well, looks like I got a bad rod bearing.
oil pressure thread - https://www.fiero.nl/forum/Forum2/HTML/038790.html
knocking thread - https://www.fiero.nl/forum/Forum2/HTML/041957.html
another knocking thread - https://www.fiero.nl/forum/Forum2/HTML/042029.html
now, being its so subtle a knock, and the oil pressure isnt in the red at idle, I'm thinking its just a worn bearing, and not actually spun & wrecking the crank. I want to just drop the pan, and change the bearing (all of them, but #2 particularly). Is my thinking OK? right now, my garage is full of my brother-in-laws junk, so I dont have room to get my car in, and my driveway has to many cracks for my cradle dolly to be useful, so I really dont have the space to drop cradle right now. do rod bearings get sloppy without damageing the crank? I got nice days untill the weekend, and want to get started ASAP, but not sure if I should try and get the oil pan out, change the bearing and go (what I want to do) or drop the cradle, pull the motor off, and redo the right way. If I gotta drop the cradle, the car will be parked, probably untill next spring, and a REALLY dont want that.

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1985 Fiero SE
Plain Red V6 Coupe

Rod bearings do not usually get to the point where they are knocking without causing significant damage to the crankshaft. Sorry, but I don't see an easy fix to your problem. Even if you could just replace the suspect bearing, pulling down the pan is a major PITA and you are still going to have small metal particles throughout the engine anyway, just waiting to do more damage. Sorry for the bad news but the only way to do it is to take the engine out and do it right - anything else is just a temporary fix at best, more engine damage at worst.

Yes, you should pull the engine. I tried to get my oil pan off when I had tossed a rod in my 1986 V6. I could not get the pan off.

Best wishes.

John

There is a lot of ignorance that floats around on this board, which is one of the reasons I stay out of tech.

But, with only a slight rod knock(I didn't read the other threads), you should be good. Drop the pan, replace the bearings with standard size(or better yet, plasti-gauge them), and replace the rod bolts if possible. Inspect the crank for damage, you might even want to measure for out-of-round on the rod journals.

To remove the pan you must lift the engine off its mounts several inches to clear the exhaust on the passenger side. Its a simple procedure, that can be done in a couple of hours with experience. I've performed this exact job before.

You might as well replace the oil pump while you're in there. Don't forget to prime the engine before starting it after the operation.

You wont know how bad it is until you look at it.
Pull the pan,

Check the crank for damage, if it’s not too bad you can emery cloth it to buff it up a bit. Mic it. Caculate which oversized bearing to start with. Plastagauge it. Buy different bearings if not correct clearance.

If the crank has major scratches in it. Then yes you will probably need a crank kit.
At this point I would suggest pulling the engine. I’ve done it while it was in the car once, and would never do it again.

If you get by with only pulling the pan and swapping bearings, you should put in a high volume pump while you’re there.

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Buddy - there are two "G"s in my name
Ling = 84SE-350-N2O-Poly-Mr.Mike seats-Sequential turn signals-short shifter
Julia C = 85GT stock (mostly)
KCFOG
got a broken stud?
car doesn't crank over?

Wow P, I guess you are going for it all! You SURE that it is the bearings?

I find it faster to just lift the engine. An engine hoist does make it a much easier job. You can buy them for ~$200, or rent one, usually $15/day.

If you're working on an '85, you need to replace the two-piece oil-pan gasket. Make sure you get it sealed well at the timing cover.

If you replace the oil-pump, make sure you measure correct clearance from the pickup to the bottom of the oil pan.

It is really an easy procedure that shouldn't scare away someone with a decent brain on their shoulders.

well, I'm still not convinced its the bearing, but its seeming more like it every day. The oil pan cant be that tough to get out. (...riiight....) so, pull the pan, pop the cap, and ***** wildy when I see my crank scraped to hell....thats my plan....

Well, I'll starting my investigation in a couple of hours.....I am starting at the topend, though....maybe we will meet somewhere in the middle, huh? I do hope you are wrong, though.....

Drop the exhaust. You'll thank yourself later.

Remove the V6 mount bracket and support the engine with a 2x4 or 4x4 block between the crank pulley and the right cradle rail. Then you'll be able to get the pan off with no problems.

