Cylinder #5 saga?kicking my butt.

[Duke]

Cylinder #5 saga…UPDATE 25 Jan

Good morning all,

I have had my Tiger since February. I do not know the history of the 260 engine but the PO told me it had been rebuilt .030 over and had very few miles on it since (take that with a large grain of salt). A recent dyno resulted in 156 RWHP and 200 RWTQ.

I have had a constant problem with #5 cylinder fouling the spark plug. The plug gets fouled out by black soot. It is not wet (no fuel smell) but a thick layer of black powder. The other seven plugs look great with the proper color for a good A/F mixture.

I figured that it was an ignition problem with a weak spark. I have replaced the distributer, running an Accel electronic module, replaced cap, rotor, wires and many spark plugs. I have determined that the plug is producing a good spark.

In the past, the cylinder produced 130 psi for a compression check while turning over the engine.

Yesterday I did a compression check with the engine running. I started the engine and the pressure was 60 psi. I pulled the valve cover and re-set the valve tension (+ 1/2 turn of locking nut once all rocker to valve clearance was out). I tuned the engine over and had 130 psi from the cylinder. I did not check the compression with the engine running.
I drove the car about 10 miles (hard) and pulled the plug….it is getting a black build up already.

I am thinking that I have a bad hydraulic lifter. My thinking is that when just cranking the engine, the lifter operates correctly, and thus I get a good compression number. When the engine is running the lifter is failing and not opening the valve enough (or too much) and I then lose compression and get a fouled plug.

I do not think it is a valve problem because I get good compression numbers under certain conditions. If a valve or the springs were damaged, I would never get good numbers.

What are your thoughts?

 

[mikephillips]

I would think, if it's lifter related, that perhaps it's pumping up too much and failing to close a valve. Since they're pressurized by the oil pump feed to the upper engine they should be less likely to collapse running. I'd say take a look in the bores and see if either of the lifters are missing the little retaining clip in the top that keeps the insides of the lifter from coming out. I'm a little reluctant to mention this due to how the cam and lifters wear together but you could swap those 2 lifter to another cylinder and see if the problem follows them. But at the same time you didn't report a miss, which I would expect as well if the mixture or compression was messed up.

 

[Duke]

But at the same time you didn't report a miss, which I would expect as well if the mixture or compression was messed up.

Oh yea...it has a miss. That is what got me to diagnosing the miss and the results are above. I would rather just replace all of the lifters at once and not just two. Would that present a problem with the cam?

When I replaced the oil the first time it was NASTY. I would not be surprised if a lifter is clogged with crud.

 

[mikephillips]

You really shouldn't replace the lifters with new ones and leave the old cam. The components wear together and replacing one or the other risks causing a failure fairly quickly. My suggestion is only a temporary move to see, if you don't find obvious problems with them, if the problem follows the lifters from cylinder to cylinder. If you swap with the one next to it and #5 still has the problem, then it's probably not lifter related. I can say though that when I removed my originals during the initial teardown several had lost the clip in the top that keeps the guts from being forced out by the oil pressure. Don't know how it affected actual running though since the car was dead when I bought it. and if you haven't noticed, swapping a lifter will require pulling the intake. But it can be done without moving the engine, I've done it.

 

[Duke]

My suggestion is only a temporary move to see, if you don't find obvious problems with them, if the problem follows the lifters from cylinder to cylinder. If you swap with the one next to it and #5 still has the problem, then it's probably not lifter related.

I really do not want to do the labor twice to move lifters around and then still have to remove them (if it is a lifter). I also do not want to spend ~$300 to replace the cam and lifters due to one bad lifter.

What about removing the lifters, disassembly, cleaning, reassembly and re install. Is that a possibility, can the lifters be properly cleaned?

 

[mikephillips]

Should be able to clean them. If they're the originals they should have a small circlip like spring clip in the center top that holds the guts in place. Remove it and they should come out to be inspected and cleaned. I'd then place the bits, separated so each one goes back where it can from, in carb cleaner to remove any baked on deposits. But if you have a collapsed or broken lifter cleaning probably will not do much. But, nothing ventured, nothing gained.

