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my homemade pop off pressure and blowdown tester :)

Discussion in HPI Baja Engine and Exhaust forum, started by sclark.

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  #1  
Old 04-11-2010, 11:56 AM
sclark sclark is offline
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my homemade pop off pressure and blowdown tester :)

hello all


Well it was killing me i had to make one!!! lol anyways i firgure i can uses this also for a blowdown test i will make a adpter that will scew into the spark plug hole and yes intake and exhaust have to be block off to do a blowdown test

parts i used are:

bike tire gauge (walmart 5.00)
car tire valve ( had that here)
a brass compression tee ($5.00) farm parts store
a bike pump (had one)
and small hoses,expoy glue, also had theses around here

the reasons for the tire valve are :

1.) a bike pump does leak a small amount of air this way i can unhook it and not have all the air come out..lol and by unhooking the pump i can get a prefect seal no air slowly leaking out

2.) bike pump is my kids and they uses it...lol so i didnt want to make it so they couldnt...lol



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Old 04-11-2010, 12:19 PM
Timmahh Timmahh is offline
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very nice simple rig to mod up! excellent item SC.

for those looking to use/need one, this is a nice inexpensive option. so easy a caveman could do it. heh.

mind sharing some info on why and how to use it? im sure many readers, including myself, would/could use a refresher, or the eduction if they are not sure of its use.

T
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Old 04-11-2010, 12:37 PM
MCRIPPPer MCRIPPPer is offline
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i think it is to measure pop off pressure of the carb. (read turboglens thread on his ts build)
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Old 04-11-2010, 12:45 PM
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DogPile Racing DogPile Racing is offline
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http://www.hpibajaforum.com/forum/sh...ad.php?t=78380

Start at post #20, this is one of the best reads going.
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Old 04-11-2010, 12:52 PM
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DogPile Racing DogPile Racing is offline
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http://www.rcaer.com/pages/files/Aer...ro%20Carbs.pdf

Hope this link works. Here is another that explains what it is.
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Old 04-11-2010, 01:31 PM
sclark sclark is offline
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yes that is right for the pop off pressure that thread talks about it as for a blowdown test that is a good way to see if you have a engine seal that is leaking,etc to do this you will need to remove carb and intake manafold and exhaust.. then you have to block off thoses ports and seal them ( make a plate with a gasket and uses the bolt holes to mount the plate to) then pump the engine to about 10 psi and see if the pressure drops if it slowly leaks out you have a bad seal,etc you could get a bucket of soapy water and a brush to test the seals,etc

note in the port info post i did post the info and links to the pop off test

Last edited by sclark; 04-11-2010 at 01:37 PM.
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Old 04-11-2010, 01:35 PM
sclark sclark is offline
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you could uses any of the ports or sparkplug to feed air into...

Last edited by sclark; 04-11-2010 at 02:00 PM.
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Old 04-11-2010, 01:55 PM
sclark sclark is offline
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i should of said leak down test not blowdown test...my bad sorry
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Old 04-11-2010, 02:04 PM
Eggbert Eggbert is offline
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When I made my leak-down tester, I took a used sparkplug, knocked the center (porcelin) out of it and welded a fitting to it for the air-line. As I was using this in mult-cylinder engines, I just cut the air-supply around 60 psi and measured the time it took for the pressure to drop from 50 to 10 psi. I then compared it to other cylinders, but it's wise with homemade testers like this to take a reading when the engine is known to be good. You can compare that reading with a new one as the engine gets time on it.

Real leak-down testers have a claibrated orifice so that a percentage can be read based on a standard. For info on this, check this link:

http://en.wikipedia.org/wiki/Leak-down_tester
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Old 04-11-2010, 02:48 PM
sclark sclark is offline
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Quote:
Originally Posted by Eggbert View Post
When I made my leak-down tester, I took a used sparkplug, knocked the center (porcelin) out of it and welded a fitting to it for the air-line. As I was using this in mult-cylinder engines, I just cut the air-supply around 60 psi and measured the time it took for the pressure to drop from 50 to 10 psi. I then compared it to other cylinders, but it's wise with homemade testers like this to take a reading when the engine is known to be good. You can compare that reading with a new one as the engine gets time on it.

Real leak-down testers have a claibrated orifice so that a percentage can be read based on a standard. For info on this, check this link:

http://en.wikipedia.org/wiki/Leak-down_tester
thanks for the link if you have a bad seal it wont hold pressure at 5 -7 psi I would think you if filled it to 5-7psi it should hold that pressure all the time so if ya leave it sit over nite and it reads 0 you have a leak. from the info i have read anyways..
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Old 04-11-2010, 02:58 PM
Mr Sexy Mr Sexy is offline
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aw, when read the title of the thread i was hoping you were making a pop off valve for a baja, now that would be awsome!!!. nice job
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Old 04-11-2010, 02:59 PM
sclark sclark is offline
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Quote:
Originally Posted by Mr Sexy View Post
aw, when read the title of the thread i was hoping you were making a pop off valve for a baja, now that would be awsome!!!. nice job
a pop off valve? what ya mean?
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Old 04-15-2010, 06:10 PM
sclark sclark is offline
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i'am glad i did a leak down test on this engine!!!! damn head gasket leaks!!! lol

I blocked off the exhaust and intake with a steel plate and made a rubber gasket for the plates ( old bike inner tube works great for a gasket) if any one would like to see some pictures of how i did this let me know i will post them
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Old 04-16-2010, 11:42 AM
sclark sclark is offline
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ok instead of answering the p.m's i will post the pics here

Like I said before i used some flat steel i had around here and a old bike inner tube i made the gaskets out of. The nozzle is a plastic piece that i bought at the hardware store i think its for ice maker's . i just cut it to the length i need and glue it to the steel plate i made i used the holes in the head to mount the plates to ohh one thing to save you the headaches DONT made the plates out of plastic!!! it wont work!!! the reason why is cause no matter how thick the plastic is it will still flex when you tighen it down making it not seal!!!!



picture of the intake plate:


picture of the exhaust plate:


picture of my head gasket leak notice the bubbles
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Old 04-16-2010, 11:43 AM
skipster skipster is offline
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Nice work
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Old 04-16-2010, 12:00 PM
sclark sclark is offline
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thanks

also you can test your intake for leaks to just bolt the intake to the engine then bolt your plate to the intake manifold
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Old 04-16-2010, 01:26 PM
Lunatik Engineering Lunatik Engineering is offline
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I sell block off plates with my engine stands!

http://www.teamgonads.com/8956.html
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Old 04-16-2010, 01:28 PM
sclark sclark is offline
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Quote:
Originally Posted by Lunatik Engineering View Post
I sell block off plates with my engine stands!

http://www.teamgonads.com/8956.html
ohhh cool i didnt know that your engine stand is nice almost like the one i made but yours looks better
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Old 04-16-2010, 02:00 PM
fastbanshee fastbanshee is offline
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What should the pop off pressure be for a 668 on a stock 26cc 5T motor with luna pipe?
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Old 04-16-2010, 02:05 PM
turboglenn turboglenn is offline
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too bad its' sold out i'd like one and some plates
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