Please tell me there's hope for my 1995 F355 2.7... I'm just going to come out and say it...cylinder #2 has no compression! @&$#%!! Here's the short and skinny: Pulled the RH plenum and fuel rail to replace an injector and clean the others. A compression test was next on the list. Hooked up to cyl #2, WOT,turned the key for a five count and got a ZERO reading!! I figured there must be something wrong with my tester. NOPE! All other cylinders have compression of 170 or greater... thoughts on what the deal is? exhaust valve? next steps?
Zero seems very odd..... If a valve is open, you are likely beating it to death with the piston. As a sanity check, connect the fitting and hose to the cylinder (without gauge), put your finger over the end of the hose and crank away and see if you feel any pressure or if your finger gets blow off the hose.
I thought the same thing. Can't wrap my head around why there is a Zero compression reading. I did put my hand over the spark plug hole and and could feel the air being blown upward. Probably get a better idea of how strong using the hose without the gauge. what will doing this tell me?
ok, so I can still do a leak down with no compression? if so, I'm going to order a leak down meter/tester tonight!
If you feel something, and can't keep your finger on the hose it will tell you that there is compression. Make sure the check valve in your gauge / hose is working if not you will never measure compression (dont ask me how I know)
Yes. A leak down will allow you to hear where the air is leaking (bottom end, rings) or top end (valves). You are not looking for a value, you are trying to hear where the leak is currently coming from
My guess would be chunk of exhaust valve missing. I would just drop the engine and pull the head. You could try to further diagnose it in the car but it's coming out either way.
No compression = Motor is toast. "All other's 170" proves the gauge works. Leak it will give you clues. Teardown will be definitive.
+1 Save mucking around, pull the engine out and remove the cylinder head. That would be the first thing I would do. Please let us know what you find and good luck with it.
sounds like you don't need a leak down testing rig with the gauges etc. You can probably get the info you want by popping off the valve cover so you can turn the engine over until all the valves in cylinder 2 are closed, then hook up your air supply to the hose in the plug hole and listen for air rushing out somewhere. Sorry for your misfortune.
I had the same thing happen late last year, and I agree with James that it's coming out one way or another. Mine is also a 95 2.7 car. Ran and idled perfectly. Solid service history with the last major in Oct. of 2014. Fabspeed headers and Tubi exhaust done in 2010. Emissions numbers were very good with no indication of any issues with oil consumption or fuel getting in to the cats. On a spirited drive during the last week of 2015, the car developed a slight miss. I was no where near the redline that day, but it was a spirited drive nevertheless. I parked it and began to diagnose. First was to check for the obvious (fouled plug, vacuum leak, plug wire issue, injector problem) all checked out fine. Next, I compression tested all cylinders. 210 on 6 cylinders, 175 on #7, and zero on #2. I just assumed that with mine being a 95 and no previous valve guide replacement of the crappy factory guides that my time was finally up. The car has 64,000 miles on the clock, and my guess is that the original owner in Southern California drove it daily fairly easy and the next couple owners before me were harder on the car. It has good service history nevertheless. Dropped the engine and tore it down to find original factory bronze guides and a broken exhaust valve in #2. Surprisingly, the valve guides weren't terrible. There was a little play that you could feel in #7 valves hence the lower compression, but there was enough carbon buildup that you could tell that it was just time. My machine shop who has done lots of F355 heads says he has seen this several times where you will have a lot of carbon buildup on exhaust valves due to guides, and with all the heat and exhaust gases over time particularly in #2 and #7, the edges of the exhaust valves can start to disentegrate. I'm lucky that mine disentegrated and exited out of the header. The cylinder linings on all 8 were pristine after a good cleaning, and it was also clear that none of the valves had ever hit any of the pitons. None of the vales were bent; even the broken exhaust valve. The heads are getting guides and at least exhaust valves as well. The machine shop is supposed to let me know later this week what parts will be needed after tear down, cleaning, and measuring are all done. Once I get the heads back in a couple weeks, I'll start re-assembly. I'm sorry for the long post, but I wanted to share my experience and perspective. Don't panic as these are fantastic cars, and at the end of the day, everything can be fixed. The modern valve guides available today 20 years later are far superior to anything in 95 whether you go with sintered steel or bronze manganese. I personally will be going with bronze manganese due to the superior heat transfer properties and lack of porosity typically found in steel. Bronze doesn't mean bad even though the factory bronze guides were notoriously horrible. Find a god machine shop that has done 355 heads before and trust their recommendations. If the terrible factory guides can make it 20 years and 64,000 miles with proper servicing, a much better set of modern guides should go much longer. Best of luck to you. Pictures of mine to be posted below.
Cylinder linings and piston tops after cleaning. Cross hatch pattern on all linings is excellent for 64,000 miles. No evidence of the valve fragment ever touching the piston or lining. Car ran fantastic until the valve came apart. That coupled with the strong compression number and the excellent looking cylinders and Pistons after cleaning luckily indicate a still healthy bottom end. It could have been so much worse. Image Unavailable, Please Login
Sorry to hear, I went through this with cylinder #2 on my car. Top-end rebuild and bottom end light refresh solved everything, at least in my case (for now! ). Going strong and fast 5 years later! I guess this is why everyone says "Have an extra $10-15k hanging around that the wife doesn't know about"... not that I have a wife. Good luck, as others have said I don't think it's your tester that's at fault.
and as others have said......with 0 pressure in #2.......forget the leak down tester as its time for a tear down.
ok...i'm picking up what everyone is putting down! Brian -- definitely appreciate the detail and pics you provided. going to map out my plan of attack for an engine out/rebuild. Was planning to pull the engine this Fall once i got my lift installed anyway. Looks like i may be pulling the engine without it (maybe). It may be a few weeks, but I'll be sure to document with pics and report back once I get started Thanks for all the input!
I haven't read the whole thread yet and someone might have asked this but how do you leak down test from zero? Seems impossible. Start with zero...end with zero... Did it leak? EDIT: I hate when people post without reading the thread. . So I read that one can actually possibley hear where the air is going? I guess I never thought of that.
