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1971 455 has gas in oil?


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I own a 71 Riviera which had previously been in a barn for 20 years. I purchased it with the fuel and brake systems replaced in a running driving car. The carb is a newer edelbrock. I’ve had it just about a year and drive it a couple times a month and never real far or fast.

  I had checked the oil this morning and it seemed awfully thin and past the full mark, smelled funny too like there’s gas in it.

  It still seems to run ok. No smoke coming from the exhaust. Plugs are a little dirty but not carbon fouled. Only difference has been that it’s harder to start than normal, have to have my foot on the gas a little for a minute until it decides to idle on it’s own.

   Any ideas on what’s causing the extra gas in the oil and if it has anything to do with the hard starting?

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Posted (edited)

Do you have a mechanical fuel pump as original? If so it is probably bad and leaking gas into the oil.

 

On the other hand If the carburetor is running way too rich, gas could just be washing past the rings and getting in that way. Is the choke opening all the way with the engine warm? Don't keep driving until you fix it. My guess is its the fuel pump.

 

Edited by Bloo (see edit history)
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DO NOT run the car if you have fuel in oil. Change fuel pump, change oil and replace oil filter. Hard to say about the starting issue as there can be many causes. First order of business is to get the fuel leak issue fixed.

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Agree with Bloo & JZRIV, symptoms you describe are classic fuel pump diaphragm failure.  Hard starting likely because the pump is not moving enough fuel to refill the float bowl to replace fuel that evaporates when the car is parked due to residual engine heat.  Definitely get that adulterated oil out of the engine!

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Besides the run of the mill pumps mentioned a QUALITY USA made excellent pump is Robb MC. ALL/MOST of the v8 guys use his pumps with little or NO failures for years.

 

Tom T.

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Thanks again everyone!

 

So I got that new pump put in today.. also new oil and filter too. Put new plugs and wires on there while I was at it.

 

The gasket wasn’t properly sealed on the old fuel pump and bolts weren’t exactly right.. 🙄

 

had a couple “mishaps” starting it as the power steering belt wasn’t on properly and one of the wires was loose (derp!) so it was hard to tell if it’s doing the same thing starting up 😕

 

It definitely runs stronger but is idling a little under where it should be.

 

  I keep it in a storage locker about a couple miles up the road... put it away for now.. going to give it a “check up” next weekend and play with the carburetor a little bit.

 

  FYI it has an edelbrock.. maybe a 650? Didn’t get a chance to know for sure, was running out of daylight :(

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Posted (edited)
1 hour ago, RivNut said:

What happened to or why isn’t the original Quadrajet on the engine? Great carbs when they’re set up properly.

It wasn’t on there when I got it.. not a purist so it didn’t bother me.. My ‘79 El Camino has an edelbrock and it’s worked flawlessly for 16 years. A Riviera is more or less a custom car from the factory so I don’t plan on doing anything crazy to it ;)

 

  Likely the same guy that put the halfway fuel pump on there halfway tuned the carb, lol! 

Edited by Raggedy Ann Riviera (see edit history)
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1 hour ago, BobinVirginia said:

Buick’s are bulletproof except for the front timing cover. The wear in the oil pump will cause low pressure in 6,7,8 rods. 
I once abused one as a teenager a couple times 

Think we owe a lot of automotive knowledge to teenage tomfoolery 🤣

 

I really need to get some gauges in that car.. drives me nuts not knowing the temp or oil pressure! 😭

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14 hours ago, Raggedy Ann Riviera said:

I really need to get some gauges in that car.. drives me nuts not knowing the temp or oil pressure!

A well maintained engine and cooling system will be more reliable than any gauge you find.

 

You can put a set of test gauges on when you first buy the car or do a major overhaul for verification. Maybe on a 1 to 5 year retest period if you need to schedule it. But the need to monitor while driving is more for extreme competition driving. 

 

Twenty years ago I bought my '60 Electra and it had a set of oil/temp/amp gauges hanging from the dash. I removed all three and restore the access taps. The oil gauge face was 3/4 obscured with oil. I preferred not to risk my carpet.

 

Still running the 50 year old heater hoses? You are right to worry. But don't need a gauge.

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Keep your eyes open for an original Quadrajet; the engine will like it.  Idle should be 600~650 RPM in Drive.  The Q-jet uses a 'spread bore' throttle body whereas the Edelbrock (like the Carter AFB it is based on) are 'square bore'.  This means that the base of the Edelbrock doesn't match the intake manifold venturi bores and the gasket used needs to ensure there are no voids that would result in a vacuum leak.  Given what you found with the fuel pump, don't assume the PO installed the carb properly.  Spray some carb cleaner around the base of the carb while idling to check for a vacuum leak at the manifold interface.  A vacuum leak will cause a higher idle speed.  This is another reason to hunt-down the correct Q-jet.

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20 hours ago, 60FlatTop said:

A well maintained engine and cooling system will be more reliable than any gauge you find.

 

You can put a set of test gauges on when you first buy the car or do a major overhaul for verification. Maybe on a 1 to 5 year retest period if you need to schedule it. But the need to monitor while driving is more for extreme competition driving. 

