Engine and Transmission Tech

Trying to decide on a new cam for my 4.6L. While I found the post with the quad carbs interesting its above my level of knowledge.
With a stock 4.6L (9.35 CR) with 28cc heads and FI cam from a 3.9L, I find the idel fine but the cam runs out of steam too early for a sports car. This is with a Buick manifold and Edelbrock 500 cfm carb. I plan to install 14CUX FI this winter and change the cam while I am at it. Appears from my searches that anything above 0.430" lift will cause interference with th valve guides etc. As long as the heads need to come off might as well port them etc. I have read about the V8 Development’s "Warrior" heads and am interested in something along those lines. Larger valves, port and polish. Can anyone recommend a shop in US or CDN for this? Idea of $$.

[www.v8developments.co.uk]

Back to the cam. What lift can be used before the piston tops require cutting? How far can one go on lift and duration before the Rover FI throws a fit? I have an upgraded ECU from Randall Smith, if that helps. With MS I assume we can go much farther, again any limits? Keep coming back to a Crower 50232 or maybe 233 but will it run with FI? Not interested in a loppy idle and want it to pull strongly to 6000 rpm. Basically I want 300 ft/lb and 300 hp. Maybe I am asking too much here I don’t know. Woddy's roller cam looks nice but is it really needed for a street driven car. Car is an MGB with T5 and 3.27 Ford 8".

Don't beat me up too bad here! Am I dreaming or can this be done without TA Performance heads, HR cam etc?



Edited 2 time(s). Last edit at 11/28/2013 05:24PM by mstemp.

Mike, I'm running 10.6 pistons in my 340 with 300 heads and a .500 lift cam and valve to piston clearance clayed out to a quarter inch. Pistons are zero decked so I doubt you have any worries about piston clearance. You can also get light weight springs to use in checking clearance.

Some of the cam grinders have a tool you can rent that chucks up in an electric drill and you use it to cut down your valve guides without removing the heads. That'll let you get enough lift from your cam.

Jim

Mike, I had the Crower 50232 in a 215 years ago. A little big for the small motor and a little small for 4.6. Be about right for the 3.9/4.0. The 50233 would be just right. Cutting the guides down for Viton seals is no big deal. The 4.0 pistons used in the 4.6 block will raise compression to over 10 to 1. Smaller dish. The 86-93 GM 2.8 and 93-95 GM 3.4 V6 valves (1.72 IN and 1.42 EX)are a size up and would need new seats. Alex's Parts has seats cheap and Vortex Chevy beehive springs also. The Vortex Chevy has the same guide problem. For the fuel injection Glenn Towery recommends at least 112 LSA which the 50233 has. I would call Delta Cams and get a similar regrind off your old cam with 114 LSA. Hap and Dave Headley use Delta Cams and Bill Jacobsen uses one in his beautiful Supercharged B.



Edited 1 time(s). Last edit at 11/28/2013 09:43PM by mgb260.

Jim N,

Thanks. Are you saying do a similar grind to the 50233 on my 3.9L cam with the wider LCA? With shipping and all might be easier to have Crower do a new one. I assume they can create the 114 or is that formed in the blank when cast?
I will have to look up the vortex beehive springs.

Anyone know a good porting guy?

Thank,
Mike

Crower can do it but, about twice as much as their stock grinds. Call Delta and compare price. The wider LSA helps idle and vacuum. I would still advance the cam 4 degrees to move power band down.

Mike,

Excuse my ignorance here if you have already thought of this but be warned that the14CUX prefers a stock cams, or very close to stock. I have a 112 degree lobe separation on my grind and am getting idle fluctuations and slight surging under acceleration (timing, etc. has all been checked). Glenn Towery is convinced it's because of my cam because the 14CUX system seems to like cams with less than 112 degree lobe separation. Here is a link to the thread that talks about cams for the 14CUX system:

[www.mgexp.com]

Chris,

I think you mean 112 deg or more, not less LSA (hence the 114 as Jim mentioned). Also you must consider that I am 4.6L not 3.5L, this should make a large difference. I am no expert either when it comes to cams etc, hence why I looking for advice from Jim x2 and Dan Jones etc. I also do not have a stock 14CUX ecu but one that has been chip which I hope helps. In the end if this does not work I will stay with my edlebrock 500 CFM or use the FI hardware with MS III.

