307 with a tick and burns oil at idle

im trying to solve an engine problem with out dumping a 1000 bucks into a rebuild or replacing the motor just yet.

when the motor runs right it runs beautiful, you can hear the tick but not badly. sometimes its louder than others. after idling a bit its starts to puff a little oil smoke, let it sit longer and longer and it starts to look like uncle bucks ride. step on it and drive and it will clear up and run ok, ocassionally i notice a little coming out while its running but its rare.

number 8 cylinder gets foulded with oil and causes it to miss but then clears itself up and runs ok for a bit.

i recently replaced a blown intake gasket and the problem didnt go away. the engine and heads were badly sludged up and i cleaned them pretty good by hand and have been flushing the motor every oil change

im pretty sure its valve guide seals on 8, most likely the exaust seal as sometimes i get the smell of fresh oil evaporating from inside the car, im not sure how far i should go to solve this issue. the bottom end makes no noise and i think the piston rings are ok because when driving it doesnt smoke or when getting down on it to really doesnt smoke, only after its idled for a while will it do it.

my options seem to be

A. pull valve covers replace valve seals and set rocker arms and hope everything else is ok. it would only cost a few bucks

B. pull intake and heads and clean them both, replace lifters, pushrods, and valve seals and hope the mechanical parts on the head are ok, replace head gasket and set rocker arms. maybe a hundred or two, the gasket set is cheap and lifters/pushrods for this motor are not bad

C. just say screw it and not waste any money on this motor just keep driving and adding oil for now, if it starts missing bad just put another plug in 8.

the guy at advanced auto tried to say the motor was shot once it started valve ticks, i think he was just trying to sell a motor, ha! not anytime soon dude.

im just not wanting to start into this process if there is something extremely costly that could be bad, im not spending 500 bucks for new heads etc on a motor that has sludge to still work out when 1200 will get me a new engine and ease any worries of the bottom end going out.

anybody got thoughts on this, im an expert on anything ive done before, i just havent worked on heads before so im not sure how bad they could be, I assume the valves to be good and camshaft lobes to be ok if it runs great some of the times, im hoping the sleeves or guides that keep the valves steady are ok. it doesnt smoke all the time so i assume piston rings are ok.

oh if i forgot to mention its an 84 buick estate wagon.

 

woo hoo its quitting time, time to start tearnin up stuff

 

In my experience with that engine (several) I would opt for C until you can drop a bigger, better engine in the car (if it's worth it). I had a couple 307's, both 80's Buicks that burned oil. When I tore one down the cylinder holes were larger at the top than the bottom by a considerable margin. Burned oil really bad. Never knew it to watch it go down the road because of the converter burning up the smoke before it got to the tail pipe. If you really LIKE the underpowered 307 then you can likely get a reman cheap. If you want more snort, drop a 350 Olds or 455 Olds in there. Fits right up. 350 Chevy works, too, with a few more problems to overcome. To me....the 307 Olds in these cars are simply underpowered and there's not much that is cost effective to cure it.

 

I fryed the 250 inline in my truck (burnt valves). Purple haze big time with that dam ticking. I bout another engine but then a old timmer friend gave me some advice that I followed.

When the engine is COLD dump a litre of diesel fuil in the motor oil, start engine, DO NOT REV, just let it idle for 10-15 minutes. Drain oil hot, fill it up with no smoke, valve medic, and tranny fluid but no motor oil. Drive engine eazy (short trips) for a day. Drain oil again. re-fill with 1 valve medic, 1 no smoke, and the rest with 20/50 motor oil and only use 20/50 perioud from then on. Motor will still yous oil but there is no more smoke and the horible smell is gone also. Every oil change add the above with the 20/50 and just drive.

1 year later I am still driving that motor, valves still "tick" but no where near as bad and as I said, 1 year later I'm still driving and I use my truck as a TRUCK, loaded, hauling etc.

I have a 307 in Suzie, it runs great, gets up hills no problem but it is a slug when it comes to the big picture. I have to agree with the Fox, If your going to spend any real $$ then start off with a better engine. If and when anything happens to my 307 I won't repair, I'll be getting a 350.


PS, I'm not telling yopu to do this, I'm just letting you know this is working for my 65 250

 

I would throw a bottle of this stuff in there for an oil change or two:
http://auto-rx.com/
It will gently break down hardened deposits and free up rings.

 

Have you used this stuff?

 

Yup, a couple of times, and it would seem to work as advertised.
You can read about it ad nauseum over at bob is the oil guy.
http://www.bobistheoilguy.com/forums/ubbthreads.php

 

replace the valve seals....then throw in some LUCAS engine treatment.

cheapest easiest

 

well i took the valve covers off and started to clean sludge out of them, they were about as bad as the top of the block when i changed the intake gasket.

i noticed both heads had oil holes by the firewall completely clogged. i cleaned them out and shot carb cleaner through the pushrods hoping to get doen into the lifters and get the rockers oiling better, some were running totally dry.

took her on a 4 hours round trip and ran so much quieter! i wish there was a way i could easily disolve every bit of sludge in this motor and wash it out through the oil pan.

when i say sludge, this is the WORST engine ive ever seen, it has extra meat in it some places up to half a centimeter thick, i scraped it out by hand. some of it has sort of crystalized and crumbles to the touch.

my buddy says drain oil fill up with 2 gallons of deisel and let it sit 24 hours then drain it out. anybody tried this?

 

i think the valves especially on passenger side were being drowned in oil as it couldnt drain back until it went all the way up to the front, seems much better on oil burning.

 

Thats the direction i was going when reading the other posts, the oil returns will clog up. Friend of mine swears by an engine flush by Amsoil. You put it in run it a few mins, then drain and refill with clean oil. he says hes stopped smoke in 3 separate 300k mile engines with it. Hes particular with his vehicles, so it must be good stuff.. However i like the idea of manually cleaning them if you have the time.

P.S. A 307 is gonna tick. I think its designed to so you can tell its running. I currently have a 307 in my 85 Riviera with a tick, and my 88 Electra Estate had a tick. Friend with numerous Rivieras complains of some of them ticking.

*sings* im gonna check you for ticks

 

Olds engines are traditionally bad oilers. We drill them out when building them up. Cleaning them out and a new high volume oil pump is never a bad idea.

 

In a funny way I could agree with you. The 305 in my Crewzer has a very faint "tic" if it was'nt for that you would not hear it running at all, same with the 307 in the Buick....ever so faint yet identical tic. Way back in the day I had a 80 Plymouth 318 and you could not hear it running perioud....a couple times I "oops" and stated it again....I hate that sound

 

The engine flush does work very well, but I have seen engines fly apart after getting rid of all the sludge...lol
Have you thought about doing a leak down test on the engine?
This way you can see if the trouble is in the top or bottom end of the engine. It's a good way to see if the rings are seated or if you have a broken ring on one or more cylinders. You can also tell how good the valves are seated.
In a typical stock street engine I would not want to see more than 10% leakage. Anything more than that is going to indicate an inefficient engine.

 

Pull the valve cover off that side and check the oil drain back hole in the back of the head by the head bolt-it could be clogged and filling up the rear valve guide. Bet if you check #7 its starting to do the same thing--clean the drain back hole out and the problem should lesson.