TheSamba.com :: View topic - OK, what' you guys opinion off "Plastigauge"?

Thu Jun 03, 2021 1:49 pm

OK I don't have a tool box of fancy measuring devices and cant really afford them. I have some OD Mic's and Calipers but nothing to write home about, But I can afford Plastigauge.
What's are you VW gurus opinion of the stuff?
I guess you can only use it on the center main and the rods, well I will be using it on a SBC too. I guess I need to start saving my pennies for a bore gauge.

eQ

Thu Jun 03, 2021 2:53 pm

If you have mics already you can get a set of snap gauges for a fraction of the price of a bore gauge. Not nearly as quick but a lot less money.

Thu Jun 03, 2021 2:54 pm

Lots of guys use it, some guys tell you it is a complete joke.

It's a very good $6 tool for those that can not afford the $100 tool. I've used it in the past on a few engines. It'll tell you if you are way too tight, but not quite as accurate if your too loose.

Thu Jun 03, 2021 2:59 pm

On a VW engine.... its easy to f' up . accidently rotate the crank... smear'd the plasti-gauge, which i know some may take argument with... but i've seen it. best methods are a dial bore and micrometers. (even if its a cheapie , a cheapie is better than nothing and if it repeats measurements i would say it can be trusted, which is why they include standards with mic's )

Please trust me when i say i know what your dealing with , it took me years in some cases to afford proper tools , and measurement tools on top of that.

Do you know anyone who may have those kind of tools that you would trust to measure for you or allow you to borrow?

I hope this wasnt taken as snarky, I really dont mean to come across that way

Thu Jun 03, 2021 3:01 pm

vwracerdave wrote: Lots of guys use it, some guys tell you it is a complete joke.

It's a very good $6 tool for those that can not afford the $100 tool. I've used it in the past on a few engines. It'll tell you if you are way too tight, but not quite as accurate if your too loose.

gosh i wish there was a thumbs up for samba posts , i would thumbs up this

Thu Jun 03, 2021 4:34 pm

I used it on my recent 2276 build. Kind of fun to do. Basically told me what I already knew but was nice to have some affirmation.

Fri Jun 04, 2021 6:25 am

It may not be perfect but it works way better than nothing!

Fri Jun 04, 2021 6:57 am

Fri Jun 04, 2021 7:40 am

Theres No reason to be messing around with plastigauge like we are in the stone age when you can buy actual tools like micrometers and telescoping gauges for $50 total and digital micrometers for under $10.

https://www.harborfreight.com/micrometer-set-3-pc-64202.html

https://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html

https://www.harborfreight.com/6-in-composite-digital-caliper-63586.html

Plastigauge seems to be for the guys that get off on thinking they are the master for figuring out how much plastic can squish.

Fri Jun 04, 2021 8:15 am

jpaull wrote: Theres No reason to be messing around with plastigauge like we are in the stone age when you can buy actual tools like micrometers and telescoping gauges for $50 total and digital micrometers for under $10.

https://www.harborfreight.com/micrometer-set-3-pc-64202.html

https://www.harborfreight.com/6-piece-telescoping-gauge-set-5649.html

https://www.harborfreight.com/6-in-composite-digital-caliper-63586.html

Plastigauge seems to be for the guys that get off on thinking they are the master for figuring out how much plastic can squish.

I have some agreement....and some disagreement. Your point is well taken though!

Yes....."useful" tools are cheap enough that for most engine measiring tasks ...one should just buck up and buy a few tools.

However....your listings.....those HF telescopic gauges are NOT accurate at all. I have run across a handful of my own clients usimg those exact gauges in sub assembly checks.....and they are all over the place because they are so rough. Considering what industrys most of my clients are in.....I was absolutely appalled to find them at all....when they have 8 figure budgets!! :lol:

In general.... the very best of these HF telescopic gauges I have seen are not repeatable within about +/- 0.0005".
The vast majority of them are not repeatable with a +/- 0.001".

After coming across a few of these sets I took one of my mics to harbor freight and did a cursory check of about six sets on the shelf. A couple of them could not be accurately tightened to hold within 0.003".

And.....that dial caliper is only a 0.01" accuracy. But I know what you are getting at. There are other models for under $20 that ARE good enough.

That micrometer set is actually not bad at all. Its a dead on knock off of a Mitutoyo set.....but because its a 0.001" accuracy....and I have not played with a set to see what its actual tolerance is.....I would not consider it accurate enough for crankshaft work.

