340 connecting rod oil squirters

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Kern Dog

Kern Dog

Build your car to handle.
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Aren't the oil squirters on the connecting rods and caps supposed to face INward or toward the outside? I thought they were inward to throw oil against the camshaft.
The reason that I ask: A buddy with a 340 Dart is having a strange knock/rattle in the bottom end and I wonder if his engine builder made a mistake. It is a fresh build with very low miles, maybe less than 100. It has a strange noise that isn't that clear to identify and I am looking at all options as to the cause. Oil pressure was 50 at cold idle. Oil is clean. He pulled the RH valve cover and watched the rocker arms and pushrods move at idle. No problems there. The flexplate is not cracked, the torque converter bolts are tight, the shield isn't hitting anything.
This noise is intermittent. It can start at idle or be silent. Once the engine is revved, the noise sort of "flares" then quiets down to about half as loud. It is not as deep as a rod knock usually sounds but who knows. I tried running the engine and pulling a plug wire at a time to isolate the noise, expecting the engine to quiet down once the offending cylinder wasn't firing. The noise remained. A stethescope showed the noise to be louder at the rear. Could the oil pump drive rattle and make noise? I've never seen it before...This is a new one.
I tried to pull the oil pan but he didn't have a pickle fork for the steering linkage. I should be able to get the pan and windage tray off tomorrow to get a look at the rod caps. If any are loose, that is obviously trouble but I was curious about the oil squirters.
Thanks!
 
Yes - they go inward. Not sure if that would cause a rattle though. I've had a 318 that had them installed incorrectly and the engine ran fine. Not a high rpm engine though.
 
Since not all rods have the oil squirt holes, I don't use that as a landmark. But, the bearing lock tabs face the outside of the engine on each side, if that helps.
 
The noise you describe sounds like classic cracked piston noise. Sort of a hollow metallic sound usually just as the throttle is cracked and tends to diminish or disappear at higher RPM.
 
Seems like a cracked piston might cause some oil burning, right? Well, unless it is cracked below the crown.
 
Kern Dog said:
Seems like a cracked piston might cause some oil burning, right? Well, unless it is cracked below the crown.
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If it's a cracked skirt, not necessarily. It all depends on where the crack is. Do you know if he reused old pistons?
 
RustyRatRod said:
If it's a cracked skirt, not necessarily. It all depends on where the crack is. Do you know if he reused old pistons?
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I don't know but the guy owns a carburetor rebuild shop and is not one to cut corners. He spends the money when it is warranted.
Nice guy too, I don't like to see him struggle with the car. He is really sharp with carburetors but the inner workings of the engines are a little out of his area of expertise. I have helped him with various Mopar specific nuts, bolts and specialty parts to put the car together. I'd sure like to see him get this sorted out.
 
Kern Dog said:
I don't know but the guy owns a carburetor rebuild shop and is not one to cut corners. He spends the money when it is warranted.
Nice guy too, I don't like to see him struggle with the car. He is really sharp with carburetors but the inner workings of the engines are a little out of his area of expertise. I have helped him with various Mopar specific nuts, bolts and specialty parts to put the car together. I'd sure like to see him get this sorted out.
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Maybe if you could get a video of the noise......
 
I had cross fire in the cap once... scuffed the skirt of no. 5 piston and hollow knock at low speed....kinda quieter after hot but definitely there

Mopar had some poorly phased distributors in the 90's that hurt a lot of motors.... they quietly fixed the issue and that was that.... but it cost me 2 pistons...same motor, changed no.5 twice before catching what was up.
 
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The squirt holes point to the inside/center of the block and the anchor slots go outward...
 
