Compression gauge, old vs new.

[SC-AW11]

I wanna pick up a compression gauge soon, which would you buy;
An old one in metal box for about 100?
http://losangeles.craigslist.org/sfv/tls/3998132248.html
this one looks like a good deal for being well taken care of:
http://orangecounty.craigslist.org/tls/3965727947.html

Or a new one for 130? (student discount)
-or a used, new one for about 60-100?
http://www.ebay.com/itm/SNAP-ON-Com..._Automotive_Tools&hash=item2c714d713f&vxp=mtr

Any difference in accuracy or reliability?

 

[03protege]

I would say there SHOULDN'T be any difference in accuracy or reliability but I am always cautious when purchasing precision instruments used.

I've heard of these gauges going out of whack from a simple drop on the floor.

For $30 more a new one sounds like a no brainer to me.

 

[SC-AW11]

Ya same here. wow jus a drop, but actually Im not too surprised. gotta be careful with the precision tools.
Ya? hmm, even though it could be delicate, its not one of those tools that "they dont make em like they used to"?

 

[wornoutoldman]

I'd take the vintage set in a heartbeat. The box alone is worth it to me.

 

[WWIIjeep]

I'd take the vintage set in a heartbeat. The box alone is worth it to me.

+1

I've had that same Snap-On kit for years, and it's great.

 

[Packard V8]

FWIW, I've got a latest-and-greatest $150 digital MAC set which reads 5-7 PSI lower than my three old mechanical dial units; Sears Penske, a Craftsman and a '40s dial Snap-on.

I need to get it calibrated so I know which one to trust.

jack vines

 

[rsanter]

That $100 set sure looks in good shape
How about you see if he will take a little less

Bob

 

[SC-AW11]

You guys are saying the 100 old one now, I get that "they dont make em like they used to" vibe. Did you guys see the one right below for 80? looks like it was really well taken care of

 

[94yj]

i would say go with the 100 dollar old school one but try and get the price down to around 75/80

 

[warmpancakes]

new, the older snap ons you cant getting hoses for snap on changed the thread about 3 years ago

 

[zkling]

If you want a super accurate compression tester. Just purchase a cheap set and replace the gauge with a known quality (calibrated if you want) one. All a compression tester is, is just a check valve, a hose and a pressure gauge.

 

[devoncoolman]

new, the older snap ons you cant getting hoses for snap on changed the thread about 3 years ago

Any local hydraulic shop can fab up a new hose for it if need be. I would do that anyway. U can get a better quality hose that will last 60 yrs at half the price of a snap-on replacement. All while supporting a local company.

 

[W-Cummins]

I'm not sure what threads they are talking about, but all the adapters I have use a quick disconnect like found on an air hose William. .......

 

[rival904]

http://www.sears.com/craftsman-compression-test-kit/p-00947089000P?prdNo=1&blockNo=1&blockType=G1

That's the best deal I've seen on compression testers.... I got my kit brand new in the box at the pawn shop for $30 out the door.

 

[jimindm]

I would not consider any compression gauge to be a precision tool. If you need one that is that good, you need to look somewhere else than automotive tools. I would really ask how accurate do you need one? Its not like a fuel pressure gauge where 4-6 PSI inaccuracy would make a difference. I would guess that a 2-4% margin of error is common, so 3-5 psi would be about right. I am not sure that I even have one that Is measured in such small indications that I could see such a difference.

In reality when using one for diagnosis, such a small amount of difference really is not a big deal. What you are looking for in compression testing is relative compression across all of the cylinders.

I have several, from different manufacturers, and I would say get one that you would be able to get replacement parts for. Most likely that is a brand off of a tool truck. They all may be the same, but you tool man will have a breakdown of his brand, with part numbers. The guy at a parts store, or sears, most likely will not.

I have kind of steered away from digital gauges. Most times they have no graph or analog setting, and you are looking at numbers. Not really sold on transducers for DVOMs when is comes to pressure readings.

I would say that with amps probes on the market now, and a good DVOM, you can do a cranking compression test electronically much faster. You may not have actual compression PSI numbers, but enough information to know where the problem is.

I think everyone should have a compression tester. There is always a chainsaw, or tiller you may want check out.

To answer the OP question, get the one you can afford to leave sitting in your box, unused for long periods of time.