Cam Lobes - Page 2

SVXRide · #16 02-04-2006, 05:42 PM

Quote:

Originally Posted by mbtoloczko

Bill (SVXRide) has a few items to check with his bench cylinder head:

1) Amount of valve lift required to cause valve collision during overlap.

2) Clearance between intake cam lobe and rim of the lifter bore

3) Amount of intake valve lift before going coil bound.

Well, I actually found some time to get to my machinist's shop and got the answers to #2 and #3 above (totally phased about #1

I'll probably get this measurement in the next week...)

The clearance between the intake cam lobe and the rim of the lifter bore (using the Delta Cam intake.....oops, is this mike on?

) is greater than .032 inches (~.86mm). The feeler gauge kit we were using maxed out at .032 and it was time to leave so we didn't measure exactly how much clearance there is. There was definitely more room to play with and you can get even more if you just radiused the lobe a little...

As far as lift to coil bind is concerned, we first did a calculation using measurements on the intake valve we've removed (getting ready for some flow work

) and we came up with 0.419 inches (10.63 mm) of lift when the spring binds. We then rigged the head up on a drill press (squaring the valves with the plunger on the press and instrumenting the press with a dial gage). I've included the measurements we got in the picture below. Enjoy!

-Bill

oh, and here's a little "teaser"

mbtoloczko · #17 02-04-2006, 06:46 PM

Thanks Bill! To summarize, the intake valve spring coil binds at about 9.9 mm of valve lift, but the intake cam lobe will hit the rim of lifter bore when the lift is set to more than about 8.9 mm lift. So, it looks like the max intake valve lift without doing any machining to the cylinder heads is about 8.8 mm.

SVXRide · #18 02-04-2006, 08:27 PM

Quote:

Originally Posted by mbtoloczko

Thanks Bill! To summarize, the intake valve spring coil binds at about 9.9 mm of valve lift, but the intake cam lobe will hit the rim of lifter bore when the lift is set to more than about 8.9 mm lift. So, it looks like the max intake valve lift without doing any machining to the cylinder heads is about 8.8 mm.

Mychailo,
That's probably safe.
-Bill

oab_au · #19 02-05-2006, 12:33 AM

It would be easier to cut the edge of the lifter well away, than radius the cam.
You can get more lift by reducing the base circle of the cam profile. The lifter will pump up about 0.75mm, you could rely on at least, 0.50mm more. But I don't think the motor could use more that 9mm.

Harvey.

SVXRide · #20 02-05-2006, 04:14 PM

Quote:

Originally Posted by oab_au

It would be easier to cut the edge of the lifter well away, than radius the cam.
You can get more lift by reducing the base circle of the cam profile. The lifter will pump up about 0.75mm, you could rely on at least, 0.50mm more. But I don't think the motor could use more that 9mm.

Harvey.

Harvey,
While my machinist mentioned both options, he did say cutting the edge of the lifter well would be the easiest...
Question for you -- how much additional lift do you think the EG33 exhaust cam can really benefit from (given that one is running the increased lift intake cams)?
-Bill

oab_au · #21 02-05-2006, 05:00 PM

Quote:

Originally Posted by SVXRide

Harvey,
While my machinist mentioned both options, he did say cutting the edge of the lifter well would be the easiest...
Question for you -- how much additional lift do you think the EG33 exhaust cam can really benefit from (given that one is running the increased lift intake cams)?
-Bill

I am looking into this now Bill, but it looks like the exhaust won't need more lift at the rpms that we are running now. It would need to run the torque to 6500 before it may help. A longer duration may help at higher rpms, but that will involve longer header branches. I'll know for sure soon.

Need some more measurements Bill, or anybody that can supply them.

The inlet/exhaust valve throat dia. at the valve seat.
The dia. of the inlet runner at the injector stack joint.
The length of the inlet/exhaust port, from the center of the valve to the face of the head.

Harvey.

NeedForSpeed · #22 02-06-2006, 01:05 PM

Retainer to valve seal clearance measurements:
.450" intake
.455" exhaust.

For Harvey's model:
Intake throat 1.220" diameter, 1.060" exhaust throat diameter.
Measured with dial calipers.

oab_au · #23 02-06-2006, 04:07 PM

Quote:

Originally Posted by NeedForSpeed

Retainer to valve seal clearance measurements:
.450" intake
.455" exhaust.

