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rmaynard

Timing Advance Cam replaced with ACR

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rmaynard

Can it be done? I have a K161 with the timing advance cam. I also have available to me a K181 cam with ACR. Can I swap the ACR cam into my K161?

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Handy Don

Curious and following!

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953 nut

The short answer is YES. Mike @squonk posted a thread here on the subject.

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squonk

You need to use the tappets from the ACR cam as well.  Different lengths. Also you may need a different cam shim for the endplay.

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rmaynard

Okay. Thanks for that info Mike. I have the tappets and I have extra shims. As soon as I get the block back from the machine shop, I will play around with it.

 

More to follow...

 

 

 

 

Edited by rmaynard
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squonk

Exhaust tappet for ACR cam is 2.02"  

 

Spark advance  1.964"

 

Cam end play .005"-.010"

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rmaynard
2 hours ago, squonk said:

Exhaust tappet for ACR cam is 2.02"  

 

So what you are saying is that I might have to mill a little off the bottom of the exhaust stem to get the correct clearance. :tools-hammerdrill:

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squonk

Yes. 

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rmaynard
6 hours ago, squonk said:

Exhaust tappet for ACR cam is 2.02"  

Spark advance  1.964

Hahaha 😂

Apparently I marked the tappets wrong when I removed them from the K181 over 5 years ago.

 

IMG_20220715_130254549.jpg.6a9daf5e19047fb7becd39d3b8765578.jpg

Edited by rmaynard
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rmaynard
On 7/15/2022 at 7:30 AM, squonk said:

Exhaust tappet for ACR cam is 2.02"  

 

Spark advance  1.964"

 

Cam end play .005"-.010"

Actually Mike, it's not. As I showed in the picture below, which I thought was marked wrong, the intake tappet is longer than the exhaust.

 

77740607_IE_Tappets_K181.jpg.92978a1d785182fece36ddf318c7ea93.jpg62

 

When I installed the 2.044" tappet in the exhaust location, it stuck up way too high. So I replaced it with the 1.974" tappet and clearly it was the correct one for the exhaust.

And to make me even more nutz, it was way too long for the intake as well. I didn't check the K181 to see if anything was different.

So I ended up with the 1.974" in the exhaust, and a 1.962" from the K161 in the instake.  I still had to grind the valve stems for both.

 

Now, for the life of me, I don't see any difference between the exhaust tappets other than 0.012" in length.

 

Anyway, the tappets are installed, and the ACR cam is installed as shown

 

ACR_cam.jpg.ead1e66d6dde76822276c6b36ce854b1.jpg

 

ACR functions correctly, and my specs are as follows:

 

Tappet clearance: .006 intake, .017 exhaust

Valve lift: .308 intake, .311 exhaust

 

So if anyone can tell me if I did anything wrong, let me have it.

 

 

 

 

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squonk

I got my info from @richmondred01

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