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Plastagage versus bore gauge

General engine tech -- Drag Racing to Circle Track

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bentvalves
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Re: Plastagage versus bore gauge

Post by bentvalves » Mon Jan 13, 2020 6:31 pm

incredible.

remember when you guys yelled at me for asking about poking a hole in a seat counter bore and it not being a racing engine?

welp, here you have it.

best wishes to all in the new year.

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Re: Plastagage versus bore gauge

Post by gmrocket » Tue Jan 14, 2020 1:30 am

My latest clevite bearing catalogue explains how to check bearing clearance using clevite plasti gauge.

Clevite does sell plasti gauge under their own name...

It's no different than any other plastic gauge, except the price.

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Re: Plastagage versus bore gauge

Post by engineguyBill » Tue Jan 14, 2020 12:02 pm

Actually, Clevite/MAHLE Aftermarket is the manufacturer of Plastigage, at their facility in Olive Branch, MS. They sell it to several other manufacturers who sell it under their own label. Plastigage product was developed and owned by Perfect Circle division of Dana Corporation for several years. PC and Clevite divisions were sold to MAHLE in 2007.
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Re: Plastagage versus bore gauge

Post by engineguyBill » Tue Jan 14, 2020 12:07 pm

engineguyBill wrote:
Tue Jan 14, 2020 12:02 pm
Actually, Clevite/MAHLE Aftermarket is the manufacturer of Plastigage, at their facility in Olive Branch, MS. They sell it to several other manufacturers who sell it under their own label. Plastigage product was developed and owned by Perfect Circle division of Dana Corporation for several years. PC and Clevite divisions were sold to MAHLE in 2007.

As I mentioned previously it is a very simple manufacturing operation and takes up about the same space as your kitchen table. The table at MAHLE is over by the restrooms, I think the janitor runs the machinery at night while he is cleaning the offices . . . . . . . .
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Re: Plastagage versus bore gauge

Post by engineguyBill » Tue Jan 14, 2020 12:08 pm

Actually, Clevite/MAHLE Aftermarket is the manufacturer of Plastigage, at their facility in Olive Branch, MS. They sell it to several other manufacturers who sell it under their own label. Plastigage product was developed and owned by Perfect Circle division of Dana Corporation for several years. PC and Clevite divisions were sold to MAHLE in 2007.

As I mentioned previously it is a very simple manufacturing operation and takes up about the same space as your kitchen table. The table at MAHLE is over by the restrooms, I think the janitor runs the machinery at night while he is cleaning the offices . . . . . . . .
Bill

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Re: Plastagage versus bore gauge

Post by tenxal » Tue Jan 14, 2020 5:57 pm

A few weeks ago I was assembling a SBC and got curious how Plastigage would measure compared to the dial bore method. As expected, it was very accurate. You can't get to the .0001's, obviously....but it's pretty easy to split the difference between .0005's.

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Re: Plastagage versus bore gauge

Post by Dave Koehler » Wed Jan 15, 2020 9:18 am

I used to include some plastigage with ever degreesy unassembled engine that went out.
As such I kept a fair amount on hand.
Even long ago I heard the stories about "fresh" being critical.
Here is the thing.
Since it never had a born on date how the heck do I know what is fresh?
I had/have no idea how long it sat on the warehouse shelf before I bought it..

Has anyone ever done a test with some 5 year old pg against what you assume is fresh?

Is this just another one of those things that became wisdom but has no basis in reality?

Edit: https://www.plastigaugeusa.com/about.html
Other than it is preferred to be used below 95 degrees (melts?) nothing is said about it going bad over time.
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Re: Plastagage versus bore gauge

Post by Kevin Johnson » Wed Jan 15, 2020 10:03 am

Dave Koehler wrote:
Wed Jan 15, 2020 9:18 am
I used to include some plastigage with ever degreesy unassembled engine that went out.
As such I kept a fair amount on hand.
Even long ago I heard the stories about "fresh" being critical.
Here is the thing.
Since it never had a born on date how the heck do I know what is fresh?
I had/have no idea how long it sat on the warehouse shelf before I bought it..

