Well yea, that was why I made the comment about it above, but you've got your mind made up, so why bother to answer your question?

The following is for others with open minds.... Rather than me repeat the Cloyes comment, think about the following a little. What is putting the stress on the lower half of the front cam bearing, a tight chain, or the chain pulled tight on the forward side of the chain by the crank gear? When that chain is pulled taunt on the forward side during engine operation, do you feel there would be ANY amount of slack on the rear side of the chain? The question is not how much (or how litttle) it is if there is ANY. Do you, the installer believe you can pull on that chain to the degree that the crank can as it is pulling against cam resistance? If a chain was that tight installed to make a diff, do you believe you'd get it on? Just cuz it feels like a tight chain to you the installer, will pulling against resistance keep the chain tight on the slack side? So what is causing this resistance? Quoting 'racer', "The damn front cam bearing wears out on it's own." Does it really? Hardly. Water pump? How 'bout those relatively mild (in comparison to aftermarkets) OEM valve springs? How 'bout those much stronger valve springs installed to handle those aggressive cam lobes so popular here? Ever wonder why some race engines use roller cam bearings? Ever see an engine with truely strong springs flex rocker studs? Do you now really think a tighter installed chain will impact the cam bearing moreso than a loose chain? It might if the installer had to literally FORCE that cam gear on the cam with a pry bar.

I'll ask a previous question again. Even if it was ALL, which I am seriously questioning, was that the ONLY variable changed?

 

Good point

 

You do it your way and I'll do it mine.
If ya put it on top of the piston there is no other way.
I "know" ya are good enough to stop it on target but I don't want to spend all day finding it.

The by the book method has always worked. Until proven wrong that is what I will use.You can do it anyway ya please,but that don't make it any more right than the positive stop way.

Like I said you know more than the people who wrote the book on cam degreeing.
Not likely.

Maybe ya should write your own book and present it to Comp,Isky,Crower,and a few others. They just might print it if it's worth anything.

 

Wow!! Shouting now? I know I stated I care not to start anything, but it is obvious to me, you really don't know. I know you are experienced and knowledgeable, but in this case, PLEASE do not attempt to snow a pro.

By the book..... Read the original copies, not the revised editions. "Until proven wrong" ..... It really is not possible that you could be in error? In no way am I stating I know more than the guys that wrote the book. Not that arrogant. What I am, is a good student. Unfortunately, your responses are showing your arrogance. I am not happy cuz of that, I am saddened.

Again a plea to anyone, as to what racer is doing wrong with the way he is establishing TDC with that indicator. A hint.... it shares a similar line of reasoning as used with the 'positive stop' method. Do not feel intimidated by racer, please post. In this case, I'm confident some of you will know more than racer. To help keep the peace, consider this my final post in this thread, if no one responds with the answer.

 

Don't use an indicator so I can't be wrong on the engines I build.
Not shouting,just thought ya couldn't READ my post's.
Again I don't care how ya do it,I do it by the book. Please post any documentation you have saying the positive stop method is the incorrect way.

You must have been off your med's too long or something.

 

My appologies for starting such a heated battle. I chose the dial method since my heads were already off. My logic fo using this method was as follows:

By switching the directional rotation, one would be absorbing the chain slack in the equation, which I hypothisized would throw off the numbers.

So my question is, since the engine operates on this one given direction, and if you measure (degreeing) the half-way point in a valve operation cycle by the forward then backward method, wouldn't the slack (however minute it may be) scew the final number?

I am only a beginner at this, and it was my first time in degreeing a cam, but the single direction, dial indicator method seemed the most logical way to do it. Was my logic flawed?

I want to thank Racer and A/G both for their insight on this topic, and hope they reach a concensus or at least a friendly "agree to disagree" position.

Respectfully,
John

 

My apologizes to you for screwing up your thread.
When you are using the positive stop you are trying to find TDC of the crank only. The slack in the chain doesn't enter the picture at this time,nor does the position of the cam. That comes in later steps. If ya aren't TDC on the crank the rest of the readings are skewed. This is to find TDC on the crank and set your degree wheel at TDC.

 

You didn't screw it up; no appologies needed. My logic was flawed by citing chain slack as an issue, so you are absolutely correct about the crank TDC. I don't know why I even brought that into the discussion about degreeing the cam (too many things rolling around in my head right now).

I used the dial indicator for both equations, the chain slack only comes into play duering the cam TDC. So, you state that since the piston resides at TDC for X degrees of duration, if you use the fist number you come to, it will not be the absolute TDC; I can see that.

