After discovering that the machine shop had recut a couple of valve seats way too deep on my old '76 heads I have got a replacement set from a '97 Discovery. Other than the usual checks for flatness, lapping the valves and new valve stem seals are there any useful upgrades/checks that should be done before install? They are going on an army truck so I am happy to get the bigger valves but don't need to get into port matvhing etc.
They are going on a 3.5L block with 9.3 CR pistons and RP4 cam.
Cheers
Gregor
Cylinder head overhaul.
Moderator: phpBB2 - Administrators
Hi Gregor
on the engine on my first Range rover I had the area immediatly behind the valve seat/ throught opened up by about 2mm in all directions using a cutter centered on the valve guide (ie bored it out!), then blended into the rest of the port and a three angle angle valve seat job done, and all the valves back cut and blended into the stem. This did not touch the short turn radius beyond very minor blending and left the rest of the port pretty well untouched appart from blending, cost me £120 for both heads and seemed well worth it, I would think you could do this at home if you can get the cutters as it was pretty straight forward (rest of the engine was 3.5 rover with 10.5 :1 pistons, tin gaskit, r87 cam and boxer inlet manifold and high volume oil pump) went very well after this on a 2" lift RR with 33" tyres and an overdrive 4 speed.
best of luck
Mike
on the engine on my first Range rover I had the area immediatly behind the valve seat/ throught opened up by about 2mm in all directions using a cutter centered on the valve guide (ie bored it out!), then blended into the rest of the port and a three angle angle valve seat job done, and all the valves back cut and blended into the stem. This did not touch the short turn radius beyond very minor blending and left the rest of the port pretty well untouched appart from blending, cost me £120 for both heads and seemed well worth it, I would think you could do this at home if you can get the cutters as it was pretty straight forward (rest of the engine was 3.5 rover with 10.5 :1 pistons, tin gaskit, r87 cam and boxer inlet manifold and high volume oil pump) went very well after this on a 2" lift RR with 33" tyres and an overdrive 4 speed.
best of luck
Mike
poppet valves rule!
