Hey guys its been a while since I've been on here. But I've got myself a problem. My 355 with double hump heads, solid lifters, roller tip rocker motor I bought has been setting so the rockers were backed off to where all springs were loose. Well now I'm going to set the cold valve lash at .016. But my problem is with all the rockers being backed off real loose, I can't figure out an accurate way to see if I'm on tdc compression stroke or exhaust. It's really got me worked up, also my intake and carb is on so I can't see cam. Any help is appreciated

 

Turn the crank until the timing mark on the balancer passes "0" on the timing indicator. Watch the pushrods. Alternating every second crankshaft revolution, the pushrods will either be moving or not moving as you pass the "0". On the revolution where the pushrods are not moving, you are at the firing (or as you say "compression") TDC on #1.

Now you can follow the firing order every 90* to do the rest, or there is another method where you can do 8 valves as it sits, turn the crank 360*, and then do the other 8. I can look up specifically in which sequence to do those if you need this info, I do not have it handy right now.

 

Get the engine on TDC compression stroke on #1. Adjust those two. Adjust the exhaust valves through the firing order. Skip #6. After #6 finish the firing order but do intake valves. Rotate the crank one rev and do the other 8.
example int#1 exh#1, exh#8, exh #4, exh#3, int#5, int#7, int#2

 

Turn the motor. Watch the #6 exhaust lifter (or push rod if the intake is still on it). At some point it will move, reach max lift, and start to go back down. As it gets near all the way down, the timing mark will come up. That's #1 firing.

The "adjust 2" method is not accurate enough for most solid cams. I prefer to adjust each valve in its own turn; extremely easy to do, since the same valve on the cyl that's 4 cyls away in the firing order, will be at max lift (180° away from the one you're adjusting) when the one you want to adjust is on the "heel" of its lobe. That is, watch for a valve to reach max lift; say, you walk up to the motor, put your crank-turning tool on it or park it on a slight hill in 4th gear and pull it forward a little at a time, and you see, say, the #6 intake raching max lift. At that point you can adjust the #1 intake, because its lobe is exactly 180° away from the #6 intake lobe. Then you can just run through the firing order turning the crank exactly 90° each time since that's how far the cyls are apart. Then run back through the other kind of valves. Very fast, very easy, ABSOLUTELY accurate.

 

This is my preferred and practiced method. Like you say, absolutely accurate. However I have to nit pick your reference to the #1 intake lobe being 180° away from the #6 intake lobe. I believe it's more like 90°, although I couldn't find a spec except for oldsmobile V8 being a 90° bank. I have referenced it many times that way but the penny dropped a few minutes ago. I do get what you mean with the 180°, it's just not correct. Or am I understanding this wrong?

 

#1 intake is ALWAYS 180° away from the #6 intake in the old GM firing order. HAS TO BE. Has no other choice.

THINK:

The crank turns exactly ONE FULL REVOLUTION between any given event occurring in both cyls #1 & #6, right?

So how far does the cam turn during that same crank movement?

So yes, 180° IS correct.

 

I was talking about the cam lobe. They have 90° difference. It has to be. It cannot be 180° offset or it wouldn't work. #1 and #6 do not operate at 180° around the camshaft. It is a 90° set up. Using the camshaft as a point of center. The crankshaft angles are maybe different. I haven't looked into that but I understand the 360 crank to 180 camshaft ratio.
That's how I see it. Am I still wrong?

 

#6 has to be 180 degrees from #1... but that's referring to the camshaft position, not the position of the lobes on the camshaft.

 

Yup...

We're talking about setting valves, not anything about which way the cam lobes have to be pointed in order to produce the desired valve events.

THINK:

There are 8 cylinders. 4 fire per crank rev, 1 every 90° of crank rotation. The cam turns at half that rate. Thus, if let's say #1 intake is fully open, then 180° of cam rotation from that point, it will be "fully closed". Likewise, when that valve is fully open, the corresponding cam lobe of the cyl that's 4 cyls away from it (exactly one full turn of the crank, or 180° of cam rotation) will be "fully closed" at that same point; since the cam will be exactly ½ turn away from that one's full open point.

The angle that the cyls are cast into the block is COMPLETELY irrelevant. Wouldn't matter if they're in-line, a 90°V, a 60°V, a radial like aircraft engines, or what. As long as it's a 4-stroke motor and there's 8 cyls and one fires every 90° of crank rotation, this is how it's going to work. Always forever every time.

 

We're talking about setting valves, not anything about which way the cam lobes have to be pointed in order to produce the desired valve events.
Yes you were. That's exactly what you were talking about. It's all about the Lobes really.
THINK: BACK:
You referenced the lobes in your first post.
You specifically stated that #6 and #1 are 180° opposite on the lobe.
At that point you can adjust the #1 intake, because its lobe is exactly 180° away from the #6 intake lobe.
Incorrect I still say. I agree about camshaft position and all the other workings described.
I will agree that the lobe is 180° away from the #1 lifter, but not the #6 lobe. That's what I'm questioning. Not in any way your vast Knowledge of these cars. I perfectly understand the rotation mechanics of the set up.
The way you re-explain the set up to me states it differently. Not as first post.
It would indeed be a different set up with an inline. Then there should be 180° lobe separation across opposites. Not sure about how a 60° set up is, don't even know what that is.
Anyway this is the righteous way to valve lash a sbc.

Guys I'm not trying to upset anyone here. Just trying to make sure I and everyone else learning from you guys have no confusion. If at all possible.

 

We're talking about adjusting valves; which is to say, valve events.

