P79 help

[fajitas]

Hello People, 

 

    I picked up a new head today for free!, although I was expecting a p90, the p79 will have to do. The goal is to use this head for a future turbo project. I need help determining the condition of this head and the necessary steps to make this head turbo acceptable. So, here are a few pictures.

 

- First, the exhaust liner on the left is loose and do i really need the exhaust liners?

 

- If you look close, there seems to be what looks like a nick on the cam, does this render the cam useless, if so what cam to use? i have a cam thats in my n47 head would this cause to much "overlap"?

 

- Finally, after flipping it over i noticed valve #2 & #3 are elevated while the rest are sitting flush. Is this a problem or is it doing what it does?

 

Also, I plan to use my n42 block.

 

Thanks for reading my post hopefully some one can help me out. Happy Easter Sunday!

                                                                                                 

                                                                                                                          , Josh

[BluDestiny]

Is it loose like you can pull it out loose or just wiggle it? Either way I've heard of one of those liners chipping and destroying a turbo, so I would never use that head, but it is completely doable. 

 

I would go for a turbo cam if you can find one, or preferably a regrind made for a turbo application (depending on what type of setup you are running)

 

Those valves are stuck. 

 

All in all this is not a head that I would just "slap on and call it a day". I would probably drop if off at a machinists and get it cleaned, and checked for cracks before I plan further. 

[Xnke]

That head is seriously eroded around the loose liner. It'll have to get decked on that face before you can see if it's too pitted to seal up.

 

The liners need to be left in place unless you are just masochistically into cylinder head port work and welding. It is possible to pick up some flow by removing the liners...but it's SERIOUSLY not worth the effort since a linered head in good shape can flow as much as 140CFM per exhaust port, and a squareport head can be gotten up to 155 or so. By removing the liners, it is possible to get the round ports to flow as much or more than the square ports, but it requires a lot of welding deep in a hole by a skilled welder and it just isn't worth the money and time involved.

 

There are a few people who run the linered heads on turbo motors, but as mentioned above, the liners are not able to take that kind of heat and flake off, possibly destroying the turbine.

 

That cam is in not good shape. The chipped area around the dowel pin would have to be welded back, and then the nose of the cam reground to the correct dimensions, and the dowel pin hole would have to be re-machined into the front of the cam. You need to find a different camshaft. The damage looks to be pretty deep...if it's a deceiving photo and the damage isn't more than a few thou deep, then I still wouldn't run the cam...