I had doubts about using vaccum......but your methodology was perfect!!!! Great tool...great job!!!

We use to build similar setups back maybe 40 years ago for testing different things. The constant vacuum source setup can be used for multiple things. Ummm, maybe the only thing I personally would add would be another valve on your red line are vacuum source so you can close it and do a count down after the desired vacuum is acquired. This release's the constant vacuum and can give you a finer reading even though you may not want to test that far. But having the other valve does allow for testing other things that may require a more definite leak test. But that is just my opinion and how some of us use to do it way back. We built multiple different plates etc. for testing different ways. It is good to see someone like you to build your setup. SO many people now days can't figure out anything past a computer are diagnostic screen.

Brilliant video . Your dam right about having to check other peoples work also .

I learned something new today, I always use a leak down tester or compression gauge after a engine build which is like putting to cart before the donkey. thanks for the interesting information!

I have tested my head with vacum but using manual hand pump, is more cheap and you can see easy enhough if the head is good or not. mine got to 25/26 on manual pump.

excellent tool and video! much more cost effective than buying the whole tool from goodson! and the electric pump could have lots of other uses like getting bubbles out when pouring urethane etc. im working on my own and looking to make an adapter that covers the combustion chamber, so can check all 4 valves at once as well as potentially seeing potential cracks in a head if the valves seal on the outer ports but the chamber itself is not!

Good info here, i was doing some diy work on my subaru heads and used the water and air method. It kept failing . I needed to work late and poked around also building a tool . I made mine from an old refridgerator compressor an automotive vacuum gauge a plastic sheet and an oring seal from an old oil filter(junk i had at my disposal) it worked flawlessly. Since the minimum is 22 i passed. It is good also for a quiet setup as the refridgerator compressor has a vacuum and makes very little noise.

You need to shut off the vacuum and see how long the vacuum holds, A large vacuum pump will pull that vacuum with a poorly seated valve. Another method is to put a bubble glass in the vacuum line to actually see air flow.

I recently duplicated your rig using a 1 Stage 1.5 CFM A/C vac pump with a 0.020" diameter Orfice Restriction fitting placed on the pump suction fitting....I also Added a vacuum In-line Ball cut--off valve between the Orfice Restriction & the Head Port Pad....These additional components let's me measure Significantly Large vac Reading Differences between known Measured valve seat Concentricity measuments of near perfect 0.0005", 0.002" & 0.006" valve seat runout with vac gauge showing Incremental Hg reading differences....The Vacuum shut-off valve closed shows Large vac leak-down rate timings....

I don't understand why everyone is saying that this test doesn't take into account valve guide/stem/seal leakage. It absolutely DOES. If the head of the valve is sealing one end of the port, and the other end of the port is sealed by the test adapter, it doesn't matter whether there even IS a stem seal or large clearance on the stem. Both ends of the port are sealed during the test. There is no place for the vacuum to leak in that case, other than the valve seat, or the seal on the vacuum tester to the port.

I did a valve job and got 3 cylinders ports or whatever maxed out and the 4th one has 25 hg vac. That 4th port valve was super pitted on the intake. MY exhaust valves are perfect

I made a tool almost identical to yours and they DO work really well and gives you Peace of Mind! ❤ Good video, better than mine, lol.

Excellent work! Thank you for sharing.

Well spoken my dude

Awesome video! Great info which I plan to follow. Do you know would I be able to test valves with a single stage 3cfm vacuum pump as that is all I can find locally? Not any 2 stage pumps Thanks

excellent teacher , all I can sa;y , thanks a million .

Thanks for a great video

Very informative, well made video. How does the test described here differ in diagnostic capabilities compared to a water test with pressurized air through the ports. I tested a used head I purchased and out of the 20 valves only two of he exhaust valves show bubbles with the water/air test. Would this method be a more reliable way of telling if there is a valve leak? Thank you

I had a shop do my engine, lower end work and head work. He did it all. And when he was done i picked it up and the only thing i had to do was put the head on. At some point i watched a youtube video about a guy who checked his valves with water and compressed air. Blowing air in the ports revealed bubbles in the burningchamber. So before i mounted the head back on i did the same test. Some valves let trough some air and i was quite pissed. All that work costed me a lot of money. So i went back with the head. The guy at the shop showed me his test with the vacuum gauge. And guess what......, all valvles seated good. Now the engine is build back together and when im done with the rest of the car i can go to a dyno-shop to set the new ecu. it is now running on a base map. Sometimes i hear a small backfire, and im hoping its because of the basemapping. Or a small vacuum leak. Really hope the valves are seating as they should.

