Compression test gone wrong

Little bastards. Threads don’t look very destroyed either. Thanks to everyone who put in helpful replies anyways.

 

Put everything back together. Plugs went in fine. Started it up and had a ton of smoke but probably from the oil I put in the cylinder I’m assuming. Runs fine.

 

I've never had to put a socket on a compression tester or adapter. They should go on by hand. If it doesn't your threads are already screwed. Chase them first. The o-rings do the sealing. If you needed to get the adapter a little more snug on the hose do that first, several tight wraps of electrical tape for insurance and twist it down into the wells. Finger tight at most and that's on the rubber hose so not much.

 

I'm trying to figure out how it got stuck in the first place. I have a very similar comp tester and I screw in the hose tight to that 17mm adaptor and then I hand turn it as a whole unit into the spark plug tube.

 

I’m really not sure either. The threads on the adapter did look a little dull but not enough to cause cross threading. Either way, I’m a little nervous to try it again tomorrow lol.

 

I had a compression tester get stuck in a hole like that. The crimp got loose and the hose was just spinning. Can't remember exactly but I think I pulled the hose off, jammed a big slotted screwdriver in the adapter and got it to come out

 

Damn you guys are making me nervous using it again in the future lol.

 

I have a 30 year old tester and I dont use any adapter just turn the rubber hose by hand until it seats, is it because the threads on the tester are wrong size?

 

That’s what I tried at first but the threads wouldn’t fully spin on all the way. When I turned the engine over the compression literally popped the hose off flying. I’m starting to think maybe it’s just the threads on that particular #1 cylinder plug.

 

Could be, anyhow aluminum engine parts just suck. You're probably not old enough to have worked on all cast iron engines but you pretty much never had stripped threads. I learned my lesson very early, helped a friend with a early Honda alum head and immediately pulled out threads. No big deal to get it fixed but its best to learn these lessons early.

Especially if you see a short bolt going into aluminum threads that's a warning sign. There is one example on the transmission mount on the R150 and I know a professional Toyota mechanic that under torques those but uses blue locktite to compensate because he seen those pull out.

Always use a torque wrench on aluminum and you should be ok but often previous owner/mechanic may have already damaged threads which is probably what happened to you. I also use anti seize on some, like the coil packs because steel bolts will bond to aluminum over time. You will hear the that "crack" sound when removing - I hate that.

However don't use anti seize on plugs or if you do a very small amount. I was overly paranoid with my plugs so I used anti seize every plug change and after several changes I had a very hard time removing the plugs, I thought I was fubared.

What happen is the anti seize builds up in the threads and makes things worse. In any case I dont think the plugs are in the engine long enough to have an issue like some other engines with 100k mile plugs, I have heard on some Fords its almost a given that threads will pull out.

 

that was a nail biter!
Compression ok?

 

Update!
Went at it again today. Didn’t use the pesky adapter this time and just threaded the hose on by hand. I’m pretty stoked with these results. Motor is at 293,000.

 

Keep doing whatever you have been doing, it works!

 

So you are recommending that he chase the threads on a head that is still attached to the block? I wouldn't do that. For obvious reasons. Put some anti-seize on the plug, screw it in and out (by hand if possible) a few times. Then do the same process with a new plug. THEN screw the adapter into the plug hole. A good endoscope will allow you to examine the threads in detail before you do this. Examine threads first, before you do anything else. The last thing I would ever do is run a thread chaser down it. Been working on cars since the 60's. Never had to use a helicoil even once. Slow down. Think. You'll get finished faster.

Liquid Wrench on all of the plug bases the night before you plan on working on it is a good way to set yourself up for success.

 

Yes. Your method is a good start but if it doesn't work there's no need to pull the head just to chase threads. Buy a thread chaser, fill the flutes with grease to catch the shavings, if there's even any, and blow out the cylinder for good measure.

 

Yeah that. Agreed.

 

I somewhat agree. That may be the short-cut a dealership mechanic would do to a customer's vehicle, or the way you would do a vehicle that you were going to trade-in or sell, but that's not the optimal way it is done if you are planning to keep your vehicle for the long term. As for "blowing out" the cylinder: there will be little that escapes the spark plug hole in the face of on-rushing air. The vast majority of particles produced by chasing the threads will just swirl around in the cylinder, even if the exhaust valve is indexed at full lift. There's the easy way, and there's the right way. Will doing it your way leave you stranded out on the trail? Probably not. However, it will certainly contribute incrementally to a vehicle death by a thousand short-cuts.