 

Twenty years ago I bought my '60 Electra and it had a set of oil/temp/amp gauges hanging from the dash. I removed all three and restore the access taps. The oil gauge face was 3/4 obscured with oil. I preferred not to risk my carpet.

 

Still running the 50 year old heater hoses? You are right to worry. But don't need a gauge.

I don’t know.. my ‘14 Impala and husband’s ‘10 GMC truck have temp gauges.. 🤷🏻‍♀️ I’d at least do that one per my experience with the El Camino.. No matter how well maintained thermostats and water pumps can fail at any time. Better to catch it before you’re stalled on the road :(

   I’m somewhat resto-modding the car so not concerned with absolute factory correctness but doubt I’ll find a gauge that goes with the interior so will find a creative way to hide it.

   

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3 hours ago, EmTee said:

Keep your eyes open for an original Quadrajet; the engine will like it.  Idle should be 600~650 RPM in Drive.  The Q-jet uses a 'spread bore' throttle body whereas the Edelbrock (like the Carter AFB it is based on) are 'square bore'.  This means that the base of the Edelbrock doesn't match the intake manifold venturi bores and the gasket used needs to ensure there are no voids that would result in a vacuum leak.  Given what you found with the fuel pump, don't assume the PO installed the carb properly.  Spray some carb cleaner around the base of the carb while idling to check for a vacuum leak at the manifold interface.  A vacuum leak will cause a higher idle speed.  This is another reason to hunt-down the correct Q-jet.

I appreciate the advice but work at a custom car shop and know if I ask the mechanics where I can find a quadrajet they’ll laugh at me.. 

 

They’d be more likely to recommend a Holley. They’re not fans of edelbrock but aren’t completely against using them.

 

Think I want to figure out what’s going on with what I have first before buying another carb. It just might need a minor adjustment.. it worked fine for a year up until recently.

 

With that my issue is NO idle on cold start and low idle once warm. 

 

If I run out of options and need a quadrajet can you get a “new” one? Or would you know a reputable source to get one that for certain works?

 

 Asking because I went on a goose chase with my ‘Camino several years ago for a functional quadrajet (went through two used ones that worked like ish) before just getting an edelbrock ..

 

  

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In my experience, if a custom car shop can’t install a small block Chevy, they are clueless as to what’s out there.  Maybe you saw one of the TV guys install a SBC crate motor in a heavy car thinking he could make a gasser out of it. Edelbrock and Holley build carbs for SBC and normally they don’t work well on other motors.  The gentleman who owns The Carburetor Shop in Eldon, MO would recommend a 850 cfm Carter Thermoquad for total performance and streetability.

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The two Chevies mentioned have stepper motor gauges. You have a couple of years before the truck gauges give false readings, the car a little longer. My experience comes from both the car hobby and industrial power plant operation. Gauges were once needed in cars. I had a 1936 Nash Advanced Six, If you pushed a button next to the fuel gauge it would switch from fuel to an oil level sensor in the oil pan and read the same F-E scale. Your Chevy truck probably has an oil level sensor if it has a factory oil cooler. Gauge usage is based on risk.

 

Most gauges aren't needed. In the mid-1950's gauges showed up again on dashboards but that was mainly a gimmick for the ex-WWII guys who had been telling lies about being a pilot during the war, even had the aircraft look. And they were pulling the dipstick on every gas stop.

 

I live 20 miles from the Rochester Products plant where the Q-Jets were made. They are an easy carb to make work, but we had a lot of the QC guys hanging out in coffee shops to give us pointers. Used to be able to drop a float in my palm and tell if it was too heavy. Main thing is to put the metering rods in after you put the airhorn on, way easier.

 

You may find you need the stock heat stove and inlet air temperature controls if you drive on days under 60 degrees. Drivability problems, as they say.

 

One thing an old GM carb engineer told me- "Carburetion is not a science. It's an art." Long list of variables even before someone tries putting their own improvements in.

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Some really good information in this thread, but some of even the good information is based on guesses.

 

From your posts, I don't know enough about your engine to make a specific recommendation

 

Some information:

 

The quadrajet many are suggesting is a spread-bore carburetor. Buick used a spread-bore intake as original equipment.

 

Edelbrock, possibly others, sold an aftermarket square-bore intake.

 

So the first question: is your intake a square-bore or a spread-bore?

 

For a time, Edelbrock sold imitation quadrajets.

 

Edelbrock still sells imitation AFB's.

 

So second question: is your Edelbrock an imitation AFB (square-bore) or imitation quadrajet (spread-bore).

 

Regardless, Edelbrock has had sealing issues where the carburetor bolts to the intake UNLESS THE GASKET SUPPLIED WITH THE INTAKE IS USED! As others have mentioned, a leak here would cause a high, less than smooth idle.

 

As mentioned by others, the imitation AFB's and imitation quadrajets were/are BOTH CALIBRATED FOR SMALL BLOCK CHEVY!