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'87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.
'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow

Dropping that pan is a large PITA. Good luck.

quote Originally posted by Will: Drop the exhaust. You'll thank yourself later. Remove the V6 mount bracket and support the engine with a 2x4 or 4x4 block between the crank pulley and the right cradle rail. Then you'll be able to get the pan off with no problems.

Yep, thats the way to do it. I have pics if you need any.

Or you could cut a small notch and save yourself a lot of time for future pan removals: https://www.fiero.nl/forum/Forum2/HTML/037399.html

Cheers
PK

[This message has been edited by PK (edited 10-09-2003).]

I read that thread - good idea with the notch. This is in the bracket that goes from the rubber mount up towards the alt bracket? Hard to tell in the picture, but I think thats what I'm seeing. your saying the motor doesnt need to be jacked up with that out of the way?

quote Originally posted by Rainman: There is a lot of ignorance that floats around on this board, which is one of the reasons I stay out of tech.

Thanks for enlightening the ignorant masses.
There is a tech section for people who need help; we are not all ASE certified mechanics. While I agree that some people sometimes get in over their heads, to say "there is a lot of ignorance in tech" is
insulting.
Go back to O/T or Chat if you don't want to share your knowledge with all the ignorant people.....Paul

quote Originally posted by PK: Or you could cut a small notch and save yourself a lot of time for future pan removals: https://www.fiero.nl/forum/Forum2/HTML/037399.html

IMO, removing the bracket isn't that bad (only 4 fasteners) and vastly improves oil pan access over even a notched bracket.

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'87 Fiero GT: Northstar, Getrag, TGP wheels, rear sway bar, rod end links, bushings, etc.
'90 Pontiac 6000 SE AWD: Leaking ABS unit fixed, load levelling rear suspension fixed, still slow

I replaced the rod bearings in my 85 GT with the motor in. Number 5 and 6 had spun. I drove it that way for over a year. (Ran Syntec) And when I pulled it down it was just lightly scored. I used 1000 wetordry and smoothed it out. Plastigaged the journal and it was well within. Popped new bearings in there and it was all nice and quiet again. Dropping the pan is a pain, but if you don't have the option of pulling the motor, it's the next best alternative. Just make sure to clean the journal and check the clearance with plastigage to make sure it's all within specs.

quote Originally posted by Taijiguy: I replaced the rod bearings in my 85 GT with the motor in. Number 5 and 6 had spun. I drove it that way for over a year. (Ran Syntec) And when I pulled it down it was just lightly scored. I used 1000 wetordry and smoothed it out. Plastigaged the journal and it was well within. Popped new bearings in there and it was all nice and quiet again. Dropping the pan is a pain, but if you don't have the option of pulling the motor, it's the next best alternative. Just make sure to clean the journal and check the clearance with plastigage to make sure it's all within specs.

thats the kinda thing I wanna hear!

quote Originally posted by Paul Prince: Thanks for enlightening the ignorant masses. There is a tech section for people who need help;

I hope I provided some insight to his questions. He is obviously not ignorant, as he is willing to ask intelligent, well thought out questions.

quote we are not all ASE certified mechanics.

Nor am I. I don't consider myself any more knowledable than many others on here.

quote While I agree that some people sometimes get in over their heads, to say "there is a lot of ignorance in tech" is insulting.

I think that only insults those who post ignorant/uneducated answers to others questions. OR, to those who have no input for tech, other than to complain about others responses. Which are you?

quote Go back to O/T or Chat if you don't want to share your knowledge with all the ignorant people.....Paul

Suggestion noted.

quote Originally posted by Pyrthian: well, I'm still not convinced its the bearing, but its seeming more like it every day. The oil pan cant be that tough to get out. (...riiight....) so, pull the pan, pop the cap, and ***** wildy when I see my crank scraped to hell....thats my plan....

GTDude passed along this suggestion for me as a test for rod bearings. Pull one plug wire at a time and listen for any change in knocking. I had to rev the engine a bit while checking it out but it worked for me.

Dropping the pan was not all that difficult. Muffler springs removed, starter removed, flywheel cover removed, engine mount bracket from wheel well removed. It was a procedure but not all that bad.

