Re: Restoring Rusty
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Vortec exhaust ports are raised relative to the header bolt holes compared to conventional heads. The trick is to find headers and gaskets that are "tall" enough. A huge percentage of exhaust flow is at the top of the port so it's imperative not to block the opening. As long as the gasket and header openings are the same size or a little larger than the head ports, you'll be fine. As I recall, 1.5" x 1.5" gaskets will work fine. I used these stock 1997 replacement FelPros on my Vortec heads. http://pic100.picturetrail.com/VOL38.../411015404.jpg And then raised the ports on my cast iron manifolds. http://pic100.picturetrail.com/VOL38.../411015402.jpg An old racing trick where rules limit header primary tube size is to raise the headers on the head. Although this covers up the bottom of the head port, that loss is FAR outweighed by the gains at the top of the port where the denser and higher velocity gasses now have more room to move upwards and outward. |
Re: Restoring Rusty
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Be sure to "lap in" the valves to the seats using valve grinding compound and a tool like this: http://www.summitracing.com/parts/oe...2c4aAoYY8P8HAQ http://static.summitracing.com/globa...5017_jy_ml.jpg |
Re: Restoring Rusty
So a couple of things while looking at your heads just thru the pictures. The valve seat width is WAY to big to be able to lap the seats in. You want the width to be about .060. This is what a proper valve job comes into play to be able to fix this issue. a 30* top angle, 45* sealing and a 60* bottom. The pitting on the valve will need to be addressed and the valve refaced to the proper angle. The valves in your old heads are a little different then the Vortec valves. They have an O-ring groove below the keeper groove. While this will not hurt anything, they are not the same. The price for GM parts is crazy to aftermarket, valves should run you about 5-6 dollars a piece.
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Re: Restoring Rusty
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however I believe those specs are for a performance valve job not stock Super Chevy article Angling For Power says: "Using a dial caliper, we measured a seat width of 0.060 inch, which is a generally accepted street-engine spec." it goes on to say "Narrower seats generally improve flow but are also less durable." |
Re: Restoring Rusty
The below info is from a guy who was involved with Vortec head design and testing. As you can see, a single angle valve job is used only on the HD version of the 906 head for use in 1-ton trucks.
The #906 casting head was available in two versions. One has an Inconel exhaust seat with a single angle grind, and the other has the conventional 3-angle grind on the exhausts as per the #062. The #906 with Inconel seat does not intrude into the exhaust port. It was used primarily on the HD and 1-ton truck applications where sustained towing of heavy loads & weight up inclines could cause eventual damage to a standard induction-hardened exhaust seat from excessive heat. The only difference between the #062 and #906 Vortec head is in the exhaust seat of the HD/1-ton truck #906 version, as described above. The #062 has a 3-angle grind on a standard induction-hardened seat, as does the non-HD #906 head. The 062 does flow slightly better on the exhaust side at low lifts but the advantage over a 906 is very slight. They both utilize back-cut exhaust valves. They both have 3-angle grind seats on the intakes with back-cut intake valves. Both heads make the same power in stock form. Unless Super Chevy mag is now into 1-ton trucks, I'm not sure why they said what they did. ??? |
Re: Restoring Rusty
The pitting on the sealing face of the exhaust valves is typically what you see from higher mileage use. You will have some leakage if not addressed.
I would send the heads out to have the seats recut and the valves ground(valve job). You should not need to buy any valves unless you have one with pits too deep to clean up, stem wear under spec, or bent/out of round. You also need to mic the guide boss OD to see what size seals you need. The ones you showed a picture of may work as they are designed to fit a size range. |
Re: Restoring Rusty
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so feeling a bit overwhelmed with all the cylinder head science and it pouring rain outside I decided to price out some "Complete" brand new Vortec cylinder heads by Chevrolet Performance part number 12558060 to reassure myself I did the right thing by buying used heads, so here we go, follow along if you like this will be fun research.
Summit has the best price: $316.99 each but looking at the pictures these heads sure had a lot of parts missing wouldn't you say? Damper Spring Included: No Rocker Arms Included: No Rocker Arm Nuts Included: No Guideplates Included: No so we gots to add $24.99 for the Rocker Arm Kit GM part number 10089648 times 8 per head so $199.92 extra so our new actually assembled and really complete heads now cost $516.91 and I stole mine for 1/10th the price, though they did come with their own set of [ahem] HEADACHES! ha ha man I sure the good ol' days where we said what we meant and we meant what we say, non of this partially "complete" nonsense, or WiFi ready (I'm looking at you Panasonic) |
Re: Restoring Rusty
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You can not run a guide plate on those heads unless you have them machined for screw-in studs and guide plates. Then you would have to run a non-self aligning rocker arm (early version). |
Re: Restoring Rusty
They're complete heads for an engine buildup. No machine work necessary.
They assume you'll be completing them with shaft mount roller rockers. They're around $240. No need for guide plates with those. |
Re: Restoring Rusty
The valves and seats look fine to me compared to a 110,000 mile engine I rebuilt. Those valves and seats needed grinding, and I just happened to know a guy who worked at a place with the correct machinery who was willing to trade favors.
Just lap the valves and put it all back together. You'll be fine. Lapping would be the first thing I would try anyway. You'll be able to tell looking at them after lapping what kind of seal you've got. |
Re: Restoring Rusty
A $200 (on average) trip to the machine shop for cleaning, crack test, resurfacing, and valve job will have your heads like new, assuming they are not cracked.
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Have you considered conventional heads for use with the intake manifold and valve covers you already have? |
Re: Restoring Rusty - Valve Seals
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The valve seals showed up today GM part number 10241743 got 'em for a song $12.99 on eBay and FREE shipping - good things come in small packages I guess
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Re: Restoring Rusty
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completely disassembled the second head today, the Driver Side
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Re: Restoring Rusty
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lets check out these studs a bit closer shall we
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Re: Restoring Rusty
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ok lets check out the combustion chambers, look closely
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Re: Restoring Rusty #1 Cylinder Chamber
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Noooooooooooooooooooooooo
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Re: Restoring Rusty
Mother trucker
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Re: Restoring Rusty #1 Cylinder Chamber
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Re: Restoring Rusty #1 Cylinder Chamber
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I did call a number of shops in Northern Califirnia and a basic head job runs us $250, thats hot tank, magnaflux, and put back your old parts plus the seals I provide myself, I guaranty you seldom they put your old parts back in |
Re: Restoring Rusty
#1 issue with vortec heads.. cracks like that and you never know till you bought them.
you now need to replace that cylinder head or take it back for a exchange. |
Re: Restoring Rusty #1 Cylinder Chamber
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