 

Can one be recalibrated to work well on a Buick? Maybe, genuine AFB's and genuine quadrajets can be, but machine work and a BUNCH of parts would be necessary. Example: the 1965 Chevrolet used a genuine Carter 625 CFM AFB number 3720. In 1965, Buick used a genuine Carter 625 CFM AFB number 3921. To make the 3720 perform well on the Buick, one would have to change the primary clusters, the secondary clusters, the primary jets, the secondary jets, the step-up rods, the step-up piston springs, and most importantly, the auxiliary air-valve! Why bother???

 

As far as the "mechanics" laughing at you if you asked about a Q-Jet, everyone has their favorite, and some shops sell either the Edelbrock or the Holley, thus have an ax to grind. But think about this: virtually every production car with a 4-barrel carburetor sold in the USA by 1972 used a spread-bore. There are a very few exceptions (mostly those the manufacturers know will be circle-track raced). Buick used a Q-Jet on their "Stage 4", Pontiac used a Q-Jet on their "Ram Air IV", both high performance engines. A "mechanic" that would laugh at the Buick or Pontiac performance engineers will get none of my business.

 

As far as your having issues with two used Q-Jets that ran poorly: there is no such thing as a usable "used" carburetor until it has been rebuilt because of what passes for gas (no pun intended) the last 30 years. Turn the clock back to the 1950's, and one could install a used carburetor, and expect good to excellent results. Also, were the Q-Jets used correct for the engine make, type, and displacement?

 

As to your idea of doing more tuning before thinking about a carburetor: YES, totally agree! I would have to be shown that the unit ran "fine" until the problem started, but if it ran to YOUR satisfaction, that is all that really matters.

 

Should you be unable to get your current set-up running to your satisfaction, I will be happy to offer advice with no obligations, as long as you don't ask about the imitations, which are permanently banned from our shop. I will not help you try to tune the imitation. Will need to know what intake you are using (and wish to use), and any major modification (i.e. camshaft) to your engine. 573-392-7378 (9-12, 1-4 Mon-Tues central time).

 

Jon

Edited by carbking (see edit history)
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3 hours ago, 60FlatTop said:

Main thing is to put the metering rods in after you put the airhorn on, way easier.

 

 

 

But Bernie - if you do that you don't bend the rods, and I don't get to sell new ones ;)

 

Jon

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5 hours ago, 60FlatTop said:

The two Chevies mentioned have stepper motor gauges. You have a couple of years before the truck gauges give false readings

 

I routinely drive my '04 Silverado around town at 120 mph with no problems...  :unsure:

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14 hours ago, EmTee said:

I routinely drive my '04 Silverado around town at 120 mph with no problems... 

And a pegged voltmeter? You known there aren't many besides you and I who are laughing at this joke.

 

In real life one of the things I work with is Liebert brand high reliability computer room AC units. Years ago they eliminated oil pressure differential switches because the safety switch failed more frequently than the lubrication systems. That was one of the things that brought me to begin to question monitoring devices, years ago.

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When I first got my 63, I did not know that the pos battery post should be closer to the radiator. I hit a pot hole, the battery hold down didn’t hold down. (?) and the positive post contacted the bottom of the hood. If it had not been for the ammeter blowing when the surge hit it, my entire electrical system would have been blown.  Sometimes a gauge does come in handy.

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*eating popcorn in my Riv*
 

Thanks for all the info on carburetors but for the record..

 

It does NOT have high idle!

 

The idle is really low and I need to keep my foot on the gas for it to warm up when cold.

 

   I’ll revisit this thread with more info on exactly what carb I have later in the week if I’m still having issues.

 

   

 

 

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  • 1 month later...

Ok, that was longer than a week...

 

Gas in oil issue is solved.. have driven it quite a bit and no funky oil, thanks for the advice!

 

Turns out carb (AVS2) is fine except it being a little small.. 650CFM instead of the factory 750CFM... Timing was off. Factory specs 4 degrees and it was at 15! It's doing much better but then decided it's going to have an angry lifter. (facepalm) I anticipated having the heads worked on at some point so spending $$ on the proper size carb will have to wait for now.. I still love her.. she's just demanding.. lol!

Edited by Raggedy Ann Riviera (see edit history)
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Raggedy Ann - In a different lifetime (well, 50 years ago) Carter made an AVS. It was rated at 630 CFM; but the "new math" changes that into a 650 ;)

 

BUT, EFFECTIVELY, IT ISN'T!!!!!

 

The 630 was broken down as 250 on the primary side, and 380 on the secondary side.

 

Now, the original Buick intake was designed for a Rochester Q-Jet 750 CFM.

 

The Rochester was broken down as 150 on the primary, and 600 on the secondary (if you refer to my first post asking about a square-bore or spread-bore intake).

 

Assuming you have the original intake, then:

 

You have a limitation of 150 on the primary side (from the intake).

You have a limitation of 380 on the secondary side (from the carburetor).

 

Adding 150 + 380 = 530 CFM total EFFECTIVE with your carburetor.

 

Of course, if the individual downgrading the carburetor also changed the intake to a square-bore intake, then disregard all of the above except the 630 instead of 650.

 

Your car, your decision, but I think your lady would be much happier if you were to acquire a Rochester Q-Jet somewhere.

 

Jon.

 

 

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