thomas1976

Just received, SUM-162108 170cc intake/69cc exhaust, 62cc chamber, 2.02 int/1.6 exh valves, aluminium heads.

They are going on a rebuilt 350 around 9.8:1 CR, with a roller, 480/488 lift, 206/212 duration, 112 LSA from comp cams.
The obiective is not the fastest, but a fun DD street strip car.

Atilla already pointed out to polish the exhaust ports, I will do it.

Also plan to smooth the machinning edges in the bowls just beneath the valve seats, like desribed in the "Engine blueprinting" by Rick Voegelin.

In the combustion chamber, around the valves there is a approx. .020in edge/step, I put it in evidence with a marker pen. Does it need too be smoothed out?

thomas1976

.

thomas1976

http://www.summitracing.com/parts/SUM-162108/

thomas1976

Looks like some surgery is needed.

See the "edge", approx. 0.080in from the valves, that goes all around the valves?

thomas1976

This sums it up https://www.thirdgen.org/forums/engi...sbc-heads.html thanks Atilla!

thomas1976

More details.
On the 4.060 bore the intake side of the combustion chamber is a little shrouded, approx. .040-.060in.

Atilla the Fun

Pretty heads. But the shrouding issue is not a problem. See, the de-shrouding cuts were done to match a gasket for a 400. Dumb, but there's nothing you can do about it, so just pretend it's not even an issue.
As for the machining ridge, it'd be great if you can polish it away, but you must remove the valves to do so. So, to protect the seats, take a tip from that Doom guy and use some Gorilla tape. Be sure you protect not just the 45 degree seats, but also ALL of the 30-degree angle. If you mess up the 15-degree angles, it's nothing to cry over.
And I think you're gonna wish you'd gone one size larger with the cam. 212/218-112, 488/495.
Those chambers look like they'll be easy to polish, just keep in mind you're not wanting to reshape them. Polishing will reduce carbon buildup, so it'll fight detonation that way. Polishing will also keep more heat in the chambers, and that would seem to invite detonation. Well, it does. Another reason to step up the cam. But it will help mpg slightly as well.

thomas1976

Grinding away the dumb machining ridges around the valves, was scary.

This is probably anough cleanup/grinding for me, did both heads, time to reassemble with comp cams valve springs.

Atilla the Fun

It's one of those things that if ever it doesn't intimidate you, you're too jaded. As it is, you're not ready for reassembly. I'm about to re-post your pic, this time with some colored outlines, so I can point out the issues. Plus you didn't polish the chambers.

Atilla the Fun

In the blue circles, that's too ragged, you're creating too much turbulence, where it doesn't belong.
In the red, WTF?! You were supposed to be grinding that smooth.
In the green, we see that you didn't actually help the ridges enough to think about. Very 1/4-assed.
Yellow A = too rough. Yellow B = inconsistent. Yellow C = not done enough. Yellow D = Where's your polishing?
Tell ya what. Ship them to me, for $30 I'll make them right. Plus you pay shipping both ways.

thomas1976

I like your attitude

Thanks for the directions/advice, I couldent finde good porting tools locally, will do whats possible.

Appreciate your offer, but shipping alone will end up like a new set from summit.



Edit: Concerning "Yellow D", the whole exhaust port should be polished much more then I did, the combustion chamber can be polished too but does not need to be a mirror finish.

Atilla the Fun

Okay.
Get a 4" mandrel and a bunch of 120 grit, 3/8" "tootsie rolls", and put the carbide away. First set aside 8 rolls for chamber work, and don't use them for anything else. Then re- gorilla tape the seats. Start with the exhaust ports, since they're easy. This'll give you a feel for what you're doing, and build your confidence.
From there, move on to the chambers. Start with the issues in the green and red outlines before moving on to polishing.
By this point, you should be good to address the intake ports. Those blue circles are in the long side, where minimal polishing won't hurt much. Just keep your rolls away from the short turns.

Twin_Turbo

iTrader: (25)

He probably wont be able to get those easily in Switserland, better buy a standard abrisives kit somewhere.

Atilla the Fun

My apologies, I never even stopped to see where this was happening.

thomas1976

The cleanest I can get them.

