I'm just doing what the old man tells me. He said take the throat out and leave about maybe a 1/16" of seat. Not sure what will happen when we install a bigger valve, I assume the seats will have to be addressed. But so far I'm feeling good with the results.
Iron head testing (update on post #65)
- Thread starter TURBOELKY
- Start date
"Use more tuliped shaped intake and exhaust valves especially at lower RPM ranges. Sink the valve job enough to get at least a full .100-inch wide top angle width above the valve seat angle.
Keep throat diameters in the .85% to .88% range (of valve size)."
"If you don’t own a flow bench or have access to a flow bench when porting your heads, then grind just enough short turn curve material to create a nice gentle curved transition. Make all your grinding mods into nice gentle turning and blending shapes. Keep the intake throat diameter in the .86% to .88% range, and the exhaust throat diameter in the .85% to .87% range."
http://hotrodenginetech.com/pipemax-creator-larry-meaux-on-race-engine-head-porting/
Keep throat diameters in the .85% to .88% range (of valve size)."
"If you don’t own a flow bench or have access to a flow bench when porting your heads, then grind just enough short turn curve material to create a nice gentle curved transition. Make all your grinding mods into nice gentle turning and blending shapes. Keep the intake throat diameter in the .86% to .88% range, and the exhaust throat diameter in the .85% to .87% range."
http://hotrodenginetech.com/pipemax-creator-larry-meaux-on-race-engine-head-porting/
Good article. Fortunately I have access to the same flow bench he is using. As any rule, there is acceptions. I cut, tested, cut, tested and so on several times. 90-95% has gained me the most flow so far with near no runner work.
That is intake with back cut stock valve, 2 angle valve job. Shooting for 200's with 1.77" valve. We'll see.
Exhaust is currently at 160 stock valve back cut 2 angle
I'll be working in the shop Sunday and Monday and I'll snap some then. I knew if anyone would reply to this thread, it would be you
TURBOTIMMER
Well-Known Member
- Joined
- Jan 5, 2002
Subscribed. I've also been sidetracked with a dozen other projects. I might have to put my heads in service soon, so I gotta get back on them. Keep the updates coming.
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I'll be following along as well, the 'new' motor I just had built and picked up this weekend required both heads to be replaced so since the guy building the motor knows someone at Kenne Bell, I got a set of nicely worked Iron heads that he sourced from KB
It's hard to tell just by looking into the exhaust ports and putting a finger in there but the bowls are clean and smooth and the short side is very round and nicely prepped! That's a nice unexpected score Motor is assembled and ready to run so I'm not gonna be getting crazy in there buit I probably will pull the IN manifold and spend some time in there, or run another one. I don't know enough about the 3.8 platform yet. Gotta put in some hours here reading threads like yours Elky, thanks
AJ in OC
It's hard to tell just by looking into the exhaust ports and putting a finger in there but the bowls are clean and smooth and the short side is very round and nicely prepped! That's a nice unexpected score Motor is assembled and ready to run so I'm not gonna be getting crazy in there buit I probably will pull the IN manifold and spend some time in there, or run another one. I don't know enough about the 3.8 platform yet. Gotta put in some hours here reading threads like yours Elky, thanksAJ in OC
fastblackracing
Well-Known Member
- Joined
- Apr 7, 2009
Your Exhaust to Intake ratio is very good near perfect at almost 80%.
Post up the Exhaust incremental flow numbers if you have them..
You will have about 7% more area with the bigger valve...so can you get
7% more flow across the lift curve is the question.
Nice job turboelky and thanks for the updates.
Post up the Exhaust incremental flow numbers if you have them..
You will have about 7% more area with the bigger valve...so can you get
7% more flow across the lift curve is the question.
Nice job turboelky and thanks for the updates.
Today was exhausting!! And thanks for the replies. I did see my intake to exhaust ratio and left the exhaust alone for now. I have to say there was very little work done to the exhaust. I knocked out the short side radius and removed the valve guide for the most part. I did leave the EGR ports open just incase I ever upgrade to aluminum, it will leave a bigger market for the heads.
I did some testing today with a sbc valve on the intake that measured 1.71" just to play around on the bench. I should have taken pics after my machinist put a 5 angle valve job in there. Crazy thing was, I LOST 7cfm!! Lol. However, he said don't worry about up top, look at how quick the lower numbers came up. I forgot my card on the flow bench...
I do know the sbc valve flowed 190 with a 45* and 30* back cut, valve seat was done by my machinist so I don't know what he put in there. There was 5 cuts where it was possible, I may have taken too much out of the throat. Seems to be working ok but if not, there is a pallet of 6293 heads out back and 2 sets of 8445 heads to keep at it. I wish the damn intake port didn't have that hump in it, what a shit design!
Thanks for the compliments. I feel pretty good about it so far, it is my first head porting job so it's a learning curve. Easy to get carried away lol.
At .200" I had to switch settings on the bench. Exhaust was flowed at 10" water so you have to multiply the value by 1.67
Apparently it is flowed at a lower test pressure to keep the head from blowing off the bench.
Mike T
Well-Known Member
- Joined
- May 3, 2013
It's good that you have the other heads as a benchmark for your numbers. As I recall those numbers were all In line with other flow benches so I doubt that your calibration or the quality of your machine will be questioned.
Would a 1.775 valve correct that?
I'll try to find the article but at least one of the top head guys actually roughens his ports for fuel mixing. After port shaping he uses a bent carbide with a few missing teeth to create a really rough texture throughout the port. Not sure if it would apply to a turbo car but he claims increased dyno numbers on every motor he's tested.
Would a 1.775 valve correct that?
Couple more pics. I didn't have the seats cut yet, and I'm not going beyond 80 grit rolls once all finished. Not the prettiest but I've seen pretty heads that didn't flow as good
I have not done any chamber work or un shrouding of the valves yet. This work is taxing
I'll try to find the article but at least one of the top head guys actually roughens his ports for fuel mixing. After port shaping he uses a bent carbide with a few missing teeth to create a really rough texture throughout the port. Not sure if it would apply to a turbo car but he claims increased dyno numbers on every motor he's tested.
As for the machine, I have been using the same techniques on every head test to ensure accuracy. I have no doubt the numbers are right on.
I think the 1.77 valve will correct the valve job so I'm not too worried about having removed so much material. If not I'll install new seats and blend them in. Luckily I have access to all this stuff. The heads are still flowing good but it's the lower lift areas that REALLY picked up. I forgot my card on the bench but I'll post them next week. I should have the valves in by then too.
You are right about the rough ports. And it's funny you mention it but there is a carbide bit on one of the grinders with a few broken teeth that is actually there for that purpose. There is a ton of circle track heads that are done at the shop and you would be amazed at some of the stuff at how it looks but how well it works. On the other hand, a lot of guys bring their heads in for repair after they took so much material out, the car will have no bottom end power lol.
fastblackracing
Well-Known Member
- Joined
- Apr 7, 2009
I really like to see people doing there own work,learning and getting smarter.
I like to add up all of the flow numbers at the different lift points to get a total number
and you can use that total number to compare different heads and see the flow variances
from a different perspective.
Larry Meaux is a proponent of the dimple ports and has done some back to back testing and found a small but worthwhile HP increase in doing so.
I like to add up all of the flow numbers at the different lift points to get a total number
and you can use that total number to compare different heads and see the flow variances
from a different perspective.
Larry Meaux is a proponent of the dimple ports and has done some back to back testing and found a small but worthwhile HP increase in doing so.
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