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View Full Version : Need a compresion tester south side


RockRunner
03-25-2010, 09:59 AM
Does anyone have one I can borrow? I had one but it seems to have disappeared into thin air.:rolleyes: I want to check my compression to see if I want to do a cam.

I am on the south west side of littleton, Roxborough.

Mendocino
03-25-2010, 10:54 AM
Tom, you can borrow mine but its in Broomfield.

RockRunner
03-25-2010, 11:00 AM
Thanks, but by the time i drive there and back and then again..............well you get the picture. Thanks anyway.

RicardoJM
03-25-2010, 12:02 PM
I have a HF tester that was handed down to me. It has a rubber plug versus a threaded connector. I don't know how that affects precision, but I do know it was good enough to let Randy know which cylinder was having issues in his FJ40. You are welcome to it.

Uncle Ben
03-25-2010, 12:05 PM
Bet there is a Sears near you!

RockRunner
03-25-2010, 12:09 PM
I have a HF tester that was handed down to me. It has a rubber plug versus a threaded connector. I don't know how that affects precision, but I do know it was good enough to let Randy know which cylinder was having issues in his FJ40. You are welcome to it.

THanks, I can get your radio back to you then :rolleyes:

RockRunner
03-25-2010, 12:11 PM
Bet there is a Sears near you!

What do you consider nearby? 5 miles? 10 miles? 20 miles?:rolleyes:

I could buy one but for a one time use I rather rent one or borrow, that is an idea. Does checker rent those and if so how accurate would they be???

Air Randy
03-25-2010, 02:53 PM
You can get them from Autozone for free, you buy it, use it then return it for a free refund. You can use my good one if you want to wait until Saturday.

Which ever one you use, remember you have to adjust for the elevation. If the FSM says you should have 150 psi compression that is at sea level. The elevation at my house is 6700' ASL. If you take the reading at my house you have to divide the number by.82 to get an accurate reading. An actual reading of 110 psi would then be equal to approximately 135 psi so it does make a difference.

Magoo
03-25-2010, 04:04 PM
Which ever one you use, remember you have to adjust for the elevation. If the FSM says you should have 150 psi compression that is at sea level. The elevation at my house is 6700' ASL. If you take the reading at my house you have to divide the number by.82 to get an accurate reading. An actual reading of 110 psi would then be equal to approximately 135 psi so it does make a difference.[/QUOTE]

this is interesting and was unknown to me.
thanks Randy for the cluesack tid bit.
:cheers:
shawn

Air Randy
03-25-2010, 05:01 PM
Yep, has to do with air density. Makes me wonder how many engines have gotten rebuilt in Colorado that probably didn't need it yet.

Squishy!
03-25-2010, 06:19 PM
Tom I have one you can borrow. It's Snap-On too. Oolala.

Squishy!
03-25-2010, 06:20 PM
I'm about Hampden and Sante-Fe. Or I can give it to my Dad tonight and you can pick it up whenever

corsair23
03-25-2010, 06:25 PM
A good/decent rule of thumb is a 3% reduction for every 1000' of elevation gain

Another parameter to consider is temperature. If you check your compression on a cold day you could expect it to be higher than on a hot day (colder air = more dense air). In aviation terms it is called "Density Altitude". On a nice 90F day at 6000' the density altitude is closer to 9.5K feet, so that is where your engine thinks it is running at...

Lots of flat land pilots coming to Colorado in the summer have met their demise because they didn't understand the effects of not only higher elevation but temp/humidity on their plane's performance.

RockRunner
03-25-2010, 09:41 PM
I'm about Hampden and Sante-Fe. Or I can give it to my Dad tonight and you can pick it up whenever

That would be great Justin, he is coming over either Friday or Saturday to pick up some stuff. If not it is no rush, just want to check compression before I commit to a new cam.

RockRunner
03-25-2010, 09:46 PM
A good/decent rule of thumb is a 3% reduction for every 1000' of elevation gain
.

Juat as it is for compression it is for HP. A 300 HP rig in Cali is only 246 ~ It really sucks sometimes living in CO. Of course you could always get a turbo:rolleyes:

Squishy!
03-26-2010, 12:56 PM
That would be great Justin, he is coming over either Friday or Saturday to pick up some stuff. If not it is no rush, just want to check compression before I commit to a new cam.

Cool I'll make sure he knows and I'll get it to him.l :D