Please recommend a leak down tester

[EricP]

I have a compression tester but I need a leak down tester for more info. There seems to be a range: cheap Harbor Freight (which I usually avoid like the plague) up to fairly expensive SnapOn (which would be my preference if I hadn’t already killed my budget). There are several that I don’t recognize the name but could be good. Can anyone make a recommendation? Would be nice to be under $100 but I don’t want crap that isn’t reliable so if it needs to be over that, so be it.

[DaveW]

I built my own many years ago using 2 60-psi gauges I had accumulated over the years, a cheap regulator, and pieces of 1/4" pipe & fittings. I made adapters out of old spark plugs.

There is a 0.020" dia orifice in the pipe between the gauges, so it is more accurate than the usual LDT for small engines in good shape. I do the leakdown at 50 psi. It works very well.

Photos below:

[EricP]

That looks simple enough... thx.... off to search McMaster...

[Steve Demeter]

Exactly what I did except I used a flow control for the orifice and made a plug to pt in the end of the hose with an 0.030" hole in it to be able to check calibration. Yep just braze a quick disconnect fitting on an old spark plug and you are in business.

[FVRacer21]

I went looking for the company I bought a unit from 30 years ago and I think this is the current iteration.

this looks interesting

https://aircraft-tool.com/shop/detail.aspx?id=2EM-KIT

no endorsement - just a price point and sample.

and I looked just for fun

https://www.harborfreight.com/search?q=Leak%20down.

ChrisZ

[BeerBudgetRacing]

https://www.summitracing.com/search/...down%20Testers

I think Performance Tool is the same source as HF.

Total Seal makes rings so they should make a decent tester.
I have a longacre.

For most you will need to make an adapter.

[Daryl DeArman]

Mine is a Tavia. Not sure if they are still available. . . cursory google search did not come up with one. Gauges are made by Ashcroft in CT.

I'm fairly frugal, so I can't imagine I spent a whole lot on the tool, maybe $100, but probably close to 20 years ago.


There's a set USED on ebay right now for $90.

[DanW]

I have one of these. Gauges are calibrated and matched with a .040" orifice. Designed for aircraft engines, I soldered the orifice closed and re-drilled to .020". I use the spark plug adapter from my compression tester. Ebay has a good selection, but avoid the Hazard Fraught model. Gauges are junk,

https://www.google.com/search?q=East...w=1920&bih=944

[Rick Kirchner]

Got mine at Aircraft Spruce nearly 20 years ago.

[T644HU07]

I have an old Snapon I'm not using if you're interested. $75.00 plus shipping from 63303.

I have a compression tester but I need a leak down tester for more info. There seems to be a range: cheap Harbor Freight (which I usually avoid like the plague) up to fairly expensive SnapOn (which would be my preference if I hadn’t already killed my budget). There are several that I don’t recognize the name but could be good. Can anyone make a recommendation? Would be nice to be under $100 but I don’t want crap that isn’t reliable so if it needs to be over that, so be it.

[BLS]

Back when I was a kid I did what DaveW did and just built it as I had the parts lying around. A couple years back when I started again I did not have parts lying around and the cost was about the same as just buying one - OTC.

Works fine.

https://www.amazon.com/OTC-5609-Cyli...-1-spons&psc=1

[Wes Allen]

While on this topic,anyone care to share the proper procedure for testing leakage? How to you find and keep the piston at TDC?

[EricP]

While on this topic,anyone care to share the proper procedure for testing leakage? How to you find and keep the piston at TDC?

Wes, I assume you mean Kent, correct? I can’t speak to that for certain...

[Wes Allen]

Yes, I was basing my question regarding the Kent

[DaveW]

While on this topic,anyone care to share the proper procedure for testing leakage? How to you find and keep the piston at TDC?

Just locate the piston at TDC as closely as you can - it won't move off TDC as long as it is close. Friction will keep it there unless it's a decent ways off TDC. And using 50 psi (as I do) instead of 100 psi makes it easier to have it not move.

Before I apply pressure to the tester, I wiggle the crank back and forth a few times to settle things in.

[Steve Demeter]

If it is not at TDC on the compression stroke you will know right away. I just run an eyeball down the plug hole and wiggle the crank like Dave said. No magic tricks involved.