What do you mean by the seats being receeded?
Sorry I should of mentioned that the heads have been took off an engine, I sent the short motor to have new can bearings so have looked at the heads whilst there off.
How can you tell if there 3 cut seats?
Rate my porting?
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No there not sold as stage 1 or anything just as gas flowed, what exactly is the short side and I'll get a photo. Cheers mikeDarkspeed wrote:Are the heads stamped with the modification stage by the tuner? If they are then I dont see the issue with a photo of the stamp to name them - if that's what they put their name to on a specific stage tune then they must be happy with it.
To be honest there are more than a few heads out there that look very nice but the material is removed from the wrong place and offer no more than casting falsh removal with an emery band.
Your photo does not show the critical area for modification on the port short side.
If they were listed as "xxx" S1 it would not surprise me.
Andrew
Hi
I would look at a set of what V8 tuner call stage 1 ported heads and see what they involve, If they include new seats and guides, all the valves correctly set to matching heights and with the first cut of the 3 valve seat job properlt set all the chambers the same size and nice clean castings with valves in good condition and seats lapped properly then 600 is a good price, however well overhaulled standard heads are better than someone attacking a set of castings and grinding them out to the gasket face, hacking loads off the short side and leaving the seats recessed. With a rover you have anly about 400 to 450 thou of lift off a new cam, if the valves are recessed 60 thou into the heads then you are now only getting flow after lift exceeds 60 thou, that results in shorter effective duration and lower lift than a standard cam and good condition heads.
If you have the kit f to replace and recut the seat inserts and a press to do the guides with the tools to do a 3 angle seat job then do the refurbisment yuorself, or you can probably get it done on those heads for £250 or sobut you will need ato find a machine shop you trust. Either way do some research so you know what to look out for and inspect before you buy, Ebay is a good start look at new aftermarket chevy/ shrisler and ford heads or pictures of the valve seat area of second hand heads to see what good ones look like some are better than others but the good ones are pretty obvious this is worth a look http://www.youtube.com/watch?v=rvhwRvDu7yk the seat is cut at the surface of the chamber not into the roof
Best regards
Mike
I would look at a set of what V8 tuner call stage 1 ported heads and see what they involve, If they include new seats and guides, all the valves correctly set to matching heights and with the first cut of the 3 valve seat job properlt set all the chambers the same size and nice clean castings with valves in good condition and seats lapped properly then 600 is a good price, however well overhaulled standard heads are better than someone attacking a set of castings and grinding them out to the gasket face, hacking loads off the short side and leaving the seats recessed. With a rover you have anly about 400 to 450 thou of lift off a new cam, if the valves are recessed 60 thou into the heads then you are now only getting flow after lift exceeds 60 thou, that results in shorter effective duration and lower lift than a standard cam and good condition heads.
If you have the kit f to replace and recut the seat inserts and a press to do the guides with the tools to do a 3 angle seat job then do the refurbisment yuorself, or you can probably get it done on those heads for £250 or sobut you will need ato find a machine shop you trust. Either way do some research so you know what to look out for and inspect before you buy, Ebay is a good start look at new aftermarket chevy/ shrisler and ford heads or pictures of the valve seat area of second hand heads to see what good ones look like some are better than others but the good ones are pretty obvious this is worth a look http://www.youtube.com/watch?v=rvhwRvDu7yk the seat is cut at the surface of the chamber not into the roof
Best regards
Mike
poppet valves rule!
Here's the spiel from v8 tuner
Ideal for fast road & track day use with hydraulic camshafts.
Bead Blasted and acid dipped, refaced -
blended valve throats, standard ports
4.6 Efi (waisted stem) In Valves
4.6 Efi (waisted stem) Ex Valves
3 angle seats
Bulleted & shortened Valve Guides
Neoprene VS seals (16)
STD valve springs - fully assembled and ready to go
20% increase in gas flow...... approx 30BHP !
Hand Finished
*£125 surcharge per unit for non exchange units
The outer row of bolts are not used as it was found that cylinder heads clamped unevenly were were prone to gasket failure. Consequently all post 1995 cylinder heads are 10 rather tahn the older 14 bolt design.
Suggested components
Standard Replacement Flanged Cylinder Head Bolts
Or for Maximum Performance - ARP Cylinder Head Stud Kit
There 4.6 p38 heads.
Ideal for fast road & track day use with hydraulic camshafts.
Bead Blasted and acid dipped, refaced -
blended valve throats, standard ports
4.6 Efi (waisted stem) In Valves
4.6 Efi (waisted stem) Ex Valves
3 angle seats
Bulleted & shortened Valve Guides
Neoprene VS seals (16)
STD valve springs - fully assembled and ready to go
20% increase in gas flow...... approx 30BHP !
Hand Finished
*£125 surcharge per unit for non exchange units
The outer row of bolts are not used as it was found that cylinder heads clamped unevenly were were prone to gasket failure. Consequently all post 1995 cylinder heads are 10 rather tahn the older 14 bolt design.
Suggested components
Standard Replacement Flanged Cylinder Head Bolts
Or for Maximum Performance - ARP Cylinder Head Stud Kit
There 4.6 p38 heads.
The short side is what you have in a picture above showing the route out to the port - they are not gas flowed and the power would be as stock as the area of main restriction has not been touched.
They are stock heads with a bit of scratching about done with a rough stone in a hand drill. Looks like no harm done but definitely no benefit to flow.
Have a read.
http://www.v8forum.co.uk/forum/viewtopi ... c&start=15
Cannot belive its been so long since I did any head work -
too much time spent welding
They are stock heads with a bit of scratching about done with a rough stone in a hand drill. Looks like no harm done but definitely no benefit to flow.
Have a read.
http://www.v8forum.co.uk/forum/viewtopi ... c&start=15
Cannot belive its been so long since I did any head work -
too much time spent welding4.5L V8 Ginetta G27
Hi
That head spec looks fine for very light work, the gains will be from the 3 angle vseat job, bullet guides and waisted stem valves, the "porting" as such sounds minimal, again less likley to ruin anything. They will certainly show gains over the ones you have.
Best regards
Mike
PS you would need to give them a very good clean when you get them as getting the bead blasting medium out the oil ways (and water ways) is not a 5 minute job.
That head spec looks fine for very light work, the gains will be from the 3 angle vseat job, bullet guides and waisted stem valves, the "porting" as such sounds minimal, again less likley to ruin anything. They will certainly show gains over the ones you have.
Best regards
Mike
PS you would need to give them a very good clean when you get them as getting the bead blasting medium out the oil ways (and water ways) is not a 5 minute job.
poppet valves rule!
Many sellers in the Midlands will get them done by Roy Burrell so you may be better off cutting out the middle man and go direct.
Automania wrote:Well cheers for the help here guys as always it's much appreciated.
I'm currently getting some prices for the heads to be done by a couple of places so I'll see where I end up then!
Cheers mike
4.5L V8 Ginetta G27
