Hello all, hope to find some help. My '66 Delta has a '68 455 in it & suffers from a complete lack of power.
Compression is good, timing is set at 5* BTDC & reads 36* BTDC @ about 2800 rpm. Dual pt dist set to .016. New Edelbrock 750 carb. Car is running a little hotter than I'd like, from 180 to 195 w/ a 160 stat. New water pump & cooling system has been flushed. Engine runs smooth, just no power. I'm out of ideas, does anyone know what else to look for. Thanks.

 

Does the car still have the switch-pitch transmission, and if yes, is the switch and throttle linkage adjusted correctly? That Edelbrock carb could have easily thrown things off, and if the converter is stuck in the wrong angle, the car will feel like no power.

195 degrees is no biggie, but if it's running that hot with a 160 stat, sounds like you may be running lean or timing is retarded. No exhaust restrictions?

 

Definately more info could help. Is this a used engine you installed? I noted you flushed the cooling system, so I assume it's not a fresh rebuild.
Is the engine basically stock? Cam, etc...
Also, personally I prefer the Qjet to the Edelbrock, was your original carb missing?
I base my opinion of the Edelbrock purely on the fuel curves I witness on the dyno, but if you intend on using it, you need to know what jets and metering rods you have, or better yet, co/hc readings under load throughout the rpm and load range.
Just a thought, have you tried bumping your initial timing up just to see what happens? It never hurts to experiment a bit.
Jeff

 

Thanks for the responses.
No, it's not the original tranny, no switch pitch. The timing is 5* BTDC at idle & 36* @ 2800 rpm.
I didn't install the engine, the car came this way. As far as I know it's all stock. I flushed the system due to it running hot. I had the q-jet it came with rebuilt & couldn't shake a bad bog it had coming off idle. I've had good luck w/ the edelbrocks before so that's what I went with. Jets & rods are stock, I haven't changed them. I haven't taken it anywhere to have the co/hc checked. It idles well & will hit highway speed, but takes a long time to get there. It actually feels like it has more power under part throttle. I'll give advancing the initial timing a shot.

 

I don't think Oldsmobile every came stock with a dual point distributor.

 

My mistake. I added the dual point.

 

I plan on using a Mallory dual point distributor on my 455. It has no provision for vacuum advance so I am going to have to set it up for only mechanical and perhaps a little more initial than stock, don't know how much total there will be or when it kicks in. Is yours a Mallory? Any thoughts or opinions on it?

 

I'm just throwing this out to see what you guys think. Could a badly worn timing chain cause the lack of power? Or possibly a replacement chain that set the cam timing 'retarded'.

Don

 

Yes, mine is a Mallory but w/ a vacuum advance. I'd set yours stock & see where your total advance ends up. You may have to change the weights around to get the curve you want.

 

yes Don,, nature of the beast, during normal running rotation can timing tends to retard further as wear accelerates.
Jeff

 

By any chance do you have single exhaust? If so please remove and throw away. If you have dual please check entire system for poor workmanship in the system-ie kinked tubing,muffler that is blue in some area etc. So many problems come from bad mufflers, muffler shop guys who don't know how to bend pipe and kink it.Interesting that it runs better at part throttle. Kind of a hint to possible exhaust issue. If not try going to a 600 carb. I had a 780 on my 455 and it ran wicked at high rpm but was a bit of a pig around town. I put in a 650 and it was NASTY around town and on highway to a point. I kept the 650.Good luck.

 

I have no words,,, help...lol,,, maybe I do, single or dual, we all know what a nicely tuned 455 will do, that's why we love them. Smaller carb? NO, properly tuned carb? YES. Any engine be it a 327 Chev, or 455 Olds will ONLY consume the air and fuel it needs. That is determined by demand,, ie, the guy with the big right foot.
You can't imagine the amount of CFM a 455 can consume. A 780 is a high school cruising carb. Now, improperly tuned, a 600 would be junk. But, a well set up 850 would be great. Let's be careful here. We all love to get our cars right, and most are not afraid to spend $$ to do it. let's not dispense advice out of hand.
Jeff

 

I disagree. Heavy cars like Deltas respond better to smaller carburetion off the line.

My 73 455 ragtop (mildly worked C's, Offy PortoSonic, 18-20 Mondello, worked Unilite thru W-Z Dynomax) could spank a moderately built Mustang's *** all up and down the street with a Holley 650. Even experimenting with jets, with an 850, it never responded until the Stang had a couple carlengths on me, and by then the weight disadvantage made it impossible to recover.

I admit part of the problem was 3.08 gearing, but not easy to find deeper gears for those rears. I had found a 73 Riviera 3.42 rear, but before I could get it in there, Bambi came along and destroyed the left side of the car.

 

My money is on the cam timing. Lots of junk out there, and it sounds like your cam is way advanced.

 

I do tend to agree that smaller Primaries, aid off the line in a heavy car with mis-matched gearing. A 4000 lb car wasn't originally intended for drag racing anyway! So to expect that, is a bit 'o dreamin in stock form.
Don't view my reflections as an ego problem, but I have been on a chassis dyno, and track tuning since the late 70's,, which frankly makes me a rookie to some brains here. But, the little tidbit I have learned is that with proper setup an engine simply uses what it wants. Now, keep in mind, a spread bore carb will offer more street range Snap at low RPM than a square bore. But, once in the range, an engine simply wants what it wants. A carburetor IS NOT a super charger, it cannot force more than an engine needs. Concerning Holleys, they are super tunable. Accel pump ccs, squirter size, cam rates, etc,, My carb of choice? nope. I like Rochesters.
But, we cannot make apples into oranges. You have a huge car, even with a 455, all of which kick butt, and you want to make it into a drag racer, carburetion is not the culprit if the package doesn't perform well with 3.08 gears or things of that Ilk.
respectfully, Jeff

 

First step in solving a problem, is to define it.