For Harvey's model:
Intake throat 1.220" diameter, 1.060" exhaust throat diameter.
Measured with dial calipers.

Thanks Ron, every bit helps.

that makes the inlet seat width 2.75mm, quite wide, could come back to 2mm. We'll see.

Harvey.

NeedForSpeed · #24 02-06-2006, 04:45 PM

Actually, it seems that the valves had a generous 60* cut below the seat before the straight throat cut. I cleaned up the little bit of casting and blended it into the throat cut. I didn't enlarge into the area of the 60* cut.

The seats were not that wide as I recall, the difference to the valve diameter is due to the angle below the valve seat. I'll estimate the seat width next trip.

Quote:

Originally Posted by oab_au

Thanks Ron, every bit helps.

that makes the inlet seat width 2.75mm, quite wide, could come back to 2mm. We'll see.

Harvey.

NeedForSpeed · #25 02-07-2006, 11:28 AM

What is the optimal ratio of valve throat to valve diameter? 90% intake?

I measured 86% on the intake and 84% on the exhaust. The intake seats are fairly narrow. The throats could be enlarged slightly by reducing the 60* angle cut.

SVXRide · #26 02-07-2006, 11:55 AM

Quote:

Originally Posted by NeedForSpeed

What is the optimal ratio of valve throat to valve diameter? 90% intake?

I measured 86% on the intake and 84% on the exhaust. The intake seats are fairly narrow. The throats could be enlarged slightly by reducing the 60* angle cut.

Seems to me I read somewhere recently that the optimal ratio is 70%, but this might have been for 2 valve heads (vs our 4 valve heads)
-Bill

NeedForSpeed · #27 02-10-2006, 01:28 PM

Delta in Tacoma, WA charges $300 to weld and grind two cams. Web Cams in Riverside, CA charges $650 to weld and grind two cams. The cost of living in Southern California is reflected in the price.

The WC lobes are Web Cam lobes, compared to stock spec SVX lobes.

Cam Lobe Duration .006"/ .010/ .020/ .050/ .100/ .200/ .250/ .300

SVX-Intake.. [.280"]: 236*/219*/206*/184*/163*/108*/66*/
WC-610....... [.312"]: 224*/218*/206*/188*/164*/116*/86*/ 40*
SVX-Exh...... [.311"]: 244*/226*/214*/194*/172*/122*/90*/
WC-505 [9MM/.352"]: 234*/230*/220*/200*/176*/134*/108*/ 76*

NeedForSpeed · #28 02-10-2006, 01:42 PM

Harvey, we don't have any flow data, other than VTsuby's thread that max flow in the stock intake port is @ .425" lift/ 10.7mm. VTSuby posted intake flow of 235 cfm @ .450".

Why wouldn't the engine prefer more than 9mm lift? I posted the WC lobe spec, 9mm.

Quote:

Originally Posted by oab_au

It would be easier to cut the edge of the lifter well away, than radius the cam.
You can get more lift by reducing the base circle of the cam profile. The lifter will pump up about 0.75mm, you could rely on at least, 0.50mm more. But I don't think the motor could use more that 9mm.

Harvey.

NeedForSpeed · #29 02-10-2006, 01:49 PM

Harvey,

Regarding the port length, I could bend some wire through the center of the port to the head face and measure, is that what you want?

The inlet runner diameter is not consistant, are you looking for a measurement of the area? Or should someone fill an intake port and record the volume? What do you need?

Quote:

Originally Posted by oab_au

I am looking into this now Bill, but it looks like the exhaust won't need more lift at the rpms that we are running now. It would need to run the torque to 6500 before it may help. A longer duration may help at higher rpms, but that will involve longer header branches. I'll know for sure soon.

Need some more measurements Bill, or anybody that can supply them.

The inlet/exhaust valve throat dia. at the valve seat.
The dia. of the inlet runner at the injector stack joint.
The length of the inlet/exhaust port, from the center of the valve to the face of the head.

Harvey.

NeedForSpeed · #30 02-10-2006, 01:56 PM

Harvey,

I would guess that the intake throat could be opened to 32.4mm/1.275". That's 90% of the intake valve diameter of 36mm. Leaving 2mm for the valve seat on each side leaves a throat diameter of 32mm/1.260". That should be easy enough.

Quote:

Originally Posted by oab_au

Thanks Ron, every bit helps.

that makes the inlet seat width 2.75mm, quite wide, could come back to 2mm. We'll see.

Harvey.