Interpret my compression test - VIDEO!

[aluminum13]

The video pretty much covers it all. Maybe you guys can help clue me into what's going on with my engine.

I don't want to come across like a lot of people on these car forums who just ask questions and never give anything back, and it's more interesting to watch than read, so I made a video of the process.

Hopefully it serves as reference material, not as a full guide on how to do the test (not it's purpose) but as material for comparison, and showing how the gauge will react (good for new guys like me), and what other F22a1's out there do when they hit 132k.

Anyway, have a watch. Works best in highest quality.

[aluminum13]

btw the oil on the plugs at the end is from oil in the spark plug tubes. I sucked most of it out before pulling the plugs but that's the gunk on the threads.

I'm getting a gasket kit for the valve cover soon.

[Ghetto_CB7]

Nice Video

To answer your question, the last comment made in your video sums it up.

It runs just fine.

If you are more concerned with performance, I would do a leakdown test. This will tell you where you are leaking from for sure, and will give you a much better indication of how bad it is then a simple compression test. In reality those numbers are not bad. Even with the 4th cylinder off a little I would not consider it a problem.

I recommend a leakdown test if you want more info, but if she runs and doesn't burn oil, then your a happy camper.

as for the plugs, how long have they been in there?

If it has been a while put some new ones in and see how they look in a week.

If they look like detonation has occurred, check timing and go from there.

[aluminum13]

To answer your question, the last comment made in your video sums it up.

It runs just fine.

If you are more concerned with performance, I would do a leakdown test. This will tell you where you are leaking from for sure, and will give you a much better indication of how bad it is then a simple compression test. In reality those numbers are not bad. Even with the 4th cylinder off a little I would not consider it a problem.

I recommend a leakdown test if you want more info, but if she runs and doesn't burn oil, then your a happy camper.

Thanks for the reply. It's safe to say there are plenty of miles left in this engine? I might do some bolt on type mods (if any), no turbo or anything, and clean up the body and do suspension stuff if I get the idea that this is a basically healthy engine.

Daily driver, but "fun" on the desired performance level. Not racing.

I'm mainly trying to assess whether getting this car (rough body) back into nice condition is worth the trouble and time to do so.

as for the plugs, how long have they been in there?

If it has been a while put some new ones in and see how they look in a week.

If they look like detonation has occurred, check timing and go from there.

I put in a new set and I'll check them out later. They were in there for about 15k, maybe more. For as long as I've owned the car. Tune-up time...

[19dabeast85]

Engine seems great...my compression numbers are 155-165 with a dry cylinder and I'm pushing over 242,000 miles and redline my engine every day!

Take good care of it and you can get another 150k at least.

[aluminum13]

Engine seems great...my compression numbers are 155-165 with a dry cylinder and I'm pushing over 242,000 miles and redline my engine every day!

Take good care of it and you can get another 150k at least.

Thanks man. It's good to get a comparison.

Anybody else have their compression values on hand?

[quaidum]

i have had 4cb7's and 3(one i bought for parts)of them had just about 210 psi give or take
all were 93 engines one was a f22a1 and the other two were f22a6's

here is a dyno of the a1 with a few mods

[sow3r]

I just did a compression check and this is what I came up with

1=170psi
2=180psi
3=130psi
4=178psi

I tried doing a wet test but I don't have a squirter thing so I just dropped a little oil in the plug hole but the compression rose to more than 300psi on all cylinders(too much oil i guess) and now my car is smoking like crazy

my car has 211k miles and it burns oil but not much.

I wonder what is going on in cylinder #3.....

[stretch JDM]

I just did a compression check and this is what I came up with

1=170psi
2=180psi
3=130psi
4=178psi

I tried doing a wet test but I don't have a squirter thing so I just dropped a little oil in the plug hole but the compression rose to more than 300psi on all cylinders(too much oil i guess) and now my car is smoking like crazy

my car has 211k miles and it burns oil but not much.

I wonder what is going on in cylinder #3.....

sounds and looks like you have a bad ring or so on #3 bro. good luck.

[aluminum13]

I just did a compression check and this is what I came up with

1=170psi
2=180psi
3=130psi
4=178psi

I tried doing a wet test but I don't have a squirter thing so I just dropped a little oil in the plug hole but the compression rose to more than 300psi on all cylinders(too much oil i guess) and now my car is smoking like crazy

my car has 211k miles and it burns oil but not much.

I wonder what is going on in cylinder #3.....

Hahaha yeah you might want to change the plugs after that.

I hadn't really thought about it when I squirted oil in there and when I started up the car with this plume of smoke - for about a half second I was thinking: "oh $#%@ what did i screw up this time" and then I remembered.

[aluminum13]

i have had 4cb7's and 3(one i bought for parts)of them had just about 210 psi give or take
all were 93 engines one was a f22a1 and the other two were f22a6's

here is a dyno of the a1 with a few mods

Wow 210 seems really high!?

I was thinking about doing some mods similar to what's scribbled on the sheet (and shown in the FAQ 'how to add 30 hp to f22a1') using salvaged pieces from part yard.

Are those mods responsible for that rise in compression or were the engines just in really good shape?



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Hey thanks for all your replies I appreciate it.

I know this is coming a week later, I just worked Wednesday to Wednesday, 74 hour week (PAYCHECK! money to put into car ) so I haven't really had a chance to check the plugs or do a leak down test.

I've also developed a start-up idle surge problem. I'll read the idle adjustment FAQ and see if that fixes it. I might post a vid of that too.

[Ghetto_CB7]

Your comp

You could easily see that high of compression on your engine if you went a few more revolutions on the motor. My guess is that he just went longer then you.

[H.M.]

Props for a well produced video!

[aluminum13]

You could easily see that high of compression on your engine if you went a few more revolutions on the motor. My guess is that he just went longer then you.

Oh, then that makes sense. I cranked for ~7 strokes each time.

Props for a well produced video!

Thanks I tried to make it interesting.

I'm bummed that loading it onto youtube made it so grainy. It was better quality otherwise. I gotta play with those settings windows movie maker.

[quaidum]

[QUOTE=aluminum13;2626256]Oh, then that makes sense. I cranked for ~7 strokes each time.....


i did mine for 10 strokes
that was what i have been told and noticed when the gauge stopped climbing