[Tom Vaught]

Where is my money for the camshaft/timing chain diagnosis?

LOL! Just Kidding.

Tom V.

[Cliff R]

Just a note on the Rollmaster timing sets. We don't look at the directions, they are a bit confusing. Instead, I reference the "0" keyway and paint it with black paint, and the tooth above the "0" dot that is lined up with the Dot on the upper sprocket. We then go to the +2 keyway, paint it with red paint, reference up and back two teeth and paint the corresponding tooth with red paint that needs to be lined up with the Dot on the cam sprocket. Next, we paint the +4 keyway with another color, reference up and back two teeth and paint the corresponding tooth that needs to line up with the Dot on the cam sprocket.

We always start out with the +4 keyway, degree the cam and move it accordingly. The vast majority off all the cams we've installed ended up at either +2 or +4 using these timing sets. The Crower flat hydraulic cams in particular are almost always very close to 4 degrees retarded when using the "0" keyway and Dot to Dot alignment.

Once one realizes that the keyways are cut slighty offset from the "0" keyway, AND that you have to reference the same approximate distance back from EACH keyway to line it up with the Dot on the cam sprocket, these things are easy to install.

Now that you are all totally confused, have a great New Year!.....Cliff

[vertbird]

I think this rollmaster thing is now making more sence thanks to you guys. Cliff, +4 on the keyway is advancing the cam 2deg right? And therefore +8 would advance it 4deg, which from a LSA of 112 to a recommended 108 would suggest using the +8 mark wouldn't it?

I have the socket thing coming so I think it'll be much easier and hopefully more accurate to degree this cam when I get home. Can't wait to get it done, I was really disappointed with how it ran and now at least I'm sure I know why!

[vertbird]

Oh yeh, Happy New Year to all!!

[Cliff R]

The keyways move the cam exactly 2 degrees for every change, it doesn't double the amount. The Rollmaster sets are very accurate, we've verified this many, many times when moving cams around for degreeing purposes....Cliff

[drew1967]

im a new guy here so dont shoot me. i have to disagree with the inability to run if the dizzy is 180 out. i put one together with the dis. 180 out and it ran. it did pop and crack but ran none the less. my suggestion though is to pull the dis. and redrop one tooth. the adjustment in the timing favors the cam being off. the one tooth might cure it.

[Jeff Walker]

Originally Posted by drew1967

im a new guy here so dont shoot me. i have to disagree with the inability to run if the dizzy is 180 out. i put one together with the dis. 180 out and it ran. it did pop and crack but ran none the less. my suggestion though is to pull the dis. and redrop one tooth. the adjustment in the timing favors the cam being off. the one tooth might cure it.

If the 'dizzy' is 180 out it's gonna take moving it more than one tooth to cure it....since 180 out is HALF a turn off.

[speedshopmike]

i'm real curious how you two guys think an engine will run when it's not firing on the correct cylinder cycle.

i'd love to run an engine on just air; teach me how; it oughta be great for gas mileage.

[Will]

I've seen an engine start and barely run with the distributor 180 out. There is no way you could have put it under any load. It was popping through the carb and the exhaust and bucking like crazy. I've installed enough distributors, both correctly and incorrectly to state categorically that if you had installed the distributor 180 degrees out of phase you would not now be driving the car.

Also, there is absolutely no point in changing the distributor/cam gear relationship by one tooth as long as you have room to rotate the distributor housing. The only reason to do that would be in the case where you've got the distributor rotated so far in one direction that the vac. can is hitting the manifold or firewall and you still haven't achieved the correct timing setting.

From reading this thread, I'm with Tom V and the others who say the cam is not degreed correctly. 130-140 psi seems awfully low. I was getting 170 psi with a cam with 20 degrees more duration than that one and only about one point more mechanical compression ratio. The low cranking compression (coupled with the overall lack of power) is the biggest red flag I'm seeing indicating improper cam timing.

[71 Ventura II]

Originally Posted by speedshopmike

i'm real curious how you two guys think an engine will run when it's not firing on the correct cylinder cycle.

i'd love to run an engine on just air; teach me how; it ought be great for gas mileage.

This question from your experience is confusing. We learned along time ago an engine will start and run with the distributor 180 out. Here's the story: Approximately 1986

My buddy had the tranny rebuilt in his 1970 Tempest. 350/TH350 car. When we went to the AAMCO tranny shop to pick up the car, they started the car, pulled it around front, and we took off after paying the bill. Tony said man the car feels really weak! Also, every time you tried to rev the engine it would pop out the carb! After getting home, we called the shop and questioned them about the trouble? Apparently, it was their procedure to pull the distributors during R/R of the trannies and had mistakenly dropped the distributor in 180 out. After pulling the distributor and re-dropping 180 degrees we set the timing and all was well. No more popping! BUT it didn't make that much different in power as it was only a 350P w/2barrel carb! All the tuning in the world wouldn't have made it fast!