What I did to over come this while finding piston TDC, was to record the initial number when the piston hit TDC on the degree wheel and the last number before the piston began the downward stroke. I then used the difference as the "absolute center". Was this method incorrect?

 

That is what I had stated in an earlier post about the indicator. To me ya got to be real quick to catch it and do it several times(for me anyway).

Some people don't catch that.

If ya are sure that your beginning and finish readings were correct and checked them there is nothing wrong with doing it that way. It just seems to take me a lot longer to do it that way.The time thing is why I don't use an indicator. If that's all ya got to do it with,then that's all ya got.
I admire your adaptability.

 

Not to throw gasoline on a fire, but what about pistons that use offset wrist pins (lots of stock pistons do)? Using a piston stop and splitting the difference in two directions might not give you true TDC in that case. No?

I use a dial indicator to find TDC, personally. PLENTY close for what I'm doing. Heck, if you can get a cam in +-1* using the tiny little degree wheels available to the average guy, plus take into account as many of the crapola differences in various measurements that show up at a million points along the way, you're doing better than me (which isn't saying much because I'm just an experienced hack).

When I degree a cam in I'm looking for large deviations from spec. Something off by 3* or more catches my eye. Something off by 1* doesn't even get a passing glance.

I DO always turn the engine in the direction of actual rotation in all cases. Don't know where I picked that up but it seemed to be the right thing to do. Especially if you see how much "slop" there is even with a fresh chain.

FYI- have you ever degreed in every single cylinder? I have. It's eye-opening. Suddenly 1* differences just on #1 cylinder look like no big deal when you see how different things can be on the other 7. I don't know if it's variations in the cam grind or the fact that the rod journals on some cranks aren't actually a true 90* apart (or maybe the cylidner banks aren't spread exactly 90* OR maybe the lifter bores aren't really trued up relative to the cam OR....), but stuff can land all over the map from cylinder to cylinder. If you have less than 2* spread from highest to lowest, you're probably about as close as you're ever going to get.

Such a seemingly simple procedure as degreeing a cam can drive you out of your mind if you think about it and play around with it long enough.

 

When ya roll it one way to the stop then the other it does the same thing with offset pins. The true TDC is 1/2 the total between readings.

Some cam grinders grind for the twist seen by the back of the cam. That may be what ya are seeing when ya degree the back cyls.

Like I said when using the stop ya are ONLY looking for TDC on the crank and to set your wheel to TDC.
The indicator comes into play when ya are trying to find the lift at .XX degree or the degrees at .XX lift

 

Damon, a true pro will use an indidator to find TDC. It is more accurate for the reason you noted, whether checking #1 piston or checking all 8 to verify the crank index. Using the piston stop method is considered a 'backyard mechanic' method as it does not need/use the indicator in that procedure, but still get respectable results. As a 'guru' here does not endorse it as the correct way or believe that I do know what I am talking about (and apparently others agree), rather than cause any more friction on ths forum or as you put it, throw more fuel on the fire, email me if you want to now how it is done correctly when using the indicator method. 'Sick Puppy' now knows, maybe he will offer it. It uses similar reasoning as the piston stop method. Really surprised and disappointed someone else did not step up with the correct procedure. It's not 'rocket science' as the cam pioneers from the 50s were not rocket scientists.

Edit: "You must have been off your meds too long or something.... Like I said, you know more than the people who wrote the book on cam degreeing."

Sorry guys, but scarcasm or attempts to belittle such as this, do not make me very receptive. Some people won't ever grow up.

 

Its unfortunate that 1racerdude has chosen this method of trying to share his knowledge. Its reaching the point where its turning a lot of people off this forum. I'm losing a lot of respect for him. Might get to the point where corrective action has to be taken, and that will lose us a valuable resource, but we're already losing other resources who refuse to come here and be ridiculed and insulted by one individual.

1racerdude... I hope you're reading this.

 

I've decided to go with the Meziere electric water pump and a roller timing set (possibly the Cloyes True Roller). I'm now performing forum research to find out what problems that will pose and what I can/if I can keep the reluctor wheel.

 

Fred,
I also am tired of being insulted and laughed at and being called first one thing and another . I don't start these arguments, but I do try to answer in the manner that is shown to me.
If someone has a different opinion that's cool but don't quote me and say thing like "You make me laugh" or "Your an idiot" or "Too old to know"
I don't attack people on a personal nature unless it's done to me.You know it is/has happened and more than once.


Aren't you kinda old to have such a negative challenging attitude?
Excuse me for laughing racer, but are you for real?