Got myself a spare 16v head, an 027, all stripped down ready to port out. Got it real cheap cos all the inlet valves were bent, belt probably snapped. Any development on this thread?
I'm eager to see more as well, got 16v head sitting on bench ready Also is it worth doing a 45 deg chamfer on the front edge of the valve rather than the rear back cut? or both?
Patience is a virtue! lol Development has stalled at the mo with the current workload, but the basics are as above. I could do with trying a couple of options as there are two distinct O.E valve shape used...a flat back and a tulip back...flat mostly in 027's and tulip in 051's...tho I've seen 051's with flat too. No need to do anything to the valve face...back cut off the seat only. Just had a quick look...see where we're up to now...I maybe able to pull some data off the flowbench for the next round soon...i.e before Christmas!...we have a couple of big power 16v's on the go so I'll be spending some time on it with a pile of heads very soon.
That should have said exhaust valve, is it worth putting a chamfer on the front face as the gas is flowing that way round on the way out? I've ploughed ahead with my head, hopefully not messed it up! I've mainly blended around the valve inserts and opened it out a bit either side of the valve guide. I see what you mean about the tools now, an aldi dremel copy is not the way to go, although its hanging in there so far! Look forward to an update!
Err...no...a dremel wont do the job successfully! It's a very small gain on the valve face...if you open the rest of the port and throat to the right size you'll get enough flow through the exhaust. Inlet flow is the most important. .get that right first.
I've pretty much finished the porting on my head and had a question about the combustion chamber side... I've tried to un-shroud the valves as far as possible but the bit I'm not sure about is the part the picture below, it's not my head just a random pic. Should I blend out this ridge to un-shroud the valve? Or is this feature there intentionally to reduce reversion or create tumble or soemthing? I see lots of others remove it but that doesn't necessarily make it right! Head will be CC'd after and skimmed to bring up compression back up.
I got my engine running last autumn but a house purchase and baby mean the car hasn't moved since! When I get a chance I'll get it on a rolling road and see what the result was. Will post pics later, maybe as an example of what not to do!
