plug hole, you can pump compressed air into the cylinder to hold the valves shut while you change the springs.

[TuxMan]

Only problem with leaving heads on you cannott see if you have any valve issues developing ect and with putting the timing back to std you may as well take the heads off , also gives you chance to fit new stem seals and make sure everything is tip top , valve problem are very rare and Andy problem was not necesarly down to valves . power depends on turbos but Gt25 should make 400bhp hopefully with a good spread of torque , capping the torque at 420lbft will protect the box !! don,t worry it will feel bloody quick :-)

[M12maniac]

That kit looks ideal! Cheers gagde.

[M12maniac]

Might be best to get the head off and have a good look then Si.....cheers as always buddy.

[Gadgeroonie]

M12maniac said:

That kit looks ideal! Cheers gagde.

no worries - i might offer to buy it off you when you are finished with it