Hello people.

I'll ask my question first. Since I developed a rod knock today after a test drive and absolutely have to drive the car from my home to a warehouse later this spring, what kind of engine damage will I cause? I have no means whatsoever to fix this now but I am taking it apart anyway at a later time so I guess I am wondering if it is ok to use it or will I end up on the side of the road w. a busted engine?

Here's what happened for you people who are interested.

I installed my new EASE scanning software today and took my car for a drive to record some data ( I will be able to laugh at this later I'm sure but not now..). After a 15 min drive (eng. properly heated up and all) and at the last pull, slight uphill and full throttle (app 5000-5500 rpm) I notice as I got off the throttle a nasty knocking sound..
Ouch...

I believe it is a rod bearing since knock is more pronounced when I get off the throttle than getting on. It's located at the rear of the block and I tested by removing the 5 and 7 plug wire respectively but didn't notice a difference.

Anyway, I am not liking my car right now.

To top it all off, when stopping the EASE recording (EASE seems really really nice) I messed up and managed not to save my run.

Ouch again..

I'm sure I'll be able to laugh at this later.

Now I just hate myself for creating more work than neccesary.

Thanks

Bjorn.

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86-IROC
305 TPI , TES, 3" cat, 2.5" Flowmaster
Crane 290 (216/216)
Direct gear drive
2800 conv, 3.73 gears
No-screen MAF, gutted airbox(es)
24 lbs injectors.
Accel cap+wires+plugs
75 corvette heads 76 cc

 

Sometimes you can get by for a while. I drove my LG4 with a rod banging for over 3k miles before i pulled it and found 3 rods that had completely eaten their bearings.
All i did to help her was heavy oil, half 15-50 and half straight 50 and keep the rpms down at all times. Yeah it's a bummer, but you gotta do what you gotta do.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

You are running 76cc heads on your 305? Does that not lower your compression?? Did you havve them milled??

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Godti
'89 Trans Am (Red)
305 TBI 5spd

 

sure its not the torque converter? i had an 82 t/a i got for 100dollars because the guy thought it spun a rod bearing. the holes in the flex plate were oblong and the converter slapped back and forth in the holes
wouldn't hurt to check it out


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have a beat to hell 87 GTA 305ci 700r4
t-tops,recaro,honeycomb wheels,digital dash
paid $600 at a junkyard for it (i had to save it)

 

Hi.

Thank's for the input about the oil, I'll have to do that and just keep my fingers crossed... hmm...

About the 76 cc heads on the 305....well... let's just say I got the car that way.. it is not by choise.. I also have dished pistons in there.

I believe I am running a comp. ratio of about 7.5-ish to 1 and yes, the car is down on power quite a bit and not very crisp either, but that will have to do for now... sigh..

Bjorn.

 

Yep, I agree completely. Heavier oil and R's down and you will be okay for what you have to do.

Jake



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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

 

me again...

Just as a reply to the loose converter theory, which I would have been very happy with, It's probably not the problem. I went out to the car and listened more thoroughly to it and the knocking is very pronounced at the back of the block on the drivers side as opposed to the pass. side where it is nearly quiet.

Thanks for your info guy, I feel a little more secure and will give it a shot w. the heavier oil..

Bjorn.

 

Keep in mind the more you drive it, the worse it gets. You could end up stranded on the side of the road at best, or at worst, blowing a part of the engine thru the side and causing a fire.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

I'm with the general public on this one (from personal experience). I owned a 68 el Camino with a rod knock. Actually, I bought it with the knock (dirt cheap), and drove it around for almost a year (just to see how long it would last). I was only 17, and drove the crap out of that thing...racing, chirping tires, high speed downshifts, etc, (basically trying to "blow" it). I had the money for a new engine, so I didn't care. I'm sure that if I wasn't prepared, good ol' Murphey would've stepped in and taken my engine a lot earlier!!! Anyway, start building your new engine on a stand, and take it easy on your current one. Hopefully, it'll last until you can complete/swap!! Good luck

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'88 Formula 350
Bright (VERY bright) red. Mods? yep, but never enough!
New toy: '73 Firebird 350/350, Bright (not bright enough) yellow
Check out the newest f-body site: http://www.lastgen.com/

 

Oh, and by the way, when it "went".....it went HUGE!! Broken rod went through the block, piston co(ked in cylinder, water in the oil.....made a good boat anchor, tho

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'88 Formula 350
Bright (VERY bright) red. Mods? yep, but never enough!
New toy: '73 Firebird 350/350, Bright (not bright enough) yellow
Check out the newest f-body site: http://www.lastgen.com/

[This message has been edited by 3rdGem (edited February 07, 2001).]

 

Say, if you heard it on one side mostly, I wonder if it isn't a broken rod?? 5500rpm isn't that much, I know. When my engine spun a bearing (probably 4 years ago, maybe more) I don't recall any difference from side to side.

Anyone else ever notice a difference side to side with a spun bearing? I could just be making this up though.

 

Hmm..

maybe I'll try to tow it instead. That'll be kinda hard in NY traffic and no p-steering.

I'll just unhook the driveshaft. What a mess this is...

Sigh..

 

Borg,

Before you go towing it through Manhattan, think this thru. You have a rod knock that is new - last week your car was okay. So, one too many high RPM blasts and it gave up what I believe is a rod bearing.

It's not the end of the world, and your car will most likely not catch on fire. Nor will it strand you in all probablity. Take the 20W-50 with a can of STP route. Jeez, in high school we ran the living SNOT out of a Buick 330 motor with a serious rod knock and that booger refused to die.

One weekend could also do a fairly good shadetree repair:

Loosen the motor mounts enough to jack the engine up - enough to pull the oil pan. Remove pan. Locate wobble-rod. Unbolt it from the crank and push it up the cylinder. Dress crank lightly with emory cloth, slip new bearings in, reassemble, and drive it.

You'll get several thousand miles out of it if you drive it reasonably. We did it on aforementioned Buford. This is a super-cheapo, fast-and-nasty repair, but it's been done a gazillion times and it works. (temporarily)

Good luck, and don't despair - you'll have kitty purring again.

BOR