Sorry about the empty topic post...

What do you think of these compression numbers?

Front- (241 RPM) 9.7/9.6/9.6

Rear- (238RPM) 9.4/9.4/9.0

Engine flooded, so I turned it over and let sit for 3 days with no plugs, then injected ATF, turned it over by hand and checked compression cold.
Do these sound a little high for a used 13B?

Thoughts, opinions, etc.....?

-Gordon

 

???

 

I couldn't tell you if those numbers are good or not. You need to change your oil though. It's been thinned by the gas. Smell the dipstick, and taste it, if you're the adventerous type.

 

Yeah they do at first glance, but it could have to do with it being cold and all that extra oil in there, maybe. It makes sense to me that it would read higher cold due to the higher viscosity of the oil.

It must be an S5 NA. I get a maximum comp @ sealevel of 10.025 kg/cm2, just working off c/r.

What are the #s when you correct for rpm? I'm assuming you're using a Mazda comp tester. Isn't there a chart somewhere for that? It wouldn't really be much I guess, since you were close.

Better than low compression whatever the deal.

 

Thanks for the replies and I will change my oil. I have always checked my compression before when my motor was running but of course not running when I did the compression test. I have never checked this engine 13b 4 port old school and I know the ATF would raise the numbers. I took the demon carb i have and sent it to TPC in calif to check my present settings so Ty can build me a 650double pumper boost referenced so I can realize the power of my supercharger. I am changing the complete fuel delivery to aeromotive with a raising regulator and wiring kit so my volts stay high(also put on a 93alternator to make sure). Now flood on me no more.

 

Cool! Speaking of 4 port 13Bs, I just got another one today.