Thanks for the update mate

And nice work on all your research!

The back of the valves are at 15 degrees which is pretty flat.
The AU spec one would not have a wasted stem, but the early type one would be ordered with the stem wasted down to 7mm. Sorry I thought I had posted that info earlier.

Just added a new converter. It will convert flow @25 inches to flow @ 28 inches.

Also reposting the port size calculator for people that missed it.

 

 

Attachments:

Port size calculator.xls [14.5 KiB] Downloaded 358 times

Port size calculator.xls [14.5 KiB] Downloaded 345 times

It's all becoming to hard and expensive to have them made as a direct drop in fit.
I'll be looking at producing a kit that contains Valves, springs, retainers, locks and spring bases.
It would require machining of the head to take the spring base and It would only be for the narrow stem valves.



Now for further progress on the head porting part of the thread.
It was about to become very expensive to take all of this to the next level, as the nearest flow bench to me is 100km away in the next town.

There were two ways I could go, shell out the money for delivery each time I wanted an idea tested. Cost reduction would come from applying 6 ideas to one head and have each port flowed.
The big draw back being turn around times.
In the end it would still cost me thousands of dollars for very little if any return at all.

The other option, though still costing $$$$$ was to buy a flow bench and do my own testing.

In the end the SECOND option looked better. Fast turn around times test as much as I like when ever I like. And lastly I can offer flow testing to the public and other workshops through my own workshop. Which gives me the ability to get a get a return on my investment.

My step into this flow bench venture will come together over the 6 months or so.

Just a little more on the Valve side of things. In case people don't see it as it started the V8 section.
Basically after a talk with one of the guys at Fabre, I realized the ford Modular V8 has a 7mm valve stem and uses a triple groove valve lock. So a second call this time to the local ford dealer had a new intake valve from a BA XR8 at my door step this morning.
It took all of about 60 seconds to put a smile on my face.

Ok so update.

There are a number options for spring retainer and locks.

Between Comp, Crane and Manley, There are machined steel triple groove locks.
Titanium retainers and a 3 or 4 conical/beehive springs to suit anything from a mild cam to an aggressive cam with over 25psi of boost pressure.

The only draw back is to the springs will not work with the sock retainer, you must use the after market retainer.

time to fire this one up...

brad what do u think is the best way to port the head to suit a cam of .517 max lift and fairly mild duration (997b actually)...

obviously to get the most from this cam you want to size it for maximum velocity....

everyone thinks you should go for max flow...but there is no point increasing flow above the lift of the cam right?

low lift flow rates would surely have to be just as important as the max lift flow right?...ie port for maxium area under the curve....

The reply to those questions is going to be LOOONNNGGG

I'll try and get to it tonight.

cool...looking forward to it..

I have just realised I know nothing after reading some of david vizards stuff...

First things first. I don't believe porting a head to suit a cam is the right way to do things.
The cam should be the last thing to decide on.




You can't assume that velocity is constant through a port. We actually aim to reduce velocity around the turn to aid in keeping the flow attached to the floor of the port.



Air flow above peak lift when we are dealing with a flow bench is important.
Consider that your head will be tested at 10" of depression or 28" of depression as most places use Superflow benches and the smaller of them will only do 10" at higher flow rate.

When you flow a head at 10" the velocity during the test is low. With increased lift and flow you can increase the velocity, this can show up issues that you might not have seen. Velocity in the port of a running engine is going to be higher then on a bench at 10" depression.
So porting for flow above your peak lift can be of benefit.
The other way to look at it is, You want to know that airflow doesn't stall just above peak lift. If it stalls and drops say at an extra 150thou above you peak lift then fine, chances are it wont be an issue.
I wouldn't go chasing flow above peak lift lift, but I would ensure flow doesn't stall or drop.

You can calculate the flow at 28" based on 10" flow, I posted an excel based calculator for this previously in the thread. But on a lot of heads if you measure at 10" and then at 28" the numbers you calculate won't be the same as what you measure.



This is one to get a good conversation going.
The first thing that I thought of is a thread on I saw on an other forum.
It was about a test that engine masters magazine did on valve seat angle.

At was 30 degree seat vs: 45 vs: 60.
The 30 degree seat has very good low lift flow but looses out a touch to the 45 at higher lift.
The 60 degree seat has very good high lift flow but looses out on low lift flow.

they basically took an engine and dyno'd it, them took the heads off and cut a 30 degree seat and dyno'd it again, then that same with the 60 seat.
The 60 seat made the most peak power and very good torque
the 45 as expected some somewhere in the middle
the 30 seat made good torque and lost out on peak power.

The average reader would simply assume the 60 seat was good for power.
What was really shown was that the camshaft just didn't suit the way the heads flowed with 30 degree seat and good low lift flow.




The starting point to porting a head is knowing how much airflow you actually need.
You then need to work out the cross sectional area you need to achieve that flow with enough velocity, which currently seems to be agreed to be 350 feet per second.
then you need measure the port to decide where the port is lacking in area.
Again i've posted an excel based calculator to work this stuff out previously in this thread,
as well as a analysis of an AU head using flow and area.

Changes in shape and direction will need more area to achieve the same flow.
Where it gets hard is working out where to remove or add to port to get the air around the short turn and past the valve.

Then after you have a head that will do what you need it to you can talk to a cam specialist about a cam to complement the head.



The flow bench I was talking about building earlier in this thread and coming along. it should have the ability to flow the I6 heads at depressions of almost 40". It will be interesting to run tests at a fixed valve lift but at 10" 20" 28" and so on to see what's really going on.
But flow numbers from a bench are only part of the story, whats going to be more interesting is testing with velocity probs to see where air is and isn't moving.

Ok i'm struggling to hold my eyes open, Been working WAY to many 12 hour days in a row. So I apologize if any of the above reads is gibberish or is off topic. Some time I wish these conversions could be had over some beers and a good steak burger.

Reading his stuff is what got me into this in the first place.
Shoot me a PM and I will give you really good books on this topic.

sorry guys but thats way too confusing for me. (not an engineer) so basics would just smoothing ports and gasket matching be a simple improvement on stock. i have heard that you shouldn't match exhaust side somewhere. would like to know as have engine on stand ready to rebuild with good bits but still budget and fairly simple. any advice would be great

Sorry for not answering sooner.

Smoothing and gasket matching doesn't address the problems with the port.
The surface finish as-cast isn't a problem.

Search back and find my pictures of the modified guides. That's IMO the best starting point.

Also after looking for quite some time for an OZ supplier of decent abrasives for porting, I found this:
http://www.abrasivesupply.com.au/speciality.asp

I'd start with the small engine porting kit. That will give you all the mandrels and enough abrasive to do a falcon I6 head.

The kit will do the basics, for people looking to go a bit further, A few long and short shank carbide burrs would be handy to speed things up. Some cheap very thin oil, like cheap air tool oil and sewing machine oil will help stop the burrs from loading up. Also turn down the grinder speed!!!!!!!

As for an air supply and a die grinder, Supercheap is your friend.
grab one of the cheap large body grinders will do just fine. The trick to getting them to last is good oil, not the Supercheap stuff, Next time you see a snap-on truck, jump in an grab some tool oil from them.

The air compressor doesn't need a big tank, What it needs is huge airflow, the easy way to huge airflow is to buy two of the cheap compressors from Supercheap and run them in parallel. You'll double flow rate that way.

thanks mate no problem all good just bought a ed xr6 motor and com for 400 bucks. gotta put it on the rotisserie and check it out but all seems good so far.


thanks again