Alfa Pages

Matty Dog · Posted: Sun Feb 01, 2004 10:31 pm Post subject: 16V Head removal

Hi,

I need to pull the head off my 16V motor to get access to bent valves.

I've dropped the motor, removed the cam-cover and found a row of charming 12-point cylinder head bolts. Put there to keep people like me out, no doubt.

I phoned the local engineering supplies shop who say these are called "tri-square". They don't have the tools in stock, but can order them at vast expense. Apparently I can also use a Torx for this, although it's not the ideal tool for the job.

What size Torx or Tri-square socket/bit do I need?

Regards,
Matthew

johnboy · Posted: Sun Feb 01, 2004 11:52 pm Post subject: Re: 16V Head removal

What size Torx or Tri-square socket/bit do I need?

Hi matt

It's a T55 bit, you should be able to get it from any good tool shop

all the best john
_________________
WODA WE NEED? MORE POWER!!

Alfa gt jtdm blackline
1990 S2 16v veloce sleeping!
2002 ts gtv the wifes now
1997 seadoo gsx 800
1999 freestyle superjet

Matty Dog · Posted: Mon Feb 02, 2004 8:57 pm Post subject:

Thanks John,

I bought a T55 bit and it fitted perfectly.

Dropped the head off at the reconditioners before work this morning.
Looks like 2 exhaust valves are a bit bent.

Time to ring the Italian Auto Centre...
*Credit card cowers and whimpers!*

Matthew

johnboy · Posted: Tue Feb 03, 2004 3:57 am Post subject:

Dropped the head off at the reconditioners before work this morning.
Looks like 2 exhaust valves are a bit bent.

Time to ring the Italian Auto Centre...
*Credit card cowers and whimpers!*

Hi Matt,

how bad are the valve's? as i bent one and my mate straightened it for me by hitting it with a bit of nylon and a hammer. reseated no problem's,try that first.if they brake buy new one's, nothing lost. it's wurth a go!

regards john
_________________
WODA WE NEED? MORE POWER!!

Alfa gt jtdm blackline
1990 S2 16v veloce sleeping!
2002 ts gtv the wifes now
1997 seadoo gsx 800
1999 freestyle superjet

Matty Dog · Posted: Tue Feb 03, 2004 9:04 pm Post subject:

I've heard of valves being straightened, but I'm a bit sceptical.
However, my scepticism is not based on any scientific knowledge or personal experience.

I would be worried that having the valves bend and then bent back, that they would be weakened. Then at 2am on a country road at 7000rpm, the valve would snap and become intimately involved with the head and the piston.

As the cost of 2 new valves is only a small part of the cost of the whole job, I've ordered new valves for my own peace-of-mind.

I take it your motor is still running strong, John.
Any 33-owning Metalurgists who can comment on straigtening valves?

Matthew

johnboy · Posted: Wed Feb 04, 2004 12:56 pm Post subject:

I take it your motor is still running strong, John.
Any 33-owning Metalurgists who can comment on straigtening valves?

Hi Matt

i can see where your coming from,but my valve was just abit bent,i can email you photo's of the side i killed, that's a different kettle of fish,all eight valves where bent big time!! as for my engine now strong as ever,ive red lined it to 7400 with no problems. fingers crossed it will stay like that Wink

good luck with your car

all the best john
_________________
WODA WE NEED? MORE POWER!!

Alfa gt jtdm blackline
1990 S2 16v veloce sleeping!
2002 ts gtv the wifes now
1997 seadoo gsx 800
1999 freestyle superjet

Matt Stolton · Posted: Fri Feb 06, 2004 10:14 am Post subject: Don't try and straighten valves

By beating the valve, or any metal for that matter, you are mechanically altering the crystal structure of the metal, not normally for the better.

When the valves are made, they are manufactured in a certain way to maximise strength, durability and suitability for being a valve. This includes a strict regime for cooling the molten metal to solid. It is this that gives the metal/alloy a lot of appropriate characteristics. A metal plunged into cold water from 1000C will have different charcteristics to one air cooled slowly from the same temperature.

By smacking it, which, by doing 'work' to it, heats up the crystals, it will have become brittle around the area of the bend. For the price of a new valve, against the cost in time/money to have to get back into the engine to replace the brittle valve, I would always replace, not bodge.
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

johnboy

I would always replace, not bodge.[/quote]

Well it was only very slightly bent, plus my mate who did it, built the lister storm chassis that won the FIA GTR WORLD CHAMPIONSHIP IN 2000-2001 he's not a bodger!
_________________
WODA WE NEED? MORE POWER!!

Alfa gt jtdm blackline
1990 S2 16v veloce sleeping!
2002 ts gtv the wifes now
1997 seadoo gsx 800
1999 freestyle superjet