Schrick 284/272 timing

[zaq123]

i happened to measure it and it is like 6 degrees advanced

6 degrees at the cam or crank? Do you know if Nuke gear scale is in cam or crank degrees?

I was looking at tinkerputzer posts and he was plotting the cam with 3' at the crank but his dyno results were with the cam set at 3' (6crank) as he replied to you earlier at that thread that he just used marks on the cam.

https://www.r3vlimited.com/board/forum/general-forums/members-rides/the-project-forum/232860-tinkerputzer-s-3-1l-m20-stroker-and-e30-build-update-on-post-64?p=5794973#post5794973

Digger, do you have the actual plot for this 284/272 Schrick with crank reference as you have in your other plots?

[digger]

6 degrees at the cam or crank? Do you know if Nuke gear scale is in cam or crank degrees?

I was looking at tinkerputzer posts and he was plotting the cam with 3' at the crank but his dyno results were with the cam set at 3' (6crank) as he replied to you earlier at that thread that he just used marks on the cam.

https://www.r3vlimited.com/board/forum/general-forums/members-rides/the-project-forum/232860-tinkerputzer-s-3-1l-m20-stroker-and-e30-build-update-on-post-64?p=5794973#post5794973

Digger, do you have the actual plot for this 284/272 Schrick with crank reference as you have in your other plots?

i double checked and best i can tell its 5 degrees at crank per my measurements. but depends how you determine centrelines so can get 1 degree either way as probably isn't perfectly symmetrical, not to mention variation in production (or all the stuff that sets this) and measurement error



i need find my nuke gear ill check

Edit: Each mark is 1 degree in cam degrees (109mm diameter x pi = 342mm therefore each degree = 0.95mm and as best i can tell each line is 1mm)

[zaq123]

i double checked and best i can tell its 5 degrees at crank per my measurements. but depends how you determine centrelines so can get 1 degree either way as probably isn't perfectly symmetrical, not to mention variation in production (or all the stuff that sets this) and measurement error



i need find my nuke gear ill check

Edit: Each mark is 1 degree in cam degrees (109mm diameter x pi = 342mm therefore each degree = 0.95mm and as best i can tell each line is 1mm)

that plot shows like 2 degrees advance at the crank, intake centerline around 108 instead of the 110 spec, was it with stock cam sproket?
I think a lot of confusion with these cam advances is that people reporting dyno results based on cam mark changes but in reality everyone thinking of crank degrees, naturally so as the crank position is the base for 4 stroke timing. Easy math but can be confusing when people report findings. I'm glad you asked something from tinkerputzer and he mentioned he used cam marks which made me think that his cam is actually 6 degrees retarded (at the crank from Schrick/M20 OEM position) and not 3 as he mentioned. Which esentially puts his setting at 4 degrees retarded from Schrick cam card numbers or 6 degrees from Schrick/OEM sprocket position (if that plot was OEM sprocket)

[digger]

that plot shows like 2 degrees advance at the crank, intake centerline around 108 instead of the 110 spec, was it with stock cam sproket?
I think a lot of confusion with these cam advances is that people reporting dyno results based on cam mark changes but in reality everyone thinking of crank degrees, naturally so as the crank position is the base for 4 stroke timing. Easy math but can be confusing when people report findings. I'm glad you asked something from tinkerputzer and he mentioned he used cam marks which made me think that his cam is actually 6 degrees retarded (at the crank from Schrick/M20 OEM position) and not 3 as he mentioned. Which esentially puts his setting at 4 degrees retarded from Schrick cam card numbers or 6 degrees from Schrick/OEM sprocket position (if that plot was OEM sprocket)

IMO the proper way to determine the ICL is the middle of opening events which gives 5 degrees rather than peak lift for one peak lift position is hard to get accurate due to dwell where slope is very low and second the engine sees the distinct open close events. yes it is a stock sprocket. Also the spec is 2.2/1.7 lift at TDC where as the measurements were 2.5/1.2 indicating advance by a decent amount. i have an offset/shifted graph that i used to determine 5 degrees

[digger]

For example at 1mm open -16 close 224 middle of that is 104ICL so you might even say 6 adv instead of 5 but splitting hairs as get slightly different numbers depending on checking height used