Hey all. My first T/A, and she's a beauty!

It's an 85. Has t-tops. All black. Real straight and glossy.

I'll be towing it home in a week or so.

















So there it is.

Looks nice...but slightly broken.


Like I said in the topic....It runs...knocks and shakes a bit...and the owner said once it warms up, it loses oil pressure....so he just shut it off. He isn't sure what's wrong with...and neither am I. It didn't sound half bad while it was running....I've heard engines knock louder and continue to run.

What's wrong with it? Any ideas??

Thanks a million!

-Tony.

 

i bet there is excessive clearances within the engine somewhere, when engine oil gets hot, it thins, making it more viscous, the thin oil is not acting like a guard, as it would when its cold, this is why the oil psi goes down, i wouldnt be surprised if the motor has been severly abused in some way, whether it be maintenance, or being "hot-rodded", you probably have a minor rebuild coming your way.

 

That or its the good ol' broken connecting rod.

 

Could have been abused. Definite possibility. Also..I should mention, the owner told me it sounds isolated to one side of the motor...specifically, the passenger side. I couldn't really tell, as I only heard it run for a minute or two, and I wasn't listening for it.

 

If the problem is a spun crank bearing....what does the repair entail? I was told I only need a crank kit, which will include the parts needed to replace the old cranshaft....and new connecting rods.

Yes?

Who are the good vendors? Should I buy from an advert on this forum? From Jeg's? Are there certain specs I need to consider before buying a crankshaft?

 

So I've had the car a couple weeks now. The battery is useless....wiring harness is a huge mess....the car is hot-wired on some random plug...I have no idea.

However...it DOES run...and I must say...not too terribly. I took it for a spin. The clutch is very um...finicky. I stalled it a bunch of times...because I'm used to my very small Geo Tracker. In order to get it to drive away from a stop sign...I was spinning the tires on every launch...oops!

It indeed does lose oil pressure like the previous owner said....but very gradually...took like 10 or 20 minutes to drop to around 15lbs at idle....and when I gave it some throttle...it jumped back to 40-50lbs.


Can it be that a previous owner never replaced the stock oil pump when boring and adding all this extra power? Perhaps it's not getting enough oil? Maybe if it indeed DOES have a spun bearing....it's BECAUSE of a lack of oil pressure....does that sound right?

 

15 psi at hot idle isn't dangerous by itself. Still, it's nearly spring, so switch to 20W50 or straight 30W for a wee bit more. The real issue is the knocking. I'd start by pulling the valve covers and checking the valvetrain. If that's all good, then drop the oilpan.

 

Big important question.....Can I replace crank bearings or the whole crank from lying under the car, with the motor still in the car? I'm lacking the equipment needed to perform such a job...so if it can be done...please speak up.

See...I had a few people suggest the crank is shot...crank bearings...connecting rods...whatever.

I'd be THRILLED if I could drop the oil pan and check/replace some of that stuff from under the car....without tearing the whole motor out. Even If I could prolong the inevitable death of the block....I don't care. I'll replace it later. I just bought it..and I'd like to make it at least drivable ASAP.


Thanks for helping me out!

 

No, it is NOT possible to pull the crank with the engine still in the car. Hard enough to pull the oilpan. But with the pan pulled, you can see if any rods are broken, you can wiggle the big ends of all the connecting rods and check the rod bearings, and you can see if you've spun a bearing, which is unlikely. At this point, it may be best to just get another block and start building a 383 or a 400. Installing it would give you a good excuse to check the clutch.

 

Damn....but I don't wanna pull the motor.... =/

Never done it...but it looks like I might be soon, heh.


Here's another fun "for instance". Let's say I take the oil pan off....and there's no metal in the pan...none of the rods are broken...and the crank isn't terribly loose or anything....but it's clear that there is an issue somewhere with the bearings or clearances somewhere...due to the knocking and shaking....

Would you call that a terminal condition? Would it survive a few months with light driving, and a strict diet of 20W oil?

 

it might continue to run but it is slowly destroying the entire engine specially if you have spun rod bearings they have a tendency to stack one on top the the other giving the piston a chance to get intimate with the head which will put a quick end to the fun...

