Engine problem

[thebandit92]

I have what seems to be a odd problem,engine will turn freely and start when front end is on axle stands but then when i lower it back down on it's wheels it won't start and engine turns slow as if battery is flat.
Problem started after i changed the pushrods (although i don't think they have anything to do with the problem) i decided to set the timing with a timing light,something which i don't usually do.It started and ran fine but then wouldn't start once hot,so thought i had a hot start problem,even though my headers are wrapped.So bought a mini high torque starter,had a few problems setting it up with shims but it turned fine on axle stands,would only turn slow once i lowered car down.
So yesterday i decided to get a ratchet and try turning engine by hand,couldn't move it at all,took plugs out it turned a slight bit but not much.So decided to pull the engine but as i undid the torque converter bolts i obviously had to turn the engine to get to each bolt,i found that the engine turned easy enough with the ratchet,again it's up on the stands.
The only thing i can think is that one or more of the rear bearings is not getting oil,except when car is on stands as i assume the oil will all go to the rear of the engine,is that possible or am i way off?When it starts there is no knocks,squeeks or rattles,just sounds quiet and smooth,although i didn't leave it running on the stands.
When i turn it by hand it is a bit sort of shuddery,doesn't turn smoothly.
I guess i am going to have to pull the engine anyway but thought i would ask for ideas first before i carry on unbolting stuff.

[bhm1712]

Although I'm at a loss with this I can say that personally, I very much doubt it's anything to do with the rear mains not getting oil on the level plane As although the oil will most likely pool up and submerge the bearings when the car is tilted on the stands, no oil will actually be forced into the oiling surfaces as you need pressure to do this from the oil pump and cold, the bearings would or should be free enough to turn without oil pressire anyway - it's when they are hot and get starved of oil that seizing becomes the issue. If the bearings had that much clearance to allow oil to seap into the journal surfaces then you would have a whole world of more trouble not just this.

It doesn't really make sense to me yet!! I can't see what being titled would change so much that the engine frees up.

[bhm1712]

If you can't turn the engine by hand - and I mean by hand not with a ratchet, with the plugs out then there is some serious grindage/bindage/jammage going in somewhere in that engine. Even on a rebuilt 461 stroker with no oil just assembly lube I could turn it over with one hand and barely any effort when I last visited autopontiac.

[thebandit92]

I have never been able to turn it by hand,don't think i have with any Pontiac i have had but that might just be me being a weakling,lol.When it's level i can turn it but only if i use my breaker bar which is 3 feet long,i struggled to turn it with just a ratchet,on the stands i can turn it easily with a ratchet but it doesn't turn smoothly,sort of juddery as if something is too tight,even thought it might be a piston but again why does it move on stands but not on level.Only has about 600 miles since rebuild.

[SUPERCHARGEDGTA]

where do you put the axle stands?
front clip rails or susp./wishbones?
are engine/gearbox mounts ok, is anti roll bar well clear and nor touching crank pulley?

[thebandit92]

I put the stands under the subframe rails,there is nothing touching pulley and engine mounts seem ok.It was fine until i changed starter,although in saying that i changed it because it was hard to start so i guess that was probably the start of whatever the problem is.
I only thought about turning the engine with a ratchet as when i was under i found a oil leak but can't see where it comes from but it is engine oil,although i checked oil level and it's ok and oil still looks new clean on dipstick.

[thebandit92]

Gonna pull engine on saturday,got all bolts undone just need to pull wiring and carb cables off,see what's going on in there,drained oil off and it looks ok,no glittery bits.Thought about starting it up on stands then leaving it running while i take stands from under but then decided against it as at moment there is no knocking etc but thought that something might just break if i do that.

[jonbullnose]

very odd one this was going to say are the box to engine bell housing bolts tight as that would cuase it, with the plugs out you should be able to turn it with a std ratchet but if a new engine it will be quite tight due to piston ring contact on cylinders ,i wonder if you have an earth strap problem reguarding the slow turning ??

[thebandit92]

very odd one this was going to say are the box to engine bell housing bolts tight as that would cuase it, with the plugs out you should be able to turn it with a std ratchet but if a new engine it will be quite tight due to piston ring contact on cylinders ,i wonder if you have an earth strap problem reguarding the slow turning ??

