Grrr can't get this 455 to idle long or stay running consistently. I have it timed WAY the hell up around 45 degrees just to get it to half way idle but when it does idle its rough and I have to have it set around 1100 RPM to keep it running. If I go lower it will eventually stumble and die. I have replaced Plugs, Wires, Cap, Rotor, Points, etc. Carb is in good shape and works well verified off my other olds as I pulled it from there. Even tried an Edelbrock on it that's new and still same results.

When Eric sold me the car he did mentioned the PO had a cam put in that was meant for a 4 speed. Even still, 4 speed cam or not the car should sit and idle at 800 and not be so rough. Once the car is moving and off idle it smooths out some and power is decent. However the first time I come to a stop it spits, sputters and tries to die unless I put it in neutral.

I tried adjusting the points but the only way it smooths out is again, when I give it more timing. At one point it was (rough guess given balancer mark/timing guage) it was at 50 degrees and was running decent with little to no sputter.

I have checked for vacuum leaks by spraying starting fluid and I did find a very small leak at rear of carb but I fixed that easily. It was doing this before I replaced the intake gasket however I did notice that since I put the gasket on and used end seal rubbers the driver side front and rear blew out at corners on first fire up of car. I have verified no vacuum is being lost in these spots. Worst case is it will leak some oil there but I am using a turkey tray gasket so.

Any suggestions on what to try next would be helpfull. I cant help but think this cam the PO installed is causing these issues since it needs that much initial timing to even run. If I set the timing to 12 where it should be with points it wont even start up or stay running when I get down past 15 degrees it dies. I guess it cant hurt to run it at 45 degrees initial if it runs there with no pinging however it still stumbles a bit and tries to die and idle is all over the place from stop light to stop light. One light its high idle next light requires neutral to keep it running.



P.S. Just so I can get this rant out of the way... I will never again use End Seal Rubber Gaskets!!! I will use RTV black from now on.

 

From previous posts I have seen about this car, no one has seen the car run correctly. Meaning you or the person you bought it from. And possibly the owner that installed the cam.
50 degrees sounds like a ridiculous amount of timing. I'm not an engine expert but I think I'd have to suspect that it's either wild cam or that it wasn't installed correctly. Timing chain or gears may be off a tooth or more. Some cams have to be "degreed" when installed. Not many people, myself included, really know how to do that right.
If it is a wild cam, you may not have enough vacuum with the factory system and may need to add a vacuum reservior or vacuum booster.
Good luck,

 

Have you checked the cam timing?

Guess #1: PO installed the cam wrong, and it's off a tooth (or two ).

- Eric

 

Thats exactly what I think is wrong not enough vacuum. According to my gauge it shows 4 on the vacuum gauge @ 1100 RPM. I do believe that's a tad low. Like I said, Eric said the original owner has told him he put in a cam for a 4 speed and that the car would be low on vacuum. Unless the balancer is wrong or timing tab, or I am overlooking something obvious then yea, it is taking around 45ish degrees of initial to run "Decent".

I'm with you guys, I think it's a mixture of cam/timing chain. It doesn't backfire, or even sputter while under load. It's almost as if it's an idle only issue. I don't even feel it missing out while maintaining speed. I'm about tempted to just yank the damn thing and put in a verified running good engine. With the way my lucks been running I'll try changing out chains, cam, chasing down vacuum and I will still have this rough issue. Blah

 

I have not. I am not sure what cam is even in there or anything. In short of pulling apart the front of the engine I have exhausted about all I can do as of now.

 

how does it run if you step on it hard? could the springs be bad on the mechanical advance and the timing be jumping around at idle? i never had that on one of these cars but i have seen this on some of the ATV's i worked on over the years.

 

I believe you should normally have about 16lbs vacuum at idle with stock setup. 4 is way too low, especially at idle. Vacuum drops as you rev the engine. I think vacuum is more important/critical and low idle which may be why you're having trouble.
I've heard that you can add a vacuum canister/reservior to increase the available vacuum. That's what that little plastic ball is on the firewall of a/c cars. Not sure one of those or even something larger would help enough in your case though since it is so low. You could try plumbing in some kind of vacuum reservior to see if it had any effect at all just to see if you're on the right track. Again, I believe they make vacuum pumps for this reason(big cams).

 

I have a bone stock 2bbl converted to 4bbl Olds rocket 350.

At idle, 21 lbs of Vacuum.

I had to REALLY tighten all the fittings, it sounds stupid but i put fuel injection clamps everywhere i could fit them, and then my engine ran great.

I hate to say it, but this is exactly the issue that i was having when my timing chain skipped THREE teeth. it was horrible. I tried EVERYTHING.

Distributor Changed
wires
plugs
carburetor
intake manifold

The list goes on. In the end, if you dont know how many miles are on your timing chain, just change it. Your car will run great for many more.