Yes the engine will start @180 out. Take an engine and try it sometime. JD

[79firebird_99TA]

Valve timing and ignition timing are two different functions. Like speedshopmike said, engines don't run when rotor is 180 out. An engine that is 180 out that runs...is one that has it's distributor (ignition timing) cranked around until the vacuum advance hits on something or the wiring harness doesn't allow it to turn any more.

[dammen8]

If the distributor is 180 out the engine will not run.... The reason being is that it will be firing on # 6 rather than #1....6 and 1 are not close in the firing order. If the distributor was 180 it would be firing #1 on the end of the exhaust and the beginning of the intake strokes, this is why it backfires through the carb....big flames been there done that...

[johnta1]

If his problem is the cam timing being off, no amount of distributor turning/timing will make it run right.
If it's off alot (cam) I'd be afraid of the valve hitting a piston.

[grandville455]

I agree on the 180 thing once upon a time I installed a cam and tried the first start thing it wouldnt start just roll and pop . and after checking TDC with my finger in the plug hole and then checking the rotor it was exactly 180 off pulled dist and put at #1 fired right up!

[speedshopmike]

having dropped in about 2457896753256778 distributors over the years of working on various v8 cars, i stand by what i said.
true 180 out will not run.

[Cliff R]

Four stroke four cycle engines, cam turns 1/2 the speed of the crankshaft. It's impossible to have the cam 180 degree's out. You can line up the Dot on the crank sprocket with the Dot on the cam sprocket at 6 oclock or 12 oclock, same end result. If for some unknown reason the engine builder would align the marks with the Dot's on both sprockets at 12 oclock, with one turn of the engine they would be lined up with the Dot on the cam sprocket at 6 oclock, and the Dot on the crank sprocket AGAIN at 12 oclock....folks, it's not rocket science?

For ignition timing, the distributor MUST be placed in the engine and the rotor aligned with the #1 wire when the #1 piston is in the compression stroke. (It really helps here to line up the reluctor or set the points where they are just starting to open) When the engine is assembled, each time the marks on the balancer align with the timing marks, either #1 or #6 is being fired. I've never seen an engine that would run with the distributor 180 degrees out of phase, but have seen LOADS of folks try to do so.

We even had one customer who we built a 440 engine for, tear the engine down and move the upper timing sprocket 180 degrees because his new engine would not fire. Of course, he cussed us for days for being so stupid when we put the engine together to make such a dramatic mistake!

After that little episode, we INSIST on installing the distributor for ALL engines built here!.....Cliff

[Tom Vaught]

You can make an engine that is one tooth off run.

You can make an engine that is three teeth off run well enough to bend every pushrod and valve in the engine, then it stops running.

You can even make a different cylinder the first cylinder in the firing order for cap/wire clearance, but you always must properly time the Piston near TDC on the compression stroke with a proper firing event. JMO

The multiple timing gear deal was a bad deal for me many years ago as a Chebby guy disrupted my Easter Dinner to call me every name in the book after he could not get his 454 LS-7 engine to run properly. He had the timing set off too. Bent every pushrod, valves, and even broke a few guides.

This was the same guy who fired up his engine without the intermediate shaft installed between the distributor and the oil pump on the previous LS-7 Engine. .

Tom V.

[71 Ventura II]

I would like to digress in the effort for clarification. As is so often times true, I may be trusting in an unverified inaccuracy. After all, my experience happened 20 yrs ago when I was 18! I trusted the proclaimed explanation blindly for to long.

First, when we were told the distributor was 180 out, we believed the story, as we were 18yrs old and didn't know any better. I do believe the distributor was dropped incorrectly to which they did correct. I now feel it was my error in believing the 180 out all these years. I'm guilty of the "Urban Myth"

Secondly, it had to be a gross exaggeration saying the distributor was 180 out. Perhaps this is a loosely used term for having the distributor out of phase? With Tom V. and Cliff R. saying the engine will not start at 180 out is good enough for me.

speedshopmike, I apologize! I made a mistake. JD

[chetv10]

in 1977 bought a 350from a buddy , the local machine shop owner was family and helped him rebuild it.he spent a small fortune on this motor,for his judge.couldnt get it to run.i payed $500.for it hoping to use the parts. ended up installing it in my 67 lemans sprint.started, drove to parts store 10 mi. towed home. removed front cover behold 180 out. they will run, not good but will run.

[johnta1]

chetv10, if you had rotated the crank another revolution, you would have fixed it.