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mike gaines
05-12-2007, 12:56 AM
Now that I have justed sorted the front suspension, the engine developes a lound knock !
I think I have identified it as a piston pin noise , it is a double knock and when I remove #5 spark plug cap it goes away. The noise only developes when the vengine has warmed up and you cant hear it when the engine is revved above idle. How serious is this problem ? can I use the car for a while before dropping the sump and removing the head to access the piston.
Also , what temperature should be displayed on the gauge when the engine is at normal operating temperature.

JDP
05-12-2007, 12:59 AM
I bet it's a rod bearing, if so, it'll get worse in a hurry.

JDP/Maryland


63 GT R2
63 Avanti R1
63 Daytona convert-63
63 Lark 2 door
62 Lark 2 door
60 Lark HT-60Hawk
59 3E truck
52 & 53 Starliner
51 Commander

StudeRich
05-12-2007, 02:49 AM
If it's a wrist pin it could be worse, very soon it could gouge the cyl. wall. I would not run the engine at all. The Temp. gauge should read 1/2 at normal, but can vary depending on if you have 160,170 or 180 thermostat. There are even higher ones, but they do not belong in Studebakers! [:0]

StudeRich
Studebakers Northwest
Ferndale, WA

mike gaines
05-12-2007, 06:33 AM
I think you are right , it now sounds like it could be the conrod bearing onto the crankshaft.The knock is getting worse very quickly.I have recently had all the bearings replaced but the workmanship was very substandard.I am concerned that this is now the second time I have run a bearing.I havnt stripped a motor before but it seems the only way to get the job done is to do it yourself. Could I access the conrod bearing via the sump without removing the head. If so how would I know if the bearing has failed and how do I work out why the bearing failed , ie blocked lubrication channels etc. Also , how do I measure up to work out the spec for the new bearing. I have the Stud manual.

John Kirchhoff
05-12-2007, 02:17 PM
Yes, you can drop the oil pan to get access to the rod bearings. I'd get some PlastiGauge at an auto parts store to check the clearance. Don't know if you've ever used if before, but put simply, it's basically a small string of modeling clay. You will need to get #5 crank journal rotated to the bottom, remove the rod cap and take a look at it. If it's scored or scratched up, most likely it was caused by lack of lubrication. I don't know how many miles you've put on it since it was overhauled, but it's not unusual for a rod bearing to have a more polished area on the center of the bearing but have a rougher finish on the ends. If you see copper showing, that isn't good and if you see steel, that's really not good at all. Most old style insert bearings have a hard steel shell covered with a layer of softer copper with a layer of very soft babbit on top of that. The reasoning is if the oil carries a hard chunk of crud to the bearing, the hard crank journal will mash the offending chunk into the babbit, isolating it and preventing it from scoring the journal. Kind of like when you have an ice cream sundae with whipped cream and a cherry on top and you mash the cherry down out of sight into the whipped cream. When the bearing gets down to the copper, that's pretty hard stuff to be trying to mash crud into. (By the way, "crud" is a technical term...crankshaft related undesirable debris, or at least that sounds technical to me.) If the bearing looks ok, push the rod and piston upwards a bit and use a rag to dry the oil from both the top and bottom half of the bearing. Pull the top back down onto the journal, lay a strip of Plastiguage across the bottom half, replace it, torque the rod bolts and then remove it. DON'T turn the crankshaft! After you've removed the bottom half, you'll see the plastiguage flattened out. You then take some of the wrapper it came in and find the segment that most closely matches the width of the flattened plastiguage and read the clearance shown at that segment. Compare that to the tolerances shown in the manual. If something seems fishy, try doing the same thing with the crank turned 90 degrees. Just remember to not turn the crank with the top half of the bearing dry if it's in contact with the crank. While unlikely, there's a chance that years ago that one particular journal was turned down and an undersized bearing used. They used to make outfits that would turn a journal with the crank still in place. I believe they still sometimes do that on over the road diesel truck engines. If the bearing seems to be in good shape visually but has too much clearance, then it might be advisable to beg, borrow or steal...no wait, buy a micrometer or vernier caliper and mic the journal to see what it actually reads. Since cranks don't usually wear evenly, I'd measure the journal in six places, both sides and the middle and again 90 degrees from that position. If it appears the crank has been turned, I'd be inclined to measure some of the other journals, for peace of mind if nothing else. Just remember to lube the bearings before you cinch things back up. Fortunately, Stude cranks are harder than my ex-wife's head and it takes some deliberate abuse to damage them.

mike gaines
05-14-2007, 03:31 PM
Thanks John , I removed the oil pan , the white metal bearing on the big end of the conrod looks fine , little or no wear. As I am now really confused , I will decscribe the knock more fully before I remove the head to check the small end. There is no knocking when the engine is cold. It only becomes audible when the engine reaches normal operating temp , about 140 on the temp gauge.It sounds like a double knock , high up in the engine. When I remove #2 spark plug cap , the knocking stops.I did earlier say it was #5 but got the numbers wrong. It is the first cylinder on the right bank. When I turn the distributor clockwise the knocking gets quieter and vice versa when I turn the distributor anti clockwise. Untill recently the knock was only audible at idle and could not be heard when I increased engine revs. Now the knock is audible at higher revs as well. Oil pressure looks ok , above 40 when cold , reducing to between 20 and 40 when at normal operating temp and close to zero at idle when warm.Does this sound like the small end , if so how do I go about sorting it out ?

dictator27
05-14-2007, 06:46 PM
The little six can develop a timing gear knock. I once replaced all the rod and crank bearings in a 53 Champion because of a knock and still had it after all that work. Turned out to be the timing gears.

