porting v8 heads - some observations

[coops71]

I'm in the process of doing some work to my v8 heads as recommended in Des Hammill's book. I have taken the valves out and have noticed a few things of interest. Note that this v8 has been run purely on LPG for about 10,000km and is very clean apart from in the combustion chambers and behind the inlet valves. I'd appreciate it anyone can check out the photos I have taken(link below) and give me an idea if the soft build up behind the inlet valves and in the chambers is flashlube build up(my bet) or if it is oil. The engine was using very little oil and I was running a semi synth. Also check out the casting deformity in one of the exhaust ports. I think that this along with the crud on the inlet valves may have been robbing a few hp.

Link:
land rover - a set on Flickr

[discowhite]

if that was purley a petrol engine ide say it way too lean, ive never seen the inside of a gas motor so the white valves may be normal???

as for porting a stock rover v8...you probably notice any differance in power, but couple it with higher comperssion ratio and then you will.

rover heads/ports are crap for HP

cheers phil

[Blknight.aus]

if its only been on LPG for 10K km that may still be the remnants of the petrol gunk coming out.

assuming that its not that

flash lube is oil so yes the carbon build up is from the motor burning oil. be it flashlube or a little more than no oil consumption past the rings its hard to tell.

the whitish stuff on the valves is lpg related but Ive not seen it quite like that before on the couple of lpg only donks Ive done its usually just a little bit around the edge of the face of the valve.

[coops71]

if that was purley a petrol engine ide say it way too lean, ive never seen the inside of a gas motor so the white valves may be normal???

as for porting a stock rover v8...you probably notice any differance in power, but couple it with higher comperssion ratio and then you will.

rover heads/ports are crap for HP

cheers phil

Not expecting any big increase in hp. Will be putting in a Crower 50229 cam. Hoping that cleaning up ports(especially exhaust) will help give some good low down and mid range. Hammill reckons on not going over 0.43" lift. The Crower cam has 0.44". Hoping this won't bind up valve springs.

[PhilipA]

Its oil of some type, maybe down the guides or maybe flashlube. I think down the guides. Maybe fit teflon guides when you have them serviced.
That cylinder looks pretty oily also.

Put quite a bit of work into the exhaust ports, as I think this is where you will pick up quite a bit, but only make the radius smooth around the bowl and raise the roof not lower the floor, and widen it around the guide. do not shorten the guide.

Inlet port work included guide off at the roof, blending into the seat, and widening towards the outer angle, exhaust bowl work and effectively 20 thou off.( 50 thou plus composite) . I also unshouded the inlet valve across to the fire ring in the chamber so the combustion chamber volume was probably unchanged. BTW the head guy could not do a 5 angle cut on the seats as the inlet valves were too small in the seat to have room.

I gained 6% across the board with work. This was dyno checked on the same dyno as previously.

It was about 30 hours with only a Dremel but 6% wasn't bad.
Regard sPhilip A

[coops71]

Its oil of some type, maybe down the guides or maybe flashlube. I think down the guides. Maybe fit teflon guides when you have them serviced.
That cylinder looks pretty oily also.

Put quite a bit of work into the exhaust ports, as I think this is where you will pick up quite a bit, but only make the radius smooth around the bowl and raise the roof not lower the floor, and widen it around the guide. do not shorten the guide.

Inlet port work included guide off at the roof, blending into the seat, and widening towards the outer angle, exhaust bowl work and effectively 20 thou off.( 50 thou plus composite) . I also unshouded the inlet valve across to the fire ring in the chamber so the combustion chamber volume was probably unchanged. BTW the head guy could not do a 5 angle cut on the seats as the inlet valves were too small in the seat to have room.

I gained 6% across the board with work. This was dyno checked on the same dyno as previously.

It was about 30 hours with only a Dremel but 6% wasn't bad.
Regard sPhilip A

So you reckon a dremel is ok for this work. Some have told me I should use an air grinder?

[Blknight.aus]

a die grinder is fine for the hheavy work but a dremel is great for the final detail and polish.

[LOVEMYRANGIE]

Use a Dremel if you aren't experienced using an air grinder as you may take out more than you expect.
Philip is pretty much on the money with the dimensions. Take out too much floor and you will suddenly find your self in a water gallery.
The head ports are not the only thing to consider. If you are going to all the trouble, make sure you
matchport both intake and exhaust manifolds otherwise it ain't worth diddly, particularly in the exhaust. The key is getting a smooth transition of gasflow across connecting parts.
RPI Engineering "RPi Engineering - Specialised Rover Engines" have a good article on matchporting. Fairly easy to do, just don't rush your measurements and mark gaskets "headside" and "manifold side" and you should be all sweet.
With the .440" lift, do the valve springs. Stock springs won't last with this particularly if their life has been spent only pushing the STD .283". Seen this too many times ans springs aren't that expensive compared to a dropped valve!
Cheers

Andrew

[coops71]

Use a Dremel if you aren't experienced using an air grinder as you may take out more than you expect.
Philip is pretty much on the money with the dimensions. Take out too much floor and you will suddenly find your self in a water gallery.
The head ports are not the only thing to consider. If you are going to all the trouble, make sure you
matchport both intake and exhaust manifolds otherwise it ain't worth diddly, particularly in the exhaust. The key is getting a smooth transition of gasflow across connecting parts.
RPI Engineering "RPi Engineering - Specialised Rover Engines" have a good article on matchporting. Fairly easy to do, just don't rush your measurements and mark gaskets "headside" and "manifold side" and you should be all sweet.
With the .440" lift, do the valve springs. Stock springs won't last with this particularly if their life has been spent only pushing the STD .283". Seen this too many times ans springs aren't that expensive compared to a dropped valve!
Cheers

Andrew

Yeah I was intending to match ports. I currently have a 500 weber and edelbrock performer manifold on the 3.5. Made a big difference to the 3.5. Once I swap it to the 3.9 it should make a fair difference. Now to get some new springs!

[loanrangie]

When i ported my heads 15 years ago i spent more time cleaning up the rough castings than actual porting, exhaust ports are very restrictive so use a gasket or the dark outline on the face to match the ports to the manifolds - both inlet and exhaust manifolds. After i did mine i fitted a bosch dizzy and a 350 holley and the difference was remarkable, heaps more revability and 70 klms extra per tank.