Did you ever find you cam data card? Would be interesting to see it.

Oops, yes Mike you are correct! I don't have the card in front of me but I am pretty sure I eventually posted all the specs on the MGE thread.

How would a difference in displacement solve this issue out of curiosity?

Cheers,
Chris

Chris, I think Mike means the same cam that would be too big in a smaller engine would be milder in a larger one. Hey did you score on the parts? Going to work now and the plant blocks this site but allows the Mgexperience.

Ah, I see. This is still all pretty new to me. I just didn't want Mike to run into the same issues I have.

Yes, I bought that crank and rods. Next is pistons and then it's off to the machine shop.

> Can anyone recommend a shop in US or CDN for this? Idea of $$.

Jon Carls of JDC Engineering in Minonk, IL hand ported my Buick 300 heads and did a good job. To properly port the Rover and Buick heads, the guides need to be removed to make room for the cutter. Depending upon the valve diameters chosen, you may also need to install larger seats. When I had mine done several years back, cost was $1050 for the complete Stage III porting, machine work, guides, valve job, etc. Valves, seats, guides and seals were extra. Last time I tlked to him, his labor cost for Stage III porting was still $1050.

> looking for advice from Jim x2 and Dan Jones etc.

I happen to have flow data for a set of 3.9L Rover heads that were treated to several levls of porting. I ran those through Dynomation (HP scale is on the right, torque on the left):



The bottom curve reflects the prediction for unported heads, Rover EFI intake manifolds, long tube headers, 10:1 compression and a Crower 50232 cam. Total intake tract length assumed is 15 inches. 10.5 inches of that comes from the EFI manifold (manifold face to stack bellmouth opening) and 4.5" comes from the head (manifold face to valve head). Note torque prediction is generally optimistic (20 to 50 ft-lbs) in Dynomation but HP is fairly close. I don't have any real dyno data for this configuration to fine tune the simulation so it's best to use the results for comparison value, not absolute numbers. The second curve from the bottom is for a set of lightly ported heads and the third curve is for a set of heavily ported heads. The top curve is for the heavily ported heads and a Crower 50233 heads. I did a quick cut at a custom cam for the ported heads an it was worth another 10+ HP above 4500 RPM:



Note the ported head numbers also assume the lower EFI manifold has been ported and the throttle body flows 600 CFM at 1.5 inches of Hg.

I happen to have a new-old-stock 4.2L Rover long block, along with a 3.9L Rover EFI system and Crower 50232 and 50233 cams on hand. I've thought about porting the lower intake and a set of Rover heads, along with a pair of steel shim head gaskets to up the compression ratio. When you start talking about 300 HP, you're going to be well off the assumptions used in the Rover EFI tables, even if you use a cam with 114 degree lobe centers, so I assume I'll need to use a different programmable ECU (Megasquirt, Ford EEC, etc.).

Dan Jones

Just a note which could be important. The guides in at least some BOPR/Buick heads as they come from the factory are not concentric because the blanks are pressed in and then machined in place. So if you press out the guides you lose registration with the seat. This may not be a problem if you plan to cut the heads for oversize seats anyway, and especially if you intend to modify the centerline spacing. But if you want to keep the original seats the preferred renewal process seem to be to sleeve the guides rather than replacing them.

Jim

Dan,

Great information, thanks very much.
Now to differentiate all the data! Interesting the Torque of the 50232 vs 50233 with the Stage 4 heads.
Not sure on the FI upgrade ECU I have. Not been able to contact Randall Smith who performed the upgrade so can't know what it will be capable of. Likely MS will be needed to get above 250 HP.



