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My 1971 521


d.p

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2 minutes ago, Crashtd420 said:

Maybe they used a 1/4 -20 helicoil so they didnt have to drill the hole to big for the helicoil.....

I'd look up helicoils and see what size hole and threads are needed...


already done.  I replaced it with 1/4-20 heli-coil (got a kit from autozone) and it’s tight but expect it to back out when I take the cover off again.  

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Just now, d.p said:


already done.  I replaced it with 1/4-20 heli-coil (got a kit from autozone) and it’s tight but expect it to back out when I take the cover off again.  

Just get some extras and call it good.... if it backs out use a new one.... 

Problem is you cant use a bigger bolt.... because of valve cover....

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28 minutes ago, d.p said:

A87 closed chamber heads any good?

You dont need a new head because a helicoil valve cover bolt.....

 

Remember closed chamber will increase compression ratio but not by alot....

What head do you have now?

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1 hour ago, d.p said:

New head if anything.  What’s the best l4 head for a street motor?  

U60 or U67 ported then port matched to intake. as far as hold down fasteners for the VC, I suggest swapping to all nut and stud. VW guys often use stepped studs for the final repair on oil sump screen plates. Me personally, id grind out the hole into a channel and tig in some new material, set the VC on to reference where to drill and tap. 

 

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Helicoils don’t just “pull out.” We put stainless helicoils into aluminum parts all the time when we know that the customer is going to be repeatedly installing/removing a thumbscrew/etc.

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I have a U60 on it now so already the most desirable?  And I know I don’t need a new head cause of that one bolt hole, I was being facetious.   

 

And @mainer311dont know what to tell you but the original one backed (not pulled) out and the new one I put it on backed out as well when I took the cover off.  I just reinstalled it and will leave it alone.  

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26 minutes ago, d.p said:

I have a U60 on it now so already the most desirable?  And I know I don’t need a new head cause of that one bolt hole, I was being facetious.   

 

And @mainer311dont know what to tell you but the original one backed (not pulled) out and the new one I put it on backed out as well when I took the cover off.  I just reinstalled it and will leave it alone.  

You never know with you.....

 

And yes just leave it alone.... 

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Haha true.  
 

can anyone recommend a shifter boot?  The one I got from eBay some years ago has seen better days.  I wonder if I could just get one made?   Anything got to be better than the Thailand rubber ones.  

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4 hours ago, d.p said:

U60 head from when I first got the engine. 

7B3D87F6-D239-4A96-87C8-A639E180E84E.jpeg

 

Been milled down some. Measure from underside to valve cover surface.... should be 4.248"

 

Loctite the helicoil in.

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The cut is slicing through the letters. A 1mm slice (0.040") would up the compression to 9.08 (stock is 8.4).... that's not impossible to do or live with. You can run regular gas with that if the timing is right.

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11 hours ago, datzenmike said:

The cut is slicing through the letters. A 1mm slice (0.040") would up the compression to 9.08 (stock is 8.4).... that's not impossible to do or live with. You can run regular gas with that if the timing is right.


I run premium with this motor.  Ran regular with the stock l16. 

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Good. Higher compression extracts the most energy from the fuel but at the risk of detonation. Higher octane will allow you to do this more safely. Maybe it pinged a little? so you increased the octane?

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Core shift happens and I've seen stock, uncut heads with casting numbers cut off at the bottom, so relying on that is not an accurate measure of CR.

 

As we've discussed before, the cam has a lot to do with how much timing and what type of fuel you need to use. I had a 2200 in my first 510 which had 11:1 and ran on pump gas with 28 degrees of timing. Eventually we installed cut down KA24DE pistons to lower the CR to just over 10:1, and installed a smaller cam. After those mods, it dyno'd at 210hp.

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Only meant it might indicate milling. Amount is anyone's guess, like how long is a piece of string?

 

Again the stock thickness from gasket to gasket is 4.248"

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