 

https://classicoldsmobile.com/forums...-rocket-4.html

Old timing chain, notice it's about 30 degrees out of time.



New Cloyes USA Made timing chain, line up the marks, slap it on, and roll down the highway.

 

If I step on it hard it will bog just a split second then proceede to roast the tires, but it doesn't do it very long.

I did drive it to work today and as previous stated on highway it runs awesome. It's got some serious balance or bearing issues as it vibrates bad at 70(Changed all 4 wheels and tires to brand new) and since tires are new and balanced not sure it could be that.

The minute I get off the interstate and come to first light it's usually high idled but by time I came to next light it was barely trying to stay running I had to do the dual foot or neutral to stay running. It fires right back up it just has a problem finding a smooth idle. The engine vibrates and jumps and..well you know what it does. It's not any where near as bad as it was when I picked it up. Its night and day from that but it's still shaking a tad when it idles.

I think I am going to do what a few have suggested and just tear the front apart and see if there is a chain issue and see where everything is at when I rotate the marks around. #1 should be TDC if it isn't then that would be the problem. I am also going to go back over everything on the intake and get rid of extra ports and use thread tape to make sure nothings leaking. The end seals are blown out I just put on but unless the intake is leaking around a port it would only leak oil from those end seals. You wee right, I should have just tosses those things and used RTV only. LOL

I do have a resivoir for air that was on my S that I no longer need. I might hook it up to this one and see if it helps build some vacuum. I thought maybe my gauge was off but it's brand new with new hoses.

On the plus it did get me to work today, and like I said on the highway she floats like a boat. Stops like crap cause the front pads are non existant so thats on tonight mission is full brake service.

As seen below she moves out off idle and runs surprisingly cool. Of course that could be that there is no thermostat in the car. Not sure havent checked yet.

 

Oh I get what your saying. I've done my share of bad timing chains. I just hate pulling the front of the motor off to check LOL

Other problem is if the cam thats in there is not stock it could need to be dialed or could give the timing marks false readings or so I have been told.

Only way to know for sure what is in there is to tear it all apart and pull cam out and check it or replace it which if I cant get this to run out right I may just have to do that.

On Idle if you stand in rear the car sounds like it does in fact of a lumpy cam but that could be like you and eric stated stated, a tooth off etc.

 

Actually, if you look in the factory service manual there is a simple test you can do to figure out whether or not the car is in time.

Remove the passenger side valve cover (if my memory serves me) you measure the height of one of the pushods at a certain TDC. and then rotate the engine and take another reading. If it's within a certain value, then your cam is in time. Assuming you have a factory cam of course...

 

Even without knowing the exact specs of the cam, you could get a sense of whether the cam timing is way off without taking the front of the motor apart by mapping one lobe out with a dial indicator every 20° or so, then comparing that to a normal curve.

And enough with everyone talking about vacuum reservoirs.
Vacuum is a useful byproduct of some engines, and a diagnostic tool. It is not a magical force that you trap to make your engine run better.

- Eric

 

But that's the problem, Tony, he's got an unknown aftermarket cam.

- Eric

 

It's Not?!

 

Oh, Didnt read that. I dont see the point of aftermarket stuff, if your engine is running well and getting you around, why change something?

I digress, back to diagnosis.

Hey, i've heard of people pulling the fuel pump and sticking a finger in to see if the timing chain is loose. That could be a quick check instead of pulling the front cover.

 

Eric Jensen may know more but as far as I was told it was a cam meant for a 4 speed but I don't think it was ever said what make, duration, etc the cam is. Without knowing that it kinda puts a tad bit of sand in the eye but like you stated previously there is a way to get a sense which I will try when I get off work. I want to say I honestly feel the chain and stuff is right. I only say this because I've had several cars over the years that have done similar but when driving down the road that spit, sputter, backfire through carb, etc even only being a tooth off on chain. This car has awesome power off idle for being 42 year old motor. It's not new power but it's got some force in her. I could be wrong though and it wouldn't be the first time.

Nothing will surprise me on an oldsmobile any more. When I get home I will check piston position on number 1 with cap off, and balancer mark in accordance to the timing tab to see if everything lines up at TDC. When at TDC the timing tab balncer line should be at 0, rotor should be facing 1, and piston should be all the way up and ready for the down stroke.

 

X2 with above! I just can't fathom that much initial timing! Plus mentioning of a vibration!

 

Thanks again for all the helpfull responses fella's. Give's me things to try when I get home tonight.

