N/a Vs Turbo Cylinder Head

[Azzman460]

Hey guys, as some of you may or may not know I'm building up a turbo motor.

I bought an N/A Block from a wreckers, and am building it up with forged bottom end and other go fast bits.

I was planning on using the standard N/A Head that is on the motor, but I am concerned about the valves.

I think the trubo head is only different in the way that the exhaust valves are bigger, but are they possibly made from a different metal to manage with the extra heat a turbo engine produces?

If need be I will replace all the valves in the head with turbo valves, or at least all the exhaust valves.

Just wondering what you guys thinK!

Cheers, Aaron

[senna_T]

Yeah, pretty sure the Turbo valves are made of Inconel - its an aeronautical grade steel and they are very very strong, can't remember if its the inlet of exhaust valves though...

[ETM]

if there is a difference it would be the exhaust valves, not the inlets

[MaTTe]

the valve seats have more hardening on the turbo heads also. You can have more hardening professionally applied if you go to the right place, I would highly recommend doing so if you plan to get any sort of power out of the engine.

[turbotrana]

If its a street car, I would leave the original valves.

[easprint]

I'm also building a Forged Turbo engine. I'm converting a XT over to a xr6 turbo running gear. I just bought a Turbo engine cheap, cause number 6 piston had let go. I was told the valves were the same, I wouldn't change them if it's a street car...dont se the need. I'm using the turbo head only because I have one now. Before that I was just gonna use the standard head with a set of f6 valve springs.

[Azzman460]

yeah its just going to be a street car, but power levels may one day reach around the 400rwkw mark so I want to make sure that the valves can handle those tempereatures and won't start burning out or receding into the head.

If I were to change the valves would you recommend getting the seats hardened as well?

Or those valves and seats should be right for what I'm after?

[turbotrana]

mate dont worry about it too much. I've run good turbo power on the race track (not endurance, just sprint) and heaps of hard street km with just normal hardened seats and stainless steel valves and have seen no recession or problems at all.

You just cant harden valve seats in the head or even out of the head. Its not a done thing. They come manufactured a certain way and they get installed that way. They will be up to the job.

Chances are anything but endurance racing and the valves will be up to the job.

You might be thinking about it too much. Dont worry, be happy.

LPG is way harder on seats than any turbo.

[01txr]

I was told when I ran my TD cortina I fitted a 351w in it and ran on deicated lpg.

I was worried about the valves recessing, some guy I spoke to back then said as it was a used engine the valve seats would be hard enough due to the valve seating on hot valve seats giving them basically hot forgeing.

I had had heads off a couple of times and checked valve heights and never had any excessive wear or seats recessing.

Now this would be totally different if it was a brand new engine having soft seats.

The other thing I would think here is that the BA exhaust seats would for sure be better quality and harder than a old windsor seats.

The only problem I would think would be if the valve can take the heat as well if you add heavy valve springs weather you risk knocking the head off the valve or stripping the grooves for the locks (collets).

Use to be a problem for the old crossflow and ford v8s running multi groove stems.

What I use to do back with them was grind the collects down so when they clamp the valve they would not touch there for clamping hard on the valve stem.

The other differance in doing that was the valves dont rotate as much but never had any problems, and no more stripping the valve stems.

If you choose to run the standard seats and valves I would suggest not to run high valve spring pressures, and keep the boost low.

If your intend spending dollars on the bottom end do the valves and have seats fitted, atleast on the exhaust side.

Hope this helps