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Checking clearances #205767
01/27/09 12:15 PM
01/27/09 12:15 PM
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Moparnut426 Offline OP
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I might have asked this before, but how accurate is plastiguage? I got my stroker kit from Dan at performance machine, and I have started making sure everything is ok before assy. I have my crank and rods on my living room floor, and Im checking each rod and Im at 2 thousands on the rods with light oil, and green plastiguage. Do I have to use a different rod on every journal also, or can I use the same one. They are Childs track master rods and are a pain to get apart to check them. Should I put them together with the bearings in and use a snap guage, and a mike?

Or am I ok. Dan said 2-2.5 , and 2.5 is ideal. Also what is the green thick gunk on the rod bolts and should I clean it all off, and use oil.

Thanks,

Hope this isnt a dumb azz question.

Kasey

Re: Checking clearances [Re: Moparnut426] #205768
01/27/09 12:21 PM
01/27/09 12:21 PM
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maximum entropy Offline
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organ
imo plastigage is not nearly as accurate as it used to be. in the olden days it was much more substantial, and actually felt like plastic. we would verify the plastgage reading with mic and dial bore gauge, and it was always spot on. now, it's waxy, and i've gotten some wildly inaccurate readings, so i don't use it anymore. imho, mic and dial bore gauge are the only way to go!


for what is the good life if not doing things thoughtfully?
Re: Checking clearances [Re: maximum entropy] #205769
01/27/09 12:41 PM
01/27/09 12:41 PM
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Moparnut426 Offline OP
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I agree, If anything its only good for checking any taper in the journal.

Ill have to buy a set of snap guages, and a mic.

Re: Checking clearances [Re: Moparnut426] #205770
01/27/09 01:26 PM
01/27/09 01:26 PM
Joined: Feb 2007
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organ
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maximum entropy Offline
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organ
i recommend a dial bore gauge over snap gauges, as they are generally more accurate. good snap gauges are as expensive as some bore gauges, although top o' the line bore gauges are REALLY expensive!


for what is the good life if not doing things thoughtfully?
Re: Checking clearances [Re: maximum entropy] #205771
01/27/09 03:13 PM
01/27/09 03:13 PM
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North Alabama
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Monte_Smith Offline
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Plasti-gauge should not even be made, much less used, at least in an automotive application, where small clearances are required. You need a dial-bore gauge. A top level one can be extremely expensive, but for the home builder, a pretty good one can be had for less than a 100 bucks. As a matter of fact, I was checking out the "tool tent" at a race in Bradenton this past weekend. I noticed on off brand dial bore set there. It was surprisingly nice and had a considerably longer handle than most of the cheapo units. It was only 60 bucks. Did not need it, but bought one anyway for that price.

Monte

Re: Checking clearances [Re: Moparnut426] #205772
01/27/09 03:14 PM
01/27/09 03:14 PM

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Quote:

I might have asked this before, but how accurate is plastiguage? I got my stroker kit from Dan at performance machine, and I have started making sure everything is ok before assy. I have my crank and rods on my living room floor, and Im checking each rod and Im at 2 thousands on the rods with light oil, and green plastiguage. Do I have to use a different rod on every journal also, or can I use the same one. They are Childs track master rods and are a pain to get apart to check them. Should I put them together with the bearings in and use a snap guage, and a mike?

Or am I ok. Dan said 2-2.5 , and 2.5 is ideal. Also what is the green thick gunk on the rod bolts and should I clean it all off, and use oil.

Thanks,

Hope this isnt a dumb azz question.

Kasey




plastigage is supposed to be used only on clean, dry surfaces. no oil. also, you need to keep the rods from twisting when you torque the bolts to get any accurate readings. i don't use plastigage. a mic and bore gage is much more accurate. snap gages are not accurate enough IMO to check that type of clearance.

Re: Checking clearances #205773
01/27/09 03:45 PM
01/27/09 03:45 PM
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Moparnut426 Offline OP
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there are a few on ebay for easy money right now, Ill get one on the way. I need a set of mics also.

Thanks guys

Kasey

Re: Checking clearances #205774
01/27/09 03:50 PM
01/27/09 03:50 PM
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Quote:



plastigage is supposed to be used only on clean, dry surfaces. no oil. also, you need to keep the rods from twisting when you torque the bolts to get any accurate readings. i don't use plastigage. a mic and bore gage is much more accurate. snap gages are not accurate enough IMO to check that type of clearance.





You'll get readings pretty easy on the mains, but to get close on the rods you need both rods on the journal before you try applying any torque & you should use a feeler gauge to take up the clearance between the rods...

Re: Checking clearances [Re: 1_WILD_RT] #205775
01/27/09 06:59 PM
01/27/09 06:59 PM
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
B G Racing Offline
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We check everything with mechanical gages,bores,journals and every componant.We still spot check on final assembly at least one rod and one main with plastic gage,you would be quite surprised how close it always comes up.We do this for the engine owners benifit and varification as it is easier for them to "see" than it is for them to get the feel or try and read or calibrated mechanical measuring devises.It may seem redundant to some but it is very helpful that an owner can feel confident.It's also a good teaching tool for the youngsters.







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