Has anyone ever done a test with some 5 year old pg against what you assume is fresh?

Is this just another one of those things that became wisdom but has no basis in reality?

Edit: https://www.plastigaugeusa.com/about.html
Other than it is preferred to be used below 95 degrees (melts?) nothing is said about it going bad over time.
https://www.yellowbullet.com/threads/pl ... t-56447370

Yes, there is a difference. Photobucket wants to be paid if you would like to see the images or write directly to the poster.

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Re: Plastagage versus bore gauge

Post by Ks Fats » Wed Jan 15, 2020 10:27 am

Dave,
About 20 years ago I was doing a resto on a 235 chevy for a customer. I decided to do a quick check with pg on the mains.
When I removed the caps the material had not compressed completely and actually left indentations in the bearing. As you say; there is no born on date so I don't know how old it was or the storage conditions. Bought the customer a new set of mains and have never touched the stuff again. Could have been a fluke but I can live with the quirks of the d.b. gauge.

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Re: Plastagage versus bore gauge

Post by David Redszus » Wed Jan 15, 2020 7:13 pm

A recent head sealing project and the mention of Plastigage brought an idea to mind.

Suppose we were to take a nice clean block surface, lay down several strips of Plastigage, install a nice clean head and
torque to specs.

What range of clearances are we to expect? Does the head/block surface remain parallel or does it distort when clamped?
Where does the distortion occur? Do the surfaces move with respect to each other?

Didn't mean to hijack this thread but could not resist the temptation.

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Re: Plastagage versus bore gauge

Post by MadBill » Thu Jan 16, 2020 1:22 am

Running with the hijack ball: that would be really interesting! I suspect all the PG strips would end up as near-transparent blots a half inch wide.

Of course for an accurate picture the use of pressure indicating film would be preferable: https://www.sensorprod.com/glossary/pre ... g-film.php
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Re: Plastagage versus bore gauge

Post by Kevin Johnson » Thu Jan 16, 2020 9:55 am

MadBill wrote:
Thu Jan 16, 2020 1:22 am
Running with the hijack ball: that would be really interesting! I suspect all the PG strips would end up as near-transparent blots a half inch wide.

Of course for an accurate picture the use of pressure indicating film would be preferable: https://www.sensorprod.com/glossary/pre ... g-film.php
If you remain seated, no-one will be hurt.

https://www.sensorprod.com/research-articles/index.php

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Re: Plastagage versus bore gauge

Post by David Redszus » Thu Jan 16, 2020 10:19 am

MadBill wrote:
Thu Jan 16, 2020 1:22 am
Running with the hijack ball: that would be really interesting! I suspect all the PG strips would end up as near-transparent blots a half inch wide.

Of course for an accurate picture the use of pressure indicating film would be preferable: https://www.sensorprod.com/glossary/pre ... g-film.php
Before we had Fiji Film, we made use of carbon paper (like typists once used, now obsolete).
The film would indicate the local pressures but not the clearance gap.

When we get back from Eagle River this weekend, I'm going to try film and Plastigage on a few applications.
Might work better than Prussian Blue.

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Re: Plastagage versus bore gauge

Post by Knight rider » Thu Jan 16, 2020 1:12 pm

I would look at like this, you're trying a measure a clearance which is either from a OEM spec or bearing supplier or even a standard for that engine by engine builders, you must use the same method they used. Let's say you had a even better way of measuring like using a scan tool with lasers and 3D imaging well now you have no reference point to compare to because that's not how it was done to come up the clearance in the first place. Cheers

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Re: Plastagage versus bore gauge

Post by Kevin Johnson » Thu Jan 16, 2020 1:28 pm

I think Plastigage supplanted the use of very thin lead wire (lead wire might still be called out by an OEM).

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