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Thinking of doing the unthinkable... *Rotor to cap gap. Normal?*

folkenheath said:
I am just going off of memory, but I believe those double roller crank sprockets are machined in the back so the sprocket slides on to the crank further since the chain is wider, they aren't flat on both sides. So it would fit both ways, but it would stick out further and the timing cover probably wouldn't fit on and the sprockets would be out of alignment and you wouldn't see the flat side anymore. But my memory could be wrong.
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Thats the problem with a question like this. When you are putting things back together, you pick up the gear, and put it on.
There is a reason you put it on the way you did, but its only obvious to you at the time.
Maybe its just because of the mark, or the way its machined like you say. But, you never really think about it. So, its hard to remember why.

Plus, you are usually trying to get it together, and don't stop to wonder if it would go the other way.
That is why I was hoping some one here had done one recently enough, or maybe had a gearset in hand they could look at.

I'm betting someone will. Even if it will go on backwards, its not the same as saying that it really is, but it would be nice to rule it out.
 
Just a general observation but gears only have timing mark on one side.

You should always match new part to old part.

The way cams are ground it's not likely any lobes are off. It's the keyway that makes all lobes off. Hence why instructions recommend checking cam timing.

But this one is way off! :eek1: May have set a record. :confused: Even adjustable gear sets can't go that far. :confused:

Do double check your cam timing after the tooth change. Double check TDC because the way you did it is not absolute! Harmonic balencer is also not absolute and usually off. HTH!
 
Just a general observation but gears only have timing mark on one side.
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Normally thats true. But there is nothing normal about this engine. It rebuilt by a now dead person, but not finished.
He finished it, and it has has strange problems ever since.

When I saw how far off the cam seems to be, my thought was that the first person might have installed the gears, realized that he had put it on backward, and just punched a mark on that side rather than taking it apart and turning the gear over.

And in doing so, missed by a tooth or so.
 
Everything you guys are saying is right on par witg what I'm thinking! There is about a million and 1 possibilities, and I'll never know the real answer. I really wonder if dead guy knows the answer! Maybe It's a cursed motor! Anyway, I screwed myself over and slept in too late again today so i got no time to work on it this morning... I work swing and they are having us work 10 hour days right now. Then, my dogs want out at about 7:30 this morning and bark their asses off. So i let them back in. And by that point i was pissed and said F it! It's too early to be awake! I'm going back to sleep for an hour! NOPE! I wake up to see 10:45... Well, that kills my morning. Just enough time to check ck5, eat, shower, and get ready for work! Oh well. Maybe I will be motivated when I get home tonight. I hope so cause Friday mornings I have even less time!
 
There is about a million and 1 possibilities, and I'll never know the real answer.
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Don't say never. You're still young. Remember I found my Jeep problem after 8 years, and it took almost 20 for me to finally find out what was wrong with a posting machine from our old office.
I just flat don't give up.
I got a call into the office many years ago. We had a machine there which was a combination of an adding machine, printer, and who knows what-all.
Incredibly complicated, all mechanical.
Made in Italy.
You put in a piece of cardstock with a piece of paper with carbonpaper on the back folded across it.
Then you entered credits and debits and it printed them onto the outside piece of paper in black and red while making a copy on the cardstock.

The outside sheet went to the customer, and the cardstock was kept.
One day it quit clearing itself and started overflowing by printing all 9s. The company that normally repaired it said it could not be fixed, so I got the call.
It had a place for a handle in case the motor failed, so I would crank it slowly watching all the gears and levers to try to see what was wrong.

Figured out how to clear it, and stop it from doing it for a few weeks, but sooner or later it would do it again.
After we sold the business, they were installing actual computers, since they had come out by then, and I saw the machine headed for the scrap heap. Grabbed it, and put it on my workbench at home.

Tinkered with it off and on for about 10 years. Months would go by, and then I would get bored or need something to distract me from something else I was stumped by, so I would delve into it again.

Finally, one evening, I was cranking it for about the thousandth time, and saw something slip that should not have.
Tiny little hook that had a worn bushing and sometimes would not trip a release.
I shimmed it up and it worked fine.
Didn't try to actually fix it, because it would have involved taking out probably 200 little levers, springs, rods, and weird stuff. And then making a bushing, putting all that back in and in the end I would have a machine with no purpose whatsoever

But, by golly, I beat it!!
 
Tested the wires and here is what i came up with. Looks like they are good.

