BC

So the 2V heads have some work to do on them. I was thinking at least to smooth the port shape it would need to have the large cutout removed from the stupid cold start injection system. This couldn't HELP flow:



So I filled it in with (ugh) JB weld. I hope it holds!

Looks much better for air flow, but you don't know until you test.






I am also smoothing the walls of the port a bit, and just rounding the short side radius so the air does not skip over to the long side of the valve. More than that I have no idea.

The chamber could use some valve UNshrounding I think:



I have done some, but I do not have a pic.

Comments? Suggestions? Boos?

largecar379

when I had my Euro heads worked over (by Nickens Bros long time Comp drag racers), I asked them about these and they said the gains would be un-noticeable on a street motor, and hardly worth worrying about on a race motor as well.

your valve guides and the material around them in the port need to be smoothed out, nearly to a point when viewed from the side of the guide--towards the big end of the valve.

similarly, you can use a valve with thinner stems (1mm thinner) and get more flow due to less valve in the port. I did not do this as it would just pile on the $$$ with new valves, guides, seats (bigger valve heads), labor, more porting....ad nauseum.

go slow with your porting if you've not done this before, or do not have a flow bench to test/check your cuttings. you can always cut more, but too much isn't a good thing.......






--Russ

SharkSkin

JB weld? Are you just using a scrap head for flow tests, or...?

largecar379

I should add that when Nickens ported my Euro heads, the only part of the injection hole area that was left was the hole itself-----no dimple in the port.

the hole could be filled with a weld, then ground flush with the port, but Nickens did not see any advantage to doing this.






--Russ

BC

I know its not the best idea in the world. But it should hold up in the head heat, don't you think? And some boost. Its the set of heads actually going on the car. I scuffed everything up, and I think the JB weld dripping into the hole before it sets up will mean that it won't come out easily.

Plus, its not structural. Its just like a bit of filler.

If its chunks and kills the motor, I have killed a 1k motor.

docmirror

No it won't, too many temp cycles for JB weld. Eventually it'll come out and go through the engine.

Porting is more art than science. Often, things are not what they seem. Without costly flow bench testing tools, it's a crap shoot whether you are doing any good or not.

For years we thought that smooth polished walls were better, now the rage is peened walls, thinking that in interrupts the boundary layer of air so it doesn't create surface tension. We also thought that unshrouding the stem improved flow, only to learn that it created serious eddies where the air rejoined after the trip around the new relieved stem area. The fact that the air starts and stops many times per second at high RPM introduces another layer of complexity with volume vs areal density. Tuning all the way back to the MAF has an effect too.

Like I said, not a lot of science but a lot of art, and a lot of testing to see what works and what doesn't. Air is a funny medium to work in........

SharkSkin

Brendan, when you say it's a 1K motor, what do you value your time at? Will you have a grand total of 10 hours in, including installation, and do you value your time at $100/hr? Or are you not counting the time at all?

Maybe it's a bit late to suggest this, but IMHO even this would be better: http://aluminumrepair.com

I'll bet you a beer that at least some of that JB comes out before you're done with the motor. I hope it doesn't cost you valves or worse!

Lizard928

I have a probably all too wild of an idea for some of you, that I have always wanted to try on a head like this.

Set it up in a mill, and mill the port straight down and slide a pipe down and in there, then weld it into the head and use a silicon sleeve to adapt an intake to it. This also will prevent a massive amoutn of heat transfer from the head to the intake as the silicone sleeve would prevent the transfer.

What say you Brendan, too wild for even you?

ibkevin

+1000 That head is just waiting to bite you in the rump.

I have seen JB cut loose on an air-cooled VW head, luckly it was on a compression stroke so it blew out.

dr bob

Brendan-- That JB Weld is fine for a flow-bench test head, but will cost you the motor if you try to run it. I've seen casual aluminum TIG 'fixes' drop out, fills done without preheating and gas-purging the head. No way that stuff will stay in.

----

I did some valve seat repair work way back on an early 50's Ferrari TR head. The head was one with the cylinders, no head gasket to blow out, so valve and spring assembly was 'interesting'. The ports on that are pretty much a straight shot, full valve diameter plus. If the valve isn't there it looks like you can almost reach through to gap the plugs in place. Makes our 928 ports look kinda puny. Made pretty good power for its day, too.

Vlocity

Negative Ghost Rider the pattern is full.

Please grind that JB Weld back out......it will not hold.

Ken

BC

Its not just sitting in there guys. It is held in by the hole that is in the bottom of the cutout.

You guys are really scaring me. I looked all over the internet and tons of people have used it for non-structural buildups in intake ports. Not exhaust ports, just intake ports.

SharkSkin

Brendan, any of those "tons of people" report back a year or two later? In the end, it's your call. If I were to try that on a throwaway engine, I would have hogged out the hole like this to make it less likely to fall out:

/__\

BPG_Austin

http://www.belzona.com/prod1k.aspx

I have a sample of this from a friend who repairs diesels. They often use it for structural repairs instead of welding. I haven't used it yet but it might be somethign to look into for your application. ?

BG

BC

http://www.mototuneusa.com/homework.htm