Terry

JDP
05-14-2007, 07:16 PM
I had a Champion six that had a nasty case of piston slap, but it got better as it warmed up.

JDP/Maryland


63 GT R2
63 Avanti R1
63 Daytona convert-63
63 Lark 2 door
62 Lark 2 door
60 Lark HT-60Hawk
59 3E truck
58 Starlight
52 & 53 Starliner
51 Commander

Dick Steinkamp
05-14-2007, 07:25 PM
I think he's got a V8 if that helps any.



http://thenobot.org/images/s2d/s2d_01.jpg

mike gaines
05-15-2007, 12:43 AM
Thanks Guys but it is a 259 V8. How would I check if its the timing gears and why would the knock dissapear when I remove #2 spark plug cap with the motor running

JDP
05-15-2007, 08:57 AM
I'm surprised it was not a rod, since I just fixed the same problem. One rod bearing was worn down to the copper, the others looked fine. I suspect one was not torqued correctly.

JDP/Maryland


63 GT R2
63 Avanti R1
63 Daytona convert-63
63 Lark 2 door
62 Lark 2 door
60 Lark HT-60Hawk
59 3E truck
58 Starlight
52 & 53 Starliner
51 Commander

John Kirchhoff
05-15-2007, 11:42 AM
Sounds are very difficult to describe since no two people have the same perception of one. The exact origin of sounds can also be very difficult to ascertain.

End play in the crankshaft often makes itself known by a single "clunk" when you rev the engine and let off of it. Kind of like thunking a piece of cast iron with a sledge hammer.

Piston slap is caused by the piston being a little too small for the cylinder. Normally you'll hear it on start up but once the engine gets warmed up, the sound is gone. That cold engine slap is nothing to worry about, I ran a bike engine for 70,000 miles with it and never had any problems. A constant noise should be looked into though. To me, the noise can be best described like firmly thumping the engine block with a hard plastic headed hammer.

Worn main bearings usually get louder as the oil gets hotter and thinner and the frequency of the noise is in direct relationship with rpms. The knock is more of a deep, solid, encompassing noise from deep in the engine, sort of like moderatly striking the lowre block with a medium sized sledge hammer.

Like main bearings, worn or loose connecting rod bearing noise becomes more pronounced as the oil gets thinner and rpm's increase. The knock isn't as "deep" sounding as main bearings and is usually most noticable when you rev the engine and suddenly let up on it. Not wide open, but maybe up to 2,000 rpm. To me the sound is like tapping on the block with a ball peen hammer at idle and at higher speeds, using two hammers like drum sticks.

Piston pin noise eminates from higher up on the block and makes a sound (depending upon severity) something like holding and tapping a large bolt with a small ball peen hammer. Piston pin noise should, but not always, increase if you remove the plug wire. The reason is because under load, the piston exerts downward pressure onto the piston pin and rod 75% of the time (compression, power and exhaust stroke) and the rod only pulls the piston down (intake) 25% of the time. When not firing, downward pressure is applied a little over 50% of the time (compression and exhaust) while the other almost 50% of the time it is being pulled downward. Any change in the direction pressure is being applied allows the slack in the bearing to make a noise.

If it is a loose piston pin, try removing the bearing cap on that piston and push the piston and rod up enough to clear the crankshaft. You should be able to slide the rod and pin forward and backward (as the car points) a little which is normal. Grasp the rod and try rocking it in an arc, like the way a kid's swing travels to and fro. You shouldn't be able to feel any play that way. Also try twisting the rod back and forth, again you shouldn't feel any movement or hear anything. Get a flashlight and peek up into the cylinder and see if there are any score marks on the front or back indicating the piston pin has come loose. If everything looks and feels ok leaving you feeling very frustrated, for grins remove the rod cap on the other rod riding on the same journal. You'll probably find nothing wrong, but when you can't find something where you think it is, you need to start looking where you don't think it is.

mike gaines
05-17-2007, 01:56 PM
I think I have found the problem , the main bearings are worn to the copper which in turn probably accounts for the lowish oil pressure. The knock only appears when the engine is at normal operating temperature , which co incides with the lowering of the oil pressure . Any way thats my theory. Crank shaft journals are very ridged , probably not machined when the new bearings were fitted.Am not sure whether to re do the motor for the 3rd time or transplant a chevy lump.

John Kirchhoff
05-17-2007, 09:37 PM
You might want to mic the journals see just how worn they really are. A visual observation can sometimes be very deceiving. Also keep in mind that a few ridges may not be too much to be concerned about since they're like brake pads, the soft babbit of the bearings will give some until they fit the journal. Within reason that is. Swapping out the main bearings would be much easier than swapping engines.

bige
05-17-2007, 09:37 PM
Just have the crank done and put new bearings in, no need to do the whole motor. I must have done that a dozen times on motors not as strong as the Stude.

ErnieR

http://i146.photobucket.com/albums/r241/AvantiR2/avnatiglamour007.jpg

studebakerjeff
05-18-2007, 11:05 PM
I had a engine built by Cathcarts for my 50 Studebaker. After I got it running it had a knock in the engine when I revved it up. When I took it out on the highway it knocked alot. I called Cartcarts and they didn't know what could would cause it. To make a long story short,it was my vacuum on my dist. I first disconected the vacuum line and that took care of the problem. Then I used the spacers to increase the tenison on the vacuum spring.
When I installed the new engine the vacuum changed, and the dist. was advancing to much. This may not be your problem, But all with all the help from the forum you will figure it out.

Jeff

1950 Champion business coupe
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