Switching from 45 to 50 deg seats - done some testing

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KnightEngines
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Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

Got a rework of an engine I build a while back coming up, it's a 355 holden making around 640hp on E85, we want to squeeze it up to around 670-680hp.
Part of that will be reworking the heads, they currently have aggressive 45 deg seats, I plan to recut them to 50 deg as well as go from 11/32 stem steel valves to 5/16" stem Ti valves.
So I grabbed out a junk head & cut the same 45 deg seat profile & ported it to roughly the same as the real heads.
I flow tested with 45 seats, then recut the seats to 50 deg & refaced the same valves to 50 deg, flow tested again with no grinder work to suit the 50 deg seats, then reworked the port a little to better suit the 50 seat & tested again.
I also flowed it in reverse.
Valve size is 2.055"

Here's the flow with 45 deg seats:

Image20191026_110422 by tony knight, on Flickr

Flow with seats recut, valves refaced to 50, but no other work:

Image20191026_110403 by tony knight, on Flickr

Flow with the port lightly reworked to suit the new seat:

Image20191026_115012 by tony knight, on Flickr


Graphed with all 3 flow tests:

Image20191026_115109 by tony knight, on Flickr


Reverse flowed with 45 seats:

Image20191026_110635 by tony knight, on Flickr

Reverse flowed with 50 deg seats:

Image20191026_110658 by tony knight, on Flickr


Results are promising enough to go ahead & rework the heads off the engine, waiting on the custom Ti valves for now tho.
steve cowan
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Re: Switching from 45 to 50 deg seats - done some testing

Post by steve cowan »

Hey Tony,
Is that the 355 with VN heads??
12.7:1 compression
268/274 -109 solid roller
490 ft/lbs @ 5600
636 hp @ 7600
1.38 ft/lbs per cube
1.79 hp per cube
I am interested in these upgrades
Do you think the engine is capable of 1.4 plus ft/lbs or will you just be pushing current peak up higher to make more hp.
If I remember that engine had a nice flat torque curve.
Same camshaft??
Are you thinking 8000 rpm peak power
Damn getting pretty serious little 355
Did you use same angles as the super stock head you done a while back,
Sorry about all the questions, just gets fun when I see serious builds getting done.
steve c
"Pretty don't make power"
KnightEngines
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Re: Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

steve cowan wrote: Mon Oct 28, 2019 5:15 am Hey Tony,
Is that the 355 with VN heads??
12.7:1 compression
268/274 -109 solid roller
490 ft/lbs @ 5600
636 hp @ 7600
1.38 ft/lbs per cube
1.79 hp per cube
I am interested in these upgrades
Do you think the engine is capable of 1.4 plus ft/lbs or will you just be pushing current peak up higher to make more hp.
If I remember that engine had a nice flat torque curve.
Same camshaft??
Are you thinking 8000 rpm peak power
Damn getting pretty serious little 355
Did you use same angles as the super stock head you done a while back,
Sorry about all the questions, just gets fun when I see serious builds getting done.
Yep, that's the one, with the split in the oil pan fixed & vac up to 12" it's in the mid 640's hp now.
Upgrades are not all set in stone yet, we'll see how the budget holds up.
Those definitely happening are a single stage belt driven oil pump & new external pickup pan - it's apart because the oil pump drive gear was wearing quite quickly. New oil pan is a better design from ASR.
We're also fitting front & rear billet main caps & going up to 1/2" main studs in anticipation of more rpm.
Conrods are being upgraded to something capable of 8500rpm.
Valves are going from 11/32 stem steel to 5/16 stem Ti with the same head size.
The heads will be getting extra port work along with 50 deg seats.
The seats will be the same profile I used in the super stock heads.

Other "maybe" upgrades are Jesel 1.8 ratio shaft rockers to get lift up to .800", if the budget won't stretch that far we'll use a stud girdle with the crane gold rockers.
Cam will likely stay the same, but if the budget will permit it may possibly get a 276/282 on 110 cam.

Carb will go from a 950 to a 1050 & we'll be testing with race e85 & ms109 fuels.

If we can do all the upgrades the final aim will be 700+hp on ms109.
If the existing cam & rockers stay it'll be more like 670hp.

I'm pretty sure it'll do 1.4lb per cube.
If all the upgrades can happen I'd very much like to see 2hp/cube - with oem iron heads & block, single 4150 carb & wet sump.

With all upgrades I'd expect peak power around 7900-8000, holding to 8500, if cam & rockers stay it'll peak around 7600-7700 holding to 8200.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by RevTheory »

This would be a great candidate for a seat-only test as you're starting with a known, good 45. I'm curious how it affected local velocities in the port.
GARY C
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Re: Switching from 45 to 50 deg seats - done some testing

Post by GARY C »

Not a lot of change forward or backwards it will be interesting to see what happens, although once you start changing port work, valve stem, valve train and valve seat design it is all a crap shoot as to what effected what.

