Missing ignition on cylinders 4 and 2, please help! (Solved, issue was torn fuel distributor orings)

[Stand-in]

Fuel is present in sufficient volume and balanced
Compression reads, 150,155,160,155 in order of cylinders
Spark is consistent and timed correctly.
I don't hear anything mechanically wrong with the engine (outside of the chop).

What gives?

[Stand-in]

found the problem, two out of my 4 new bosch spark plugs short to ground instead of arcing.

[Stand-in]

Not the problem, I'm stumped.
I am afraid it might be air supply, and that the cylinder head, whilst beautify sealing, is not allowing for ingress

[Jeroen]

Weird? Spark plug cables checked for correct firing order? Correct spark plugs used?

[Stand-in]

Update spark is fine, so is compression. I have problems with fuel, and potentially vacuum. Fuel injectors were clogged, cleaned them and the car started back up after it had died finally. Anyways, still not running good, I think the WUR is fouled and my fuel distributor is throwing off Permatex gasket adhesive. I had a very dirty fuel system but dropped the tanks about a month ago now and have cleaned it up until where it enters my engine bay. I have a WUR rebuild kit and Distributor rebuild kit coming, also I have a fuel injector cleaner. Presuming it gets it back into stock working order I will check compression again, though I dont suspect problems there as it blew 150 155 160 155, and finally look for vacuum leaks; I can hear something around my intake manifold. I need to measure fuel flow at max throttle vrs spec too.

[uwbuurman]

What is the state of the fuel filter?

[Stand-in]

It works now, turns out that the orings in the fuel distributor were busted. Enough ring to allow flow at <45% throttle but not enough for idle.

[Stand-in]

Was fuel the entire time. Now its running, though be it rich and therefor with a bit of burble. (Tuned it after the video.) Video pans to hood to emphasize the lack of shake. All I can ask is, is this how a m10 sounds regularly? Custom exhaust curtesy of the prior owner aside of course.

Took it out for a 13 mile jaunt, its down on power slightly,(14 second 0-60) but all in all its starting to get quite good. Brakes however are quite soft, I believe new brake lines are in order.

[Jeroen]

Glad it's running quite well again! At the front it sounds pretty familiar, but the exhaust burble gives me the impression something's off, ignition timing, fuel mixture? Hard to tell for a video, but a full exhaust gas analysis might give you a clue what's off, if anything!

[Stand-in]

Glad it's running quite well again! At the front it sounds pretty familiar, but the exhaust burble gives me the impression something's off, ignition timing, fuel mixture? Hard to tell for a video, but a full exhaust gas analysis might give you a clue what's off, if anything!

Yeah it was mostly fuel mixture, I have not taken a C0 sniffer to the exhaust yet but the burble has pretty much disappeared. I have been looking online and a CO sniffer for my purposes are not to easy to find/ are extremely expensive, and while I can play it by ear and 0-60 times I would much rather a bit more certainty. Would you have any recommendations? Short of buying the tool it may make more sense just to take it to a shop.

As for timing, I have it in the ball park as per the timing light, but the rpms were jumping up and down and I think I can use my idle screw now to get it done due to my increased efficiency, making my timing more accurate. I wonder if I can run greater than 18 degrees advance as I have it on high octane gas, and had it accidentally set to something like 30 degrees at one point just trying to get it to run. Back fires and pinging was not present, but then again it was very rich. And I don't want to get extreme with advance as I know it would be extremely dangerous for my engine and wallet. So probably just a more accurate timing is in my future.

