Leak down Tester

[diesel pig]

I now realise I should of of got one years ago for my Two Stroke engine building. But I am wondering whether I can get away with a cheap one from like Topmaq or bite the bullet and pay for get a high quality from like Lectron?
Any idea's would be welcome.

[F5 Dave]

For engine building you just want low pressure. Like about 4psi. Thus you only need a low pressure gauge as your semi expensive part.
I have a hollowed out sparkplug with a tube brazed to the top some hose and a 3 way brass fitting gauge /hose to plug/ shrader (tire) valve. That way it fits anything.
Bicycle pump to valve.

Then plates to block off inlet and exhaust.
Exhaust with modern ports require a expanding mandrel .

But easier is just to thread gauge and tire valve into inlet plate. Have to make a new one for every bike though.

Spray bottle of soapy water and you can debug the places your test jig is leaking. Then reedblock gaskets.


I first started with 10psi which is too high.

[diesel pig]

For engine building you just want low pressure. Like about 4psi. Thus you only need a low pressure gauge as your semi expensive part.
I have a hollowed out sparkplug with a tube brazed to the top some hose and a 3 way brass fitting gauge /hose to plug/ shrader (tire) valve. That way it fits anything.
Bicycle pump to valve.

Then plates to block off inlet and exhaust.
Exhaust with modern ports require a expanding mandrel .

But easier is just to thread gauge and tire valve into inlet plate. Have to make a new one for every bike though.

Spray bottle of soapy water and you can debug the places your test jig is leaking. Then reedblock gaskets.


I first started with 10psi which is too high.

Good to know, I am in no hurry just will want a good set up before I do my next engine built.