So, I recently acquired an 86 4runner DLX 5speed manual and while I knew there were some top end issues when I checked it out it seems the issues are far worse than I though... overall I still paid bellow market price out here in CA but the engine is having some cooling issues plus I think I've diagnosed a blown head gasket as well at cylinder 4.

The first issue I've tried to dig into was the valve train noise which seems to be coming from the #4 cylinder. I've got a ton of exhaust pipe clap when I put a piece of paper up to the pipe so I figured I had a stuck exhaust valve. I ran a coompression test on all 4 cylinders and compression is within spec not factory New but not horrible

compression numbers:
cyl1 155psi
cyl2 155psi
cyl3 160psi
cyl4 158psi

the thing is even though compression was good in cylinder 4 the spark plug was totally clean and wet compared to the other cylinders which had tan carbons on the plugs and were dry. I've also got some serious smoking from the tail pipe that appears to be steam although it smells really rich and doesn't have a coolant smell to it. And the engine flutters bad like water in the combustion chamber or something.

Second issue is cooling system related as well The way I discovered this coolant issue was While I was running the engine to warm it up for the compression test I noticed the radiator never got even close to warm and the return hose at the top of the rad had no pressure and was also cold like the rad. I though great the thermostat is stuck closed so I pulled that and did the hot water test which resulted in the thermostat opening at 194 degrees (confirmed using a mercury lab thermometer) although spec for this thermostat is 180 it still opened within normal op temps . I also noticed the waterpump is leaking so it may have failed completely but I've also got almost no heat from the heater core and the gauge inside the cab reads 1/4 warm and was like that the entire 500 mile trip home. Thing that has me stumped is as far as I understand with no coolant flowing I should be running at overheating levels not sitting near the C most of the time and certainly not making a 500 mile trip without blowing up. What the heck could this be? I'm sure it's multiple issues but the no heat/cold coolant situation is stumping me... Clogged heater core?

I read a thread here with a guy with a similar problem and that was suggested as an issue but it didn't fix it for him and he never replied back with what was the fix.

I guess I should also mention there seems to be a knock for maybe 2-3 seconds on cold start up ... hard to tell if it's knock or timing chain clatter which I also started noticing at the top of 1st and 3rd gears when shifting. Seller said this thing was rebuilt 15k ago with a metal timing chain guide but the tchain clatter tells another story, although I won't be able to pull the valve cover to look until the weekend. Also after the truck has been sitting after running it has hard starting maybe 15 seconds before it fires ... I thought this might be the warm soak cold injector sensor issue I read about in a tech bulitin but now I suspect maybe coolant is getting in and sitting on the cylinder causing combustion issues? This thing runs like a Harley Davidson at the moment and I'd like to get a plan of attack in order so if anyone has any insight I'd really appreciate it. I'm not that experienced with wrenching on my own rig but this is why I bought this truck so I could learn. Any help would be appreciated.
I shot a couple of videos showing the top end noise and the smoking tail pipe see bellow. Thank you in advance.

Top end noise:
http://youtu.be/MdhRTKWbOJ4

tailpipe exhaust after idle dropped (was smoking more on startup before I filmed) https://youtu.be/oGbUKfrEp04

exhaust output when reved:
https://youtu.be/Y7dmV79S9cs

I should mention this is my 3rd 22re equipped vehicle, two pickups one 86 and one 94, before the 4runner, both were bullet proof aside from the timing chain guide needing replacing so I am fsrmiliar with the injector sound and how these motors should sound and this constant tick sound isn't in sync with the injector sound it is REALLY loud and constant like a metronome at first the engine runs too rough and over powers it but after a couple of Minutes the ticking overpowers everything else. The stethoscope is a good tip and I happen to have access to one too so I will try your suggestion. Thank you!

guess its time for invasive surgery and a rebuild or replacement depending on what I find in there. Thanks again

I agree with TT. Those compression numbers suggest your head gasket is ok. If you drove this thing 500 miles home, the problem would have worsened, you would have been on the side of the road. In the video I hear valve clatter and probably an exhaust leak.
The heat in these vehicles is not great, even when working correctly. Put a laser thermometer right above the thermostat housing for an accurate engine temp.

Thank you guys this gives me a little more hope for this engine. I can see a weld spot on the y pipe so this must had had an exhaust leak before that they patched but I'll look around for other exhaust leaks ... strange that the seller produced a valid smog certificate from earlier in the day (the day I bought it) in CA it shouldn't have passed with exhaust leaks or how rich it's running. I'm thinking he put some liquid sealer crap in to sell it to me and all that crap gave way on the trip home.

Anyway thanks for the suggestions I'll check the manifold and get back with results.

yeah sorry it looks like a y coming off the manifold probably part of it ... looks like it continues on to the cat. I tried tracking down a digital version of the 86 FSM but links are dead ... plenty of 87 fsm available will that work or are there drastic changes between years?

About the one way leak I was thinking that too since my plug in cylinder 4 is totally clean compared to the others and I read it is possible to have a headgasket failure but not lose compression. Would a leakdown test give confirmation on a failed head gasket even if a compression test was good?

the oil looks fine as far as I can tell but I don't know if there is water sitting in the pan ... but there is not milkyness in the oil or foaming on the cap. The radiator looks like ˟˟˟˟ though it is filled with that green crap for one and also I see rust particles but I'm not sure there is oil in there ... guess I can get my hands on a hydrocarbon tester to see if exhaust gasses are entering the cooling system. A cooling system pressure test won't help me with all the leaks I've got though right?

do you guys think my heater issues are related to all the breaches in my cooling system allowing air in?

interesting that you mention pressure in the system because when I pulled the thermostat yesterday I didn't drain coolant before hand and I had some serious overflow happening like pressure was built up in there .. not just what was still in the upper hose it was overflowing for some time out of the thermostat housing.

good idea I'll try another compression test with the radiator cap open and see what happens... my compression tester instructions state to turn the engine over until the needle stops gaining pressure so it's possible there is a breach into the cooling system that was being pressurized and giving me a false reading right?

well, since I had the thermostat housing open and I had a spare hour today I decided to throw a catch pan under the truck and run another compression test and even with the cooling system open to atmosphere it didn't seem to effect compression levels in any cylinder. This test was done cold but still there was no deviation between cylinders. I'm going to run a leakdown test this weekend to figure out exactly where the breech is. Thanks to everyone for the ideas on wrangling this problem(s).

you know what? I thought about that but only after the fact so now that you emphasized the point I went out and did another test . These are cold numbers only because my cooling system is FUBAR and I don't want to run the engine any more than I have to. So with that said I have a new data set including number of crank revolutions before the needle stopped gaining psi and it does kind of point at cylinder 4 as being different than the rest.

Cold test numbers:
Cyl 1 140psi 21 cranks
Cyl2 145psi 22 cranks
Cyl3. 140psi 22 cranks
Cyl4. 135psi 26 cranks

This is about as scientific as I can get with a harbor freight tester (I guess?) but it doesn't tell me a whole lot except that cyl4 is not in as good of shape as the other 3 cylinders... (again I guess). keep in mind I just bought this as a quick indication of uniformity between cylinders but obviously I didn't consider the deviation in number of crank revolutions throwing a wrench in the accuracy of the test. It would probably help to know if others with these Pittsburg compression testers need to crank their engine over that many times to get a reading, otherwise I've really got no baseline to work from.