Should be 4A just a dot(zero) and 4R keyways on the crank sprocket. You want to point the cam dot to the 4R dot on the crank.

https://cloyes.com/3-keyway-crank-sprockets/

OK, I thought for a minute I needed a different sprocket. So we're talking about setting it at the mark that is the factory setting, not retarded or advanced? I'm easily confused!

Scott, you want to use the 4R keyway to eliminate the 4 advance built in.

https://cloyes.com/wp-content/uploads/2019/06/3-keyway-instructions-general.pdf

https://www.youtube.com/watch?v=_cWiKqjxVCc

Thanks guys, I think i've got it. I did go down a rabbit hole watching a guy using an indexing wheel? That was way over my head. Please tell me I don't need to do that!

Cam is in! I have it roughly lined up as the marks show. Now the question is whether the cam is 180 out or not. Are the lobes supposed be down opening the valves or do i have that backwards? The sprockets aren't installed, just loosely sitting there. Do I need a degree wheel to get this spot on? Clueless here!

I think that looks right.

Now a word about retarding/advancing the cam if I may. The usual justification for retarding the cam is that it shifts the powerband upwards which gives you more horsepower at the expense of low speed torque. Usually a good thing right? Well maybe, it sort of depends on how your engine is built and how the car is geared. Even more it depends on how you intend to drive it. Honestly the factory balance isn't bad for all around general usage. Bear in mind of course we're basically talking about  someone like a doctor driving a 3500 lb car with an engine built with a bias towards torque. It makes the car easier to drive which is mostly what those owners wanted, and factory redline was 4800.

But that's not exactly the engine we're building is it? A hotter cam with a higher redline naturally shifts the powerband higher all by itself even if you do nothing else except upgrade the valve springs.

Now the question has to be asked, do you really want to shift the powerband even further upwards? Because you certainly can if you like. But what are you reaching for? First, what is the quoted powerband of the new cam? Is that the range you want to use? Or do you anticipate a good bit of freeway cruising in overdrive down around 2 grand or maybe even lower to get better economy? An engine that makes it's power between 3 and 6 grand may not give quite the cruising economy you are expecting if that is the case.

I tend to stay with the zero mark myself, I could see advancing it for an RV or retarding it for a car that saw some competition use but hey, with a 300 in the MGB I suspect you won't exactly be lacking for power most of the time. Give it some thought.

Jim

Jim B, He as the same cam (Crower 50233) that Chris used in his Stroker 300. Plus, he has 10.5 compression. The only reason Crower has the 4 advance built in is if you have 8-9 to one compression. Plus by retarding it, it is really zero and will lower Dynamic compression a bit for pump gas. No degree wheel necessary. You did make sure #1 piston is all the way up? TDC. Lubed good for breakin?

Yes the piston is at the top, the cam lobes are down in its current position with the sprocket marks facing each other. Am I correct in thinking with the cam lobes down, it's on the compression stroke? 

Jim, I'm not disputing that but that's a hotter cam for a 215 than it is for a 346 (.030 over 340) so the DCR should already be lower shouldn't it? And the powerband will be higher with a 215 than it will be with a 350, Crower should have those specs.

Jim

That cam is a little big for Scott's motor but he has 10.5 compression. It was pretty mild in Chris's 350. He was .050 over. I believe maybe some unheard detonation contributed to the broken rings before. I've done a Desktop dyno and the DCR was around 9.2 with the built in advance and 10.5 compression. Without it was very pump gas friendly at around 8.8.

Thanks guys. Before I install the timing chain can you confirm that the 2 #1 cylinder cam lobes should be facing down on the compression stroke or do I have it backwards?

Both lobes will be down. If lifters and pushrods were in, valves would be closed. If you think about it, they will be down no matter what if the dot on the cam gear is at 6 Oclock. What confuses you is, the cam turns 2 revolutions for every 1 crank revolution. So, the crank could have #1 piston down and the marks will still line up. Turn one more time and you would be good. That is why you have to make sure #1 is at TDC.

OK, got it. So, after several tries, the chain is on and the marks line up. The cam lobes are down, the piston is at the very top. It rotates and seems fine. On to the next step.

Scott, looks like you are on the factory position with 4 degrees built in cam advance. If you wanted the 4 degrees retard you would use the square key slot and have the square timing mark lined up on the crank sprocket.

 I'm at zero which gives me the 4 degrees advance. That's what I want right?

You'll probably be fine. Definitely run premium gas and set your distributor for 32 total when you get that far.

Do you guys recommend replacing the head bolts when rebuilding these motors? I had the timecerts  installed.

Nope, Reusable, but I clean threads with a wire wheel and lube with anti-seize. You can tell which ones go through the water jacket on the Olds heads as they will look crusty. Use pipe dope on them. I think from memory they are the long Rocker hold down bolts because the others are the same as Buick's. We found every one of the exhaust studs went into the water jacket. Previous owner replaced them with bolts. We went with new studs and Loc-tite sealant.

Quote from: mgb260 on February 22, 2026, 02:44:48 PMWe found every one of the exhaust studs went into the water jacket.

On the Olds?  Interesting.  On the Buick 215, all the head & exhaust have blind holes.

Ive decided to reset the timing set. In my confusion I set it 4 degrees advanced which isn't probably what I want.
 I now understand 4 degrees retarded gets me to  0 degrees  advance.. Am I on the right path?

Yep. Square key slot and square mark on crank sprocket.

I got the timing set corrected (4degrees retarded) and after looking at my photos, I know how the distributor gear and fuel pump wheel go on.

Look at the imprint on the cam distributor gear for spacer orientation. Helps oil the gear.