You would basically have to make all these changes with your current seat design then switch seat design to know whats what.
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KnightEngines
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Re: Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

Gary - it's not going to be a back to back 45 vs 50 test, it's r&d prep to step up an existing race motor.
I gained 7cfm at .700", that will translate to at least 10hp on this motor.
I'm looking for small gains in a bunch of places to add up to a significant gain.
When you're at 640hp from 355 cubes with oem heads there is no low hanging fruit, gotta refine things to see gains.
cjperformance
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Re: Switching from 45 to 50 deg seats - done some testing

Post by cjperformance »

Looks like this will be a rewarding fine tune/rework on this engine Tony. Just the small refinements in peak flow and reduced low lift reverse flow are respectable gains. Lighter valves, and the possiblility of a faster rocker and the extra lift should comfortably get you to where you want to be. Im sure that during strip down and inspection you will find other finnicky little things you'll want to alter.
I really like these builds based on OEM block/heads, so much more interesting and rewarding than just bolting on catalogue parts, but as you well know a hell of a lot more work!!
Craig.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by ClassAct »

KnightEngines wrote: Mon Oct 28, 2019 1:13 am Got a rework of an engine I build a while back coming up, it's a 355 holden making around 640hp on E85, we want to squeeze it up to around 670-680hp.
Part of that will be reworking the heads, they currently have aggressive 45 deg seats, I plan to recut them to 50 deg as well as go from 11/32 stem steel valves to 5/16" stem Ti valves.
So I grabbed out a junk head & cut the same 45 deg seat profile & ported it to roughly the same as the real heads.
I flow tested with 45 seats, then recut the seats to 50 deg & refaced the same valves to 50 deg, flow tested again with no grinder work to suit the 50 deg seats, then reworked the port a little to better suit the 50 seat & tested again.
I also flowed it in reverse.
Valve size is 2.055"

Here's the flow with 45 deg seats:

Image20191026_110422 by tony knight, on Flickr

Flow with seats recut, valves refaced to 50, but no other work:

Image20191026_110403 by tony knight, on Flickr

Flow with the port lightly reworked to suit the new seat:

Image20191026_115012 by tony knight, on Flickr


Graphed with all 3 flow tests:

Image20191026_115109 by tony knight, on Flickr


Reverse flowed with 45 seats:

Image20191026_110635 by tony knight, on Flickr

Reverse flowed with 50 deg seats:

Image20191026_110658 by tony knight, on Flickr


Results are promising enough to go ahead & rework the heads off the engine, waiting on the custom Ti valves for now tho.


What angles did you use? I usually see a much bigger loss in reverse flow. You didn't loose very much.
KnightEngines
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Re: Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

Yeah, I had an aggressive 45 seat in there that behaves pretty close to a 50, 38/45/65/80 with a big throat. Gone to 45/50/65/85 with similar throat.

We're doing the 1.8 ratio jesel rockers, which will take it from .700" lift to .800".
We'll also be trying ETS Z85 fuel.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by ClassAct »

KnightEngines wrote: Tue Oct 29, 2019 9:43 pm Yeah, I had an aggressive 45 seat in there that behaves pretty close to a 50, 38/45/65/80 with a big throat. Gone to 45/50/65/85 with similar throat.

We're doing the 1.8 ratio jesel rockers, which will take it from .700" lift to .800".
We'll also be trying ETS Z85 fuel.


So what did you have for a throat with the 45...88-89%? I think that 50 will only get you 90% or so, so yeah, hat makes a bit more sense.

And if you are back cutting the valves, and/or using nail head valves you'll see more reverse flow than no back cuts and tulip valves. I always try using tulip valves with a 50 degree or steeper seat. I'd rather give up some forward flow to get a bigger reduction in reverse flow.
KnightEngines
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Re: Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

I don't have the actual valves yet, still about a week away.
When I get them I'll start on the actual heads with before & after flow tests.

My main aim was to see what we could gain given the bowls are pretty much maxed out already, there is not enough metal to reliably go to a larger throat so I was concerned that the gains would not justify the work with the same size throat.

Gains on the actual heads should be bigger as it currently has 11/32" valve stems.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by cjperformance »

Ah ! I was going to ask earlier if you were already running undercut stems but assumed(never do that!) that you would be.
Craig.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by steve cowan »

Hey Tony,
Wondering if the parameters changed much when you plugged it to pipemax
I purchased the latest version from Larry a couple of weeks ago
Really amazing information, can't get off it at the moment :D
steve c
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Re: Switching from 45 to 50 deg seats - done some testing

Post by KnightEngines »

I've got it, but I still default to the older version, it's quicker & tells me what I need to know in 2 minutes, the rest just sorta fills itself in once you've built enough of the same type of engine that you don't have to think about it other than to make it do something a little different to others.

This one I just need to peak a little higher in rpm while maintaining current peak hp ve%.
I also need to cut power wastage from parasitic loses & speed combustion to allow higher peak rpm.

It'll be on the dyno in roughly 4 weeks I reckon.
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Re: Switching from 45 to 50 deg seats - done some testing

Post by BradH »

KnightEngines wrote: Tue Oct 29, 2019 9:43 pm Yeah, I had an aggressive 45 seat in there that behaves pretty close to a 50, 38/45/65/80 with a big throat. Gone to 45/50/65/85 with similar throat.
You've done reverse-flow testing w/ that 45* seat config vs a "less aggressive" 45* seat config? If so, anything you could post? Thanks - Brad
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