Compared to what?

Has it been rebuilt? Did you buy it that way? When did the problem start? Anything unusual happen, or changes made, at that time?

Define "good".

Are all eight the same? How close? What numbers?

Should be OK, if the Balancer hasn't shifted on its hub. After the "power" problem is corrected, you can consider shortening the curve.

Not a factor.

Why? A part "thrown at it" in an attempted repair?

Is your gauge accurate? You can check the actual temp, with



a kitchen thermometer.

Does it run cooler at highway speeds or in "stop and go", or at idle? How long does it take to "warm up" under those conditions?

Not a problem. Unless the actual spark advance is retarded, it's not related.

Why & why?

Flushed by a professional? Did it affect the flow rate?

Norm

 

Thanks Norm,, sometimes I think adult on-set adhd gets me sidetracked and off on a tangent. Thanks for asking valid questions.
Jeff

 

Use good 'ol common sense, it's bitten all of us at one time or another. I've known Norm for a few years, he knows his stuff and knows how to make things work. Norm, I think you need to come up and tell Spence what he needs to do on his '65 425. And between you and me, his son (who has my 1st 442) tells him what to do on the car, but his son also thinks you can fix anything with a timing light and Dura Lube, and is a new car sales geek . Spence needs help, and I would like for him to have it from the right people. When we went to drop off my 400, he had this look of shock on his face when Jim Grubbs himself told him the exact same thing I told him when it came to what oil to run. I even told him what dyno shop to go to get it dialed in, Grubbs said the same place. Maybe he'll start to listen to me if you come into the picture.

 

"Compared to what?"
Compared to anything short of the last Omni/Horizon I had.

"Has it been rebuilt? Did you buy it that way? When did the problem start? Anything unusual happen, or changes made, at that time? "
Other than carb, dist, water pump, tune up, engine is as I bought it.

"Define "good".
Are all eight the same? How close? What numbers?"
All eight 155-165

"Should be OK, if the Balancer hasn't shifted on its hub. After the "power" problem is corrected, you can consider shortening the curve."

"Not a factor."

"Why? A part "thrown at it" in an attempted repair? "
Somewhat. Qjet wasn't working & I've had good luck w/ edelbrock. New carb did eliminate a bad bog off idle.

"Is your gauge accurate? You can check the actual temp, with

a kitchen thermometer."
Good question, I'll have to check.

"Does it run cooler at highway speeds or in "stop and go", or at idle? How long does it take to "warm up" under those conditions?"
Cooler at highway speeds. Warms up within 5-6 minutes.

"Not a problem. Unless the actual spark advance is retarded, it's not related."

"Why & why?"
Started running hotter, water pump bearing had play. I always flush system if I replace major parts.

"Flushed by a professional? Did it affect the flow rate?"
No. It appears to flow well in radiator.

Norm[/QUOTE]

Thanks, Jerry.

 

If he wants my help, he knows how to contact me.

Norm

 

If you cannot code the quotes properly, at least delete the parts you are not responding to.

Throttle blades opening too far? Easy to check visually.

Not helpful. I do not know anything about new cars.

Diagnosis, is basically a process of elimination. In this situation, there are some who have unrealistic expectations, based on the “reputation” of the 455. In order to define the problem, in this one, we must eliminate it as a factor.

Would it be fair to say, that you have a “stock” engine in a luxury (read heavy) car, with a rear tire/gear (read high) combination, suitable for cruising “comfortably” at highway speeds? Doubtful, you expect it to be a race car, but we need to know what you do expect.

Do you have any actual experience that might lead you to expect more power than you have?

And with those changes, the power output has remained the same?

No plugs, engine warm, and at WOT?

“Quick and dirty” test: Move the initial (with the vacuum disconnected) from 5° to 15°. It should start normally, but after its warm, exhibit heavy pinging under load.

If you see a power increase and no ping, the balancer is the problem.

How did the engine even run? Unnecessary parts changes can complicate the troubleshooting process.

Is that the only difference? The source could have easily been a worn vacuum hose. New carb vs a 50¢ hose? The cash difference would have bought a lot of beer.

Then again, if manifold vacuum was used, for advance on the Q-jet, and was changed to ported on the Edelbrock, you could have saved the 50¢.

Indicates an airflow problem at idle/low speeds. Fan clutch is a likely source.

Over what period of time? What was changed at the time it started.

As was verified above, re: lower temps at higher speeds.

Norm

 

Thanks to all for the help. Problem seems to have been a combination of the balancer & low fuel pressure. Advancing the timing helped, changing the fuel pump & increasing the pressure from 3 lbs to 6.5 helped. Next up to replace the balancer so I can nail down the timing.

 

Ya. Timing an old engine with a timing light can kill you. Using the ear works much better. The specs in the book were written how many years ago? With fuel formulated back then when it WAS ACTUALLY gas.1 question though. How did you know you had 3 psi fuel pressure and why not post that tidbit? Happy it worked out for you. Now it's time to put a hurting on those back tires.

 

So far it sounds pretty good by ear. A friend recently suggested checking the fuel pressure & I put an inline gauge in place. Tires get expensive but at least it's running as an Olds should again.

 

yikes, timing by ear can occaisionally lead to melted aluminum, but a bonus, I hear scrap prices are up!!!
Jeff

 

A new or good used balancer will not be hard to come by. Why a d/p distributer and not an HEI ?

 

I'll be picking a balancer up soon, probably new. I tried an HEI & had interference w/ the intake. The d/p came from a buddy who had no use for it anymore.