Compression tester, what type?

Chuck Moreland · 06-14-2002, 06:35 AM

I have an old compression tester with a flex hose between the dial and the threaded fitting. No way it is going to screw into the 911 spark plug holes due to the deep plug sockets.

What kind of tester works and where to buy?

Talonz82 · 06-14-2002, 07:11 AM

Good question, I've been looking for a factory made product myself, I have a really nice *Mack*, but as you mentioned it had a flex hose, I had to take it to a machinist whom made me a stainless steel tube out of 4140 which the gauge screwed into then he made me a brass fitting for the other end in the exact specs of the original for the spark plug hole
I use this for my leakdown tester (JC whitney) as well.

Formerly Steve Wilkinson · 06-14-2002, 07:44 AM

You want a leakdown tester of the sort that are used to test the compression of lightplane engines, not a plain old compression tester.

Stephan

Talonz82 · 06-14-2002, 07:46 AM

Stephan, if that reply was for me, I should have said,

"I use this adapter for my Mack compression tester *AND* for my leak down tester, that I bought at JC whitney."

sorry for the slip...

Peter

jkeyzer · jkeyzer's Garage

The flex hose versions available at Sears et al. will work with some skill and patience, believe it or not.

I've done it before and by the end I had gotten the hang of threading the tube in blindly.

speeder · speeder's Garage

I would say that a snap-on, (or equivalent), with detachable hose should work fine. The hose is just stiff enough, but flexes enough to meet the plug-hole.

zuffenhausen · 06-14-2002, 11:27 AM

Check into the gauges made by Tavia. Very nice.

-zuff

pbs911 · pbs911's Garage

For those of us who are inept at putting a flacid tube in a hole, is an extention such as the one described by Talonz82 available commercially? I was all hyped about doing a compression check and picked up one up. When I went to do the check, I realized the errors of my ways.

Early_S_Man · 06-14-2002, 12:20 PM

Paul,

Such an adapter ... typically called an 'air holding chuck' must be available by now from suppliers such as Lisle ... for the Ford modular V-8 SOHC engine, and its' plugs are even further recessed than a 911's.

For those with oxy-acetylene rigs, it probably wouldn't take more than an hour to make one from an old spark plug, scrap of iron 3/8" pipe, and suitable fitting.

emcon5 · emcon5's Garage

Quote:

Originally posted by pbs911
For those of us who are inept at putting a flacid tube in a hole,

Paul, you know they hava a pill for that now, right?

Tom

911pcars · 06-14-2002, 02:17 PM

Chuck,
If you're doing compression tests for a living, get the Snap-On (or equiv.). If not, the Sears two-piece (detacheable hose) compression tester works fine (at least the one I have). I suppose the Sears return policy gives you an out if it's not easy to use. The price difference buys a lot of brewskis.

Sherwood Lee
http://members.rennlist.org/911pcars

Chuck Moreland · 06-14-2002, 03:06 PM

Turns out I'm better at putting floppy hoses down tubes than I thought. I am happy to say I have no similar experiences to draw upon.

Based on above comments I gave the old tester a try and it works pretty easily.

I've worked a deal on a '73 coupe. I'll be checking head studs and compression on the motor tomorrow AM. If all is in order we close the deal.