Poor Dauntless Performance

"The Black Plugs is a sure sign of it burning oil"

Crusty and/or oily black, yes.

Dry, sooty, carbon black would be over-rich mixture (gas, not oil).

 

Yep PeteL I agree...............and doing another compression test throttle closed wet is not going to bring it back from the grave either.........

1st test dry throttle closed average 74 lbs / 2nd test throttle open wet averaged 88 lbs...............I would suspect that if you did a leak down on this motor , you would find that the compression issues extend into valve leakage at the cylinder heads and even perhaps head gaskets.................Could it have Piston to valve timing issue's in the front cover at the timing chain? Sure it could and maybe even a flat cam! But that alone if it was off with a stock camshaft it's doubtful that the overlap would ever be great enough to bleed off compression.

Point is , it's a sick puppy and no magic pill is going to fix this overnight.............If you want to try and isolate the problem further do a leak down test on each cylinder and that will at least point to the heads or pistons & rings..............but I think it's time to think about doing the obvious and the first thing I would do is just pull the heads and take a look at all the components.

 

I'd check the timing chain before you do anything drastic. I still think all your symptoms could point to a cam chain being one tooth off. Coincidence, possibly, but one thing I've learned from a life with jeeps, don't ever underestimate the stupidity or neglect of previous owners.

 

I have a new water pump coming tomorrow. Since its not that much more work to pull the timing chain cover at this point, I'll see what the timing chain etc. look like to cross valve timing off the list. Then I'll do another compression test with oil in the cylinders and the throttle closed. If i need to pull the heads, i can do that too. This jeep is driven to school by my teenager so i can limp it along till he graduates. I'll post my new findings tomorrow.

 

Low compression (by itself) doesn't explain the backfiring through the carb. I'm with the thoughts on timing, timing chain or flattened cam lobe. I recently replaced the cam and timing set in mine - what a difference. The lifters were cupped about .030".

 

Update: I am having trouble getting the vibration damper off. I smacked it with a hammer and wood for 20 min last night. When I gave up I sprayed it with penetrating lube. What's the secret? Pulley puller? Bigger hammer? It's the last piece between me and the timing chain!

Also, is there a better or upgraded vibration damper available?

 

Wow. Really? Every one I've ever had almost fell off once the big bolt was removed. I guess use a puller if there's a way to get a good grip without ruining the pulley groove?

 

Wow.............hitting it with a hammer , not the right way to take it off......and if you have upset that outer ring it may now be junk.

First take off the drive belt pulleys that are bolted to the front and then use a puller that bolts up to the dampener and pushes it off by pushing against the crankshaft snout , on the reverse you pull it on with the same puller by using the threaded hole in the crankshaft snout....................and don't use an external jaw type puller as it will try to pull off the elastic ring that is part of the dampening system..............and if a vibration dampener was ever loose enough to fall off ..........it's junk as how could it ever do its job in both dampening internal vibrations and sealing the front cover? It's a press fit.

 

Exaggerated a hair. Sorry. They slid off without too much effort. Machined fit, yes. Press fit? None that I've seen. Just my experience.

 

I had a 2x4 against the innner portion, I was trying to be careful to not pry or hit on the outer ring. I have the drive belt pulley's off. I'll track down a harmonic balancer puller.

 

Interference fit , also known as a press fit or friction fit, .............there all that way.

 

Sorry, have to disagree on this one. You left out the rest of the wikipedia sentence.
"An interference fit, also known as a press fit or friction fit,[1] is a fastening between two parts which is achieved by friction after the parts are pushed together, rather than by any other means of fastening."
If that were the case, it wouldn't need a big bolt to hold it on, and you definitely wouldn't be able to tap it off with a soft-headed hammer, like the service manual suggests.

 

That's why I was hitting it with a 2x4 and a hammer.

 

Sorry I'll also have to disagree..........an Interference fit means just what it says! ................."which is achieved by friction after the parts are pushed together,"

And Crankshaft bolts are present in most motors including all of which have an Interference or friction fit to hold the dampener on....just an added safety feature I assume in case the dampener gets loose and tries to walk off............In any case by all means grab your 2x4's and hammers and beat away!

 

By the manual, it would seem to call for a "Tunk Fit." Technical term for when you have to "tunk" it with a hammer.

But after 30 0r 40 years, who knows what gription there is from corrosion.

Next time I'd suggest using the penetrating oil before, rather than after. Even a day or two before.

 

That (a taper) is not an interference fit.
Interference fit is basically putting a too-small bore onto a too-large shaft - hence the "interference." In essence it has "negative" clearance specs, or a deliberately "wrong" size match, as machined.

As I understand it, it is for parts that are pressed together with considerable force and not intended to be routinely removed.


"Making the first part's joint location slightly larger than that of the second part creates an interference fit joining the two parts. Since the two parts' joints are not the same size, they must be pressed together with force. It is actually the friction created by the interference of the two parts at the joint that holds the two pieces together. One of the advantages of an interference fit is that many times no adhesives or screws are needed to hold the parts together."

 

Thank you.

 

I'm surprised it's being so difficult to remove too. I hooked up my wheel puller to mine and it just slid off without even using the bolt. I doubt there's been a Dauntless any more abused than mine. There was so much mud left under the hood caked on, it etched all the metal parts.