Coil 412
#1 1361
#2 1458
#3 1183
#4 1499
#5 1045
#6 1293
#7 981
#8 979
 
An interesting little tidbit. When I first got this motor I posted up with the bore and stroke asking what size motor it was. Someone mentioned that it could be a very random circle track spec motor. Others suggested I measured wrong and that it was just a normal 350. I shrugged it off and accepted that it was a 350. Fast forward to last night. I'm over at my best friend Scott's house and he's telling me how he was telling a guy at work about my situation. The guy says something like, that sounds like a circle track motor. They used to take and flip the crank gear around and it would give them a full 10* retard cam. So, while I'm still assuming It's a normal 350, It's awfully strange how two separate occasions can suggest circle track spec AND validate a 10* retarded cam! Awfully strange indeed.
 
Sounds like we have two votes.
One says that they don't think a crank gear can be put on backwards, and now someone says that not only can it be, but is done under certain circumstances.

I'm neutral right now. But if I knew where there was a motor with a double timing chain that I could get to, I'd know for sure pretty quick.

My idiot cousin's 350 sitting in my shed will probably never run again unless someone buys it and rebuilds it, but its factory and would not have the double timing chain.
 
Well i went ahead and re degreed it now with it skipped forward a tooth. Came up a degree and a half retarded! I think im just going to leave it there and forget anything ever happened! This motor isnt long for this world anyway. Probably will see 10k miles TOPS before it gets something else in there. So, if it just runs better in the mean time i will be more then happy. So, with that, i just have to finish putting it back together and turn the key and see what happens.
 
Why not go get a new adjustable timing set? They are not too terribly expensive and should get your cam timing where it belongs. If it is still out beyond what the timing set can account for then I'd be thinking something is up with the cam.

Getting the cam timing right is going to make a HUGE difference in how your truck runs.
 
I thought about it. Really i thought about doing those advance bushings. But i figured a degree and half is just not worth worrying about in this application. And yea, i am thinking its actually a messed up cam. But who knows?
 
That's the second time in a month I have seen where the cam was most likely ground retarded. That's why I won't build an engine without degreeing the cam.
 
Yea, talk about a lesson learned! At the time it was just an extra expense and time that i didnt view as needed. Now, I will degree the cam every time!
 
Well here is the log from today. While i can say i think its better because it doesnt surge anymore, it still runs bad. Right now i think i have a normal engine that just runs bad and now i need to find the culprit. I think once i do, i will have a good running engine. As it is it just feels like it has a miss of some kind. Just runs rough. I plan on pulling the plugs back out some time this week and seeing what they look like again. Anyway, here is that log,
 

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Well at least your entertaining yourself!

Good job though and your making head way I think.

About the timing chain deal, when we were hangin out i may have had a few drinks by then, but anyway from the factory they retarded the cam by 10 deg. They did this in the timing chain. This was to help with emissions in the 70's and early 80's. So the circle track guys would just flip the crank gear (mark timing tooth of course and cham'fer it so it will fit snug on end of crank) because a stock timing set was cheap and then run whatever cam they wanted. So I think that the cam is ok the timing set is ok but for a stock cam. Just sayin man.
But really me and your mother are proud of you for hangin in there buddy.
 
I hate to say this... but you were so close to pulling the crank gear and checking the back side.... I never heard that circle track trick... until I see it, then test it... it is a rumor... :dunno:

Or is this coming from reliable source that this is done?

But you do have more compression now right?

So it may be that rumor is true, or cam timing was off, or gear markings were off, and now it does not matter because you timed the cam and it's not totally accurate. But it is in realm of running! Couple degrees off is not bad, will run fine.

Now look at vacuum at idle after you find the miss! :waytogo:
 
Vacuum is already much better. Yes i have more compression! Thats very exciting. I had previously been disappointed with the compression numbers on this motor. Now its right where i think they should be! The cam timing, I have no idea. The source was someone repeating something repeated to them. Lord only knows if its true or even applied to me. All i know is that mine is back to around where it should be. And i know that it doesn't surge any more! Now, if only it just ran good! Im going to go ahead and put a new set of autolite 25's in it and check each cylinder's compression numbers.
 
I agree with the timing being a rumor, until I see and do it myself, but the guy I work with knows a lot when it comes to sb chevys and was around all the race guys up in Bremerton, wa and what not growing up so I want to say it is true.
anyway I wish we would have just for fun flipped the crank gear then re degree the cam when we had it a part. In the end it runs better than before and I still have my vote in for an 8.1!
 
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