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jetman
Silver 86 SE 2M6 4-speed, with "check wallet light"

I've got a couple questions about Knocks as I may have one aswell

A) Is it supposed to go away after the engine warms up?

B) How can you tell if the Bearing is Spun?

C) What is Plastigauge?

D) What is emery cloth?

E) How would you calculate which (over)size bearing to you?

...I've got a 4Cyl that has a Knock...its there big-time when it starts up...once she warms up...it goes away. No loss in performance or studdering. Once the Temp gauge hits 1/4 it goes away. I've changed the oil to 5W50 and its still there. Is it a rod knock? or valve / piston related? Should I just ignor it?

Please PM or E-mail me if you've got the answers to my abundance of questions.

Steven Rossi

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quote Originally posted by stevenrossi: ...I've got a 4Cyl that has a Knock...its there big-time when it starts up...once she warms up...it goes away. No loss in performance or studdering. Once the Temp gauge hits 1/4 it goes away. I've changed the oil to 5W50 and its still there. Is it a rod knock? or valve / piston related? Should I just ignor it?

Anyone able to answer this for me as well? I seem to have similar symptoms except mines is a 2.8l. When the car starts up, it's a clanking noise. The first few seconds of acceleration, it's more noticable but quickly goes away and never shows up again even at idle. Hard to explain sounds on the internet, could be a loose heatshield for all I know.

quote Originally posted by Pyrthian: I read that thread - good idea with the notch. This is in the bracket that goes from the rubber mount up towards the alt bracket? Hard to tell in the picture, but I think thats what I'm seeing. your saying the motor doesnt need to be jacked up with that out of the way?

Yep, its the one that is attached to the RHS of the cradle. After notching the pan simply 'plops' out when its undone

Cheers
PK

quote Originally posted by stevenrossi: I've got a couple questions about Knocks as I may have one aswell A) Is it supposed to go away after the engine warms up?

Typically it gets worse as the engine warms and the oil thins out.

quote B) How can you tell if the Bearing is Spun?

If its spinning you will be able to hear a god-awful noise. If not, you need to visually verify.

quote C) What is Plastigauge?

Its a product. Specifically a plastic "thread" that expands at a controlled rate when when exposed to pressure. You use this to measure clearance between journals and bearings.

quote D) What is emery cloth?

Used to polish the rod journals. Its very light abrasive.

quote E) How would you calculate which (over)size bearing to you?

Plastigauging will tell you what size you need.

well, Oil pan is just about ready top come out. Dont have much time between getting home from work & it getting dark...
I see why you should move the exhaust too. which brings me to an idea - maybe I should start a new thread for this - that the exhaust is real close to the pan. like an inch away. 3" from the oil pick-up. I painted my oil pan, and now theres a BURN spot on it. no wonder we have oil problems. we need a heatshield there.

quote Originally posted by stevenrossi: I've got a couple questions about Knocks as I may have one aswell A) Is it supposed to go away after the engine warms up? B) How can you tell if the Bearing is Spun? C) What is Plastigauge? D) What is emery cloth? E) How would you calculate which (over)size bearing to you? snip Steven Rossi

You can usually tell if a bearing is spun by the sound it makes. It's a distinct knocking sound that changes with acceleration/deceleration. It's often hard to distinguish from a valvetrain knocking, but if you climb under the car with a long screwdriver, and with the handle to your ear, put the tip against the oil pan, engine running you can hear very clearly what's happening down there.

Plastigage is a method of measuring tolerances within a closed area, such as between the crank and the bearing. It's a small plastic strip, manufatured to very specific tolerances. You break off a little piece, and stick it on the crank or bearing, tighten the bearing down, which smashes the plastigage flat. The tighter the fit, the flatter and wider the plastigage gets. You pull the cap again, and use the guide on the side of the package to measure just how wide the piece is after being flattened, this translates into clearance between the bearing and the journal. Whether or not you need oversize bearings can be based on the outcome of the measurement with the plastigage.

Emery cloth is an abrasive cloth, like sandpaper. It's often pretty course, I wouldn't use it to polich a crank. If you have to use anything on the crank, use wetordry sandpaper with oil. If it's bad, start out with 600; 400 at the most, and finish it off with 1000.

so a knock that goes away after warm is....? And how should I go about fixing it?

