Head Gaskets and clearances

ThatV8sound · Post by **ThatV8sound** » Sun Oct 28, 2012 1:51 pm

Hi All,
brand new here so please excuse a possibly repeated question. I want to put Range Rover EFI heads on my 3500, (part of a bigger project to FI it) does anyone know if the finished height of the heads will cause any problems with valve lift? I'm not sure and don't have early or late pushrods to compare at this time. I aim to fit a composite gasket and as the heads are not from anything I own - I'll need to get them checked and possibly skimmed before putting them on. I'll be using ARP fasteners rather than the existing head bolts from either age, as I've a set of these on a 4.6 and they were great to work with.
Any advice is helpful.
Thanks

Post by **katanaman** » Mon Oct 29, 2012 12:13 am

efi heads will be ok assuming they haven't had a heavy skim and you aren't using a big cam. In short all rover heads can fit on all engines.

DEVONMAN · Post by **DEVONMAN** » Mon Oct 29, 2012 8:35 am

The RV8 heads come in 2 different thicknesses from the factory depending on whether they are designed for use with tin gaskets or Comp gasket.

There are 2 machined surfaces at each end of the heads to enable you to measure the thickness.

For tin gasket these dims are.
23.9mm & 63.5mm

For composite gasket these dims are
22.94mm & 62.56mm

From these you should be able to establish which gaskets your heads were designed for.

Hope this helps.
Cheers Denis

DaveEFI · Post by **DaveEFI** » Mon Oct 29, 2012 10:15 am

With unknown heads, it's worth having them planed down to the dimensions of the later heads and use composite gaskets, with the outer row of bolts omitted. You will have no tappet pre-load problems as the relative dimensions remain the same.

ThatV8sound · Post by **ThatV8sound** » Thu Nov 01, 2012 8:03 pm

All, many thanks for your replies. I managed to get hold of a set of heads off an early - to mid P38, so I'll attempt the check as per Denis's figures. Denis would you be kind enough to just give me a better location on the head to take these measurements from?
Thanks again - just didn't want to end up burning a valve or two...

DEVONMAN · Post by **DEVONMAN** » Thu Nov 01, 2012 11:19 pm

Place the heads on a table with the gasket face down.
Now at each end of the heads you will find a flat machined surface near the top of the heads close to the rocker cover gasket.
Now measure down to the table surface from these machined surfaces.

Denis

DaveEFI · Post by **DaveEFI** » Fri Nov 02, 2012 9:11 am

ChrisJC · Post by **ChrisJC** » Fri Nov 02, 2012 5:17 pm

Well done Dave - saved me looking out the image!

Chris.

DaveEFI · Post by **DaveEFI** » Fri Nov 02, 2012 5:52 pm

ChrisJC wrote:Well done Dave - saved me looking out the image!

Chris.

Thanks to whoever drew it - I can't remember.

ThatV8sound · Post by **ThatV8sound** » Sat Nov 03, 2012 2:45 pm

Thanks all,
great diagram - makes it all clear now. I'll have the valve seats recut and stems checked, then its the long haul to FI the engine. I see theres various posts for porting the heads, will probably only match these as I hear there's not much body to playwith!
Thanks again.