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Old 07-07-2020, 09:05 PM   #51
AcampoDave
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Re: Need help with my first 350 sbc

Wow, good news. Usually when a cam lobe goes bad the lifter gets all mushroomed out and won't even pull out like that. The valley looks nice and clean too. Is the pushrod nice and straight?
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Old 07-07-2020, 09:26 PM   #52
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Re: Need help with my first 350 sbc

I think you have 2 issues going. 1 the timing chain skipped a tooth and needs replaced. 2. The heads need pulled and taken to a shop for repair. I would probably go for screw in studs but that is a discussion for you and the machinist. My thought is that you jumped time and smacked a valve causing the rocker stud to pull out. Now is a good time to check out threads on rebuilding heads vs replacement.
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Old 07-07-2020, 10:09 PM   #53
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Re: Need help with my first 350 sbc

Rotating the balancer back and forth while watching the distributor rotor for movement will give you an idea of how much slack is in the timing chain.
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Old 07-10-2020, 01:47 PM   #54
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Re: Need help with my first 350 sbc

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Originally Posted by AcampoDave View Post
Rotating the balancer back and forth while watching the distributor rotor for movement will give you an idea of how much slack is in the timing chain.
I know everything looks pretty good!
The pushrod was nice and straight!

Okay cool I am going to check that maybe today. If the rotor doesn’t move as fast with the crank then that means there is slack in the timing chain?
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Old 07-10-2020, 01:50 PM   #55
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Re: Need help with my first 350 sbc

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I think you have 2 issues going. 1 the timing chain skipped a tooth and needs replaced. 2. The heads need pulled and taken to a shop for repair. I would probably go for screw in studs but that is a discussion for you and the machinist. My thought is that you jumped time and smacked a valve causing the rocker stud to pull out. Now is a good time to check out threads on rebuilding heads vs replacement.
I looked up the stud replacement kits, they look pretty good, I might get the shoulder type with the hex head in the center.
What kind of tap with I need? A bottoming two correct?

will I need tO replace the crank and cam pulleys as well along with the timing chain?

If my cam is off because of the timing chain skipping, how can I get the cam to re-time with the crank?
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Old 07-10-2020, 02:35 PM   #56
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Re: Need help with my first 350 sbc

I would think that a stud repair kit should have all the parts you need to accomplish the job, including the tap. Don't start until you are sure you have everything, including the stud.

Normally the chain and sprockets come as a set because not all chains or sprockets are the same. The mark on the crank sprocket goes up and the mark on the cam sprocket goes down (or up 180 across because one is half diameter of the other and turns twice to the others one turn). It is pretty easy to figure out when you see it.

Last edited by vince1; 07-10-2020 at 02:45 PM.
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Old 07-10-2020, 02:52 PM   #57
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Re: Need help with my first 350 sbc

There is a little more going on than just drilling and tapping the head. Can it be done, yes. The problem is that you don't address valve installed hieght or spring pressures. If the motor is stock than you will probably get away with it since the cam lift is usually pretty mild. It may be money ahead to see if any local machine shops have a set of heads they want to get rid of cheap. Alot of times people will leave them for whatever reason and the shop will sell them cheap to recoup their money.

For the cam timing issue you will need a new timing chain. It should come with the chain and 2 gears. You will remove the balancer, water pump, oil pan and timing cover to install it as mentioned above. I personally locktite the cam bolts and the balancer bolt to keep them from coming loose. Its cheap insurance.

The distributer will rotate at half the crankshafts speed. This is because the cam gear is twice the size of the crank gear. Look for delay when rotating the crank back and forth. Badically rocking it. This will tell you the slop in the timing set. It generally takes alot of slop to let it jump time. There is a little slop in a new chain usually.

If you don't pull the motor down to the timing chain you will need a poston stop to figure out where TDC is so that you can correctly time the motor. If the chain has jumped it will do it again.
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Old 07-10-2020, 03:51 PM   #58
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Re: Need help with my first 350 sbc

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Originally Posted by Isaiah92260 View Post
I looked up the stud replacement kits, they look pretty good, I might get the shoulder type with the hex head in the center.
What kind of tap with I need? A bottoming two correct?

will I need tO replace the crank and cam pulleys as well along with the timing chain?

If my cam is off because of the timing chain skipping, how can I get the cam to re-time with the crank?
The hex style studs need the top of the rocker casting to be machined down, one to accommodate the height of the hex section and two, to provide a flat surface for the new stud to lock to...

If you want to save some money and your use is basically street, you can follow these directions...be aware perform this at your own risk...if there are more than one or two studs are pulled, you are better off pulling the heads and having the posts machined.

In the old days this is how we stopped studs pulling out when using high spring pressures.

Place the nut back on the stud upside down and flush with the top of the stud....drive the stud back into the head until the end is the same height as the others....take a 1/8" drill and drill through the cast post approx 1/2" down from the top of the post. Drill thru the cast post and the stud and back out the other side of the post...then drive a 1/8" short roll pin thru the hole. Make sure you use lube on the drill and pack the area with grease covered rags to catch the shavings.

This will lock the stud to the post.....
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Last edited by AussieinNC; 07-11-2020 at 03:37 PM.
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Old 07-18-2020, 09:49 PM   #59
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Re: Need help with my first 350 sbc

I don’t think my Timing chain skipped. All the teeth look good and I was able to get the timing marks to line up easily with just turning the engine over a few Revolutions. There is a little slack, if I bump the crank a little, the crank with turn very slightly and slack will build in the chain and then it will turn the cam. But I’m sure the is normal?
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Old 07-18-2020, 09:59 PM   #60
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Re: Need help with my first 350 sbc

This is crazy I really don’t understand what the hell is making the timing marks on both the old and new balancer not line up with the pulley....
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Old 07-18-2020, 11:22 PM   #61
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Re: Need help with my first 350 sbc

Maybe my distributor was 180 out?
I checked and my engine is at TDC with the timing marks on the gears as well, both valves on #1 are closed.

I didn’t check where my distributor was at before because I got too excited and had pulled the manifold off first, I have the distributor set in now currently and it’s facing towards the #1 cylinder currently like its supposed to be by the book
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Old 07-18-2020, 11:32 PM   #62
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Re: Need help with my first 350 sbc

Cam dot at 6 and crank dot at 12 is tdc compression #6.
If you point the rotor at #6 on the cap it will start up.
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Old 07-19-2020, 12:52 AM   #63
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Re: Need help with my first 350 sbc

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Cam dot at 6 and crank dot at 12 is tdc compression #6.
If you point the rotor at #6 on the cap it will start up.
Oh okay thank you, where are the timing marks on the gears supposed to be point at TDC on the #1 cylinder?
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Old 07-19-2020, 08:16 AM   #64
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Re: Need help with my first 350 sbc

Tdc compression for #1 the dots are both at 12 o’clock.

Where the dots are has been a very long time confusement for new engine builders.
I believe it was set up like that by the factory only for accuracy and time/money savings during Engine assembly. Much easier to eyeball two dots close togethor than six inches apart.
Or maybe it was the design engineer thinking he might screw with the minds of novice motor builders for the next 70 years!
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