Doom86

do they not sell industrial abrasives in Switzerland or something? The stuff I found at the local industrial supply store was better then the crap in my SA porting kit.

Atilla you are a great help with the porting advice.

That exhaust port looks a bit a rough yet. Good effort though.

Atilla the Fun

First, thank you for going back and doing better. Your intake port looks very good. What you did of the chamber looks good enough. What you did of the exhaust port is excellent, but it looks like you didn't even try polishing the guide boss. There's still another 10 cfm there. Go in through the valve seat.
Then you'll be done. Polishing is tedious, but depending on the rest of your combo, there's still up to 20 more free HP waiting for you to unlock. More than 30 if using a power adder, like nitrous or boost. Please go at it one more time, as just described. You can do it. I can tell by what you just posted.
Doom, thank you for the compliment. I'm just trying to help my fellow enthusiasts get the best results they can, for the least money possible.

thomas1976

I dident anticipate well anough, could have ordered the proper tools, but dident expect that much work for a cleanup.

I only have 120 grit flapweels and even the smallest worn ones cant go any deeper/closer around the walve seats, used the carbide cutter as good as possible.

The polish weel I found disintegrated in less then 10 minutes.

Atilla the Fun

Even the best rolls don't do well when run at maximum rpm. I generally run my air tool at about 2/3 speed for most polishing. You might find it easier to adjust your regulator down to a lower air pressure.

Doom86

I find flap wheels and the polish wheels just about useless. You have to use some sort of lube (LW machine oil, WD40, ect) to make the wheels not tear up so fast, it helps polish too. They are so bulky and awkward though it's impossible to get them in the tight spots they need be.

Atilla is spot on about the cartridge rolls, running my grinder at 50% will shred a new one in seconds, while if the speed controller is turned down to 25% it will last for as long as it still has grit(at that time I trash it my self). I'm using an electric grinder with speed control. I don't know how you guys do it with air grinders; the first set I ported with one and I found it way more difficult to control then the elec one and most my focus was on controlling the tool and not the porting. (those percentages I'm quoting I don't think they in relation to 0-100% duty since my dial doesn't go to 0%, it's a percentage of where the dial is in it's range)

Atilla the Fun

I've tried polishing with WD40, it makes the same job take 4 times as long. WD40 is great lubricant for porting aluminum, but I polish dry. And my rolls never shred. The far ends usually wear away, turning a cylinder shape into a cone shape, but that's mostly because of what I'm doing, not bad rolls. The rolls last for hours unless I'm doing sharp edges. Running the rolls too fast or too slow leads to bent or broken mandrels, also called arbors.

Doom86

The sharp edges do make a huge difference I always run slower in the bowls, port openings, ect then in the common wall floor area. I can run the bigger rolls quiet fast in that area actually.

Yeah they don't actually "shred" (just using colorful language) they come unrolled at speed for me. That's both with the SA porting kit rolls and the brand from the local industrial supply store.

I do like different rolls for different parts of the heads. The one's I use most though are the thin cylinder shaped (look exactly like the pictured one in Atilla's head porting thread), and a shorter wider tapered roll.

Johnny Blaze

iTrader: (15)

Did you ever get the heads on?

thomas1976

Yes, have been using them for almost 2 years now.

With 700r4, 3.23 gears, all possible options, full fuel tank, medium tool box in the trunk, one heavy passenger it beats stock ls1 4tgens and GTO's by about 1 to 3 car lengts after around 1/4 mile




Edit: here is some information from the Car Craft September 2012, techarticle I just found
http://www.carcraft.com/techarticles.../photo_10.html

"Summit

Long acknowledged for offering house-brand cylinder heads for an affordable price, Summit delivered a solid Fourth-place finish in terms of both peak and average power, but keep in mind that, while not a podium finish, the difference between First and Fourth is a relatively small margin. We call out some very small differences that would be difficult to distinguish in back-to-back tests in a car. Plus, the Summit head was worth a solid 34 hp over the stock iron heads. That’s power you can feel in the seat of your pants.

