It's head porting time!!
Discussion
It's mighty morphin portin time!
Yes, the heads are off the SBC and it's time to port them, seeing as we put them on raw and ran into the 9's, I have a feeling they'll assist in producing a little more power
Hodgy587 has been very busy with the die grinder, so the heads are now port matched to the intake manifold (we estimate that based on the port size now, we were effectively running on 7 ports) and one head is nearly finished on the porting side of things...
Here's the unported head, excuse the gaffer tape, we're trying to protect the valve seats!
And here we have the nearly finished product, going rather nicely, Hodgy's got about 15-20 hours invested in this one so far with a little bit left to do..
It should have a bit more bark & bite when it's finished
slinky
587racing.com
Yes, the heads are off the SBC and it's time to port them, seeing as we put them on raw and ran into the 9's, I have a feeling they'll assist in producing a little more power
Hodgy587 has been very busy with the die grinder, so the heads are now port matched to the intake manifold (we estimate that based on the port size now, we were effectively running on 7 ports) and one head is nearly finished on the porting side of things...
Here's the unported head, excuse the gaffer tape, we're trying to protect the valve seats!
And here we have the nearly finished product, going rather nicely, Hodgy's got about 15-20 hours invested in this one so far with a little bit left to do..
It should have a bit more bark & bite when it's finished
slinky
587racing.com
Combustion chambers with view down the port, nothing has been done with the chambers themselves (although they may get a polish), all of Hodgy's effort has gone into ensuring good port flow..
Inlet Ports, unfortunately I haven't got a before shot of these, but beleive me, there is no comparing the two, especially when put up against the inlet manifold, they actually match now!!
Exhaust Ports, these are probably going to end up mirror shine, they're already feeling pretty splendid...
We're not making any predictions, but lets say Desktop Dyno is telling us nice numbers!!
slinky
Inlet Ports, unfortunately I haven't got a before shot of these, but beleive me, there is no comparing the two, especially when put up against the inlet manifold, they actually match now!!
Exhaust Ports, these are probably going to end up mirror shine, they're already feeling pretty splendid...
We're not making any predictions, but lets say Desktop Dyno is telling us nice numbers!!
slinky
Edited by slinky on Tuesday 30th January 10:16
chuntington101 said:
look great mate! just remeber just how close the water gallies run to the ports! sure you fully awaer of it though. 
cant way to see what a difference it makes in the power and torque departments and how much it reduces your 1/4 mile times
Chris.
cant way to see what a difference it makes in the power and torque departments and how much it reduces your 1/4 mile times
Chris.
Actually there's a lot of metal between the port walls and water jackets on the darts, the main area for me to be careful was where the head bolt passes between the two intake ports, mainly because the ports are so large to start with (215cc), the pushrod pinch was also another concern area although not much was removed from here as there was plenty of cross section area.
On the combustion chamber front I just polished them to promote flame travel and reduce surface area as to avoid hot spots. Didn't really feel the need to unshroud the valves as it doesn't make masses of difference on these until you get into valve lifts above 0.550" due to the 4 angle valve seats. also as you pointed out I didn't want to mess with the compression ratio to much think I may have done more harm than good seeing as this is my 1st proper porting job.
All in all im very pleased with how they've come out but bloody thankfull its over, don't even want to count how many hours its took, although apart from the gasket set its some nice free power.
cant wait to hear her run again
www.587racing.com
Can you please explain what "port matching" is all about to a layman. Is it making sure the inlet manifold ports all match up as far as possible with the inlet ports on the cylinder head. Same with exhaust ports. But how do you know they are lining up or not?
I see you also polished the surface inside the ports on the cylinder head, I read there is some dispute that inlet port polishing is always a good thing, sometimes good sometimes bad. But exhaust port polishing is always a good thing.
I see you also polished the surface inside the ports on the cylinder head, I read there is some dispute that inlet port polishing is always a good thing, sometimes good sometimes bad. But exhaust port polishing is always a good thing.
Sunim said:
Can you please explain what "port matching" is all about to a layman. Is it making sure the inlet manifold ports all match up as far as possible with the inlet ports on the cylinder head. Same with exhaust ports. But how do you know they are lining up or not?
I see you also polished the surface inside the ports on the cylinder head, I read there is some dispute that inlet port polishing is always a good thing, sometimes good sometimes bad. But exhaust port polishing is always a good thing.
I see you also polished the surface inside the ports on the cylinder head, I read there is some dispute that inlet port polishing is always a good thing, sometimes good sometimes bad. But exhaust port polishing is always a good thing.
As you say port matching is getting the ports to match from head to manifold. You cut a card template of the ports in say the head then lay that on the manifold to see where material is to be removed. You may need to do this several times.
Exhaust ports should be as polished as possible but personally I doubt it makes that much difference unless you then try and polish on down through the manifold.
Inlets are said to work better if left lightly rough. The turbulence this causes serves to mix the air and fuel better. It has also been said that leaving the port in the inlet manifold slightly smaller than the head port leaves a step which also produces the required turbulence.
Steve has pretty much answered that one..
How do you know they are lining up? The gasket is a great help!!
As far as how much do you polish, I'll drop Hodgy a line and get him to reply, he's done an awful lot of reading on this one and knows far more than me what the desired results are!
slinky
How do you know they are lining up? The gasket is a great help!!
As far as how much do you polish, I'll drop Hodgy a line and get him to reply, he's done an awful lot of reading on this one and knows far more than me what the desired results are!
slinky
Slinky has prompted the last bit I forgot to mention.
When you have matched the ports you also have to modify the gasket to the same profile.
Another thought. If the manifold and gasket are a loose fit on the head studs/bolts all your work will go to waste if things are not aligned when you bolt it all up. To resolve this I have bolted the manifold and gasket into position and drilled 2 dowel holes so that the manifold and gasket go back in the same place every time.
Steve
When you have matched the ports you also have to modify the gasket to the same profile.
Another thought. If the manifold and gasket are a loose fit on the head studs/bolts all your work will go to waste if things are not aligned when you bolt it all up. To resolve this I have bolted the manifold and gasket into position and drilled 2 dowel holes so that the manifold and gasket go back in the same place every time.
Steve
dinkel said:
Let us know the hp figure Slink . . . or even better: a torque / power line.
I don't believe I've ever saw one of a dragster
I don't believe I've ever saw one of a dragster
I put all the figures in desktop dyno and was very conservative with port flow figures (I aimed between stock flow and the figures for a pair of cnc ported darts)
it pumped out 526 bhp @6500 rpm and peak torque was 465 ft lbs @ 4500 rpm
The torque curves the nicest bit, it makes 401 ft lbs @ 3500 rpm and doesn't drop bellow 400 ft lbs until 6800 rpm, that means we don't drop bellow 400 ft lbs through our entire operating range
I know desktop dynos not 100% accurate but its about as good as a virtual dyno gets also i think i was underestimating port flow slightly so we could possibly be making a bit more than that.
This is still on a hydraulic flat tappet cam, swapping this for a race roller cam put us in the 580 bhp range so we still have lots more potential
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