Steve

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quote Originally posted by Rainman: I think that only insults those who post ignorant/uneducated answers to others questions. OR, to those who have no input for tech, other than to complain about others responses. Which are you? .

I post to tech based on my experience with the Fiero. I don't preface my answers with insults. I don't claim to be an expert. Tech is an area where an exchange of ideas and knowledge takes place. My only complaint about your answer was the first sentence, it was unnecessary......Paul

bad bearing. #2. didn't spin tho. cap & rod surface untouched. wooohooo! crank doesnt look to bad, no deep scratches, some lines, no burn signs. looks like motor can stay in, a little cleaning on the crank, new bearings and on the road again. coulda been alot worse if Cplensdorf didnt spot that noise for me! thank you thank you!
anyways - the exhaust so close to pan bugs me, I'm going to try and make a heatshield that hooks on the motor mount near there and goes over & around between the exhaust & the oil pan.

quote Originally posted by Pyrthian: I'm going to try and make a heatshield that hooks on the motor mount near there and goes over & around between the exhaust & the oil pan.

Congrats on finding the issue. Don't neglect to measure bearing clearances, or you might be doing the job again sooner than you want.

A tip on making a heat shield: Go to local harware store and pick up a sheet of steel or aluminum, and come cutters. Then just fab one up. I've done it before with other areas of the car, but never there, never thought of it, but its a good idea. Hope all goes well.

quote Originally posted by Pyrthian: bad bearing. #2. didn't spin tho. cap & rod surface untouched. wooohooo! crank doesnt look to bad, no deep scratches, some lines, no burn signs. looks like motor can stay in, a little cleaning on the crank, new bearings and on the road again. coulda been alot worse if Cplensdorf didnt spot that noise for me! thank you thank you! anyways - the exhaust so close to pan bugs me, I'm going to try and make a heatshield that hooks on the motor mount near there and goes over & around between the exhaust & the oil pan.

Good find and I'm glad you didn't need a complete overhaul... This was the point of Rainman's not so subtle comment on ignorance. He is right though. It is always worth a shot to take an easy path until the exact situation is known and in this case it worked out for you. I don't think you need to shield the heat from the exhaust unless you do a lot of urban (slow) driving. There is enough air keep the heat from radiating into the pan during normal driving. I pulled the pan and thought about the notch w/o PK's advice but opted not to do it. If I were to do it over again I probably would notch it as it doesn't hurt anything and would make the repair faster. I put a high volume oil pump on my 2nd car as a knock deterrent.

thank you all for the help - especially Rainman. The notch on the bracket is a great idea. I left the exhaust, only because it looks to brittle to move. (Borla one day....)
+'s for everyone

[This message has been edited by Pyrthian (edited 10-13-2003).]

P-

Did you get it back together? Noise still there at 2000 rpm?

Cold start rattles that go away are collapsed pistons. Only way to fix is to replace the pistons. Eventually the cyl walls will score and you will have to bore it to clean if left to long.

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85 GT 4 speed 2.8L auto X'er

[This message has been edited by red85gt (edited 10-20-2003).]

quote Originally posted by Cplensdorf: P- Did you get it back together? Noise still there at 2000 rpm?

Just finished last night. waiting for the silicone to dry now.....gonna fill with oil, prelube, and fire it up in about an hour.

P- I would love to hear the 'new' engine...want to hook up this week sometime? Between your place and Downtown Detroit maybe? Give me a call. Or if you wanna stop by and take a look at my car, I would not mind showing her off a little bit.

I could make it out this weekend sometime.
early sunday afternoon would probably be the most likely. The knock is gone, but the running funny @ 2000-2200 isnt. Sounds like minor misses. Anyways, that's for a new thread if I cant I cant find it. Anyways, now that I did it, Dropping the oil pan is not a bad job at all.

Im going out to Chicago this weekend to see the Lions lose to da Bears in the new stadium...Leaving Friday, back on Monday....anytime prior or after is fine though...

well, it gets to dark to quick thru the week. PM and we'll find some time