First valve job with stones

[steve cowan]

Hi guys,
Being the novice that i am I wanted to share some photos of my cast iron dart heads,these started as 165cc when I purchased a few years ago they are now 182cc 1.94" - 1.5" valves.
Machine shop flat milled half the top cut away and they went bad on the bench because of that,Tony Knight offered to repair for me but I know he is super busy so I decided to have a go myself,keep in mind the SSR was getting thin when I sonic tested so sinking the valve job and SSR was a serious issue for me.if people want details or to make comments or suggestions that's great.
This is more for the guys on the forum that want to do some cylinder head work and are not confident I am here to say have a go,Yes there is a cost on materials and equipment but its more about the learning and satisfaction.

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[Fatman]

Did you cut 50deg seats on those valves? How thick is the valve margin now?

[mt-engines]

I don't have a problem sinking the seat to get a top cut.

Depending on your application, you could just run it and not think about it. Often time people over think builds. Especially when it is some street deal with less than 220@.050 Cam.. The non measurable amount of power loss Vs wasted time argument.

[FloydODB]

you can do some really nice custom work with the old stones.

[steve cowan]

Did you cut 50deg seats on those valves? How thick is the valve margin now?

Yes 50 deg on intake and exhaust
Good margin on exhaust valves, a bit thin on the intake 0.040".but is that thin??
I plan on running a meeting and some street miles then pull heads off for a look.

[steve cowan]

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[rebelrouser]

I have only messed with 50 degree valve seats, on heads that have the beryllium copper seats. I have read that 50 degree seats flow less at lower RPM, so if you are not going to spin it over 7,000 rpm, it may hurt rather than help? in messing with my flow bench on some junk heads, seems to back this up. But as I said, I have only ground 50 degree seats on heads that already had them. I do know that a lot of older slow reving engines had 30 degree intake seats, and lots of modern diesels that don't rev over 3,000 rpm have 30 degree seats, kind of back up the idea that the seat angle should match the rpm of the engine.
The other issue is that beryllium copper seats work well with titanium valves, but they also help with the wedging action of a steep 50 degree valve angle. I was under the impression that 50 degree seats cut on regular cast iron heads may lead to seat issues? But as I said never done it myself.
So I am asking the experts if I need to change my thinking?

[steve cowan]

I have only messed with 50 degree valve seats, on heads that have the beryllium copper seats. I have read that 50 degree seats flow less at lower RPM, so if you are not going to spin it over 7,000 rpm, it may hurt rather than help? in messing with my flow bench on some junk heads, seems to back this up. But as I said, I have only ground 50 degree seats on heads that already had them. I do know that a lot of older slow reving engines had 30 degree intake seats, and lots of modern diesels that don't rev over 3,000 rpm have 30 degree seats, kind of back up the idea that the seat angle should match the rpm of the engine.
The other issue is that beryllium copper seats work well with titanium valves, but they also help with the wedging action of a steep 50 degree valve angle. I was under the impression that 50 degree seats cut on regular cast iron heads may lead to seat issues? But as I said never done it myself.
So I am asking the experts if I need to change my thinking?

Yep its a controversial topic for sure but its the road I want to travel,what I will say on the bench is the valve job knocked the low numbers down a bit but fattened up the mid range,this intake port only has a average CSA of just over 2" with a 1.94" valve went to 264cfm at 0.700" @28",tested out to 45" with a victor jnr intake and went 300cfm.
Exhaust 228 cfm @ 0.600" @ 28 and 268cfm at 45"
Very stable airflow and I found this valve job is so smooth and quiet compared to what I have heard in the past,I am not saying it is the be all to end all but it is certainly interesting.

[1980RS]

Hi guys,
Being the novice that i am I wanted to share some photos of my cast iron dart heads,these started as 165cc when I purchased a few years ago they are now 182cc 1.94" - 1.5" valves.
Machine shop flat milled half the top cut away and they went bad on the bench because of that,Tony Knight offered to repair for me but I know he is super busy so I decided to have a go myself,keep in mind the SSR was getting thin when I sonic tested so sinking the valve job and SSR was a serious issue for me.if people want details or to make comments or suggestions that's great.
This is more for the guys on the forum that want to do some cylinder head work and are not confident I am here to say have a go,Yes there is a cost on materials and equipment but its more about the learning and satisfaction.20210126_093607.jpg20210126_094054.jpg20210126_094321.jpg20210126_094539.jpg20210126_094649.jpg20210126_094657.jpg20210126_095146.jpg20210126_095156.jpg20210126_095205.jpg20210126_100024.jpg

Looks dang good to me, props on your work.

