How to build a leakdown tester:
 

I was in a hurry, and wanted a leakdown tester. I was going to just buy this tester:

http://www.harborfreight.com/cpi/cta...emnumber=94190

but I did not want to wait a month for Harbor Freight to ship it to me. No local stores carried a leakdown tester either, so I decided to build one myself.

I did some searching online, and found these directions:

http://www.xs11.com/tips/misc/misc3.shtml

The directions were helpful, but did not cover some of the problems I ran into.

First, I do not see any way to tap a sparkplug to thread in a pipe. On all the sparkplugs I had sitting around, the hole was just too big, and there was not enough steel to work with. I ended up just shoving in the pipe, and JB welding it in place. It has worked VERY good so far.

Second, the size of the hole you drill is very important. Start small, using a #60 like the directions described, and only work bigger if needed. The smaller the hole, the more sensitive the meter will be. Once you assemble it all, try it out to get a feel for what readings can be considered "normal" by using it on a good vehicle or two.

I also tried to improve on their design by placing the quickcoupler directly on the sparkplug. This allows me to thread the sparkplug in more easily.

Here is the completed tester:

http://img321.imageshack.us/img321/2...arge8cp.th.jpg
http://img321.imageshack.us/img321/3...arge6jh.th.jpg
http://img321.imageshack.us/img321/2...arge6gg.th.jpg

This whole tester only cost me about $40. It would have been cheaper, but I ended up buying a pipe tap, and a few other parts I did not need. I also used a few parts I had sitting around the shop.

Next I plan on trying to adapt a compression gauge over to the spark plug quickcoupler adapter, and maybe making a set of sparkplugs with quick couplers on them so I can quickly go from cylinder to cylinder while testing.

Re: How to build a leakdown tester:
 

Damm i just bought one from Snap on but that is awesome.You are officially a hard core mother fucker :y

Re: How to build a leakdown tester:
 

Thats some good info, i might have to build one.

Re: How to build a leakdown tester:
 

Have you tried using it yet? It seems like the quick-connect is going to be down in the spark plug bore, with no way to remove it once you put it on. :1

The pics in the how-to link have a 12" or so length of rubber hose between the gutted spark plug and the quick connect.

Re: How to build a leakdown tester:
 

I used it on my 1989 Accord and it fit fine. I do not know about how well it would work for other vehicles.

Worst case I could always attach a small cable to the quickcoupler to release it remotely.

I moved the quickcoupler down to the sparkplug so that I could get my sockets over the plug to tighten it down.