But the subject of "Plastigage".....yes....it is accurate. The manufacturing tolerances of its durometer and consistency are far above the hard tools we are talking about here.

The problem with it.....is age/shelf life....and the technique or ability of those using it. Plastigage is dated and changes hardness with crush. It has to be stored properly...cant be frozen or overheated....or handled roughly etc.

My agreement is that if you can possibly avoid having to use it....do so.

The BIGGEST problem is that people who dont have tools....frequently use plastigage.....to try to verify machine work they had done. :lol: ....and probably have little or no experience with using it....have no idea of its age and how to handle it......and usually get results that are poor.

Ray

Fri Jun 04, 2021 8:26 am

X2 on those telescoping gauges. Accuracy and repeatability suck.

Fri Jun 04, 2021 8:33 am

I kinda agree plastigauge is a bit pointless. In a pinch or for a real budget rebuild I'm sure it does the job as long as the person using it isn't an idiot

I have a set of cheap HF snap gauges. I didn't study them too much, and yes it's kind of junky build quality, however I couldn't find any measurable variation using my set of basically NOS mitutoyo mics, maybe 0.001" at most. But I didn't check the very biggest ones... only the one for my bearings and smaller.

I was still a little concerned with the accuracy, mostly given my lack of experience using these precise measuring tools, so I just measured everything about a dozen times. Good practice for me and gave me confidence in my clearances.

I will probably keep my eye out for a good used Starett telescopic snap gauge set. Honestly those are not even too expensive. Maybe $50-$100 for a good complete kit from what I've seen. I also got my NOS Mitutoyo's for a really good deal after I checked ebay over a couple weeks. A seller listed a few separately and I sent him a message to strike a deal for all of them and he was game. I got a 25, 50, and 75mm all for $100 shipped. They had the orange box and tan case, plastic wrap, instructions, the original the standards were still covered in wax. They all have a Suzuki parts sticker on them for some reason, I think these must have come from a Suzuki dealer that closed somewhere?

Anyway my point is the cheapest stuff is usable, but for only a little bit more cash you do very well if that's your thing 8)

Fri Jun 04, 2021 9:27 am

Somehow plastigauge always felt like groping in the dark to me. I'm not a terribly huge fan, but it can be useful if you don't have access to more advanced stuff.

Fri Jun 04, 2021 9:30 am

do not use snap gauges. PG is ok. a good dial bore gauge is cheep I probably have 8 of them now for various things even valve guide clearance. just get the cheep china one off flebay for $28-$38. or less, just keep klicking and looking at the results under the one that comes up. even the main stream manufactures are putting their names on them,,like mitsitoyu, folwer,nsk etc. they are good quality and do the job just as good as the extreamly expensive ones. and yes you can also use them on your SBC, and try to build the vw like a SBC so it might last... remember the engine nor the car does not know what it is. mine thought it was a viper. the main issue with PG is age and tempature and oil. oil degrades it, you do not need to scrape it off as oil disolves it...so any oil will make it spread differently, as well if oil is on the other side fo the journol you will be reading the thicknes of it too, not the real clearance... age also tends to change the squish...thus a $36 dial bore gauge is extreamly worth it. do as niki says....just do it.

Fri Jun 04, 2021 9:33 am

During my last engine build I used a bore gauge and HF micrometers. Since then, I splashed on a set of Mitutoyo mics. Comparing them, the HF mics were really not bad at least for the accuracy required for my engine build. I use plastigage as a backup to check my work and then check how the parts feel when I mock them up.

At my current skill level, I am just trying to ballpark it within the Bentley specs. I am fooling myself if I think I am nailing down a specific number to a ten thousandth.

Fri Jun 04, 2021 10:02 am

orwell84 wrote:

Quote: I use plastigage as a backup to check my work and then check how the parts feel when I mock them up.

At my current skill level, I am just trying to ballpark it within the Bentley specs. I am fooling myself if I think I am nailing down a specific number to a ten thousandth.

X2!!!!!!

Tom

Fri Jun 04, 2021 10:38 am

orwell84 wrote: During my last engine build I used a bore gauge and HF micrometers. Since then, I splashed on a set of Mitutoyo mics. Comparing them, the HF mics were really not bad at least for the accuracy required for my engine build. I use plastigage as a backup to check my work and then check how the parts feel when I mock them up.

