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Ow no another NA build!


itsLeon

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On 12/01/2020 at 21:56, harryjackson said:

Any updates on this @itsLeon

Well yeah i got an update. 
After talking about clearances with alot of people and doing some heavy research on it we decided to change to main bearings again so that we have more clearance (from 0.0015 to 0.0025) because of the higher load and much higher RPM. 

@350Butcher is see that you have the same clearance as me, im changing that based on this article (and talking to king etc): http://www.substech.com/dokuwiki/doku.php?id=oil_clearance_and_engine_bearings
 

Other news. 
Yesterday i picked up some new buckets because still some aren't in spec. So hopefully i can finish the heads tonight. 

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22 hours ago, itsLeon said:

@350Butcher is see that you have the same clearance as me, im changing that based on this article (and talking to king etc): http://www.substech.com/dokuwiki/doku.php?id=oil_clearance_and_engine_bearings

 

Cheers for passing this info on...........however I wont be opening up my clearances. My opinion is, that opening them up and especially for the reasons of increased load and revs. You'll just be losing oil pressure and wearing out the bearing faster as the load isn't spread as well across the bearing surface as with tighter clearances. 

 

The only advantage of increasing clearances would be additional cooling due to higher flow of oil but at a far higher cost to dropping the oil pressure. In a "modern engine" the components and obviously with the use of high quality oils the heat can be handled so isn't so much a consideration as if you were building say an old war time classic car engine for example. 

 

As always just my thought's on it........it's your build and I'm following it with interest. 

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1 hour ago, 350Butcher said:

 

Cheers for passing this info on...........however I wont be opening up my clearances. My opinion is, that opening them up and especially for the reasons of increased load and revs. You'll just be losing oil pressure and wearing out the bearing faster as the load isn't spread as well across the bearing surface as with tighter clearances. 

 

The only advantage of increasing clearances would be additional cooling due to higher flow of oil but at a far higher cost to dropping the oil pressure. In a "modern engine" the components and obviously with the use of high quality oils the heat can be handled so isn't so much a consideration as if you were building say an old war time classic car engine for example. 

 

As always just my thought's on it........it's your build and I'm following it with interest. 

Just passing the info i can find. 
Well it was a though decision to make to change the bearings but the 'old' ones measured a clearance of 0.0015 while the minimum must be 0.0014. So the new ones will be around 0.0025. 
We have seen a couple of spun bearings here on build engines here with OEM spec clearances so people told me to go a little bigger.
In the article i linked they say: 

Quote

The optimal range of clearance is 0.0015-0.003” (for a bearing with 2” diameter). Looser clearances are more suitable for highly loaded engines working at high rotation speeds and with thicker oils. Tighter clearances provide a better combination of hydrodynamic parameters in less loaded engines working at lower rotation speeds and using thinner oils.

  This was for me the reason to go a little bigger. 

In my research i found that there is a rule of thumb (https://www.enginebuildermag.com/2017/03/high-performance-engine-bearings-2/). 

Quote

Most rod and main bearings run best with .0007˝ to .001˝ of clearance for every inch of crankshaft journal diameter, or .0015˝ to .002˝ inches of oil clearance for a 2-inch diameter shaft

My crank is 2.36 inches so that calculates to a min of 0.001652 of needed clearance again higher then what i have currently. 

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  • 3 weeks later...

Time for a small update. 

We discovered that the cams need different timings then the Nissan manual describes. So we contact the manufacture on this issue and started over...
We need to find to absolute TDC as show in the image below and then time the cams by how much they push valves down @TDC. So tonight we will once again time the engine. 

gbI4bnC.jpg

 

 

Also new parts have arrived (EGT sensors)
D3mo3r6.jpg

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40 minutes ago, RobPhoboS said:

How did you end up discovering they required different timing ?
I know the duration of your ones are much higher than my C8's.

Well when we first timed the cams and installed everything we did a check if everything was oke. We then found out that one head was wrong and started to discuss about the cams and the fact that these cams are missing the little knob for the sprockets. After contacting the manufacture about it they told us how to time these cams. 

so basically we found out by accident. 

For your cams i would suggest you send JWT an email if it needs special timing or if you can follow the Nissan manual for timing the cams. My bet would be that you can just follow the Nissan manual because i haven't heard this case about the JWT cams and the fact you can still use VVT if im correct.

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19 hours ago, itsLeon said:

Well when we first timed the cams and installed everything we did a check if everything was oke. We then found out that one head was wrong and started to discuss about the cams and the fact that these cams are missing the little knob for the sprockets. After contacting the manufacture about it they told us how to time these cams. 

so basically we found out by accident. 

For your cams i would suggest you send JWT an email if it needs special timing or if you can follow the Nissan manual for timing the cams. My bet would be that you can just follow the Nissan manual because i haven't heard this case about the JWT cams and the fact you can still use VVT if im correct.

 

Ahhh now that makes sense !
Oh I already fitted and used the cams last year (so all cool), just that now I'm in full rebuild mode. You could say my timing was out :teeth:

Nice one, looking forward to seeing how you develop it.
My one is going a bit slow at the moment but hoping to have the bottom end back very soon.

 

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  • 2 weeks later...

Small update: 

We have a problem installing the cams with the correct timing. Already called the engine building company's but they can't provide a solution...
The problem we have is when we put on the sprockets the timing will change when we tighten the bolds. But one company (specialized in old American cars) is coming to help to create a tool to have both the intake and exhaust cams fixed in place. 

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Finally it's done!!! Took a day of from work so me and my buddy could spend all day on it and we finally have the cams installed and the timing chain is placed and triple checked to make sure everything is according to spec.

 

But my God that was hard, none of the OEM markers are in line with the new cams so we had to calculate everything from scratch.

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  • 3 weeks later...
  • 2 months later...

So finally found some time to start working on my car again. 
 

3fylWkg.jpg

 

The old engine is out of the car so now we can start moving some parts over the new engine. I expect this to finish within the coming 2 weeks and then we start the proces to put everything back into the car. 

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  • 2 weeks later...
  • 2 weeks later...

Small update again: 
The engine is in, transmission is also installed. Now working on the wiring. 
Parts to make our own 4" intake are being shipped, new laptop also ordered for tuning use. 

I estimate that at the end of the month we can start the engine for the first time

jolDQOJ.jpg

Edited by itsLeon
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