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V6 iron cylinder head by lordfiero
Started on: 11-25-2018 10:34 AM
Replies: 52 (1062 views)
Last post by: lou_dias on 02-14-2019 09:18 AM
Blacktree
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Report this Post01-28-2019 03:06 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post

That looks pretty promising for high-lift camshafts.

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lou_dias
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Report this Post01-28-2019 09:23 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

https://www.summitracing.com/parts/slp-v-4644

What do you guys think of machining down this valve? It's 0.119" taller than the stock 1.72" valve. I was thinking about getting it down to 1.8" in diameter and then shaving it to between 4.75" and 4.8" then machining it for flow as well as narrowing the valve stem near the opening to 6.5mm... Then also opening the port a hair more to match...
I picked this valve because it will work with the Fiero valve guides (etc..) and it's super cheap...

[This message has been edited by lou_dias (edited 01-28-2019).]

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lordfiero
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Report this Post01-31-2019 07:39 AM Click Here to See the Profile for lordfieroClick Here to Email lordfieroSend a Private Message to lordfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by lou_dias:

https://www.summitracing.com/parts/slp-v-4644

What do you guys think of machining down this valve? It's 0.119" taller than the stock 1.72" valve. I was thinking about getting it down to 1.8" in diameter and then shaving it to between 4.75" and 4.8" then machining it for flow as well as narrowing the valve stem near the opening to 6.5mm... Then also opening the port a hair more to match...
I picked this valve because it will work with the Fiero valve guides (etc..) and it's super cheap...



Check the stem diameter.. My fiero heads have 8,7mm, so look for 11/32" or 0.344" . If you use CSB valves you will probably have to use longer pushrods and spring spacers.
You can find 0.344" with undercut/narrow stems ends from summit, ebay or other places.

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Report this Post01-31-2019 06:45 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post

Yes, the iron heads use 11/32" diameter valve stems. The aluminum heads use 8mm.

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lou_dias
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Report this Post02-01-2019 04:57 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

Ah yes, valve stem diameter is one of those "hi-tech" reasons aluminum heads flow better. Have you guys ever seen the valve stem diameters of foreign engines?

https://www.summitracing.co...t-21471800/overview/
So I guess these wouldn't be cost effective...

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lordfiero
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Report this Post02-06-2019 03:26 PM Click Here to See the Profile for lordfieroClick Here to Email lordfieroSend a Private Message to lordfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post

Time to put the D-shape to rest, it was taking to much metal from the walls.
The next step is the oval shape (higher than wide) with a circular conical port opening matching the gasket of 34mm diameter.

Oval shape runner material removal


Oval shape runner step 1, rounding of corners and smoothing the surface


Nothing is done to the bowl more than removing som dirt.


This is the flow, notice this stock port started out approx 20cfm less than the last port used for the D-shape. The area around the valve guide are slightly different on all ports on these heads which results in different flow of the ports, the amount of dirt in the stock ports do vary also..


Im very pleased with the shape of step1, it exceeds the flow of the stock port on all valve lift points and the healthy max flow can be reached with a medium performance cam and high ratio lifters.

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lordfiero
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Report this Post02-07-2019 06:09 PM Click Here to See the Profile for lordfieroClick Here to Email lordfieroSend a Private Message to lordfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post

Step 2
Some quick polishing to the runner surface and removing the sharp (very small) edges where the valve guids meets the bowl, the flow is slightly increased

Step 3
Starting to cut down the valve guide to make a smooth, more flat and even surface, and better looking port just as porting guides describes well yeah.. in my ports this is a recipee for decreased perfomance, the flow dissapears fast. Just like I experienced in the previous D-port design. This is a good thing since reshaping the valve guide would be the most difficult part of the porting job.



So after a couple of months digging and measuring in these exhaust ports I do think the oval port step2 is pretty much as good as it gets, and Im running out of cylinder heads.

Conclusion
Massive gains in the exhaust ports flow can be achieved, with stock valves. These steps did improve the flow without side effects.
Increase the runner, more straight and more area, stay away from the hump.
Round over all edges from the bowl into the runner
Clean up the edges around the valve guide
Polish the new shaped port

The bend between the runner and bowl is what limits the maximum flow, this is why the graphs takes a jump when smoothing out the edges leading to the runner.

Following modifications are according to my studies, questionable
Larger valves, There is not enough metal to remove to fit them
Reshaping the bowl, loss of flow with realistic valve lifts, although very high max flow could be seen.
just polishing the stock shape port, gains to small to justify the time to do it. If not the heads are removed from the car for other reasons.

Now I have to make 6 identical ports..

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lou_dias
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Report this Post02-10-2019 03:18 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

Looking back to an older picture of one of my sets of heads it seems my guy did do some work on the guides as well...

This images is larger than 153600 bytes. Click to view.

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lou_dias
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Report this Post02-11-2019 06:59 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

This images is larger than 153600 bytes. Click to view.

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lordfiero
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Report this Post02-13-2019 12:31 PM Click Here to See the Profile for lordfieroClick Here to Email lordfieroSend a Private Message to lordfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post

You may have lost some of the improvements with the porting job by doing the valveguides smaller. But really hard to tell without flow bench measuring..
I suspect this is the reason for the very small gains in previous published porting jobs on these heads, on this and other forums.

I even tested to grind one of the valve guides down and used epoxi filler to get a perfect flat surface, it looked very nice and "high flowing", but it reduced the flow.

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lou_dias
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Report this Post02-13-2019 08:09 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by lordfiero:

You may have lost some of the improvements with the porting job by doing the valveguides smaller. But really hard to tell without flow bench measuring..
I suspect this is the reason for the very small gains in previous published porting jobs on these heads, on this and other forums.

I even tested to grind one of the valve guides down and used epoxi filler to get a perfect flat surface, it looked very nice and "high flowing", but it reduced the flow.

Judging by the way my two 3.4's w/ported heads perform, I have no complaints! I do use the 31000/3400 block as a base though... One uses the DOHC pistons and the other uses stock Camaro pistons.

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lordfiero
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Report this Post02-14-2019 05:34 AM Click Here to See the Profile for lordfieroClick Here to Email lordfieroSend a Private Message to lordfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by lou_dias:

Judging by the way my two 3.4's w/ported heads perform, I have no complaints! I do use the 31000/3400 block as a base though... One uses the DOHC pistons and the other uses stock Camaro pistons.


Which cam Do you use for your 3.4?

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lou_dias
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Report this Post02-14-2019 09:18 AM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by lordfiero:
Which cam Do you use for your 3.4?

On the high compression one, I use the WOT-Tech 480/480 cam. On the 9.0 compression ratio one I use the stock 96 3100 cam.
I want to swap out the .480" cam for a .510" one but I am waiting on a machine shop to develop some valve cover spacers...

[This message has been edited by lou_dias (edited 02-14-2019).]

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