Sprintex on a 4.6L Stroker

[Russ Pottenger]

I think you'll find out that Comp won't have a late core, but doesn't hurt to ask.

I keep in stock to custom grinds that I think could work for you.
68-235-4 and 68-239-4. Rather than the 111° lobe separation angle, they'll put it on 113°
Another recommendation would be to add the nitride heat treat to the camshaft. It'll add $118.00 to the cost of the custom grind but it's well worth it.

The cost of either camshaft with the nitrite is $298.00

[Mopud]

I think you'll find out that Comp won't have a late core, but doesn't hurt to ask.

I keep in stock to custom grinds that I think could work for you.
68-235-4 and 68-239-4. Rather than the 111° lobe separation angle, they'll put it on 113°
Another recommendation would be to add the nitride heat treat to the camshaft. It'll add $118.00 to the cost of the custom grind but it's well worth it.

The cost of either camshaft with the nitrite is $298.00

Thanks a lot, Russ. The lobe separation at 113 is exactly what i'm going for - the specs of the 239 look good when combined with that, i'm just not sure yet where i want my power band to be. And absolutely I will be getting it nitrided, the extra cost doesn't bother me for what it gives you in the long run.

[dwg86]

looking at your pictures and the way the pin has worn into the timing cover, I don't understand what could have caused the cam to have so much pressure pushing it forward?
Did that cover have the bump for the pin to ride on?

[jasonb]

Were the oil pressure relief holes in the #4 cam journal as they should be?

[Mopud]

looking at your pictures and the way the pin has worn into the timing cover, I don't understand what could have caused the cam to have so much pressure pushing it forward?
Did that cover have the bump for the pin to ride on?

Sorry for the delayed response, i didn't catch the alert in my email and haven't made any progress with the build.

Yes the cover had the pump, you'll see in the pics that the bump wore away. It was only an aluminium dimple that was tacked on so I figure it wasn't durable enough.

[Mopud]

Were the oil pressure relief holes in the #4 cam journal as they should be?

Yes all of the journals looked good, it didn't appear to be an oil delivery issue

[Mopud]

I have stock valve sizes of 1.91" and 1.50" on a 0630 head.

I am thinking of having them increased to 2.00" and 1.60". The supercharger will keep the velocity up and i'm certain will benefit from more flow.

Any thoughts? I've seen the flow specs on Dino's site of all the cylinder heads but can't see much about the 0630 - i think the same as the 7120 in which case perhaps the Russ Pottenger ported 7120 will be similar? I think the 7120 and 0630 have near identical flow figures.


HO head #7120 & #0630 (Courtesy of John Brown)
Valve lift (in)... 0.1 ... 0.2 ... 0.3 ... 0.4 ... 0.5 ... 0.6
Intake flow.... 66.0 128.0 179.0 206.0 209.0 209.0
Exhaust flow. 55.0 100.0 120.0 136.0 141.0 141.2

Russ Pottenger ported 2.00/1.55 HO head #7120
Valve lift (in)... 0.1 ... 0.2 ... 0.3 ... 0.4 ... 0.5 ... 0.6
Intake flow.... 75.5 138.0 194.0 235.0 261.0 276.0
Exhaust flow. 59.6 106.3 153.3 180.7 193.4 198.8

[jasonb]

Were the oil pressure relief holes in the #4 cam journal as they should be?

Yes all of the journals looked good, it didn't appear to be an oil delivery issue

Oil delivery isn't what I was getting at. There should be two (at least one) oil relief holes drilled through the #4 cam journal from back to front. The purpose is to relieve pressure buildup between the cam and the cam plug in the rear of the block. Without the holes the oil has nowhere to go resulting in the cam being turned into a hydraulic ram and forcing its way forward.

Old cam:

[Russ Pottenger]

Your correct. There will be no difference in flow numbers between a ported 7120 and a 0630 head

[Mopud]

Your correct. There will be no difference in flow numbers between a ported 7120 and a 0630 head

Oh great, thanks a lot, Russ. I notice you port to 1.55" on the exhaust. Is that a physical limitation or the max you're prepared to go?