[Stand-in]

Alright, so I in my YouTube consumption found two items of interest. Namely regarding timing and fuel afm adjustment. Now these were for classic Mopar cars but as far as I can tell will be roughly analogous to my situation as AFM is an universal adjustment as well as the fact that my mechanical timing is shared.
Firstly it was recommended to adjust AFM at idle while measuring vacuum off of the manifold. That is to measure how well the engine is pumping air with the given fuel load relative to the static throttle. This way I can avoid a CO sniffer and get it done for cheap. Though it will probably result in a 14% afm rather than the 12.5% or so efficiency tune as this optimizes for horse power. But as a young man outside of an emissions testing zone who's really going to complain other than my wallet.
Secondly on well worn engines advancing timing to account for slop in the dizzy gears and timing chain can correct the low power status as the crank is now slightly out of time with the rest of the engine.
And I will revert my high valve lashing to the lower end of the spectrum as I think my engine will need all the breathing it can get.
But I cant expect a perfect engine with the wear on it. So a rebuild or timing chain, tensioner and gear set are in my future. Personally I am leaning towards a rebuild but more rather an engine swap as that would be more fun. Right now I am thinking I will purchase another m10 and slowly buy parts building it for high horsepower and good streetablity + mpgs. Aiming for a helpful handing of 180 horses stroker and all. Then I will probably rebuild my original m10 to factory condition and performance as to preserve the antique value.
All and all its neither here nor there, I think I can get most of my horsepower back via a bit of tuning. The 0-60 conversion worked out to something like 70hp given my weight and 14 second time.

Videos for reference


Honestly this explains the aforementioned lack of knock and pinging at higher timing values (according to the crank)

*edit
Also reflecting on the mechanics of the engine, I figure that with this timing solution it will fix most problems but still leave the exhaust stroke acting as a compression stroke in the beginning and remove some of the displacement and compression given the fluid dynamics of having the valves effectively mistimed. So a timing chain job is probably not a bad Idea.

[Jeroen]

Well, good progress sofar sir!

[Stand-in]

Well no need for "sir", I am younger than your account! Lol
Anyways, I have a new timing chain coming and tensioner/guides on close out for about 60$ combined, excluding shipping. That said I am concerned with the sprockets, and to get sprockets I would need to convert to single chain as unused ones are impossible to come by, do they tend to wear out as much as the chain? Also I guess I will reference my sprockets to the unworn ones.
All of this aside I adjusted the timing, and found that the car idled better.
The timing chain is lose to the point of one links retard on the cam and therefor a new chain and tensioner set up is in order. Also the spark dizzy has some vertical play that with how the gears intersect would easily add a solid 5-6 degrees of retard, thusly explaining why my car in the current set up knocks while starting but then has no problem. And also the centrifugal advance seems to not be actuating well as the car seems to have no "kick" as it accelerates. I understand that its no rocket ship but I would still expect more of a hood raise as its lighter, and more powerful than my fathers econobox in theory.
The fuel distributor is acting up again and has a too well acting injector, causing popping in the exhaust. I know this is not a clogging issue but rather the opposite because I had it tuned to the point were it did not smoke out the back and by the time we got off our test drive it was blowing and smelling quite rich. So it looks like I need to rebalance the system.
Plus I suspect I have a vacuum leak as I hear hissing and now as it is running better, making it more susceptible to said problem, it has acquired a "seeking" idle.
As a final note when I advanced the timing past the 18 stock the inside of the car was much quieter, to the point where listing to music was now possible! Wind noise and road noise still troubles me however, and that's just part of its character. Also said noise comes back (not exhaust per say) when accelerating/high rpms so the timing advance is still slow.

[Stand-in]

LOL
I'm breaking down my engine right now and come to find out the timing chain tensioner was not engaged! So that thang was just slobnobin around in there!
Any how unless the tensioner bolt area is completely destroyed I should be able to get back my 70 horses. All I can presume is that my compression went from 145-130 and my spark advance rendered itself 30degrees inaccurate because it skipped a few notches! (plus the distributor was sticky and had slop that accounted for at least 10ish degrees but so be it.)
Between him (owner of ten years ago) cranking the fuel and timing back to account for the problem that's why the cylinder head cracked in the first place, thus taking this car off of the road!

[Jeroen]

You gotta be glad it was still running! How could the tensioner not be engaged, fitted incorrectly? Stuck?

Anyway, in that case there might be excessive wear on the sprockets as well , if new ones are NLA chances are you can find used examples in a better shape than yours. As far as I know these engines are not known for excessive wear on timing chain components, under normal circumstances.