PULL it now and fix it before the is nothing left to salvage

 

If you have a bad rod, pull the appropriate head, and pull that rod and piston out. Check the crank. If it's good, once the rod is tended to, it can be reassembled and driven for a long time. I've done it many times in my 9 years as a professional automotive machinist.

 

Do you know exactly where on pass. side the noise is at if it is in the front your timeing chain could be streched and causeing the noise and your cam will not work the valves right so it will knock and shake as for oil pressure cam bearings can be worn and lower oil pressure . If everything checks out ok run 10w30 or 10w40 oil with Lucas oil stabilizer to keep oil from breaking down to fast and it will help lube all internal parts. If you do have a 60 over and it isn't a stroker I would pullit and give it freshup and drop in a stroker crank if it was mine .

 

Could be, but The seller would have said the sound was coming from the front. Timing chain slap is pretty easy to figure out. with the block being 60 over already, unless the rebuild was recent, then there's no point in trying to stroke it. 350 blocks are easy to find for $100.

 

What I was trying to say is that if the cam or bearings are worn it could be a good reason for oil pressure drop and the shakes the chain may not be the problem . As for 350 blocks for $100 bucks not if you live in East TN . A bare block rusting at the junkyard maybe but a good clean bare block for a 2 bolt block is $200 + .

 

I can easily get an entire engine for 100 dollars at a local junkyard. You could almost trip over a small block chevy around here....it's ridiculous.


So....here's a gameplan. Pull apart the top end while it's still in the car. Check the valvetrain...camshaft...pull connecting rods. Then take appropriate steps, depending on what I find.

Another gameplan....get another motor ASAP....quick swap.....and rebuild the big bored 350 in my free time.


Thanks for all your opinions! I really appreciate the help. Without this forum...I'd have no idea where to even start...or what to even do at all.

 

If infact you spun a rod bearing you now have lots of metal particuls floating in your oil which will continue to do damage even after you replace the connecting rod and NO the oil filter will not take care of this problem not to mention you have no idea of why that bearing spun that engine could be a time bomb waiting to self destruct...

 

Lindenmooch you have the right idea there . Let us know if you build the engine into stroker and if you plan on putting it back in or getting another car to build.

 

You worry too much. =P

Like I said...I can EASILY get another motor for a hundred or two. Even a 350...ready to drop right in. Then I can put all my cool go fast parts from this terminally ill motor, onto whatever one I find at the junkyard. Makes no difference to me...as long as it runs. Chevy produced so many small blocks in the late 70's and 80's....it's no wonder that almost every gearhead has one lying on his garage floor somewhere.....and there's thousands of em just sitting in wrecked cars at the "U-Pull It" junkyards. Millions even! =)

I'm just gonna run this one until either A. It ceases to run...or B. I find a new motor for it....which won't take me very long.

It will be harder to find cheap used tires than it will be to find a used, complete 350 for less than $300. Hell....new tires will cost me more than a good used engine!



*EDIT* Oh...and I almost forgot....I don't plan on stroking this motor. It's already bored 060 over....I'd rather build/stroke one that's got more life left in it. The only thing the block is good for now, would be to make a coffee table out of it.

 

So...It's been for sale for a couple weeks, and no takers.

I have a couple hundred bucks, so I might look into rebuilding this motor finally. I know someone with a garage where I might get some help and/or access to some more tools.

I'm just afraid because I don't know how much money it will take to fix it. I can throw hundreds of dollars at it...and get nowhere. People have said it could be the crank bearings...rod bearings, which could be the same thing and I wouldn't even know. lol. I was also told the lifters or cam could need to be adjusted, or could be worn.

I can buy a crank kit right now, and get the rods machined.....but that's about it. I don't have enough for all new internals...so if I go ahead and start this build....I'll be praying I don't waste all my money troubleshooting.

Any thoughts? Want to donate? =)

 

I hope you have some good hiking boots. It could be a long walk home when the motor seizes. You don't seem to be familiar enough with the engine to NOT worry.