4.5/4.9 Cadillac V8

[mgb260]

People have asked me my thoughts on porting the 4.9 heads. I agree with David Vizard's theories on porting. 52 percent of bore for max intake valve size and 80 percent of that for max exhaust valve size. This is to prevent cylinder shrouding. That calculates to 1.886 intake valves and 1.509 exhaust valves. SBC 1.84 and 1.50 305 HO valves would be ideal. Unshrouding chamber on outside of both valves and polishing to help prevent detonation at higher compression. Removing cast iron guides and replacing with tapered bottom bronze guides with .500 Viton seals. The floor of the port should be flattened in the corners dropping to the throat and bowl. An old head cut in two for intake and exhaust would be beneficial to see how far you could go. The intake manifold ports that curve around the pushrod hole can be ground out on opposite side to maintain width or a tube pressed in and ground down on that side. If you can get 200cfm intake and 150cfm exhaust at .500 lift, similar to ported SBF or Buick/Rover should support 350HP with the Delta E303 grind cam. Remember to use longer pushrods to compensate for reduced base circle of reground cam.

[mgb260]

Recent thread from Pennock's Forum on John's Supercharged 4.9. Studs and stud girdle. ARP rod bolts. I contacted John for more info. WOW! 52,700 hits on this link!

http://www.fiero.nl/forum/Forum2/HTML/142387.html

[mgb260]

May have found an answer to replace the aluminum tie bars for the rockers. This would be for the V8 not the V6 shown, plus staggered  instead of straight. Ties them all together and prevents rotation.

[mgb260]

If you are using the Delta E303 cam you have to Dremel the rocker slot longer, also tap for longer rocker bolts Like John explains in this thread:


http://www.fiero.nl/forum/Forum1/HTML/098839.html



Broken tie bar pic for thread above. Dremel the connecting piece off and use bottom fixture like above. I will have a prototype laser cut for the 4.5/4.9.

[Johns 4.9]

Jim,
I have been working on this Ford BB 1.7 rocker arm swap also. This is what I have come up. Mounts to the Cadillac rocker arm rail. Keeps the pedestal fulcrum from rotating. I can cut the orange piece out on a CNC plasma cutter.
Cheers,
John

[mgb260]

John, Very Cool! Welcome aboard!

[Johns 4.9]

Thank you, Jim. Its nice to be here!

[Johns 4.9]

Do you think these headers would work in a MG with a Cadillac 4.5/4.9 engine?
Cheers

[Johns 4.9]

Maybe the long tube headers would me a better option for a MG with Cadillac 4.5/4.9 engine.
Cheers

[mgb260]

John the shorty ones with a longer, straighter  collector without flange would probably work good. Most use the RV8 style that goes through the fenderwell. The hole also lets some of the heat out of the engine compartment. Pictures of RV8 style headers:

[Johns 4.9]

Thanks a lot for the pics, Jim. Pretty small engine compartment, I see why they are fender dump headers. And what engine is that for? RV8? I'm new to all these engines.
Cheers

[mgb260]

John, Buick 215/Rover 3.5, 3.9, 4.0 and 4.6. 75-80 have a little larger engine compartment as it was designed to fit the Rover V8. The width of the 4.5/4.9 is almost exactly the same as the Rover V8 at the header flange. It is much shorter though which allows more room between motor and radiator. Simple motor mount idea:

[mgb260]

John have you thought about a oil pan baffle, Cometic MLS head gaskets and/or electric water pump?

[Johns 4.9]

Jim,
Stock 4.5/4.9 oil pan has baffle built in. I'm not real sure about the RWD 4.1 oil pans. Allante 4.5 has a cast aluminum oil pan unique to itself. I can't speak on the Allante pan baffle because I have never seen one of these oil pans live before. I have been pretty happy with Fel-Pro and Victor Reinz head gaskets, but those two are the only ones I will use. Not sure on Cometic MLS gaskets. I'm not a big fan of electric water pumps. Thats one reason I went from SBCs in my Fieros to Cadillac 4.5/4.9 engines. Would the stock Cadillac water pump be a problem in a MG?
Cheers,
John

[Johns 4.9]

Thanks for the info on the Rover RV8. I'm very familiar with the Buick 215 engine, but had no idea it was related to Rover..
John

[mgb260]

John, I've heard the 4.5/4.9 water pump and gaskets are a problem. The GM Delco brand was best?  Do you use gasket sealant and locktite on the bolts? I prefer the old green antifreeze over the Dexcool because it wicks and eats up the gaskets.

[Johns 4.9]

Jim,
The only water pump gasket problem I had was installing it. That was because of user error and a cheap eBay gasket. I just use regular antifreeze. A few of the water pump bolts need sealant or it helps to seal it. I have used a modified 4.1 water pump on a 4.9 so I could run a power steering pump.

[mgb260]

John, Thanks! The 4.1 water pump looks more like a conventional water pump.

[Johns 4.9]

So how about a pic of your ride, Jim? 1973 MGB , 260 Ford V8. Very Cool! Sounds like Sunbeam Tiger inspired!
Cheers

[mgb260]

My73 MGB was originally for the 260 but now I have a 65 Sunbeam Alpine for the Ford V8. I have a 93 4.9 in pieces in my shop in WA. My projects have been on hold the last 6.5 years as I am in AZ working in a Power Plant. 3 more months before I retire back in WA. I have helped a few on this and other boards and plan on a performance parts business similar to yours but not on the Caddy V8. My  parts business will be more to fill the gaps on what other vendors don't offer. I probably have at least a year of home improvement projects first!

[Johns 4.9]

I had an extra 4.9 intake manifold and decided a cross section view would be nice. Perhaps a starting place for a custom intake manifold?
Cheers

[mgb260]

John, Looks like the port spacing is pretty common. SBC and SB Mopar intakes have been modified to fit other motors. Or fabricated
sheet metal intake. Here is a pic of SB Mopar cheap offshore Air Gap intakes made to fit a Cadillac V8. I think you are onto something!

[Johns 4.9]

It would be nice to 3D print an intake manifold for the 4.5/4.9 engine.

[Johns 4.9]

I'm building a set of 180 degree headers for my Cadillac 4.9 V8 engine. These headers will even out the exhaust pulses from left to right engine banks, increase exhaust scavenging and produce more of a European V8 sound. Cheers

[mgb260]

John, Very cool!