Edited 1 time(s). Last edit at 12/01/2013 04:57PM by mstemp.

Great info as always, Dan!

Both Crower cams are good but I thought there would be more difference between the two. The 50232 looks slightly better under 4000 RPM and very close to 5000. Evidentaly you don't gain much with the higher lift. Probably limited with the smaller ports and valves on the Rover heads. Dan, could you do a similar graph comparing the 300 heads ported,bigger valves. Maybe one for Chris's 300 stroker(350 crank and rods).To me looks like Mike would be happy with the 50232, but Chris's larger displacement would like the 50233 or equivilant. Also,WOW, look at the difference the porting made!



Edited 1 time(s). Last edit at 12/02/2013 06:31AM by mgb260.

> Interesting the Torque of the 50232 vs 50233 with the Stage 4 heads.

Remember the peak torque values are likely optimistic but the differences between the two should be realistic.

> Both Crower cams are good but I thought there would be more difference between the two. The 50232 looks slightly better under 4000 RPM and very close to 5000. Evidentaly you don't gain much with the higher lift

These heads peak (flatten out) at around 0.450" lift so a bunch of lift isn't necessarily a beneficial as it might be. The duration and lobe centers are more important here. When comparing cams, I like to look at the area under the power curve between shift points. That's what maximizes acceleration. Below that you're mostly at part throttle and more interested in how well the engine behaves.

> Dan, could you do a similar graph comparing the 300 heads ported,bigger valves. Maybe one for Chris's 300 stroker(350 crank and rods).



Bottom HP line is the Rover 4.6L with Stage 4 ported Rover heads and Crower 50233 cam. Note that it is a bit different from the previous plot as I found an error in simulation. Next line up is the 4.6L Rover with Crower 50233 cam and Buick 300 aluminum heads (Stage 3 hand porting by Jon Carls). Both assume a ported EFI lower and throttle body of 600 CFM. Next up is Buick 350 cubic inch Buick 300 stroker (3.8" bore by 3.85" stroke) with the ported Buick 300 heads and Crower 50233 cam. The top line is the same engine with a cam I designed to give best power between 4000 and 6500 RPM. Both Buick 300 strokers assume 11:1 compression, a ported Buick 300 dual plane intake (Extrude Honed with spacer) and 800 CFM of carb flow.

Dan Jones

Thanks Dan! Is your custom cam straight up? What LSA?

Very interesting Dan! Thank you.

It looks like some porting is in my future...

Mike,

In Europe the Tornado camshaft (grinded by Comp Cams) of Real Steel is quite popular for the RV 4.6 in light weight cars, such as the MGB.
Duration of the Tornado is @ 0.050" 224/231, lift 0.508"/0.512", LSA 110 so its more or less a compromise between the Cowler 50233 and 50234.
I used this cam on a 4.6 with standard 4.0 pistons, stage 3 RV 4.6 heads with CR 10.3, Edelbrock performer inlet manifold and Edelbrock/Weber 500CFM carb, and got 298 bhp at 5750 rpm on the dyno.
Now it will be build up with Merlin heads and EFI manifold to see if there are any improvements.
Pistons are the standard 4.0 Rover pistons without valve cutouts, which will increase compression ratio with about 0.5 CR.
The tuning of the ECU 14CUX is very restrictive so I will probably use the Mega Squirt stuff.
Seeing the dyno graphs of Dan Jones it seems that the Cowler 50233 would be the best choice as it would give good performance and at the same time you will be able to cruise around.

Cheers
Rik

Interesing Rik, I have a Tornado cam that I want to try with the Merlin heads. I am currently using the Typhoon cam with the practically same setup as you (except single plane intake and Merlin heads). I have had the Tornado for 3 or 4 years but never got around to swap the cam. Will swap it during the winter :-)