Summit PN 162109, $995.95
Peak HP 405 at 5,900
Peak TQ 416 at 4,400
Valve Sizes 2.02/1.60
Intake Port 170cc
Chamber 62cc
Valvesprings 1.250-inch single spring

Read more: http://www.carcraft.com/techarticles...head_shootout/ "

"Horsepower Chart
RPM-----Stock---Vortec---Edelbrock---Summit---Speedway---Jegs---Dart---Patriot
3,600....270.......270.......264............268.........270............275......272.......275
3,800....270.......289.......285 ...........287.........289............296......295.......292
4,000....288.......307.......308 ...........311.........309............317......315.......314
4,200....303.......325.......327 ...........331.........327............336......333.......333
4,400....317.......341.......341............348.........340............351......347.......348
4,600....329.......351.......354............361.........352............362......362.......362
4,800....336.......362.......366 ...........374 .........362............374......374.......376
5,000....343.......371.......375 ...........384 .........370............383......384.......387
5,200....350.......376.......382 ...........392 .........378............391......395.......398
5,400....354.......378.......386 ...........399 .........381............399.....406.......406
5,600....356.......376.......390 ...........402 .........380............403......411.......412
5,800....358.......370.......394 ...........405.........380............407......413.......418
6,000....355.......360.......395 ...........403.........381............408.....419.......420
6,200 .....--.........--..........--..............--............--..............--........417.........--

Avg.----325.5----345.7----352.3--------359.7-----348.5 --------362.7----364.4----365.4
Peak----358------378------395----------405--------381-----------408------419------420

Horsepower Graph
Overall graphs often do not show enough detail to give you a clear picture of the results. Rather than create a graph of the entire power curve, we decided to produce just the curve from 4,500 rpm up through peak horsepower. Here you can see how each cylinder head performed from roughly peak torque through peak horsepower.

Peak Torque and Horsepower
Cylinder Head---Peak Horsepower---Peak Torque
Patriot..............420 at 5,900 rpm...417 at 4,300 rpm (2)
Dart.................419 at 6,200 rpm...417 at 4,200 rpm (2)
Jeg’s................408 at 5,900 rpm...421 at 4,300 rpm (1)
Summit............405 at 5,900 rpm...416 at 4,400 rpm (4)
Edelbrock.........395 at 5,900 rpm...409 at 4,200 rpm (5)
Speedway........381 at 5,400 rpm...409 at 4,200 rpm (5)
Vortec.............378 at 5,300 rpm...408 at 4,300 rpm (7)
Stock Iron........358 at 5,800 rpm...379 at 4,300 rpm (8)

Read more: http://www.carcraft.com/techarticles...head_shootout/ "

"Cam Specs
Camshaft, Summit (PN 1105) Duration at 0.050 Valve Lift (With 1.6:1 Rocker) Lobe-Separation Angle
Intake 224 0.465 (0.496) 114
Exhaust 234 0.485 (0.517)

Read more: http://www.carcraft.com/techarticles...#ixzz2Q67BeY4X "

Johnny Blaze

iTrader: (15)

Good to hear, I was set on going to a vortec swap, but for the price of heads and intake, I can get these heads and still have cash left over!

acr

Thomas, thanks for the info. & great pictures. I noticed those Summit heads are on sale now for just over $900.00! Thanks to Atilla for the advice.

thomas1976

Little update, I had the engine out due to oil pressure dropping under acceleration, short story, the oil pump pickup came off and was laying in the oil pan.

Inspecting the heads I found burned oil in the combustion chamber and on the top of the valves, so I decided to change the valve seals + valve locks and PCV + rubber grommets.

Valve locks part # TFS-51400444 (7 degree for 11/32 in. Valve Stem, the black ones in the pics)
Valve seals part # TFS-30400454 (0.500 I.D. for 11/32 in. Valve Stem, the blue ones in the pics)

The old Valve Locks were really stubborn to get out ouf the Retainers, I had to use the following technique to break them loose
(at around 4 minutes)

thomas1976

The real world results https://www.thirdgen.org/forums/tbi/...imple-fun.html

acr

Summit has these on sale now, I just bought a pair for $995.97 with free shipping. Remember there are two models of these heads:
#SUM-162108 has center bolt mounting location.
#SUM-162109 has perimeter mounting location.

thomas1976

Hi there, all the porting information is above in post #11.
All I did to the heads is: "porting" it's more a clean up really, replaced the valve springs to match the cam, replaced valve locks and valve seals.