Thread: Maximum Valve Lift Before Retainer Hits Valve Guide

Originally Posted by Richard Kaye

I have just rebuilt a 4.6 to put into my 1988 RRC. New pistons/rings, bearings, adjustable timing gears etc. Also, a new set of valve springs to suit the extra lift of the new cam.

Specs for cam are;
204/214 duration at 0.050”,
intake valve lift 0.450”
exhaust valve lift 0.474”

Specs for valve springs;
coil bind at 1.020”
installed height 1.590”
105lbs @ 1.625”
245lbs @ 1.125”

With the installed height and the lift on the exhaust I have 0.096” before coil bind so this is good.

Question I have is about the valve guides. Can I get 0.474” on the exhaust before the spring retainer hits the valve guide.

Also, are the spring pressures too much for the camshaft, think I read somewhere that the standard springs have 65lbs @ 1.590”.

G`day , most of the things are in the book - how to power tune rover v8 engines by des hammill .

if you are using the 4.6 type heads that use stem seals , the book will tell you if you remove 0.100"from the guide top it wll allow the seals to be kept and will allow up to 0.500"lift , std these heads have 0.450" clearance between base and seal and so the book says any lift over 0.450" will cause contact .

If you don`t use the seals there could be enough room you could measure and then you would know if room for an early flat washer seal ?

If your heads are prior to the clip in stem seals there is 0.525' clearance the book says .

HRC 2479 type heads use the blue stem seals ( 1994 on )

HRC 2210 type use the blue stem seals (92-93 )

ERC 0216 use the flat washer stem seals ( 87-92 )

When I checked the motor yesterday the exhaust valve retainer is hitting the valve stem seal at 0.460” lift, I need 0.474” plus a safety margin. Today I will look at the retainer to guide clearance.

Just been reading that very early motors had the flat seal on the intake and no seal at all on the exhaust.

If I have enough clearance between the retainer and guide on the exhaust, could I then run it with no stem seal on the exhaust? I think I have a set of 8 flat seals for the intake somewhere, this will give me the required clearance on the intake.

Just pulled the valve stem seal from No. 1 and 6 exhaust valves. I have around 0.080” clearance between the guide and retainer at full lift. I did have these heads rebuilt years ago, the rebuild may have included machining the top off the guides as this is definitely not standard.

It looks like I will have to remove the valve seals from all the exhaust valves.

The intakes clearance between intake oil seal and retainer is just under 0.050”, I think I will run with these still in.

G`day , there are different length guides , it could have them fitted when reco .

The early engines didn`t use stem seals at all , i have only ever put any type on the inlet .

An engine not used well the blue type seal will hold valves open after time with carbon build up .

If all else fails an o ring will work as a seal .