Well... I'm not a happy camper tonight. Was just working on the "new to me" truck - '93 F150, 2WD, E40D, only 137K well documented miles - and I thought I was getting to the point where it would be a good, reliable vehicle. It only had a couple issues that I was aware of when I bought it; coolant recovery system was all screwed up (now fixed) front wheel bearings were going (now fixed) and front shocks were gone (just fixed last night.) Tonight I got home from a long day at work and decided to clean the throttle body to see if that would help a cold stumble. It did! So I drove it to the Metro station to pick up SWMBO... on the way back, I hear a definite rod knock.

Crap.

I guess I'm not really looking for any help here as I am 99% certain that it is indeed a rod knock and I don't have the $$ to fix it so it will likely be sold "as is" to try to recoup some of my losses. Just posting to vent a little and thank y'all for answering my questions during the two weeks and couple hundred miles of ownership that I've, um, enjoyed.

If there is anything you can think of that may be faking me out, please post it, but I'm pretty sure that this isn't an exhaust leak - it sounds like classic rod knock. I've heard this exact noise before on an old VW, and replacing the rod bearings made it go away. I have neither the time nor the energy to attempt an "in the car" bearing replacement now though...

nate

 

I would just mak shure that it isnt an exhaust leak. A few options are finding another motor and swap in such as a 302, 300, or 351w you may or may not find one cheap. Depending on the condition of the crank journal you may just have to replace all of the bearings. Its just that you may have a hard time selling a vehicle with a crapped out engine.

 

I'm betting that it's a rod knock. for one thing it only happens at light throttle, an exhaust leak tends to get louder on heavy throttle. For another I went back outside to check the oil and you know what, it's barely registering on the dipstick. Now it had oil in it when I gassed up last week so this is Not Good.

I'm seriously considering selling my old Stude project, which I dearly love, because a) I'm becoming rapidly broke and b) I ain't gots no truck, and I ain't gots no money, and the Stude is worth some money.

very frustrated,

nate

 

if i were you, I'd get a a bottle of Lucas oil stabilizer and fill it up with 20w50 and ride out. you should get at least 6 months more out of it till you have to replace the bearings

 

Yep and people will talk you down to nothing on it even if you've already came down on the price because of the motor.

 

Like what was said previously you may be able to ride it out untill you can get a new motor or bearings. What motor is it.

 

Sorry man. Sometimes life is good at kicking you while you're down. I'll say a prayer for you.

 

I'm so confused... after the other night I just couldn't look under the hood anymore so I threw in two quarts of the oldest oil I had and dropped it off with the korean mechanic at the end of the street... he said he couldn't hear a thing but put in some "BG oil treatment" for insurance. I figured he just had a tin ear because the noise was faint but audible to me. So I thanked him, gave him a couple bucks, and drove around the neighborhood for 20 min. or so. You know what? I heard the same noise exactly ONCE and then never again. Hmmm.

Pop hood, check oil. Oil is about a quart and a half over full. what gives? I was checking it on a slope before but not enough to show it that radically off I wouldn't think. Do 300's have a problem with the oil getting trapped in the heads when the engine gets old and sludgy like the Stude V-8s I'm used to? I can't really check for sludge because of the long oil fill tube, I cant fit my fingers in far enough to reach the underside of the valve cover or any of the valvetrain bits.

Well, I didn't have a mechanical oil pressure gauge but I did have the sender I bought to "fix" the stock gauge. So I installed it, bypassed the 20 ohm resistor on the back of the gauge cluster, and put everything back together. Not much movement on the needle - it's about between "O" and "R" at idle, and maybe in the middle of "M" at high-ish RPM. This is after driving but then spending an hour or so futzing around with swapping the gauge etc. Temp gauge was still on "O..." That doesn't sound all bad, really, assuming mid-scale is 40-50 PSI... I used a Borg-Warner S334 which was listed at my FLAPS for a '80 F-150 with a 300. Is that the sender I should have used?

so what do I do? I don't trust the freaking thing at the moment, but do I just write it off to a fluke and keep driving it until I trust it again? What about oil? My usual oil is 15W40 "fleet" oil (Rotella or Delo,) and I'd think that'd be more appropriate for a 300 (or really, any older design engine) than the factory specified 10W30, or am I mistaken on this?

any opinions or thoughts greatly appreciated.

nate

 

update: picked up SWMBO at the Metro station, and let the engine idle the whole time I was waiting. By the time I got back home, the oil pressure was sitting in the middle of "N" at idle in drive, back up between "O" and "R" in neutral. So this all appears pretty normal... did not hear the rod knockin' noise once.

I'm just completely puzzled how the engine can sound like it's got weeks to live one day and sound fine the next.

nate

 

Loose carbon on top of a piston can do that too. With a carb, you can just rev it up and pour a little Marvel Oil or ATF fluid into the top of the carb, and it will soften it and let it blow out the exhaust. Dunno how you would do that with an EFI.

 

you might have hit it... I'd just sprayed a bunch of seafoam through the intake before this happened, if some gunk had happened to come off the backside of a valve and fall in... and then after the mechanic drove it around for a while it blew out the exhaust... I like that theory. any of y'all buying it?

 

well it is a sound one i have had a LOT of these 300 i6's and they will carbon up with lots of ideling and city driveing and Sea Foam WILL nock it out. did you put high graid fuel in it, that will do it to. did you flog the engine on your way there. Oh a word to you about oil, only 10-30 and up trust me you be much happyer lol. i hope this helps

 

I think the PO never really drove it; I've done two highway runs to Annapolis and back (about 50 miles each way) since I got it. so basically, yeah, I've blown it out more than it's been in a long time...

Still not sure why I only heard the noise under throttle, but if it is gone I will just keep an eye on the (now proper) OP gauge and keep driving it.

nate

 

Well, Nate, these I-6's are a funny lot. The engine is not "bulletproof", like some people say, but they sure are a lot more durable and forgiving than a lot of other engines you could name. Sounds like yours was kind of crudded-up maybe, and some TLC and running might have helped it cough out the crud. Mine had crusted oil in the valve cover, two injectors were misting the dinosaur juice out the tops, and the oil pressure was low. Mostly crud that eventually washed out, a set of new matched injectors, and it's happy as a racoon up a tree. The oil pressure still isn't what i would like, but the compression is all high and it doesn't use any oil so that's another program for some day when i don't have anything else to do.
Don't give up on it, it'll probably outlast the Studebaker. BTW, that Stude doesn't happen to be one of those fancy Avanti's that came out somewhere back in the '60's, is it? (or am i not remembering who built the Avanti?)

 

Has it had a recent oil change with a cheap filter?