Recommendations for compression tester kit

[MBI Houston]

I am going to buy a compression tester kit. Any thoughts on what to look for when buying one? What features are unique to the Model A? What do you look for in comparing quality?

Thanks,
Marshall

 

[Special Coupe Frank]

Personally, I would regard this type of purchase as in investment in shop-equipment that can / will be used on other vehicles, and should last a lifetime.

Therefore, I would be inclined to shell-out a few $$ for something decent ( ie: Craftsman, K-D, Snap-On, etc.)

I would shy away from really cheapo stuff from Harbor Freight or other bargain crap, but others will disagree...

When it comes to tools and especially measuring equipment, you usually "Get what you pay for" in terms of durability and accuracy.

I like the compression testers that come with a flexible hose and have a check-valve that keeps the needle on the highest reading until you press a little release-valve on the side. Most kits of this type come with a variety of adapters for 10mm, 14mm and 18mm spark-plug ports. You will either have to purchase a 14mm to 7/8" adapter from one of the model A suppliers ( they run about $6-8 ), or make your own out of an old 7/8" spark-plug shell with the porcelain broken-out and tapped for 14mm or with a 14mm "anti-fouler" welded in to the 7/8" plug shell.

Good luck !

SC Frank

 

[Jim/GA]

I agree with Frank, Marshall. I have the type he describes. I have had it for many years and it has served me well. (Stop by and check it out, if you want.) You can screw it in, operate the starter switch from under the hood with your right hand and hold the gauge head in your left hand to read the pressure increases in 3 or 4 steps (so it is a one man job).

There is another style that I have used that is a bit easier to use on a Model A. I think it was from Snap On, but not sure if they still sell it. (I borrowed it once from Bill Coleman because I did not have the plug adapter that Frank mentions for my gauge.) It has a large rubber cone tip on the end that you push down into the sparkplug hole, instead of screw in. It is faster to test each cylinder with this style because you are not screwing things in and out of the head 4 times. But you have to reach over the engine and press it in firmly while someone else cranks the engine (two man job).

When doing the test, remove all the plugs and use the throttle lever to hold the gas pedal fully open. Record at least 3 pressures in a row as the engine cranks (with key off obviously, and fuel turned off). Do the test on an engine that has been running recently, not stone cold.

 

[A-Jay]

MBI- I had been wanting to purchase the same thing and was looking at sears, local autoparts places etc. I bought a compression tester adapter from brattons part #8371 cost $6.50 and then found a descent tester at a Carlisle car show a couple of months ago for $20 with two other adapters for modern engines new from the big white trailer tool guy, that is always there. So for around $30 bucks I think it will do what I need for at least checking the "A" See photo