[Charlie Stylianos]

Very good thread on rocker shafts/seal installs. JW recommends 18ft/lbs on the shafts.

http://forums.pelicanparts.com/showt...hreadid=118406

I'll post the intake side runner pic later tonight.

Edit: Runner Pic........

[Marc A]

Wayne's book is wrong then because there are 4 pointing in the opposite direction. Those on the corners are reversed I believe. The way to tell is that the 5 mm end is always visable while the 8 mm end is inside the journel when the shaft is centered.

edit: I just read JW's post and he said what I just said . . . no really.

[William Miller]

Thanks for the details.
I feel like I'm on spring break because as of a few minutes, I'm outa-here.

Planning to go to the eastern shore for a week. If that get's delayed I'll be working on the engine. OOOps chores arround the house first!

I'll try and check back from home if I get a chance before I go.
Otherwise......... see ya!

[William Miller]

Back to the project:
Last night I installed intake rockers #1 & #4
I set the basic timing on #1 and noticed that when I turned ir over by hand that I had some resistance. (Intake valve touching piston)
I adjusted the timing per the 930/10 specifications which is 1deg btdc. (dial the crank to TDC at 1mm valve lift.)

After I did this I felt no resistance. Turned smoothly and I could watch the dial indicator spin as the valve opened and closed.

I installed #4 rocker and timed it. I could not get it exactly to the spec because I could not get the hole and the sproket to line up perfectly. I ended up with this one a little advanced like 1.09mm lift at TDC. The other choice (next hole gave me slightly less than 1mm lift at tdc.)

Next I checked the valve to piston clearance. (Intake only so far)
#4 first since the dial gauge was there and I could watch it spin.
I adjusted the screw one turn (1mm) in past the point where it touched the valve stem. I turned the crank around several times. No resistance. Everything fine. I turned the screw in another 1/2 turn and felt resistance as I turned the crank (the valve was touching the top of the piston just before tdc because the valve starts to open before the piston starts to go down.)

I started to realize that the tolerances are in fact very tight. This is probably the cause for the marks in the tops of #1 &#4 pistons and which ultimately led to the ring breaking.

On #1 I did not encounter the resistance until I turned the screw in abou 13/4 turns or mm.

I began to wonder how the cam timing would effect this measurment.
I attempted to time both sides to 1deg or 1mm of lift. the right side ended up advanced slightly because of the hole and sprocket alignment. I decided to reset #4 (retard it to the next hole) This gave me just a hair under 1mm lift. It's really hard to tell because the pully is about 1/2" from the split in the case.

After this very small cam timing adjustment the piston to cylinder clearance went above 1.5mm as recommended by wayne.

I began to try and think "what's going on." I set the cam timing to the euro specs. the center of the range is 1mm to get you 1deg btdc.
I suspect if I set it to the US spec 7 deg btdc (center of range 1.55mm) I would have substantially less valve to piston clearance than the 1.5mm recommended in Wayne's book.

I'm beginning to wonder again if I have the euro cis pistons.
In the whole set up the main difference between the us an the euro version is 9.3:1 vs 9.8:1 compression.
Everything is equal except for the dome volume of the piston. Is there possibly less valve to piston clearance with the euro set up? Maybe that is one of the reasons they retarded the cam timing.

I guess the isue may also fall with the camshaft profile itself. The camshafts appear to be stock, but who knows.

In any case I have read a lot about the variations in valve timing. I mostly have read that there is some minor differences in where the torque is the highest.


I think for now I will leave it at the current setting where I know I have adequate valve to piston clearance.

I hope to install the exhaust side rockers and check the clearance on them they are supposed to be 2mm. I doubt there will be any problem.
Charlie, do you have any thoughts?

[William Miller]

Charlie, Engine is ready to go back in tomarrow. I decided at the last minute to put in a new clutch disk and throw out bearing.

I actually tried to put it in late friday night. 1-2am. and was having trouble getting everything aligned.

I decided to hold off untill I had a clear mind.

Went crabbing yesterday in the Eastern Bay. Caught a little more than a bushel! We ate as many as we could and ended up giving away 2 doz!

[Charlie Stylianos]

Bill,

Thats great to hear!! I finally got the cams timed last week within ~.002" of eachother. Figured thats as close as they'll (or I) could ever get them. I found a cracked rocker shaft and I'm currently waiting for that and some other small odds/ends from Pelican before I can button it up.

All is left is a little CIS tune-up, change the fluid in the tranny, and R&R the flywheel.

Hopefully the engine will be ready for installation in a couple weeks.

Maybe, just maybe, I can make the 29th fun run.

[Rick Lee]

I'm certainly no expert, but have had it emphatically pounded into my head that cam timing must be precisely matched with no margin at all. PM John Walker to confirm, as it's a lot easier to redo while your engine is still out of the car.

[William Miller]

Charlie, I have a few spare rocker parts if you need something in particular let me know. I bought one shaft because I somehow lost one. Bought some other bolts, nuts and adjusters just in case.

On the cam timing, If there is a way to get it closer, I'm missing something. I may have been a little closer than Charlie, but had to make a choice as to which hole in the adjustment sprocket to put the pin in.
My left side went dead on, but my right side was off an amount that was finer than the sprocket would allow.

What's the deal? Maybe JW has some insight that I haven't seen published.

[Rick Lee]

Again, no expert and I've never even done it. Rather, I learned the "hard way" about mismatched banks. My Carrera has WebCams, for which there are different specs than stock cams. There's a range, something like 1.9mm-2.2mm. You can be anywhere in that range, but both banks have to be exactly the same. You can pick advanced or retarded, as long as they match each other. I was assured by the rebuilder and previous owner of my engine that the cam timing was dead on and that I shouldn't waste my time or money having it checked. You can guess what happened.... Yeah, a few hundred dollars later I got the "I told you so" and lecture by Stan at RPM on how mismatched my banks were and blah, blah.

[Charlie Stylianos]

Richard,


There aint no way I'm touching those cams again It took me quite a while to get them that close.

In this case, perfection is relative.....the closer the better, but trying to get them EXACT is a true feat. At .002" we are talking many fractions of a degree difference between the left and right side. I agree, perfection is the goal to have a perfectly timed left/right bank, but there are so many variables.

1) The minute machining tolerances/differences in the cam chain links will give you off readings. RoninLB mentioned to rotate the crank 9 times to get the same link back onto the same cam sprocket tooth to verify timing....this is true....I saw a variation of ~.002" on the same cam before coming back to my initial link/tooth. If there is a variation of .002 in one cam, .002" (max) between left/right banks is close enough.

2) Initial valve gapping has to be the same on both sides (.004"). If the gap on one side is a little bit tighter than the other, this inconsistency will come out in the cam timing.

3) Even torquing the sprockets-->cams to spec will move the timing around.

I honestly think I got them as close as I could w/o driving me to jump off a bridge.

You should have been there, its easier to see/feel/do than explain.

I think yours were 1.90 and 2.05 left/right before you had them timed again, difference of .15mm, which is a little easier to get closer than my .05mm.