How big are Big Valves ??

[BadRedWedge]

Rev ? 43 - 37 ?

[rev-erend]

I measured mine at 36mm and 41.5 MM - so that seems to be what many quote as the stage 3 head sizes.

Stage 4 and the largest seem to be 38.1mm and 43.11 mm

My new heads will have 39.4mm and 47mm

[BadRedWedge]

I Need to measure them properly did not know about the .3s etc

47 !!! 47mm will they be touching each other 43.? and 37.? are mighty close. nice BIG

Edit to add Thanks Alan

Edited by BadRedWedge on Wednesday 21st November 13:40

[eesbad]

rev-erend said:

My new heads will have 39.4mm and 47mm

Wildcat heads? Must have centralised valves and offset rockers for those sizes?

Nice!!

[gsx600]

Wish I'd measured / photo'd my 450 when I had the head of on install as they seemed really large compared to the standard 400, and seemed very little gap between them only max 2-3 mm, but then the engine was a Chimera BV engine - 1 of 5 or so.

Oneday I'll find the specs for it

[900T-R]

OE 'Big Valves' have 43 mm intakes and 37 mm exhausts. The 'Stage 3' heads from the usual suspects normally have 41.5/35.5 mm which can be used with the standard valve guides (reground obviously) and the standard (Vitesse spec) RV8 valves are 40/34 mm.

Anything bigger than the 43/37 combo requires a different head casting (i.e. Wildcat) really...

[BadRedWedge]

Thanks Eric, makes sense now.

Another question

How many head bolts 14 ?

[Boosted LS1]

900T-R said:

Anything bigger than the 43/37 combo requires a different head casting (i.e. Wildcat) really...

Or stock heads with offset guides plus headwork, not cheap though.

[Number 7]

BadRedWedge said:

Thanks Eric, makes sense now.

Another question

How many head bolts 14 ?

Even if they're drilled for 14, you can use only 10, leaving the outer 4 out. I believe that these 4 can pull the head over and leads to problems. Use ARP studs while you're at it.

7.

[BadRedWedge]

Number 7 said:

BadRedWedge said:

Thanks Eric, makes sense now.

Another question

How many head bolts 14 ?

Even if they're drilled for 14, you can use only 10, leaving the outer 4 out. I believe that these 4 can pull the head over and leads to problems. Use ARP studs while you're at it.

7.

Just taken 28 out ! me thinks I want to put 28 back in again

[rev-erend]

The extra 4 bolts are not torqued up very tight .. can't remember the exact value but it's something like 15~25 ft lbs.. whilst the others are around 70 ft lbs

[eesbad]

Not telling us anymore about your new heads then Rev?

[pwd95]

Do you have to take them off in any particular order? Doing mine tonight

[pwd95]

Ta. Anyone know the fastening sequence?

[GreenV8S]

Quinny said:

The heads can come off in any order. If you mean the bolts then they should be undone in the reverse of the fastening sequence.

[eesbad]

pwd95 said:

Ta. Anyone know the fastening sequence?

http://www.landrover.ee/est/files/manuals/engine/V8overhaulManual.pdf 

All in here

[pwd95]

GreenV8S said:

Quinny said:

The heads can come off in any order. If you mean the bolts then they should be undone in the reverse of the fastening sequence.

[pwd95]

eesbad said:

pwd95 said:

Ta. Anyone know the fastening sequence?

http://www.landrover.ee/est/files/manuals/engine/V8overhaulManual.pdf 

All in here

[BadRedWedge]

BIG Valves




Ported and polished





Double Springs


But only half a box