[gregsgtos2]

I have the roller cam for a 13- 15-1 engine. I ordered one last year and did not use it. Brand new still in the box. Had to wait 3 months to get it.

[Don Chapman]

Originally Posted by NHRASuperStock455SD

We have the intake tooling done, but now we are trying to verify deminsions for machining. We dont have a stock intake to compare. Tom S was so good to send us Hogan, but not really a good indication of "stock". I really need a "stock" 400 RA-V intake to borrow for about a week for verification. I can make sure all my stuff fits together, but not something I dont have. We might have to do the first run of intakes without knowing if the exact numbers are right for interchangine with stock castings. If someone is willing, I can send you a shipper.

Lynn

Lynn Ihave one you can borrow. ill be out of town till sunday night. ill email you then.
Don

[Jim Robertson]

Some progress...Seat work complete

[Jim Robertson]

Finally purchased a set of Pass-Around-Plates (100, 200 and 300cfm plates) from Bruce. So I calibrated the bench and flowed a couple of intakes ports…
4.210” bore with small chamfers (width across both chamfers 4.350")
Radiused port entry
28” pressure differential
2.150” REV pro flow valve
45 degree seat with 60 and 75 degree undercuts
1.930” Throat diameter (this is as delivered from McCarty)
28.47” Barometer
60 degree plenum temp


Test 1 Port #5 intake as cast port/chamber; 3 angle valve job only; with .5625” stainless pushrod tube
.100 77.7
.200 137.3
.300 208.2
.400 258.1
.500 287.5
.600 297.4
.700 304.2
.800 317.3
.900 326.0
1.0 331.5


Test 2 Port #3 intake; Smoothed port walls/chambers and adjusted some areas; with .5625” stainless pushrod tube
.100 78.5
.200 151.3
.300 218.3
.400 262.6
.500 288.8
.600 306.7
.700 319.7
.800 328.7
.900 338.5
1.0 347.5

Port #3 flowed 423.4 cfm at 43.7” pressure differential (100% blower capacity of our bench)

Test 3 For information only we removed the pushrod tube and filled/smoothed the openings at top and bottom
.100 78.7
.200 151.3
.300 220.7
.400 271.0
.500 296.2
.600 325.8
.700 326.4
.800 345.4
.900 350.8
1.0 359.0

Exhaust numbers are coming...

[WDCreech]

If you used offset lifters and .700 offset shaft rockers and offset the pusrod toward the center of the cylinder moved the opposite port wall you could still have a straight port that pointed toward the center of the cylinder without a pushrod bulge.

Maybe not, Im just thinking outloud.

Marty Creech

[Tom Vaught]

Originally Posted by Jim Robertson

Finally purchased a set of Pass-Around-Plates (100, 200 and 300cfm plates) from Bruce. So I calibrated the bench and flowed a couple of intakes ports… .

Whatever you post now "I will take to the bank" Jim, as I know the accuracy of the "Pass-around Plates" from Bruce. Tony has some of the plates too and he eliminated a lot of "BS comments" after he checked his bench with the plates.

So the 100, 200, and 300 plates gave you the lower flow number accuracy, do you have a 400 cfm plate from bruce?

Tom Vaught

[Jim Robertson]

Yes we like Bruce's Plates for two reasons...They are nice pieces and they revealed we were a bit short on our numbers over the years. Better to Under-promise and Over- deliver than the other way around. Our "238 CFM at 25" H2O" plate from Superflow was not a sharp edged orifice which was giving up some accuracy on the low side.

400 and 500 cfm plates are coming when we have a head that needs them...Just kidding Lynn.

[J.C.you]

jim, why do you think the port stalled on the no pushrod numbers between .600 and .700 lift?

[tom s]

Jim,the foils will go out monday.Will be interesting as to what they do.Tom

[Jim Robertson]

J.C.
Not sure exactly what happened but I noticed this stall during testing. No distinct sound change or other problem was noted and I believe I reported the correct numbers.

The plan is to flow these on a bigger bore (4.310") before delivery. Valve location on this set has the valves close to the bore.

Thanks Tom,
Send a stock pushrod tube with the foils if you can.

[tom s]

Jim,dont have one,you should be able to open them up a touch.Tom

[NHRASuperStock455SD]

Thanks Jim,

I suspect that the stall is valve shrouding from trying to cram too small a valve in that head. I believe that even a 2.19 valve is a bit soft, but yes we must consider valve shrouding.

We have some valve seat angles that address the valve shrouding to reduce the "shower head" affect created by the seat. This allows the flow to head more straight down instead if towards the cylinder wall. Our bore was 4.220 and it is what we have based our Street Crate motor engine build up on. Of course then we ported the heads without making the CSA of the intake any larger.

I think if you do this you will see about a 5-10% improvement. It takes some smoking of less than desirable substances to put a 2.15 intake valve in a RA-V head, dontcha think? ;-) Just joking I know you are trying to optimize power on a small bore engine.

Lynn

[Jim Robertson]

If we do the math...
2.150" Intake + 1.720" exhaust + .177" between the valves = 4.047"

4.210" Bore - 4.047" = .163" Available space between valves and bore wall

Assuming the valves are centered at the widest part of the bore at the time they pass the head gasket and enter the cylinder, that leaves only .0815" between the bore wall and the intake valve for flow (with no bore chamfers.) But our flow fixture has an intake chamfer approximately .070" wide at widest point as measured at the deck surface and tapers approximately .150" down into the bore. Since our valves are at 14 degrees to the bore centerline the clearance gets tighter the higher the valve is lifted from its seat.

Agree there is likely valve shrouding issues on this bore size/seat angle/valve placement.

[J.C.you]

jim, can you move the fixture so the chamfer is not below the intake and get another set of numbers?

[Jim Robertson]

I think I understand what you mean and thus...No. Our 4.210" bore fixture is stationary and does not employ removable bore sleeves. And it uses the dowel pins to position the test head over the bore so the head/chamber is in the same position each time.

[slowbird]

Can you get offset dowel pins?

[PONTIAC DUDE]

Originally Posted by slowbird

Can you get offset dowel pins?

Moroso makes them in 2 different offsets. I used them for SBC circle track 120 degree angle milled heads to relocate the valve centerlines.

[Tom Vaught]

Jim, I would order the 2 different offset dowel pins sets and do the flow again.

Cheap info and will tell you if it is worth the bang for the buck to try moving the valve.
Sometimes you have to move the valve location a LOT to see any REAL benefit.

Great suggestion Ken.

Tom Vaught

[tom s]

I think these heads are going on a 4.125 bore!Tom

[Tom Vaught]

Still be good info to have in case someone ever put the heads on a "Big Bore" engine.

You understand Tom that the factory did those valve scallops for a reason. You going
to put the scallops in your 4.125 bore block?

Tom Vaught