How do valves go holding vaccum when you turn off the vac pump or close off the suction source? Do they hold that vacuum or how quickly does it drop?

With the pump on it would have to be a leak so bad that the pump couldn't keep up, which is not likely. A real test would be to isolate the pump after vacuum is applied then wait to see if vacuum drops.

Hi i took my head cylinder for suction test to 2 shops.they both said the test was ok.i put water with detergent on the valves and blow is compressor; some valve were bubbling badly.which sould i follow?.

Thancks

Is it possible to use a smaller pump? That pump’s a little pricey so was wanting to get a smaller less expensive one that would do the job. Thoughts, suggestions?

What if u'll going to reverse the process put a pressure on the head and test for any leaks

I love the idea of making this tool at home. But I think there might be an easier way of doing it. An R134 A/C manifold set already includes the gauge, and the fittings to connect to the A/C Vacuum Pump. You will need the valve test plate and an adapter to connect it to the low side (blue hose) fitting.

Great job how to make one of that tester

Tqvm👍

Hello are these values -0.7bar just for petrol engines or for diesel as well? Thank you for the great content

Nice video & you've got the correct concept, but your rig needs a few tweaks to be functionality helpful....Your 3 Cfm pump is way too large & grossly Over-pumping the typical 200 cc (0.01 Cu.Ft.) cyl head port making your tester Very Insensitive to all but extreme leaking valves...Use a Smaller 0.2 Cfm pump or put a small 0.020" diameter restriction Orfice directly on the large pump...You Must also add a vacuum isolation/shut off ball valve to the vac test pad hose line to enable the critical "pump off/vacuum hold" timed test where > 10 sec per 10 lost Psi is required for test pass....

Is the health of the valve guids and valve seals taken into consideration of your testing? Because they are going to affect how much vacuum is held a great deal.

If you check on the in.and ex. Ports what about the clearance in the valve guide How does that hold a vacuum?

It’s very good tools, you might be able to make it and sale online , is it possible to leak down test with this tool

Do you check the valves hold the vacuum with the pump also switched off?

Can you list the brands for those plates please? I would appreciate thanks

i couldn’t find the vacuum plate ? i search amazon ebay and google only find the whole kit which is 99 dollars

Can you help me with a parts list so I can make this tool please.

Were the spring installed when you did this? I have a problem where i had seats done and the valves still leak. i believe the issue is weak springs and this would help me narrow down the issue.

So, it looks to me that you’re supplying a consistent negative pressure to your test area? Wouldn’t you want to see how much negative pressure the runner or chamber can hold on its own?

After having more testing time & Experience with this type of Vacuum Tester, my takeaway is the Highest gauge Hg reading With Running pump Only test Can mask some slightly Leaking valve seats & confuse the Real valve sealing Quality Evaluation...With any pump ( at least capable of 25" Hg vac) the Highest Resolution leak Detection Results Is with pump Off, valve closed & Carefully Timing the Leak-Down Rate....A known High Quantity valve seat Will hold Vacuum with Leak-Down rate of > 10 seconds per Hg" or > 100 seconds per 10 Hg"...

do u have a parts list for this.

I need to buy this can you make one for me please

Holle I need your help

Where did you come up with the 22 in Hg / .7 bar threshold number for determining a good valve seal?

the real test isn't how deep a vacuum can be pulled with a 3CFM pump, the true test is how long it can be held(decay test)

Geeeeemz!!

Or you could do like machine shops do and use a thin liquid.

U sale these

I need one of those...

You're not doing it right. You pull a vacuum then you shut off sustion from the pump and watch to see how long it holds the vacuum. If it doesn't hold it at least 7-10 seconds you don't have a good seal on your valve.

Its not good, the vacuum is way too powerful. even in fou introduce a HUGE leak it wont move too far down.