[Ron Miller]

Steve,

What are you using to hold and drive-spin the stones? I would like to see that set up. My Sioux electric grinder is gonna need repairs or replacement. I have been thinking about going to a air grinder. Any body else reading this, what do you guys suggest?

Thanks,

[dannobee]

Looks good Steve. I can't tell by the pic, but are the intake valves backcut? That usually helps get back some of the low lift flow. If you have spare valves, try some different angles on the bench. Something between 20 and 30 degrees works. And one trick you can use is marking the seat with dykem, then seeing where it transfers to the valve, then backcut it almost to the mark using the valve grinder.

[steve cowan]

Steve,

What are you using to hold and drive-spin the stones? I would like to see that set up. My Sioux electric grinder is gonna need repairs or replacement. I have been thinking about going to a air grinder. Any body else reading this, what do you guys suggest?

Thanks,

Ron,
Live pilot and adjustable clutch stone holder,I used air die grinder at full speed,touch up stones on my valve grinding machine and cut dry,
Good quality oil on the pilot,this is my first time round cutting seats full stop and I might be doing some things wrong,extremely time consuming but satisfying.i bounce test valve then blue valve and back blue seat and inspect also trying to get the feel of feeling the seat in NWSE positions but will take some time to get proper feel
Hope the photos help Ron.

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[steve cowan]

Looks good Steve. I can't tell by the pic, but are the intake valves backcut? That usually helps get back some of the low lift flow. If you have spare valves, try some different angles on the bench. Something between 20 and 30 degrees works. And one trick you can use is marking the seat with dykem, then seeing where it transfers to the valve, then backcut it almost to the mark using the valve grinder.

danno,
You have a good eye,on the intake valves there is a shadow of 45 cut as the margin was getting close to 1mm so I left it alone,will it affect anything ?? I have not done anything with back cuts and flow bench testing, the Manley intake valve has slight radius cut as per factory make you lose a little bit more in margin area.

[dannobee]

If you have access to a bench, try some different intake valves. And way back when in SS, we would gain flow by cutting the diameter of the intake valve down since by rule we weren't allowed to unshroud the valve by cutting the chamber. The affect was the same and we would just cut the valve down to the minimum diameter allowed by rule. But again, check it on the bench by cutting an old valve. If you have time (and by the looks of it, you have a valve grinder), you can also try a few different angle of cuts (and also two back cuts like 20 AND 30 degree). It really just depends on the port.

If you don't have access to a bench, a modest 30 degree cut on the backside will nearly always help flow on the intake.

On the exhaust side, leave the ski jump there as it normally helps flow (and hinders reversion). I usually check the heads in reverse flow too, just to make sure that we're not helping reversion sneak back in.

[steve cowan]

Update-
Finally got to the track yesterday after a couple of false starts.
Car weighs 3650 with me
11.25:1 comp 383 010 block
Dart cast iron 165cc heads out to 182cc,1.94" - 1.5" valves
Flow 266 - 228 . 50 deg seat intake and exhaust.
Port matched Vic jnr,a bit of plenum work but more to be done.1" tapered spacer and shear plate.950hp carb
Howard's shelf solid roller
241-251 @ 0.050"
1.6 - 1.5 rockers.600"-570" lift
108 lsa in at 104.
1 5/8" tri-y headers
Testing with 30% MS 109/ pump
Turbo 400 with 8"5600 converter
9" rear gear 4.1:1 255/60/15 radials.

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Sampled weather-
82F,29.73",56%H,2344DA,91GOW,0.614VP,64.6DP,1.053CF.

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79F,29.77",59%H,2087DA,87GOW,0.586VP,63.3DP,1.046CF.
First pass is with 30deg timing,shift points 6500 1st ,7000 2nd.AFR reading 11.7 plugs show a bit rich.
2nd pass 34 deg timing, dropped fuel pressure to 5psi from 5 3/4psi,shift points 6000 - 6800 and finish line 6500rpm
AFR shows 12.6 .
I am pretty happy with results considering how basic the engine is and my skill level as a engine guy,plenty of things to try,spacers. Different headers and exhaust, more intake manifold porting, different fuel ratios,go to 4.5 rear gear,different drag radials etc
Any comments welcome.