 

[Duke]

Thanks for the advice Mike. I am going to start with a quart of ATF added to the oil for the next 100 miles. Hopefully, that will clean the gunk’d up lifter if that is the problem. If that does not work, I will remove and inspect each lifter and replace any that are broken or collapsed.

 

[saltykracker]

try some marvel mystery oil, instead of atf.

 

[jmthehermit]

You could also use Rislone. Always had favorable results using it. Google it, it has a very long history in the automotive world. Jeff

 

[MikeH]

I'd try the Marvel Mystery oil first. I've got a '57 Old's that started acting up shorly after I bought it. Could hardly keep it running to get it back in my driveway and it was clacking like anything. Ran some Marvel in it and it smoothed right out.

 

[64beam]

Hi Duke,

Ah, the dreaded previous owners!! I agree, definately try the oil additive to try and loosen up the lifter and a bit easier than tearing your engine apart. Did you notice if your fresh oil was looking black fairly quickly (a sign of a poorly maintained engine)? Maybe change the oil a bit more frequently until everything is back to normal as well. Hopefully this will be the end of your Tigers issues.

Good luck,

Regards, Robin.

 

[agmason]

If you have a miss, it may be due to a burned valve. If the miss is only at idle, and compression is less than the other cylinders, I would suspect a burned valve.

 

[Duke]

If you have a miss, it may be due to a burned valve. If the miss is only at idle, and compression is less than the other cylinders, I would suspect a burned valve.

The miss occurs once the spark plug gets fouled. The compression number is the same as the rest of the cylinders. I check yesterday and the compression while the engine running is 90 psi. I checked this on #3 and it was 90 psi also.

I have also notice black soot in the intake manifold for the plane that feeds #5 (F4B manifold). I am figuring now that the intake lifter for #5 is loading up at higher rpm and thus keeping the intake valve from closing and I am getting combustion gasses in the intake at higher rpm.

Will be doing the engine cleaning stuff this Friday.

 

[MikeH]

Or, and I'm not sure how it could happen, you are getting a rich mixture to that cylinder.

 

[Duke]

Or, and I'm not sure how it could happen, you are getting a rich mixture to that cylinder.

I would expect three other cylinders to be rich also if that side of the carb was off and running rich. The plug is not a wet/black it is a very dry powdery black.

If it was fuel injected (BTDT) I could see that.

 

[Chuck Ingram]

I sure can relate to your problem This is not my V8 sunbeams as they are so easy for me to set up.At least so far in all my doings.The 302 started on the first turn.
My problem is the 2.3 Pinto I have in the 29 ford.I have a miss like fuel starvation every few hundred RPMs.I have done and rechecked everything at least 4 times.Removed all the smog stuff etc and no solution.I believe it is the Holley carb but that was rebuilt and then rechecked as well.I'm waiting for a Weber 32/36 that I have ordered.If that doesn't work I may end up pulling my hair out and I really don't have that much too pull anymore.

I would expect three other cylinders to be rich also if that side of the carb was off and running rich. The plug is not a wet/black it is a very dry powdery black.

If it was fuel injected (BTDT) I could see that.

 

[MikeH]

I would expect three other cylinders to be rich also if that side of the carb was off and running rich. The plug is not a wet/black it is a very dry powdery black.

From a guide on reading plugs:
CARBON DEPOSITS
Symptoms: Dry sooty deposits indicate a rich mixture or weak ignition. Causes misfiring, hard shifting and hesitation.
Recommendations: Check for a clogged air element, high float level, sticky choke and worn ignition points. Use a spark plug with a longer core nose for greater anti-fouling protection.
Is it possible that the spark plug in #5 doesn't go into the head far enough to prevent fouling?

 

[Duke]

From a guide on reading plugs:
CARBON DEPOSITS
Recommendations: Check for a clogged air element, high float level, sticky choke and worn ignition points. Use a spark plug with a longer core nose for greater anti-fouling protection.
Is it possible that the spark plug in #5 doesn't go into the head far enough to prevent fouling?

Thanks for that reasearch.

I will check the depth of the plug, not sure how, but will check. The rest of the causes would affect all plugs and not just one.

 

[MikeH]

Check to see if a washer is stuck in the plug hole for #5 from a prior plug change ????

 

[husky drvr]

Or maybe a bad plug wire on #5.