Spark Plug and Compression Test Talk and Evaluations

[89Suburban]

I am wondering how that insulator on the #3 plug broke though...

 

[RetroC10Sport]

Speaking of a good ****, I'll be right back.

 

[HotRodPC]

Hahahahaha!!!!!!

AGood **** guys, it really helps to have pals to help me through this **** and point me in the right direction.

I guess if you got 2 people saying the same thing at the same time, if must be right. I'd a beat him, if i wasn't typing in more detail.
But it don't skeer me none. I can edit or delete his post if I wanna !!! I'd never do that though. How bout I just move it out to the off topic thread. I don't like sharing the glory of being right.

 

[HotRodPC]

Speaking of a good ****, I'll be right back.

See, while he's away, I'll just take care of that post.

 

[89Suburban]

Yep, I'd also do the PB Blaster as suggested in the hole. Its not going to get down in there right away, but it will seep in as you slowly remove it. Just work it in and out as mentioned slowly, and bring it out a hair more each time til you feel it give way if it ever does. Also, it probably would not hurt to do with while the motor is fairly warm The heat might help a bit.

Yah, I didn't have any with me, I will try that this weekend.

By the way, that broken plug, I put it on the #1 cyl so I can reach it easy and replace it, now that's some thinkin, aint it?

 

[HotRodPC]

I am wondering how that insulator on the #3 plug broke though...

It happens. Just hope it broke up small enough to exit the exhaust valve and not do any cylinder damage. Sometimes that happens when you are taking them out. The strain with the socket will crack an insulator that has been heated and cool a million times while installed. I've seen lots worse.

 

[89Suburban]

I guess if you got 2 people saying the same thing at the same time, if must be right. I'd a beat him, if i wasn't typing in more detail.
But it don't skeer me none. I can edit or delete his post if I wanna !!! I'd never do that though. How bout I just move it out to the off topic thread. I don't like sharing the glory of being right.

Yah, that sucks, I know how ya feel, lmao. I am sitting here at my desk at work and I am still laughing and smiling and everybody is looking at me, but I can't help it, and it's all yinz guys fault.

 

[89Suburban]

It happens. Just hope it broke up small enough to exit the exhaust valve and not do any cylinder damage. Sometimes that happens when you are taking them out. The strain with the socket will crack an insulator that has been heated and cool a million times while installed. I've seen lots worse.

I'm gonna replace it tonight after work, and the battery, and I'll have more pics, write ups, and horror stories to share tomorrow, lol...

 

[RetroC10Sport]

You'll get 'r dun...

 

[HotRodPC]

Yah, I didn't have any with me, I will try that this weekend.

By the way, that broken plug, I put it on the #1 cyl so I can reach it easy and replace it, now that's some thinkin, aint it?

 

[GreaseDog]

I'm thinking 90PSI is going to be good on a low compression 8.0- 8.5:1 motor. More importantly is if all cylinders are within 20% of each other. 65 is obviously a little low, but that could also be cuz the motor wasn't cranking good enough. The proper way to do a compression test is to pull all the plugs, then test each cylinder.

you're thinking wrong. i've never seen under 150 on a decent quality small block, regardless of how high or low the compression is, and the size of the cam.

forget the compression test altogether, it obviously needs work, so the heads will need to come off anyways... now to find the cause of the problem... you're going to need to get ahold of a leakdown tester... or build your own...

http://www.fullsizechevy.com/forum/...324596-built-myself-new-tool-other-night.html

 

[89Suburban]

 

[RetroC10Sport]

Yep, thanks for posting.

 

[HotRodPC]

I've seen many SBC run well under 150psi and work just fine for DD. Is all you work on is new motors? Not saying, 90 is optimal by any stretch, but its doable. IMO the leak down test is a waste at this point. Compression is low, we know the motor has mega miles, so why waste money and time to come up with a leak down tester that is only going to tell us what we already know. Yep, its a tired motor and is in need of a rebuild sooner than later. And his compression may be higher with a shot of oil. So is it really important to know percent of leak down at this point? Kinda moot now. I'd say even IF the heads were redone and new head gaskets, the slightest raise in compression is going to spit the rings into the oil pan. (NOT LITERALLY OF COURSE) And less than 500 miles of use on that patch job, the truck will be blowing blue smoke out the tailpipe too. If it were me, I'd finish the compression test, replace those damaged plugs, clean the others if you don't want to spend the few bucks on new ones since they didn't appear to be that bad. Drive it as is and be putting funds aside for either a used low mileage motor out of a wreck, a crate motor, or rebuild your current motor yourself. But doing that means a week or 2 of downtime. Ordering parts, block and heads in the machine shop etc., then once you got it all gathered up, time to assemble it, where as the crate motor, just swap it. Then, I'd keep that current motor for a builder. Never know if you get another square for cheap wo a motor, or convert a carb motor to TBI etc.

 

[Old77]

That Greasedog.....he's the face of optimism!! that rascal....