 

Pull #1 plug and crank it until it spits your finger out. Then look at the timing marks and where the distributor rotors pointing. If the balancer is close to TDC move it to TDC and look at the rotor. It should point to #1. This will get you in the ball park. That’s just an initial test to see where everything’s at. A tooth off either at the chain or at the distributor it will still run but will exhibit some of the symptoms you describe. 4Hg of vac isn’t enough to get a good signal to the carb at least not at idle, hence the stalling.
Sounds to me like you have a vacuum leak. If not then the distributors a tooth off or the chain & sprockets are suspect? Could be any of the three. An intake will leak in the lifter galley and you won’t be able to detect it unless it’s pulling in oil. Pull the intake and examine the gasket for witness marks indicating a leak path.
A Low vac signal indicates a vac leak or late valve timing. Check out the link below.
http://www.freeasestudyguides.com/en...cuum-test.html

 

I only say this because I've had several cars over the years that have done similar but when driving down the road that spit, sputter, backfire through carb, etc even only being a tooth off on chain.

I have seen cars with new chains and sprockets spit and fart as well. The cams were missing some lobes. Maybe the cam wasn’t broken in properly? You can have a look at the lobes when you pull the intake (and lifters of course) just another thought.

 

Granted I am guessing its around 45. I am coming up with that figure by how far PAST the end of the timing tab the balancer line is. THe tab goes up to 12degrees and is roughly 1" wide my mark is about 3 inchs before the timing tab or roughly 3 of the timing tabs. 3x12 = 36 plus the initial 12 of the tab its self give or take is roughly 45 to 48 unless my math is wrong. I know Im porbably off on exact mesurements but that is a rough guess.

 

Already did that. Pulled intake 2 days ago when I had to replace a fulcrum. I removed the cam braket thing at bottom of vally and checked what I could and the cam looked relativly new. Still had initial lube grease on it as well as QC markings and colors on cam. The cam def hasn't been in there very long and the lobes all looked good and both sides were checked for signifigant valve train up and down to make sure they were all moving freely and alot and not just barely moving from a worn lobe.

But again, I could have missed something. I take nothing for granted so if I run out of options I will pull the intake again and check everything again.

 

i will contact my buddy that i got all this from and see if he remembers what cam it is.

 

And this is at idle, with no vacuum to the advance can?

 

You pulled the intake but not the cam drive access cover?

"Vacuum is a useful byproduct of some engines, and a diagnostic tool. It is not a magical force that you trap to make your engine run better."

Oh, yeah, then explain why it causes such problems when it leaks out!


4" Hg is absurdly low- your power piston WILL be up, richening the mixture and making things worse. The carburetor's systems largely run on vacuum signals. If you have no good vacuum signals, how can you expect the carb's systems to behave correctly? Eh wot?

Cam timing is easy to check- with the right tools.
as is lift at the lifter/ pushrod- which is how I spotted the wiped lobe on my friend's 455 recently.

I would speculate that it sounds like a 45' cam in a 39' motor, but until you verify your cam events and your timing mark vs true TDC, there's not much point. It's all guesswork.

Verify your TDC mark, and degree your cam / replace the timing set if needed.

Chances are all the problems will go away then. Pretty sure a 39/45' cam error will show up right away in the degreeing process.

 

Correct sir. On number 1 cylinder with timing light cable, standard light with no dial back, vacuum advanced disconnected and plugged at source, idle set to 1100. The balancer mark is roughly 3" BEFORE timing tab or BTDC plus the initial 12 degree 1" long tab it's self lets me come to the figure of 45ish area. If I move it closer to the tab it will continue to run but it starts chugging, jumping, puking, etc and eventually dies. I figured maybe my light was bad so I tried a neighbors standard ligjt since my only other is a dial back and his showed same reading.

 

If you read up you will see I did in fact pull the cam cover thingy to inspect due to the main fact one of the lifters retaining clip and came off and I had to make sure it wasn't lodged anywhere and luckily it wasn't.

Agreed on the vacuum being low. It's so low brakes barely work, etc. I have inspected as much as I can to see if there is a missing vacuum leak, hose, crack and found nothing. I've tried propane and starting fluid around obvious areas to check for idle up from a vacuum leak and nothing. As mentioned earlier I found one small leak but I threw some thread tape on it and it went away.

I am going to get a new gauge and take readings again. I don't 100% trust the gauge I had. It was new but new **** can be broken. I'm going to exhaust all my resources to find out the issue before I start tearing things apart. Knowing my luck I would tear apart the entire engine, replace chain, cam, etc etc and it still do this.

Could there be an underlying head problem causing these issues? I mean, then again all my issues are IDLE (sitting still) only. Off idle I feel the car runs damn good for 42 years old. I could use a tad more power for a 455 but it's not bad.

Also if advanced auto sold me the wrong points/condnsor could this cause an issue? I believe there were some physical differences in what was on there and what was replaced. I'm half tempted to throw old back on and see if it helps anything. As it stands it has a complete tune up and carb. I spared no expense and bought quality parts as I could get locally.

