gords88

Just purchased 1955 Oldsmobile 88 with a 324.
unit has been sitting in storage for 25 years.
former owner gave me a bottle of lead additive that he used when he last run the car in 2003.
my question do I need to continue this procedure as well as possibly using 94 octane gas.
just got it running tonight but wow it needs a tank flush.
pretty skunky smelling fuel.
but the engine is running like a top.
im over the moon excited.

Charlie Jones

Your '55 Olds has 8.5 to 1 compression , so it should run fine on 87 octane regular gas .
There is debate as to whether lead additives are even necessary , but if it makes you feel good , use them .
I would get rid of that old gas . There is no tank drain ,
It can be siphoned safely by raising the car , disconnecting the fuel line at the pump , and pressurizing the tank slightly .
to start the flow .

Have you changed the oil and filter yet ? If not I would recommend doing so .

If this car has been in storage for 25 years without being driven , I would recommend a complete brake system overhaul for your safety .
Brake fluid draws moisture , which causes rust in the brake cylinders .
When used again , the seals inside the cylinders can be damaged by the rust , causing them to fail .

Do you have a 1955 Oldsmobile service manual ? If not , they are available on E-bay .
Original printed copies are best :
1955 OLDSMOBILE SHOP MANUAL SERVICE BOOK ORIGINAL RARE OEM REPAIR GUIDE | eBay

oldcutlass

You do not want to run that old gas through your engine. It will gum up everything.

jaunty75

I don't get it. He says his engine is "running like a top," presumably on the old gas still in the tank. If it's running so well, how can it be gumming up the works at the same time?

Draining the tank is a lot of work. How about just filling it with fresh gas to dilute what's in there and just burn the stuff through the engine. After all, if it's running like a top on the 25-year-old gas, imagine how much better it will run on 25-year-old gas diluted with fresh gas.

redoldsman

Clean the tank out and get that old crap our of there. All it will do is contaminate new gas. I run 89 octane in my 54 since it wants to clatter a little on the 87 octane. Maybe I have the timing off a little. The only thing I put in the gas is Sta-Bill for the ethanol. If you are not running at sustained high RPM's you don't need the lead additive. When you change the oil be sure to use oil with zinc or use a ZDDP zinc additive. Many folks (myself included) run Valvoline VR1 Racing Oil which has the needed zinc.

oldcutlass

It will run fine until you turn the engine off and it cools down. All that varnished fuel will harden like glue especially in the valve train. Don't ask me how I know.

Fun71

I had a similar issue with trying to use up old gas from the Cutlass in my lawn mower. The mower would run fine while I cut the grass, but next time the engine would not start and I'd have to clean out the carb. This cycle repeated until I finally gave up and quit using the old gas in the mower.

Koda

Been there on the carb cleanout due to that reason.

gords88

Thankyou very much for the advise.
I will absolutely do as we discussed draw out the old fuel from the tank.
I hope I have not gummed the engine up as the gentleman said.
I will fill the tank with fresh gas and hope the engine will continue to run well.
unfortnately I have the brake pedal on the floor and need to address that issue next.
I understand from a previous thread the Oldsmobile brakes can fail without warning.
thanks again for your time.

jaunty75

Where did you hear this? This sounds like a rumor that needs to be quashed immediately. Oldsmobile brakes are as good as any other make's brakes, and any brake system will "fail without warning" if not properly maintained.

jaunty75

Did you use the old gas undiluted? I've used last season's gas in my lawn mowers without a problem. Gas sitting from November to March isn't that old. I've always diluted it first, though, with fresh gas.

jaunty75

Well, if the engine is "running like a top," as you put it, on the old gas, it's hard to see that that gas is, simultaneously, gumming up the engine. Gummed-up engines usually don't run like a top.

How much of this old gas is in the tank? If it's more than half, then, yes, I'd consider draining it. Probably just by siphoning. But if it's something like a quarter tank, fill it with fresh gas, which will dilute the old gas to 25% of the total in the tank, and just run it through.

I think the process that Charlie Jones talks about with pressurizing the tank is more complicated than it sounds, and possibly dangerous. How many shade-tree mechanics have a way to pressurize a fuel tank laying around the garage? I sure don't. What is the condition of the tank on this car? Will it take any kind of pressure without rupturing? Will pressurizing it cause leaks down the road? You don't want to cause new problems in the process of fixing current problems.

The bottom line here is don't fix what ain't broken. If the engine runs fine with what's in the tank now, it's hard to see that you're damaging anything by continuing to use it.. Dilute the old gas with new, run it through the engine, and move on to the brake problem.

droldsmorland

Ethanol-free gas if it's available. Or the ethanol remover additive.
You should drop the tank. Boil it out. Replace the fuel lines, pump, and go through the carb...if you want reliability.

Read this...the part about reviving a hibernating vehicle.

ignachuck

My '56 sat for 20 years. I had the tank boiled.

Tedd Thompson

I agree with everyone except Jaunty, get that gas out of there. If you drop the tank be sure to change out the nylon strainer at the end of the gas pickup if it is still there, most dissolve and go somewhere.? While you are down there change out the ground to the frame on the sending unit as they are attached to the gas line and seem to lose their abelite to make a ground.... Keep us posted and drop on down to the Vintage forum where most of the 50's guys hang out, good group..... Lost in the fifties ...Tedd

gords88

I lucked out and the tank had a bung installed. I dropped the old fuel last night and noticed a black sludge in the container.
I was told when I purchased the car the owner had added a lead additive.
thinking this must be a part of this black sludge.
tonight I will add new gas and hope for the best.
the big project for tonight is I located the master cylinder.
ugly spot to say the least.
im going to try to do a top up on brake fluid and talk my wife into helping bleed the brakes.
my buddy told me to add a small amount of brake fluid and look for the leaks.
he told me to replace the master cylinder regardless upgrade to a dual system for the safety factor.
thanks for your advise and attention to my project.
will keep you advised on my progress

gords88

Just read your post Tedd I was not aware nor did I think about the pickup tube sock or the wiring issue.
pin my opinion when I don’t do the job properly with the points you brought forward
it has a huge potential to bite me I think I’m going to run with the free advise
I know it is in my best interest
Thankyou

harwooddan

Make sure you get the gas tank cleaned out properly. If you actually drop the tank put a new filter sock on the fuel sending unit. If the sending unit is gummy clean it or just replace. You do not need a lead additive just make sure you use a quality name brand premium gas. Lastly I would change your oil and filter using a quality conventional motor oil but as a precaution add a zinc additive with the oil. I also have a 55' that sat for a long time. Good Luck with it !

Charlie Jones

If you do decide to drop and clean the tank ( which I would recommend ) then you can check the sending unit .
Get a volt -ohm meter and check the resistance between the terminal and the base .
With the float hanging down in the " empty " position , the meter should read 0.5 ohms or less ( continuity )
With the float halfway between the " full " and " empty " stops the meter should read 15 ohms ( + or - 1 )
With the float at the " full " stop the meter should read 30 ohms ( + or - 1 ohm ) .