Hey there, guys! I'm new, so first off, I can't tell you how glad i am to find a forum dedicated to the Slant Six. Hopefully this makes my work ahead a lot easier.

Okay, I recently obtained a '69 Dart which has a 225 in it. The car was cheap and the body seems pretty good to me. My real concern is the engine. it knocks. Not a lot, but a little. It's a rod knock, specifically. Now, I've done some research, and i can get crank kits pretty cheap. New crank, gaskets, and rod and main bearings. it's all under 220 bucks. Cheap is good. I need this to be cheap.

Here's the question part. I have not yet isolated which rod is knocking, and don't really care to. I am going to have to pull the motor out and yank the crank no matter what I do, so I'm going to avoid running it in an effort to avoid further damage. What parts, besides the crank should I be checking for problems? Suppose one of the rod bearings is spun. Would it be simpler to have the rod worked over, or should I just buy a replacement rod? Whatever I do, I need it to be as cheap as possible. Is it advisable to replace only one rod in a situation such as this? Is a used rod a possibilty?

Feel free to share your ideas and experiences.

I hope to hear from some people soon.

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Keith C. Adams

1969 Dodge Dart Custom

If it's still runnin' I really doubt that any of your connecting rods will need more than two glances. If you had spun a bearing, there's a good chance that the engine wouldn't even turn. It's not always that way, but usually they jam up and won't even turn.
So worry 'bout nuthin.

Well, that was a quick response. I'll keep that in mind. I know when i pulled the plugs out of it and rotated the crank back and forth that it turned smoothly and I didn't hear any clunking that would indicate slop. Hopefully a crank kit will take car of my problems. I good engine flushing would help, too.

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Keith C. Adams

1969 Dodge Dart Custom

Old Slants make a lot of noise compared to newer engines, I wish I could hear your's first hand, these days I'm getting pretty good at knowing what each little noise is.

Anyway, beside a loose rod bearing, piston slap, wrist pin wear, and lifter tappet noise are also common and can get pretty loud.

It would be a drag to get a crank kit, then open the engine to find a piston problem, or worse, a bent pushrod or loose tappet screw. Have you had the valve cove off this engine yet?

If it is a con rod bearing problem, yes, pay close attention to the con rod "big-end", it needs to be the correct size or it will not hold the new bearing to proper clearance and that equals a quick failure. I can say that I have swapped-in lots of used rods into "patch job" engine and these engines went on to live long and happy lives. Bottomline is if it measures OK, it's OK.

If you plan to do the "flush", do it right before you pull everything apart and be sure to completly clean the oil pick-up screen when you are in there.

Hope that helps.
DD

Yeah, it's definitely a rod knock. I can feel it through the firewall, deep and hard. It's completely non-existant at an idle, but when you increase the RPM, it becomes more evident. Putting a load on tne engine by dropping it in to gear also makes it knock. According to the lady who owned it, she was on her way home from about an hour and a half away when it started clunking away as she drove down the highway.

I do know that the valves are adjusted perfectly on it right now. The motor also purrs beautifully. No missing, no hesitation, just nasty black oil and that darn knocking. She never changed the oil the entire time she owned the car. Ouch.

I do know that I'm going to pull it apart before I buy anything for it. So, I guess I'll justhave to wait and see how everything looks. My biggest concern was with the rods and wether or not it was sane to try to re-use them without being worked over by a machine shop. I guess I'll just measure everything and see what I come up with.

BAH! it would help if I LOGGED IN before posting!

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Keith C. Adams

1969 Dodge Dart Custom

Sounds like you have a good "handle" on what needs to be done.
If the cylinders look good with no big ridge or double ridge (broken top ring) then you can get away with a "patch job".

Put in a good crank and swap-out the rod with the spun bearing. Get a good machine shop to press-off the piston and install it onto another good used con rod. (I have a bunch of them if you need one cheap) Lightly sand the cap's mating surface to give the bearing a pinch more crush.

Use some plasti guage to double check the clearances and all should work well.
DD

It might be a good idea to replace the oil pump as well, just as a safety precaution. A similar thing happened to a buddy of mine and he kept driving...now he's gotta replace rods/crank/rockers/push rods/lifters...the whole "nine-yards". All because of the oil pump...it shouldn't be expensive, so it will probably be adventageous to do it when you rebuild the bottom end. Good luck with it!

-Don

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Forget the flowmasters...here come the good ol' GLASSPACKS!!!

If you go the crank kit route, or heck, even if you don't by all means chk to make sure the crank is straight.

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'70 Cuda AAR
'74 Duster 360
'79 MagnumGT
'79 Chrysler 300