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yup go ahead and give a little piece of mind and notch the girdle. whoring out photos from my build:


-Luke
 

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a credit card is roughly 0.025in , can you fit 1 under? if so you have plenty of clearance. Nothing magically grows a significant amount.

edit: Im running a 1996 y8 bottom end with fjt i-beams and i had plenty of clearance, no notching needed. Block had to be notched a lot however.
 

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i don't see the point in taking the risk; especially when looking at the picture you posted OP. You don't need to take out a ton of material but why chance your build on something simple.

-Luke
 

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I had SYSC H beams in my ZC, and I didnt have the girdle notched.

[EDIT] But in your case, I would go ahead and do it just in case.
 

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Discussion Starter #14
I can def. fit a credit card in there...I really dont know what to do though...i really don't wanna take this all apart again but if i have to then i have to I have no choice....I think its just the way the angle is on the pic. I can take the girdle off with the oil pump and everything already on right?
 

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If you notch the block it is safe to say you should notch the girdle too, even if you can turn the motor over by hand. Things change at 200F and 7000rpm's.
 

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With my "old" set of Eagles w/ ARP 2000s I didn't have to notch my girdle...though I did anyways. With my "new" set, I definitely had to notch!
 

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The parts you installed are not made out of plastic. They are a type of metal. My Credit card measure in at a whopping 0.0310 inches. Your parts might expand a little from heat. The RPM will have nothing to do with it. So, you need to figure out what your clearance actually is. What else can you fit under it? Some thing common like a big watch battery or something. Maybe cut an old credit card in half and try to get both pieces stacked to clear. If it won't you will probably need to shave a little bit. It won't hurt the strength of the girdle. Just make sure you smooth it real nice. Sharp edges will give it an area to crack. Like a stress fracture. Smoothing it lessens that chance. I did a buddy of mines DOHC ZC. I polished that thing where I had to notch it. Put tape over all holes and you won't have to worry about too much clean up time.
 

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Get a piece of wire about 1mm or 0.040" dia.

If it can be pulled along the girdle between the girdle and the rods at the closest points you are good to go.

The girdle is as cast and ever one varies a bit, so what works on one engine does not necessarily work on the next. Also if the block was align bored the girdle moves a bit closer.

If you do grind it only remove as much as necessary to get a minimum of 0.040" clearance.

Make absolutely sure you do a proper job of cleaning it inside and out even if you did cover the galleries. Shit does find its way in. Every time someone argued with me on this point I scored a big I told you so as we replaced the bearings soon after.

IT DOES DEPEND ON RPM AS WELL AS THERMAL EXPANSION. The engines do flex and the higher the rpm the higher the flex. Also, generally, the higher the rpm the higher the internal temperatures.

For instance, a SBC on nitro methane at over 2000hp needs about 0.006" main bearing clearance. A factory engine can survive on 0.001" clearance at the same rpm and oil temperature.

The difference is the distortion of the webs in the block and in the crank. Data I have seen shows up to 12 deg twist between points in the power and points in the compression stroke. I would expect less in a short crank like a Honda with it's relatively light rods and pistons, but it will flex.

I think I have seen data for a production engine that showed around 3 deg twist at WOT. Torsional vibration dampers where invented to help reduce this twisting and thereby reduce the tendency for cranks to fatigue crack.
 
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