Some "Dynomite" Heads!

[GOLDCYLON]

Originally Posted by Locobob

Dr. Evil says:
One Miiiillion Dollars..... Muuuuhaahaa Muuuuhaahaahaa

Hmmm and One Miiiiiilion Horse Power

[GOLDCYLON]

Originally Posted by Locobob

Made a little trip out to the powdercoaters yesterday....

LT5 porn I love it

[Locobob]

Originally Posted by LGAFF

Siamese: 235-240cc
Stock: 180-185cc

Lee

Full 36mm Injector housings are about 215cc

My partial siamese came in around 220cc

The 220cc partial siamese IH's along with my B port plenum raised hp to 480rwhp but lost some low/mid range torque on my 368. Your full siamese at 235 is really wide open in comparison - probably more appropriate for a stroker I would think. It'll be interesting to see how your project turns out.

[rhipsher]

Bob! I have a question. Are the head ports pretty much striaght down perpendicular to the face of the head. Because unlike the plenum and the injector housings which are curved." Those head ports look straight. Its got me thinking and stroking my chin. I'm thinking of a way to port the heads on the CNC mill with as little hand work as possible. Figuring out the bore taper angle from top to bottom isnt a big deal. I'm thinking a lolipop shaped 1" dia endmill. Writing a program that spiral feeds down the bore as close to the bottom as I can get. Then finish the rest by hand. You want to talk about fast. Accurate and with any finish you could desire. This would be it. But you can also scrapp them real fast. Id rather try it on a set of trashed ones first to be sure. And next would be mine. But the bores look pretty symetrical. But since you, Paul and Pete have already been there and done that you can tell me if my assumptions are correct. Because I have incredible capabilities to make it happen. Top notch software and top of the line CNC equipment.
I'm not looking to take anybodies bread and butter away from them. I would just do it to my own ZR-1 thats all.

[Locobob]

The majority of the head intake port is relatively straight. You could pretty easily do the area above the valve guide with a CNC program. Once you get close to the valve guide you need to transition into more of an oval shape (width wise) for better airflow and to avoid expensive problems. The exhaust side would likely be a bit more challenging to program. I think Pete has done the CNC route - might ask him about it.

[Locobob]

The heads are now at the machine shop - pressure tested good, seats and valves cut, decking to bring chambers down to 39cc. I managed to space off getting new valve seals but Jerry's Gaskets fixed me right up, amazing quick and efficient service - Thanks Jerry, you are terrific!

[4DSZR1]

Sounds like you're getting close to putting the engine back in....cool

[Paul Workman]

Originally Posted by Dynomite

Sounds super especially the pressure testing

Sounds good so far! I recon Bob already knows this, but just a thought:

Marc told me he recommends throwing in a pellet of that powdered walnut stop leak (available from a GM dealer) into the coolant, "for peace of mind". A vacuum test is needed to verify no oil seepage near the spring seat. If there is, Locktite 620 applied while the runner is under vacuum will draw the goop into the leak(s) seal any minor seepages. Or, Bob G has a line on some aluminum based sealer that has been used by some racers. (Maybe Bob or Pete can reveal their "better mousetrap", namely the maker and part number of the aluminum material he used to cure an oil seeper.)

Then the nail biting begins until you have several heat/pressure cycles behind you. Marc says if it doesn't spring a leak after about 500 miles, then your probably "good to go".

Just hope Bob ain't charging ya by the hour!!



P.

[-=Jeff=-]

I did not think marc did anything for the L98 as far as PROM/Chip recalibration's were concerned

[Paul Workman]

Originally Posted by Dynomite

I would hesitate using stop leak or aluminum based sealer if there are leak potentials. I will just pull the heads at that point. The trick is to determine if there are leaks with either water in oil, water in exhaust, oil in water or oil in exhaust. I am using Randy's ARP studs vice head bolts so I can pull the heads as many times as required. Something about torquing Head bolts into aluminum several times that is an issue which using ARP studs eliminates

I am picking the heads and other top end up in a drive by vice having them shipped UPS which should save some money for that hourly charge

Paul....as I recall...you have heads ported also....how did you check for leaks of any kind (confirming you had no leaks) and did that potential really concern you?

I am assuming you used new head bolts vice ARP studs?

Marc will have two EPROMs coming his way for recalibration (one 90' L98 and one 91' ZR1).

Maybe two 91' ZR1 chips...one for 87 octane and one for 91 octane

Testing was done before installing the heads!! NO way would I be interested in installing LT5 heads (whole engine has to come out) before attaining some confidence thru preliminary testing.

Understand this from a neophite under direction of FBI gurus (an expert I ain't and don't pretend to be!):

Coolant leak: I pressure tested the water jacket using Pete's homemade steel plate jig and RTV to block off the combustion ports and testing by spraying some detergent down the holes and looking for bubbles/foaming while applying 30# air pressure (thru a standard air hose nipple mounted port on the jig).

Oil leak: Sealing the runner at the combustion chamber and applying vacuum thru the valve guide, a piece of plexi sealed with an O ring over the runner allows one to observe the runner for bubbles/foam the same way - using soapy water to observe bubbles in the runner AND monitoring the vacuum gauge on the "Mitivak" - the "acid test", so to speak.

Yes, the head bolts were re-used. Pete has reused head bolts many times without any problems. (The bolts in the 90 are massive SOBs - weighing something like 24# for the bolts alone!)

FWIW,

P