I thought about the earth strap,i do have one from bell housing to chassis,don't have the one that went from rear of engine to bulkhead near heater box.I rebuilt engine just over a year ago.Thinking about it,last time it did start and drive it did seem a bit under powered as if something was holding it back.
I will have engine out this afternoon so will hopefully find out.

[Retro]

Any luck with sorting out the engine problem?

[thebandit92]

Any luck with sorting out the engine problem?

No,got sump off,can't see anything that's obvious and still couldn't turn it with ratchet,until i turned it upside down on engine stand but when it did turn it was sort of juddery when it turned,as if something is dry and dragging,i am thinking it's got to be a bearing or a piston Although there was no knocking which i would expect if it was a bearing,not sure if a damaged ring would make a noise,or stop it turning.
So i guess the only thing to do is pull it all apart.Not took heads off yet to check bores,i might do that first,even though it will still have to come apart if i find anything there.

[bhm1712]

Before ripping it apart I would remove the pushrods and rockers and see how it turns then.

[bhm1712]

The reason I say that is because I've been reading some info I printed years ago about Pontiac engine valve assemblies and associated problems. One is talking about incorrect rocker nuts and torque causing rockers to seize up on the studs as the engine is turning over. Seem to remember a few weeks ago you installed some new rockers pushrods and nuts just a few weeks ago?? Maybe they are causing an issue...?

[thebandit92]

The reason I say that is because I've been reading some info I printed years ago about Pontiac engine valve assemblies and associated problems. One is talking about incorrect rocker nuts and torque causing rockers to seize up on the studs as the engine is turning over. Seem to remember a few weeks ago you installed some new rockers pushrods and nuts just a few weeks ago?? Maybe they are causing an issue...?

You know,i did think about that but then thought,no it won't be that,mostly because i thought it wouldn'y cause it to turn over on stands but not when level,but then any of the other things i thought it might be wouldn't cause that problem either.So when i start on it tomorrow the first thing i will do is take pushrods out and try turning it.

[jonbullnose]

this is a very odd one i will be very interested to see the out come i think it might be a bit strange

[SUPERCHARGEDGTA]

same here

[jonbullnose]

had a thought maybe worth checking the main bearing caps for tightness as if come loose with the dif torsion from jacking the car may cuase it to missline the crank but this is clutching at straws lol

[thebandit92]

had a thought maybe worth checking the main bearing caps for tightness as if come loose with the dif torsion from jacking the car may cuase it to missline the crank but this is clutching at straws lol

TBH i did think about something like that as when i fitted new high torque starter it took me a while to get it shimmed right and it did make a bit of clattering noise against flexplate which made me wonder if it could cause anything to come loose.I will try pushrods first as that's easy and simple and free to do.I can't check torque on caps as i snapped my torque wrench working on van,lol.So will have to buy one but was waiting to see if i needed to pull the engine apart first.

[thebandit92]

Just been out,undid all the rockers on 1357 cylinders,started from rear of engine,got to front and pulled push rod out,that's when i saw something silver near push rod hole,turned out to be a washer Don't know how it got there but it was against the push rod,engine turns easily now but i can't help thinking that surely that couldn't have stopped the engine turning.Although i guess that's why it turns with engine on a slant as the washer probably moves away from the rod?? Can't see any damage to anything and the push rod has no damage,not even scrape marks.
Feel a bit stupid now,if that's all it was

[bhm1712]

Just been out,undid all the rockers on 1357 cylinders,started from rear of engine,got to front and pulled push rod out,that's when i saw something silver near push rod hole,turned out to be a washer Don't know how it got there but it was against the push rod,engine turns easily now but i can't help thinking that surely that couldn't have stopped the engine turning.Although i guess that's why it turns with engine on a slant as the washer probably moves away from the rod?? Can't see any damage to anything and the push rod has no damage,not even scrape marks.
Feel a bit stupid now,if that's all it was

I can believe it. Doesnt have to be big to jam up a mechanical system.

[jonbullnose]

good stuff as we all thought it was something odd lol thank god it was simple and no cost bar the time

[jonbullnose]

you might want to roll those push rods on a sheet of glass to make sure they have not got bent with that washer rolling around

[thebandit92]

I didn't check them all for straightness just the one that had the washer against it,the others i just pulled out and put back in,just had a quick look at them.

[thirdgen]

you was lucky

[thebandit92]

you was lucky

Yep