Head's off - SEAC..

[rev-erend]

Had a few spare hours today and took the head off

Bit of a rubbish montage - as my camera did not like macro focus (taken in haste..)


Head's seem to be what is generally described as stage 3 :

41.5 mm inlet
36 mm exhaust

Bore is 94 MM

Picture show's it as it was removed - so not cleaned up at all .. bore/ psitons is/are in really good shape as confirming the hot CR test I did before removal : 175 lbs on all cylinders.

I was almost disappointed to find a big valve head - as I thought with 268 bhp and 296 ft lbs of torque there might be more to come from the heads - as I suspected smaller valves.. WRONG.

Oh well - onwards and upwards as they say

Edited by rev-erend on Wednesday 3rd January 16:40

[wedg1e]

Porting looks as aggressive as on my car. Are those 94mm bores, they look like standard 3.9 pistons...?

[badredwedge]

So rev, what are you going to do for all them extra horses you crave ??

[rev-erend]

They the bore is 94mm .. I guess the 4.6 uses same pistons as 3.9
but with a longer stroke. You can just see the valve cuts outs in the piston - they are only very slight.

V8 developments built the engine in 1996 using a cross bolted block - it's a 4.6.

Always want more horses .. just want to control the fuel and air and sparks better this time round.

I cleaned it all up with a few kitchen towels this evening and sprayed a bit of light oil over it all.. it's all come up nice
with no horror stories showing them selves

Edited by rev-erend on Wednesday 3rd January 20:44

[AM400]

Rocker arms look nice

Not yet had the need or the nerve to take my engine apart, nice one

[350zwelgje]

Cam still ok Rev? If yes, the heads are and were always THE blocking factor of performance as you know. So probably the inlet, plenum (ACT ring a bell?) and heads to look at. Getting the fuelling and ignition right will probably give you the maximum from the built block (ditching the std ECU etc). To me it is awsome what you have compared to my std 350i of course! All this before topcats heads or putting a supercharger on.....
Good to see your engine is in good nick.
Enjoy the rebuild.

Rob

[Boosted LS1]

rev-erend said:

They the bore is 94mm .. I guess the 4.6 uses same pistons as 3.9
but with a longer stroke.

Edited by rev-erend on Wednesday 3rd January 20:44

FYI 4.6 rangie pistons aren't the same as 3.9 or 4.0 pistons. You'll have suitable pistons though

Boosted.

[wedg1e]

rev-erend said:

They the bore is 94mm .. I guess the 4.6 uses same pistons as 3.9
but with a longer stroke. You can just see the valve cuts outs in the piston - they are only very slight.

Aye, I thought it was a stroked 3948.

I had to have the valve cutouts milled into my new pistons when I did the rebuild - didn't have the milling skills myself but luckily my mate runs a machine shop

FYI my engine was on its original (93.5mm) bores at 102,000 miles with no appreciable wear (bore step, ovalling etc.), proving that a looked-after RV8 is bombproof.

[number 7]

Rev., TVR's own BV sizes are 42.8mm inlet, 36.8mm exhaust, which is what mine measured.

Maybe room for a bit more headwork?

7.

[rev-erend]

The engine has only done 20K miles (since 1996) and the cam V8D 404 Mech has done < 10 K .. so it's all pretty fit.

I'm considering my options on the engine front but the ECU is going and a bigger plenum will be one the list too (currently 73mm).

Did I mention I bought some new paint too..

[mikeb]

Better get the missus some new tea towels to!

MikeyB

[Boosted LS1]

number 7 said:

Rev., TVR's own BV sizes are 42.8mm inlet, 36.8mm exhaust, which is what mine measured.

Maybe room for a bit more headwork?

7.

Not much you can do to increase valve sizes unless you offset the guides. Might be possible to increase the c/r with a head skim.

Boosted

Edited by Boosted LS1 on Thursday 4th January 09:19

[badredwedge]

rev-erend said:

Did I mention I bought some new paint too..

What colour Rev ??

[gandalf]

badredwedge said:

rev-erend said:

Did I mention I bought some new paint too..

What colour Rev ??

My guess would be a sort of Rainbow effect, possibly

[rmeier]

Come on Rev tell us the colours. You mentioned you had bought 2 colours???Or is it just Go-Faster-Stripes
Bob

[rev-erend]

Sorry - it's a secret.. but the g/f does not like it

[badredwedge]

Tall bloke style PINK !!!!!!

[campbell]

[quote=rev-erend

I was almost disappointed to find a big valve head - as I thought with 268 bhp and 296 ft lbs of torque there might be more to come from the heads - as I suspected smaller valves.. WRONG.

Oh well - onwards and upwards as they say

Edited by rev-erend on Wednesday 3rd January 16:40

[/quote]

I neary have that much at the rear wheels Rev
An engine spec like that sould get you over the 300 to 320 bhp mark and a lot of torque to boot
Still it will keep you out of troble i gess.
Talking of troble, ill have to get a move on and get the mine sorted out

Cheers

Cambelt

[rev-erend]

Cambelt - what did yours make flywheel and wheel figures..

I'm not really sure 320 bhp is possible from a 4.6 : certainly not with a 73mm inlet.

With a twin plenum maybe and fully mapped fuel and ignition - then sure.

I have a really knackered ignition amp and Dizzy .. so it's not been at it's best for a while.

I'm very skeptical of most RR's .. but they can help a good operator to get the best out of a car.

[number 7]

Rev., just noticed that unless you have removed them, the heads are not secured with studs (ARP or similar). I understand this is a recommended mod.

7.