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-   -   building block, need suggestions (https://www.homemadeturbo.com/hybrid-tech-8/building-block-need-suggestions-12385/)

Dr.Boost 12-25-2003 03:23 PM

Re:building block, need suggestions
 
I think we're talking about slicing atoms. I doubt you could even get a measurement of the movement because it is so minimal.
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MikeJ-2009 12-25-2003 03:27 PM

Re:building block, need suggestions
 
Well put. ;)

turboboy 12-25-2003 06:51 PM

Re:building block, need suggestions
 
i know what you're trying to say stealth, but (and i agree about the minute possibility of the posts ------- up the sleeves) if a sleeve was out of whack, remember that although the head is bolted to the block and not the sleeve, it still puts pressure on it when you tighten it down...i dont care either way since my block is posted and in the car with no problems yet

sean88accord 12-25-2003 07:33 PM

Re:building block, need suggestions
 
i undersatnd the basci thoery with what your saying about the cylinder floating. that however doesnt add up. the head clamps the fire ring of the head gasket to the tops fo the cylinders. if it didnt youd never get a head seal. That clamping force will distort the bores. Also the bolts pulling on the bottom of the block will and does change the shape of the bores. albit a small amount its still fiarly critical to build the engin to exacting tolerances. Go with a machine shop that has the tools to do the job. I seriously have seen problems from posting. even at 2 inch pounds. you forget that during combustion that the cylinder walls themselves see roughly 2000psi of pressure. and that post wont allow the wall to expand evenly all the way around. Ive pulled a apart a few motors with post that saw moderate to heavy boost. and in every one there is alsways a low spot where the post is.

just stuff to think about.


MikeJ-2009 12-26-2003 03:34 PM

Re:building block, need suggestions
 
Stolen from HT about bearing clearances. I guess I was wrong about the aftermarket rods not needing consideration in the bearing sizes. Take it as you will:

Here is a chart of Honda B series bearing thickness by color. To calculate actual bearing clearance, use the following formula:

BC = IDBT – ODC – (2 x BT)

BC = bearing clearance
IDBT = inside diameter of bearing tunnel (housing bore)
ODC = outside diameter of crank journal
BT = bearing thickness

Main Bearing thickness by color
Blue 2.013-2.010 mm 0.0793”- 0.0791”
Black 2.010-2.007 mm 0.0791”- 0.0790”
Brown 2.007-2.004 mm 0.0790”- 0.0789”
Green 2.004-2.001 mm 0.0789”- 0.0788”
Yellow 2.001-1.998 mm 0.0788”- 0.0787”
Pink 1.998-1.995 mm 0.0787”- 0.0785”
Red 1.995-1.992 mm 0.0785”- 0.0783”

Rod bearing thickness by color
Blue 1.510-1.507 mm 0.0594”- 0.0593”
Black 1.507-1.504 mm 0.0593”- 0.0592”
Brown 1.504-1.501 mm 0.0592”- 0.0591”
Green 1.501-1.498 mm 0.0591”- 0.0590”
Yellow 1.498-1.495 mm 0.0590”- 0.0589”
Pink 1.495-1.492 mm 0.0589”- 0.0587”
Red 1.492-1.489 mm 0.0587”- 0.0586”

Although most people do not have inside micrometers, bearing micrometers or snap gauges, you can still use this chart when using plastigage to check bearing clearance. If you want to increase or decrease a bearing clearance, you can calculate how much of a color change is necessary by looking at the changes on the chart. Remember you can mix colors for even a more fine-tuning but it would not be wise to jump more than one color. In other words, do not mix a brown and yellow bearing together to equal a green clearance value. Just use the greens together. It is ok to mix a green with a yellow or a green with a brown. When doing your rebuild and replacing bearings with like colors, you still must check your results with plastigage to be sure. Don’t assume anything. Also remember, when swapping to aftermarket rods, throw the color codes away as they will not work anymore. You need to start from scratch to obtain your desired clearance. On the other hand, you really cannot measure accurately to the nearest .0001” without machinist quality tools, so don’t get carried away on that last one ten thousandth of an inch variance.


88crxSi 12-27-2003 08:26 AM

Re:building block, need suggestions
 
nice find. I think plastigauge would be the best choice as it gives clearences with everything tourqed down. Im sure there's measurements change when its not tourqed.

sean88accord 12-28-2003 12:45 AM

Re:building block, need suggestions
 
typically if i measure something with and inside and outside MIC its TQ'd to specs. Yes TQ can and does change bearing clearances

88crxSi 12-29-2003 01:26 PM

Re:building block, need suggestions
 

Originally Posted by sean88accord
typically if i measure something with and inside and outside MIC its TQ'd to specs.

sorry sean, that sounds a little confusing to me.. you mean you could measure w/ MIC's etc while it's tourqed into place? did u manage that?

sean88accord 12-29-2003 06:02 PM

Re:building block, need suggestions
 
if you put all the main bearing in the block and the rod bearing in the rods before you put the crank and rod int eh block. You can actually meausre the diameters as they would exist inside the engine blah blah blha. yeah i build motors this way al the time and i plastiguage to. I honestly dont think you can over measure or over build an engine. just a few small mistakes and you can be out $$$$$$$$$$$$$$$$

thats all.

MikeJ-2009 02-10-2004 02:20 AM

Re:building block, need suggestions
 
Little thing I learned today while talking to the guy doing the machining of my block. I was wondering what bearings to buy becuase I didn't have any specs on the finished crank and ----.
He said that it is ideal to order 10 over bearings, do the measurements on the block and crank, then have the crank sent out to have it cut to the exact tolerance that is desired. He told me that this is better than trying to switch factory "colors" of bearings to achieve your desired tolerance. You just have the crank cut to fit into the rods/girdle to match what figure your looking for. Sounds good to me. ;)


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