[Mopud]

Were the oil pressure relief holes in the #4 cam journal as they should be?

Yes all of the journals looked good, it didn't appear to be an oil delivery issue

Oil delivery isn't what I was getting at. There should be two (at least one) oil relief holes drilled through the #4 cam journal from back to front. The purpose is to relieve pressure buildup between the cam and the cam plug in the rear of the block. Without the holes the oil has nowhere to go resulting in the cam being turned into a hydraulic ram and forcing its way forward.

Old cam:

My bad, I'll take a look tonight. I believe these are all OK. It's a Comp Cam 68-231-4 - I believe they have these drilled out correctly. If they were not there I imagine the problem would have surfaced much earlier than the failure I just had at 80,000kms but I'll inspect tonight.

[Russ Pottenger]

Your correct. There will be no difference in flow numbers between a ported 7120 and a 0630 head

Oh great, thanks a lot, Russ. I notice you port to 1.55" on the exhaust. Is that a physical limitation or the max you're prepared to go?

The exhaust port is the limiting factor. A 1.600 valve won't Improve the airflow over a 1.550 diameter valve.

[Mopud]

Your correct. There will be no difference in flow numbers between a ported 7120 and a 0630 head

Oh great, thanks a lot, Russ. I notice you port to 1.55" on the exhaust. Is that a physical limitation or the max you're prepared to go?

The exhaust port is the limiting factor. A 1.600 valve won't Improve the airflow over a 1.550 diameter valve.

Ok, good to know. Thanks a lot.

[Mopud]

I think you'll find out that Comp won't have a late core, but doesn't hurt to ask.

I keep in stock to custom grinds that I think could work for you.
68-235-4 and 68-239-4. Rather than the 111° lobe separation angle, they'll put it on 113°
Another recommendation would be to add the nitride heat treat to the camshaft. It'll add $118.00 to the cost of the custom grind but it's well worth it.

The cost of either camshaft with the nitrite is $298.00

Hey Russ,

Compcams aren't coming to the party and I feel that waiting indefinitely isn't going to net the result I want given how they've communicated thus far. I'd be keen to look into one of these cams you have here if you're prepared to ship to Australia.
I currently run the Mopar Performance P5249464 valve springs with matching retainers and they seemed to do the trick with the old Comp 68-231-4. Will they be fine do you think with either of these two cams? I haven't decided on which cam just yet either, I see they offer different characteristics, perhaps leaning toward the 239 only because I feel it'll put up bigger numbers and perhaps cater to the supercharger a little better. Not entirely sure on this yet though.
-Definitely want the nitriding
If you can also supply i'll be needing:
-Matching lifter set
-Chromoly pushrods. I was running the OEM rods from the 4.0L before. I have yella terra 1.6 adjustable roller rockers - i think 9.600" will suit?

I'll match this with a Cloyes double roller timing chain - previously ran the comp cams one but I think the cloyes are a step up.

Additionally taking my 0630 cylinder head into the machine shop tomorrow. It already had some port work done to it from the last build. 0.015 has been faced off it and it has 58cc cylinder head volume. I'll see if they are able to increase the valve sizes a pinch but I understand this isn't particularly easy. At least it may not be here for me in Aus. Just letting you know the plan in case this information is useful for any of the above.

Thanks a lot Russ.

Regards,

Anthony

[Mopud]

Well, I'm still chasing a camshaft but I went and saw the machine shop who are cleaning and prepping all of my kit. He's tested the springs and reported the followings specs:

Installed = 110lb
.200" = 160lb
.300" = 192lb
.500" = 254lb
.600" = 290lb
Bind @ .690"

Provided I'm not running over .600" lift on the cam the Mopar Performance springs are good for any and all camshafts that I've been looking at. However I've decided to run with the Comp Cams 68-239-4 with 113 lobe separation and will have it nitrided also. Comp Camps aren't coming to the party so I've just pm'd Russ to supply.

Hoping to have my block parts back early next week. But interestingly I'm getting my cylinder head flow tested also so I can't wait to see the specs on that one. Looks like I'll be keeping the standard valve sizing, namely for the sake of simplicity, saving some coin and the minimal gains that would come of it.