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Discussion Starter #1
So I have a question that is not answered on here or donovans garage.

I have a 1989 common block 2.2 engine with all 1988 square tooth sprockets.

Is it possible to change the crank sprocket over to round tooth or do I have to change the crankshaft so the round tooth sprocket will fit?
 

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the 88 2.2 crank is all its own. It is also an older block so I would question whether or not it is actually a common block you have there. Post up a photo of the engine between the alt and oil filter
 

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that is an older block, not a common block.

I haven't done much with a tall block 2.5 but I've heard they had a round tooth. If you can find one that may work for you.

But if you want to use the engine because you think it is a common block, it isn't. So to use it you most likely will be keeping the square tooth
 

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Discussion Starter #5
that is an older block, not a common block.

I haven't done much with a tall block 2.5 but I've heard they had a round tooth. If you can find one that may work for you.

But if you want to use the engine because you think it is a common block, it isn't. So to use it you most likely will be keeping the square tooth
That contradicts what donovans garage says though. NO fuel pump block off plate, meaning this is a common block with a 1988 crank and sprockets correct? The side of block says 2.2 T

or it can be a common block crank with 1988 sprockets?
 

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it uses a non common block oil pan and 88 blocks are older blocks, first year being 89. I looks like 88s didn't get machined for an electric fuel pump. But as 87 was the last year of a carb on an L body I can see why that is.

Donovans garage is very old and out dated and it is not 100% truth. Doesn't mean there isn't a ton of good info on there. As far as he is conserned you can't make any power with the older block, far from true. As far as that site is conserned a 655 head doesn't exist.

Common blocks use a different oil pan and different aluminum end plates than the early block. 88 was the last year of the early block. You engine is dated right and has the right oil pan castings for an early block. It just isn't machined for a mechanical fuel pump. But as there were no carb 2.2s in 88 I can see why.
 

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It's an early non-common block so you CAN use the round tooth crank sprocket from a round tooth year.

The common block setup, as indicated earlier by Pope, uses a different front crank seal retainer plate, crank sprocket (which is a different design and thickness), oil pan and oil pump pickup. Its also a different crank obviously since that's the why you have to have all the different stuff! Beyond that U cant mix and match early style pulleys with later units it's all one or the other. And also remember that the water pump changes it rotational direction in 89 on the common block setup...another sign or difference in a common block.
 

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Discussion Starter #8
So am I able to just take my 88 sprocket off and press in a 89+ round tooth sprocket? or do i need that new special seal too?
 

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an 89 crank sprocket will not work on an 88 crank. The 89 crank has a shorter but larger diameter snout.

2.2 early vs CB

88 crank on the left, CB crank on the right.

Now, if you have a lathe and some aluminum round bar you can make your 88 crank sprocket work on a CB crank as shown here: 2.5 Masi buildup

where I had to recreate the Masi CB crank pulley using an 88 sprocket :)


I know I have a couple CB's casted in 88. Now if you use an 88 crank, front seal retainer and oil pan you should be able to bolt an early crank into a CB but don't quote me on that.
 

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Well- I gotta ask--Why do you want to change sprockets?

GLHNSLHT2 yes you can put an early crank in a CB by using the early retainer and oil pan etc. You just have to drill the CB block for the early seal retainer.Very easy swap--we've done it in our 85 Daytona.(edit)
Luckily ours was a 2.2 CB so it didn't have the cutout place(for the balance shaft chain) where the old seal holder needs to go.
 

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Discussion Starter #11
I've heard the round tooth sprockets are better and improve timing belt life span and have more gripping force? Yeah this isn't going to work then. Oh well keeping square tooth then going to build up a common block on the side.
 

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I personally believe they switched to the round tooth for noise reduction.The square tooth is harder to strip because of the design. The round tooth it sees would be easier to ride up and out of the sprocket. I will admit though it might be like a crank fillet. The round tooth might have more lateral sheer strength. I wouldn't worry about it. Most of my engines are square tooth and I have over 90 k on the 84. Our 85 CB engine conversion uses a Sq tooth also because we used the 85 crank in the CB.
 
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