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We had a noises like that from a fresh rebuild soon after starting it. Here is what we found to be the culprit. The engine was balanced and the heavy metal welded into the side of the counter weight the weld was hitting the rear of the blocks main cap saddle. Drop the pan you will see what I mean. Clearance the block, Do not remove metal from the crank. Many times a motor with not enough stall for idle with a larger cam. pushes the crank forward in gear from pressure . This will cause premature thrust bearing wear. Put a dial indicator on the damper. move it front to back and check the measurement of movement. If it is not to spec it will make noises if a protrusion of weight welded in contacts the block somewhere. I cannot tell you how many times we have seen this. Find another builder ?

also When ever you install a larger cam with a idle lope. If it dies more than a couple RPM's in gear it is pushing hard on the crank from hydraulic pressure from the torque converter. when Ever I hear a car with a large cam die down in idle when putting it in gear. I just laugh some of you guys just don't get it. If it don't sound like horses in gallop while in gear. You have stall issues or timing drop off. I heard cars at Carlisle leaving sounding like an old steam engine pulling a hill. They think that sounds cool . It is only doing damage to the thrust bearing.
 
Wrist pin clip came out. Pin beating on cylinder wall. Hope I'm wrong!
 
Since the oil squirter holes are not required, I would not think that would be an issue (my rods don't have the holes).
 
pauly said:
I’ve got a 340 block in the garage that happened to. She’ll need a sleeve.
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My son sleeve and do any block work you can imagine. From 4 cyl's to Hemis He does everything now. He just got a new machine and fixtures again last week. He has been resurfacing aluminum blocks the correct way. You have to remove the sleeves after you measure the the sleeve height at temp. of 250 degrees. Take the sleeves out square deck the block , Reinstall the sleeves the square deck the sleeves to the required needed Height above the deck . The new Dart block he is doing now. The sleeves are .003 above the deck When the block grows with heat they are zero. This keeps the compression ring sealed under High boost when hot. He also puts in inkenal wire if you are running extreme boost. Methanol and nitro motors run cooler so there is a different equation for that I would believe .
 
SPUN bearing!
Son of a gun. I got the center link off and pulled the pan. The windage tray was okay. The oil pan had chunks and grit in a metallic paste. It feels like brake rotor shavings. I pulled #s 5 and 6 rod caps off. # 6 was heavily grooved and to copper. # 5 was spun. The ends were worn to a taper. I suspect the bearing halves were sliding in and out of each other since the rattle was not consistent. The pistons are new, they looked fine from what I could see. He is going to strip the accessories off and I'll help him pull and transport the engine.
Thanks for the help!
 
Well I'll be danged. What are yall gonna do, build it?
 
It would rattle, then sound normal, then rattle...
He is going to have the shop go back through it. Me? I'd want the shop to pay to have someone else fix it but that is highly unlikely to happen. As we were talking today, he mentioned that he watched the owners son assemble the engine and he asked why the guy wasn't using Plastigage. The guy said that they already checked the parts with their micrometers. I doubt that...The crank was likely ground by an outside vendor and chances are, the dude just assumed it was right and screwed it together.
 
I worked at a very small mechanic shop years ago when I was a kid. It was the owner, one of his dopehead friends and me. They were cool and all......that's just how they were. Anyway, Billy, the other mechanic had a 68 I think it was Chevelle wagon. 307, powerglide. Just a go to work, go to the bar car. This is no lie.......Buster, the owner and I got there first every mornin.....Billy always late from gettin drunk and or chasin tail......Buster an I could hear the guy coming literally over a city block away long before we saw him. Knock knock knock knock. It had a spun rod bearing. I swear as I'm sittin here typin this, he drove that thing a solid year at least before he found something else and moved on. ....and it was STILL RUNNING when he left. He just kept his big toe on the gas and kinda let it idle around. It was funny, but it got him everywhere he needed to be.
 
I had a slant six in a 73 Dart, the engine ran great but it had a LOUD knock. I would disconnect the #3 plug wire and it quieted down to barely a tick but connect the plug wire and CLANK-CLANK-CLANK.
I pulled the pan. There was no bearing left at all.
 
Plastigage is considered old school now. A good motor man mics everything now. Seems like the motor needs to be assembled better. At least you will need a new crank with reconditioned rods and ARP bolts. Clean out the block to remove metal particles. Save what you can. Good luck to your friend.
 
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