NOT which direction the lobes on the cam point. That doesn't matter. You're the only one who wants to bring it up.

If you want to argue instead of learn, or instead of sitting back and opening your mind and letting TRUTH and REALITY flow INTO it, that's OK too; but before completely making a fool out of yourself, go study valve train events on an actual engine. Go turn the crank on a motor and watch the valves. Watch the cam lobes, even. See for yourself that cylinders that are half of one engine cycle apart, have their corresponding valve events EXACTLY OPPOSITE each other. Then come back and agree with us.

Inline, 90° V, 60°V, "boxer" opposed, radial, DOESN'T MATTER. If a 4-stroke motor has 8 cyls, and they fire 90° apart like most 8-cyl motors do, then the valve events are EXACTLY OPPOSITE on cyls that are 4 cyls apart in the firing order. That's all there is to it. And since that's the case, then when one cyl has a valve at peak opening (the "nose" of the lobe) then the one 4 cyls away in the order has the same valve fully closed (on its "heel"). Quit arguing, and go look at one.

 

I did. I even drew one.
I feel like you're getting a wee bit too upset about a small correction.
I read here most of the time. I post when I feel like it or have questions.
I'm not making a fool out of myself. You are. It's in black and white up above sir.
I totally understand what you're saying about it all. And how it's ALL now explained.
I agree with you 100% on all of it.
There.
I'm still right about the lobe though. No matter what you say. No matter how you claim me to be arguing. Go look at it. AGAIN. And AGAIN if you have to. Yourself. Look at it like you first stated it.
Doesn't feel good when people talk down like that does it. Mostly why I refrain from doing it.
I'll agree to differ.
You are 100% correct with your explanation of the valve train.
Ach I guess I'll leave you all to it then.
I won't even lower myself to address your TRUTH and REALITY flowing nonsense. Mostly because it's uncalled for and also inaccurate.

 

D00d, you're not "correcting" anything.

You're wrong.

We have enough mis"information" on this forum already, we don't need yours added to it.

That's all there is to it.

Don't "draw" anything; go LOOK AT ONE.

When #1 intake is all the way open, #6 intake is all the way closed, and ready for adjustment. Or if the cyls are flipped. Or if it's exhausts. Or if it's cyls 8 & 5, 4 & 7, or 3 & 2. When one cyl is fully open, the same valve on the cyl 4 cyls away in the firing order is fully closed, PERIOD. GO LOOK AT ONE.

Not sure why you need to "differ" when you're "differ"ing with TRUTH and REALITY.

Please quit arguing. You've passed the point of simply not understanding, and are now making a fool out of yourself. It's really not necessary to do that to yourself.

 

Yes, the #6 lobe is 180 degrees from the #1 in degrees of camshaft rotation. With experience it's immediately recognized as such, because it is the only usage of degrees in discussing camshafts.

You never, never, never never actually talk about the actual physical relationship of different lobes to each other, much less in degrees. There's never any reason to care about it at all, unless maybe you've got a blank in your hand and you're grinding a new cam.

 

That's how it's written. "#1 intake, because its lobe is exactly 180° away from the #6 intake lobe"
How many times do you have to read that to want to correct it? Or to NOW add that we mean camshaft rotation and not lobe degrees.
Just please don't say none.
If that is not what is meant then do it right or clarify in a more positive way.
Don't get all high and mighty telling people they are making a fool of themselves, explaining three times the basic function of a combustion engine. I know all that already, for 30 years I've known engines. Keep telling me to go look at one. I close my eyes and see it just like you do.
Proof reading your posts( that may be a little strong...but) will avoid any discrepancies and guarantee the right info is conveyed. Like the re-explanation does. And if someone does misinterpret what you mean when you give specifics, then it might be better to clarify the original statement instead of proceeding to shoot down a member like you're doing.
Thing is that I agree 100% with you dude.You have awesome knowledge as does Apeiron.
However you are implying that I don't. That I passed the point of not understanding. That I don't understand an engine that I can practically work on blindfolded. That I just want to argue. That I'm putting misinformation on this forum. 4 wrongs. Questioning information is not misinformation in any form.
I SHOULD HAVE JUST ASKED IF YOU MEANT CAMSHAFT ROTATION OR LITERALLY CAMSHAFT OPPOSITES? Even though I thought I knew what you meant. That would have cleared it up for me right away and avoided this whole conversation. Instead I get everything above. Nothing unusual for a car forum tho. But me like a dumb@ss had to nit pick for accuracy. (Learning experience there) Go figure. Shoulda known better, seen it a hundred times.
I'll take the info from the rest of the topic and continue to treasure it. Forever. Teach it to my son.
I have had zero arguments on this forum.
When providing information it should be 100% accurate.

I'm not going to argue with both of you now.

I've discussed lobes and degrees on camshafts many times, many times. Explained it a few too in relation to crank position. The other day being the most recent. Lashed a friends 93 gmc pickup. As a learner he had lots of Q's. So it's not NEVER discussed really, but I do get what you mean 100%. However new, young members and learner mechanics may not.

I get it all. I'm not arguing the whole process. Just that one point.
The only way I was a FOOL was to point out a little discrepancy I needed clarifying. I guess for that I have to say SORRY. Sorry if that upset anyone.. I am in no way trying to argue the process. 0%. It was probably YOUR advice that I followed in my own thread years ago. And was extremely grateful for the info.

LETS JUST CHILL OUT. I think we're arguing different points and it's gotten poles apart. Rather quickly too.

Consider yourself Saluted sir. Thank you for your valued knowledge sharing. I mean that from the heart and the head. Truly.