Who's gasflowed their V8 heads?

[Quentin]

'97 D1 3,9l V8 (yea it is a 3,9l...... we only got those in RSA )
Well the time of engine rebuild is coming and I am toying with the idea of gasflowing the heads (both the inlet and exhaust ports). Just lookig for more power and and economy :rofl: that's if I can stay off the "Loud Peddal".
A friend of mines' enginebuilder that does all of his race cars has offered to machine them for me and is talking of at lest 30% power increase. :drool:
I'll obviously be doing:
cam, remachine the crank, rebore, new pistons & rings, oil pump, (water pump already done), valves, seals, guides, bearings, litfters, etc, etc
Any of you guys running with modified heads? What sort of power are you getting??
Gasflowing will cost a small fortune so I'd like to see what sort of cost vs benefit there is.
THe old D1 does well in the sand dunes of Namibia, but more power is always welcome

 

[noee]

IMO, instead of all that hoopla for gas flowing, just have him radius the turns and do a P&P. There's a lot of material that can come out of those heads without creating hotspots.

 

[jymmiejamz]

Why not just put a 4.6 crank and rods in it with 4.0 pistons, and add a hotter cam. If it were mine I wouldn't bother replacing the oil pump unless it very cheap.

 

[Quentin]

Mmmm, yup it is a lot of moola for the heads. Maybe a tweak here and there. He's a VW specialist not a Rover, so I'll probably get a breakdown of what he can safely do to the heads without comprimising reliability once I give them to him.
More input please

 

[xengineguy]

How often do you run at wide open throttle WOT ???? If the answer is not very much,You will see little power increase with Port and Polish.
Remember the throttle is a power/airflow limiter.. You may get better throttle response with P&P.. If you want more power, might try a little N.O.S.! X2 on more cubic "s

 

[KyleT]

build a 5.2l or swap in a 350 vortec, might be quite a bit cheaper than building up a rover v8.

IIRC the max n/a hp out of a rover v8 is about 370hp. it cant breath anymore than that.

there are the merlin heads that are supposed to flow alot better than rover heads as well.

 

[robertf]

build a 5.2l or swap in a 350 vortec, might be quite a bit cheaper than building up a rover v8.

he's in south africa, and its inability to breathe is exactly what he is fixing.



I support the bench flowing of heads. If your guy hasn't done rover head before, finding a 3rd one and section it on the 1 and 4 (1 and 7 or 2 and 8, depending on perspective) so he can see the limits that the cooling system will allow him to grind away without compromising reliability.


if you've got the coin, extrude honing the lower plenum would compliment the flow matched machining. There are a few companies that do that here in the States, it turns the manifold into an abrasive play-do factory and does a great job of eliminating turbulent areas in the runners.

 

[KyleT]

merlin f85.

 

[Quentin]

he's in south africa, and its inability to breathe is exactly what he is fixing.



I support the bench flowing of heads. If your guy hasn't done rover head before, finding a 3rd one and section it on the 1 and 4 (1 and 7 or 2 and 8, depending on perspective) so he can see the limits that the cooling system will allow him to grind away without compromising reliability.


if you've got the coin, extrude honing the lower plenum would compliment the flow matched machining. There are a few companies that do that here in the States, it turns the manifold into an abrasive play-do factory and does a great job of eliminating turbulent areas in the runners.

Good idea. A friend of mine has an old buggered one lying in his workshop that I'm sure he'll let me chop up.
I'll have to do some research into the plenum here in South Africa.