VETDRMS
15+ Year Contributor
- 340
- 21
- Jun 1, 2006
-
Vancouver,
Washington
I got the cams degreed in. I used a spare trigger plate modified to mount to the head to use as a dial indicator base. It actually worked surprisingly well and I had no issues with it. It looks a little funky but it works.
I was unable to find a dial indicator extension locally so I went to the hardware store and bought a 3/32" brass rod which fit the dial indicator perfectly. I also ordered an extension from Summit for next time.
To attach the degree wheel to the crank I got a 14mmx1.5x120mm bolt and a 14mmx1.5 die and threaded the entire bolt. I used jam nuts to secure the wheel and the bolt to the crank.
Here is the entire setup ready to go:
I had a bit of an issue with checking valve timing the first time as I had some lash. The only thing I could set with lash in the system was the cam centerline. I marked the cam gears 1/2 tooth off to account for the additional 6mm of deck height of the 4G64 and installed the belt with the modified marks lined up.
I re-did everything the next day and set zero lash by adjusting the BLE solid lifters, installing the rocker arm, cam, and two camp caps and made sure I could not fit a .001" feeler gauge and confirmed that the roller turned with no force on the cam. It was trial and error to make sure the valve was not opening off the base circle but after a little while I got them both set as close to true zero lash as possible.
Once that was done I could accurately measure the valve open and close events and compare them to the cam card.
Here is the cam card again for reference:
Here is the valve timing per my measurements:
Intake:
Exhaust:
So, the duration @ 0.040" appears to be about 3* less than advertised. The intake cam opens 3* late but closes when it is supposed to and the exhaust cam opens when it is supposed to but closes 3* early.
I am used to the advertised duration being measured at 0.005" for the domestic cams I have degreed, but it looks like GSC uses true seat-to-seat duration for their advertised duration.
On my setup the exhaust cam needed to be advanced 3* to be on the correct centerline and the intake cam was right on straight up.
Here is how the cams look dialed in at true TDC:
I would have had the motor pretty much finished by now but I found this little gem when inspecting my set of Evo rocker arms.
I found one other rocker that had a small pit on the roller so I am swapping them out with a couple good ones tomorrow morning and I should have everything together by the weekend.
I also picked up some other goods last week:
I got a case of the SAE 30w for break-in and a couple cases of the 20w50 that I plan to run when the motor is broken in. I will probably run regular Valvoline or similar dyno oil until it has about 500-1000 miles on it. I also use the 20w50 in my solid roller 11:1 406ci SBC. It will be getting the lifters rebuilt before spring as well as some other maintenance once the Talon is "done."
I was unable to find a dial indicator extension locally so I went to the hardware store and bought a 3/32" brass rod which fit the dial indicator perfectly. I also ordered an extension from Summit for next time.
To attach the degree wheel to the crank I got a 14mmx1.5x120mm bolt and a 14mmx1.5 die and threaded the entire bolt. I used jam nuts to secure the wheel and the bolt to the crank.
Here is the entire setup ready to go:
I had a bit of an issue with checking valve timing the first time as I had some lash. The only thing I could set with lash in the system was the cam centerline. I marked the cam gears 1/2 tooth off to account for the additional 6mm of deck height of the 4G64 and installed the belt with the modified marks lined up.
I re-did everything the next day and set zero lash by adjusting the BLE solid lifters, installing the rocker arm, cam, and two camp caps and made sure I could not fit a .001" feeler gauge and confirmed that the roller turned with no force on the cam. It was trial and error to make sure the valve was not opening off the base circle but after a little while I got them both set as close to true zero lash as possible.
Once that was done I could accurately measure the valve open and close events and compare them to the cam card.
Here is the cam card again for reference:
Here is the valve timing per my measurements:
Intake:
- Opens: 8* BTDC
- Closes: 44.5* ABDC
- Max Lift: 0.454"
- Centerline: 106.875 @ +/- 0.050" from peak lift
- Duration @ 0.040": 232.5*
- Duration @ 0.005": 263*
- Duration @ 0.000": 273.5* (seat-to-seat)
Exhaust:
- Opens: 50.5* BBDC
- Closes: 2* ATDC
- Max Lift: 0.451"
- Centerline: 112.75 @ +/- 0.050" from peak lift
- Duration @ 0.040": 232.5*
- Duration @ 0.005": 263*
- Duration @ 0.000": 273.5* (seat-to-seat)
So, the duration @ 0.040" appears to be about 3* less than advertised. The intake cam opens 3* late but closes when it is supposed to and the exhaust cam opens when it is supposed to but closes 3* early.
I am used to the advertised duration being measured at 0.005" for the domestic cams I have degreed, but it looks like GSC uses true seat-to-seat duration for their advertised duration.
On my setup the exhaust cam needed to be advanced 3* to be on the correct centerline and the intake cam was right on straight up.
Here is how the cams look dialed in at true TDC:
I would have had the motor pretty much finished by now but I found this little gem when inspecting my set of Evo rocker arms.
I found one other rocker that had a small pit on the roller so I am swapping them out with a couple good ones tomorrow morning and I should have everything together by the weekend.
I also picked up some other goods last week:
I got a case of the SAE 30w for break-in and a couple cases of the 20w50 that I plan to run when the motor is broken in. I will probably run regular Valvoline or similar dyno oil until it has about 500-1000 miles on it. I also use the 20w50 in my solid roller 11:1 406ci SBC. It will be getting the lifters rebuilt before spring as well as some other maintenance once the Talon is "done."