If I cant figure it out on my own I will drive it over to Scotts this weekend and maybe between everyone showing up we can combine head power and figure it out LOL I have it in me to believe this engine runs good it's just solving the problem.

 

If you have mentioned this, I missed it.... Disconnect every vacuum line you see, and plug every one along with every port on the carb. I have 2 ports in the back of my carb, check to see that you don't have one open.

Plug everything.

I had a loose PCV valve/hose connection that gave me fits (much like your problems) until I plugged everything.

I have found that when all of the common approaches to a problem fail, it ALWAYS ends up being something completely simple, and is usually followed by 'I ain't never seen that before'.
Good luck.

 

Have you verified that the timing ring on the balancer hasn't moved? My guess is either the chain isn't installed correctly or the balancer ring has moved. If its a aftermarket performance timing set its pretty easy ti install the gear on the crank wrong or use the wrong timing mark. If all else fails, read the instructions!

 

I wouldn't worry about the points being wrong - there are a few different flavors (high-RPM, etc.), but if they fit, they should work fine in your situation.

- Eric

 

Get that thing on #1 TDC and see if your balancer is lined up on 0 and rotor is pointing to #1. I agree with above, that your balancer is spun.

 

Double checked quite a bit today. The harmonic balancer has not spun, verified this. I also verified that when I put the line on 0 degree mark that the piston is all the way up and getting ready to start going down. I also checked distributor to make sure the button was facing 1 and it was. Fired it all up and again, it will not run at all any where below about 30 degrees. Even at 30 I have to keep feeding it gas or it stops. The entire time its shaking and sputtering. At 45ish degrees it doesn't ping, it runs decently smooth, still has a tad rough idle but power is there. It will roast the tires plum off with no hesitation or sputter if I nail it from idle. ***** strange and is bugging me. I bet it's something small and stupid causing this just cant find it. All signs point to a vacuum leak or like stated above a tooth off causing rough idle but still enough in time to have power.

I guess this weekend I am going to tear the front down and see what I have. If I have to I will yank the cam and put in a stock cam so I at least know what I have and what its supposed to be. Just wish I could get it working the way it is.

 

Gotcha. I figured as much but wanted to make sure.

 

About 25 years ago, I had a 455 cam in my 66 425. If I recall 65/66 had 39 degree lifter bank angle and they went to 45 degrees later. The builder had put a 45 degree lifter bank angle in my 39 degree block. Not sure if my memory is correct other than 2 different LBA's. So see what year your block is from and if it's 65/66, you will need a cam for the 39 degree LBA.

 

Just for **its how do your plugs read? What happens if you put your hand over the carb at idle...

 

You know, i wanted the exact same thing, i changed everything i possibly could before taking the front cover off. And you know what? It woulda probably been a better idea to just pull the front cover right away. i'ts not that bad, just get a nice gasket set from Fel-pro and replace em'!

 

Plugs read normal. No oil, carbon, heat deposits, light tarnish thats about it. When I compared them to my plug chart at home they match normal usage. There brand new plugs but I have drove to and from work 2 days and checked them all last night. If I pull them off one by one the car stumbles bad on each one I disconnect.

As far as covering the carb with my hand, it dies. If I even partially cover the carb it dies. She loves the air!

 

I know man and thats just my last resort type of thing. I have it in me to believe it's not a bad chain just because how great it runs off idle. This car has insane power off idle, no sputtering or the sort. Even on the interstate kicking it down this thing just goes without hesitation.

From experience in the past with cars that had jumped a tooth or more or a sloppy chain I would get sputtering backfiring, spitting, sluggish on power and hesitation at idle and off idle. I'm not saying it isn't the chain or a tooth off it very well could be. Just doesn't feel right to me for a car that had a jumped tooth. I've owned a few cars with this issue, namely my S I still have. It was the first thing I had to do to it was a timing chain, battery and tires. It was about 2 teeth off and it ran like complete crap. Wouldn't even run over 50 MPH. Sputtered the entire time, hesitated, doggy etc.

Either way, like stated above I have been wrong before. I coulnd't find any obvious vacumm leaks, the car was checked again last night for firing order, incorrect instalation of condensor and points, cap and rotor, new carb gasket, added tape thread to every last fitting, rechecked all the current fittings for leaks, etc. The only thing it could be is a bad brake booster but not sure it could cause problems like I have.

Added, I got a new vacuum gauge lst night and as I thought first was bad.(Go figure, brand new auto crap junk being bad.)

It didnt test much better though but 3 times where it was at. Read 10 on the dial at idle. This guage is a snap on I burrowed from a mechanic friend at Chevy dealer. Seemed to be legit in working right.

 

I could see the wrong cam in here causing the issue. Would explain the limited vacuum at idle. I have absolutly no brake power at idle or much of any vacuum.