Fixing over compression on a 2FE (Camshaft analysis?) (1 Viewer)

[RockDoc]

Hope this helps.... Original (i assume) 3FE camshaft I have on the shelf. From measuring 4 lobes quickly with calipers, base circle is 32-32.2mm, major axis is 38.5mm, for 6.3-6.5mm (0.248-0.256") of lift at cam. I believe the rocker ratio is 1.5, for 0.372-0.384" of valve lift. The chart ERNRAM put together indicates 0.377" of valve lift.

These pics may help some with the modeling:

 

[RockDoc]

I was hoping I could get you a measure of the piston top to deck relationship, but the spent 3FE shortblock I have on hand is rust-seized and won't budge with a 40" bar to get a piston to TDC.

 

[ChaserFJ60]

Hope this helps.... Original (i assume) 3FE camshaft I have on the shelf. From measuring 4 lobes quickly with calipers, base circle is 32-32.2mm, major axis is 38.5mm, for 6.3-6.5mm (0.248-0.256") of lift at cam. I believe the rocker ratio is 1.5, for 0.372-0.384" of valve lift. The chart ERNRAM put together indicates 0.377" of valve lift.

These pics may help some with the modeling:
View attachment 3241351View attachment 3241352

exactly what i needed! I was able to map out my lobe profile by butchering sombody elses algorithim, All thats left is to filter the dataset to produce those fancy camshaft bellcurve charts you see online

 

[Wanna Cruz]

One simple thing to try is adjusting the AFM. On my 2fe I was also having pinging under light acceleration when the motor was set to stock timing. By adjusting the cog in the AFM richer I was able to keep decent timing without hearing any pinging. For safety I dialed timing back another degree past what I could (couldn't?) hear. I've been meaning to install an air fuel ratio gauge but haven't gotten around to it.

Seems like most people in threads on mud were looking to go more lean.

AFM adjusted on 3FE MUCH BETTER!

Just screwing around today and thought I'd play with my AFM. History: Last year I took off the "2 SCREWS OF DEATH". Bought a used AFM here on the MUD for $125. It did the job. This was during a big job to replace a piston (I posted on that too). Spring 2013 - running rich: She just wasn't...

forum.ih8mud.com

My thought is the afm was calibrated for a set of parameters that's changed and moving it a few clicks at a time was an easy experiment that worked for me. On my 2fe I've also got a delta cam, oside tiger injectors, bored throttle body, larger exhaust, egr delete, and air pump delete. In the end I went 5 or 6 clicks richer. I'm sure I wrote it down someplace but cant find it at the moment. I also run premium gas all the time

 

[ChaserFJ60]

One simple thing to try is adjusting the AFM. On my 2fe I was also having pinging under light acceleration when the motor was set to stock timing. By adjusting the cog in the AFM richer I was able to keep decent timing without hearing any pinging. For safety I dialed timing back another degree past what I could (couldn't?) hear. I've been meaning to install an air fuel ratio gauge but haven't gotten around to it.

Seems like most people in threads on mud were looking to go more lean.

AFM adjusted on 3FE MUCH BETTER!

Just screwing around today and thought I'd play with my AFM. History: Last year I took off the "2 SCREWS OF DEATH". Bought a used AFM here on the MUD for $125. It did the job. This was during a big job to replace a piston (I posted on that too). Spring 2013 - running rich: She just wasn't...

forum.ih8mud.com

My thought is the afm was calibrated for a set of parameters that's changed and moving it a few clicks at a time was an easy experiment that worked for me. On my 2fe I've also got a delta cam, oside tiger injectors, bored throttle body, larger exhaust, egr delete, and air pump delete. In the end I went 5 or 6 clicks richer. I'm sure I wrote it down someplace but cant find it at the moment. I also run premium gas all the time

Holy schmoly, Ill need to try that.
As for the camshaft analysis im in too deep with too much time invested already, The only logical thing to do is complete the project whos end I have not yet determined.

 

[ChaserFJ60]

So I figured out the nose diameter dilemma. If we know the valves duration we can use those values to plot 2 points on a circle, then draw two tangent lines from those points to a new point of intersection. we can restrict the nose diameter to be tangent to the two lines previously drawn and restrict its final DOF with the value of the lobe height parameter.

All this being said. I am confident that a 2F intake camshaft lobe with these given values below...
intOpen @17deg
IntClose @53deg
LobeHeight = 38.46mm
HeelDiameter = 32mm

Has a nose diameter to be ~14.62mm.
Assuming the ramps are straight lines and not arcs. Which I fear they might be. I'll have to take a straight edge to a lobe and see...

 

[CruiserTrash]

@ChaserFJ60 Just popped in here to say … wow. I’m running a stock 2F so the 2FE stuff doesn’t apply to me, but damn is this thread fascinating. Keep going, I’m gonna hang back and watch.

 

[ChaserFJ60]

@ChaserFJ60 Just popped in here to say … wow. I’m running a stock 2F so the 2FE stuff doesn’t apply to me, but damn is this thread fascinating. Keep going, I’m gonna hang back and watch.

Im not saying what im doing is 100% wrong but im also not saying its 80% right. What im doing is an ~okayish method to analyze hard to measure camshaft dimensions based off of easily measured dimensions from the camshaft.

What ive done as of now is not how camshafts are designed nor even an accurate representation of a camshafts actual shape. From what I can tell camshafts do not typically have flat smooth ramps leading from the heel to the nose as Ive done above, instead they are arched. I would expect that camshafts are designed based off of other predetermined calculated values such as required valve lift, valve duration, intended engine operating speed, rocker arm ratio, offset distance from the rocker arm, lifter type(roller or flat), lifter diameter, etc. The more I look into camshafts the more complex it gets. Hopefully I will be able to produce a more realistic evaluation in the future.