At my current skill level, I am just trying to ballpark it within the Bentley specs. I am fooling myself if I think I am nailing down a specific number to a ten thousandth.

I have a couple of dial bore gauges. A very good one and a cheap China gauge....which is JUST as accurate even when compared to a couple of Sunnen gauges I have played with side by side......BUT ONLY WHEN.....you swap out the dial gauge that came on the cheap china bore gauge with something better.

The gauge that came with the bore gauge is not bad. Its Chinese but smooth...but only reads in 0.0005" increments. I put on my Starrett 0.0001" gauge and its an order of magnitude better.

And...to get that butter smooth accuracy that a Sunnen gauge has....you need to remove the spring on the transfer rod inside of the China gauge and rely only on the spring in the dial gauge.

As for teh telescopic gauges.....I needed a set and use them...because my dial bore gauges will not work down to the diameter of lifter bores and brake master cylinder bores. I needed them for that.

BUT....I will say this. This Mitutoyo telescopic gauges are not all that good either. Until I started shopping again about two years ago...I had been relying on a no-name Japanese set I bought about 20 years ago.

The fit and finish is far better than the HF gauges....but they are still clunky and variable. They are probably Mitutoyo seconds or rejects.

But when you compare then to a set of Starrett telescopic gauges.....the Starrett are WORLDS better. Very smooth and very repeatable once you learn how to use them.
Once you see them side by side....you will understand how Starrett can fetch the seemingly stupid high prices they do.

I have the same issue with tools for measuring valve guides. I just cannot justify affording them for the very limited work I do. I rely on very good shops to do my work....but I do like to check their work....because I don't trust ANYONE :lol: ....sorry...its just a flaw I have.

So...a year ago I started shopping for something better than my existing "half ball" expanding gauges. They are also 20+ years ago Japanese no name gauges....and they work pretty well.

But I found a full range set of Starrett half ball gauges virtually brand new in the box on Ebay a year ago.....circa 1965 :shock: ....I snapped those up for about 1/3 the cost of what they are now new.

The quality level, smoothness and accuracy of tension in the locking is again...worlds away better and more accurate than teh cheap Japanese half ball gauges I have.

Small hand tool gauges like telescopic, half ball expanding and feeler gauges...I have not found any equal to Starrett products. However....in micrometers....I have found many Mitutoyo's to be equal or better in quality, fit, finish and accuracy.

I still use PG....on anything I have to measure with a dial bore gauge...just as a backstop. I do not do enough engine work to say I am good enough with a dial bore gauge without concerted time and effort.

I probably have to spend 5-10X the amount of time measuring case bores as a "REAL" machinist would with the same tool.

If I am using fresh plastigauge and get a reading that is unreasonably out of tolerance to what I measured with the dial bore gauge....its a signal to me to measure again.

Its too cheap compared to engine parts to NOT use.
Ray

Fri Jun 04, 2021 10:42 am

The worst China dial bore gauge that probably works is $60. A really solid Fowler China dial bore gauge like my "shop beater" is $100. Why wouldn't you? I have a real Sunnen since I worked there for 4 years, and I haven't caught my Fowler telling me filthy lies compared to it, even once... so... why wouldn't you?

I'm with Ray here!

Fri Jun 04, 2021 10:59 am

I'll bet 90% of the hobbiest that just build one or maybe two engines have no clue how to properly use a telescoping snap gauge, dial bore indicator or even a simple micrometer. It's just plain foolish to tell a guy he must buy several hundred dollars in tools he will only use once and never use them again.

The $6 plastigauge is just as accurate as any of the $10-$20 HF junk.

For those that don't have the tools and knowledge to build just one engine for themselves it might be cheaper and more cost effective to buy a long block or turn key engine from an experienced engine builder.

Fri Jun 04, 2021 11:21 am

I disagree starkly. If you aren't willing to drop $150-$200 on tools to assemble what is often thousands of dollars of engine parts even for a "somewhat mild" build, that's just fundamentally flawed decision making. That's probably 10% the cost of a lot of sporty budget builds on here, which seems totally reasonable. Tool up, do it right, don't look back.

A decent set of heads alone is 3-4 times the cost of the measuring tools you need. All ya need is HF stuff if you're just starting out, and lots of the tools are useful in many different situations. Heck, you can fixture a dial bore gauge to set endplay!