Purple Cams!

[Daniel]

When it comes to Cams each company has it's own approach to base circle size, profile design, timing etc .

Mark brings up a good point I remember having a very hard time installing race cams in the past that had very
high lift almost 12mm . I was having trouble getting the whole cam all the way in the housing if the lobes were
any bigger i would of needed to notch reliefs into the bearing surfaces of the towers .


I've heard of people machining the cam towers down but never tired this myself I thought it was a clever ideal
personally .

[maytag]

I've degreed the intake cam, and plotted the profile in 5d increments. For kicks, I did the same with the OEM cam, thinking I would overlay them. But I can't seem to find a freeware software tool that'll let me do this. (I do not have CAD, and wouldn't know what to do with it if I did)
I think it'd be interesting to share this. Does anyone know of a tool that can be used to do this?

if it comes to it, I'll draw it by hand . but I'd sure rather not!

[FiatMac]

I've degreed the intake cam, and plotted the profile in 5d increments. For kicks, I did the same with the OEM cam, thinking I would overlay them. But I can't seem to find a freeware software tool that'llEo let me do this. (I do not have CAD, and wouldn't know what to do with it if I did)
I think it'd be interesting to share this. Does anyone know of a tool that can be used to do this?

The plots could be done on the same graph in Excel if you have it and know how to use it. If not you could send the data to me via email and I could plot it out and post it.

[Daniel]

used alfa shims

BEEK

What was the advantage or purpose of using the alfa shims ?

[maytag]

used alfa shims

BEEK

What was the advantage or purpose of using the alfa shims ?

Daniel, the Alfa shims are basically the same as what you and I are calling a lash-cap. Ducati uses them as well. they are designed to fit on the 8mm stem, and come in various thicknesses.

[maytag]

okay, somebody check me, will ya? It's late.

I've got the cam mapped, marked, etc. I've got valves in #1 only, and I'm dry-fitting to check piston / valve clearance. If I'm looking for 110d FL timing (as we discussed above), then as I understand the procedure:

1) bring piston to TDC (already dialed / degreed for accuracy)
2) turn intake cam COUNTER-CLOCKWISE 55d from full-lift.
3) Turn exhaust cam CLOCKWISE 55d from full-lift.
4) put belt on and readjust with adjustable cam-pulleys

is that correct? did I miss something?

I'm still looking for an appropriate way to check my valve/valve clearance. any suggestions?

[maytag]

Progress!
Once I got back at it this afternoon it all came together for me. I "rough-timed" the motor with the marks on the cam towers. then I put my degree-wheel on the crank and slowly turned-through. I had a moment of panic when the crank stopped-short: only to discover that the aux-shaft was poorly-located. I'll need to review that positioning, as my new lightened pulley has no timing 'hole'.

At 110d ATDC I adjusted the cam-pulleys so that my intake was at the (previously determined and marked) full-lift position. Then I did the same with the exhaust cam at 110d BTDC. then I rotated through several revolutions, double-checking everything.
Then I advanced my intake cam 3d by placing the crank at 104d ATDC and moving the cam back to full-lift. then I rotated some more. Everything seemed to go well. So I disassembled to look at the plasticine I had placed in the valve reliefs of #1 piston.




measuring the cross-section, I've got about 1.5mm in the smallest clearance. should be PLENTY. Especially considering I used a .060 head-gasket, where the one I ordered from Mark is a .080. Plus, until I get my tophats for the intake valves, I can only go either very loose or very tight on the shim clearances. So I did this tight, for worst case scenario.

So I'm breathin' easy right now, with no valve/piston clearance issues.

[pastaroni34]

Your aux shaft pulley should have a mark, its just closer to the OD of the pulley. Should be a hole about 0.100" and marked with red paint.

[maytag]

Your aux shaft pulley should have a mark, its just closer to the OD of the pulley. Should be a hole about 0.100" and marked with red paint.

I am not looking at the pulley right now, but I was specifically looking for a hole, because that's what my manual uses to line everything up. However, there IS a mark on the outer rim of the pulley. It's a cast-in mark, like one would expect to use to line up with something else to locate it. But my book has no information about where that should point to.

Does anyone know where that type of Aux-shaft mark should line-up to?

[narfire]

What kind of fuel delivery system were you going to use? Mechanical or electric pump? If electric perhaps consider whacking the lobe off the end of the aux shaft? and drilling out the passage and re-plug. No issues with the aux shaft position then.
Great thred on the build,I look forward to the new posts.
Chris

[spiderrey]

If I recall, I think it points at like 1;30 on the clock. I think, its been a while since Ive done this.

[pastaroni34]

Does anyone know where that type of Aux-shaft mark should line-up to?

It lines up the same as the hole closer to the middle, set it about 1:30, same as Rey indicates.

[maytag]

Does anyone know where that type of Aux-shaft mark should line-up to?

It lines up the same as the hole closer to the middle, set it about 1:30, same as Rey indicates.

cool! All my parts are here this afternoon, so maybe I'll do it tonight!

[maytag]

question:
when all of the valve shims that I own are too thick to provide any clearance whatsoever, what is the trick to determining what shims I need?
The thinnest I have is a 3.75mm, and with that installed, I cannot get any feeler gauge in at all. Do I just order some very thin ones and then measure and reorder? or is there a trick someone knows to be able to measure without the shim?

(I feel like I'm in for a "duh" moment? )

[So Cal Mark]

earlier you had too much clearance, what changed?