HELP! 455 olds sputters around 4k rpm

« **on:** July 17, 2016, 12:00:33 PM »

So I rebuilt my 455 olds and got it back in the boat, but around 4k rpm it sputters. It has a brand new edelbrock 750, all new valves, valve guides, and springs, offy tunnel ram, newer holley fuel pump, new coil, mallory single point distributor, brand new autolite platinum spark plugs. Any help would be appreciated

« **Reply #1 on:** July 17, 2016, 12:25:52 PM »

Little info
Fuel pressure?
Float level ?
Timing ?
How does it run when u take off?

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« **Reply #2 on:** July 18, 2016, 12:20:50 AM »

I'm not sure about fuel pressure, but I know it's getting enough fuel because I took the fuel line off and pumped gas onto a bottle to see how much was coming out. Timing is set right around 11* I believe. And as far a driving the boat, I have no idea, bought the boat months ago as a project and haven't taken it out yet.

« **Reply #3 on:** July 18, 2016, 05:48:43 AM »

Hopefully your pump is disconnected
While your running it on trailer

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« **Reply #4 on:** July 18, 2016, 10:51:35 AM »

Ditch the mallory single point and go hei or electronic,had the same problem years ago with a dual point mallory,it was on a bbc 461, I know it's not the same motor but symptoms are similiar

« **Reply #5 on:** July 18, 2016, 11:11:53 AM »

Which carburetor?

Your fuel test is worthless (sorry).

What fuel pump?

When you say sputters, how? Carburetor, exhaust?

Just misses?

What exhaust?

How are you cooling it?

Compression test?

Timing test is worthless too... What is the timing at over 2,500rpm?

Vacuum advance?

Why points?

How much voltage on the coil with the engine running? What coil? ....

Sorry. Had to.

GT

« **Reply #6 on:** July 18, 2016, 11:19:38 AM »

Quote from: GT Jets on July 18, 2016, 11:11:53 AM

Which carburetor?

Your fuel test is worthless (sorry).

What fuel pump?

When you say sputters, how? Carburetor, exhaust?

Just misses?

What exhaust?

How are you cooling it?

Compression test?

Timing test is worthless too... What is the timing at over 2,500rpm?

Vacuum advance?

Why points?

How much voltage on the coil with the engine running? What coil? ....

Sorry. Had to.

GT

GT will get u on the right track if u listen to what he says👍👍👍

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« **Reply #7 on:** July 18, 2016, 11:29:53 AM »

I gotta hand it to GT, he called on the variables of the equation as I would.
Answer most of those questions and we have a picture.

« **Reply #8 on:** July 18, 2016, 11:58:19 AM »

Quote from: chrisx2 on July 18, 2016, 11:29:53 AM

I gotta hand it to GT, he called on the variables of the equation as I would.
Answer most of those questions and we have a picture.

I may have gone a little over the top, but I was trying eat my lunch and realised I forgot a fork, napkin and my iced tea, I had a salad and the dressing decided to somehow get on my pants.

Lol

Another thing to add.

My grandfather always said "brand new" is just another way of saying "unproven".

You have no idea how awesome that statement is until you think about it for a minute.

Lol

GT

« **Reply #9 on:** July 19, 2016, 11:06:52 AM »

It sounds more like timing. Your points and mechanical advance might be hanging up. BBO's like about 30* on the average total advance.

« **Reply #10 on:** July 19, 2016, 02:58:48 PM »

If he has the old coil I'd try that first. If not that, then the condensor (what's that???). And like GT said, verify voltage at the coil while running.

« **Reply #11 on:** July 19, 2016, 03:00:00 PM »

Also, verify that your coil polarity is correct.

« **Reply #12 on:** July 20, 2016, 02:33:58 PM »

I have even seen new valve springs that were not set up right, or for the correct application. = Valve float.

« **Reply #13 on:** July 20, 2016, 03:02:07 PM »

Quote from: GT Jets on July 18, 2016, 11:11:53 AM

Which carburetor?

Your fuel test is worthless (sorry).

What fuel pump?

When you say sputters, how? Carburetor, exhaust?

Just misses?

What exhaust?

How are you cooling it?

Compression test?

Timing test is worthless too... What is the timing at over 2,500rpm?

Vacuum advance?

Why points?

How much voltage on the coil with the engine running? What coil? ....

Sorry. Had to.

GT

I'm just catching up on this thread.
GT Jets, I hope you're having your BP issues checked by a medical professional. If not, I am glad, disregard this.

Quote from: GT Jets on July 18, 2016, 11:58:19 AM

I may have gone a little over the top, but I was trying eat my lunch and realised I forgot a fork, napkin and my iced tea, I had a salad and the dressing decided to somehow get on my pants.

Lol

Another thing to add.

My grandfather always said "brand new" is just another way of saying "unproven".

You have no idea how awesome that statement is until you think about it for a minute.

Lol

GT

« **Reply #14 on:** July 20, 2016, 03:17:37 PM »

Quote from: vwagon13 on July 20, 2016, 03:02:07 PM

I'm just catching up on this thread.
GT Jets, I hope you're having your BP issues checked by a medical professional. If not, I am glad, disregard this.

Other than drowning on stupid and lazy at work, I'm cool. Lol

No medical issues here (at least that I'm aware of. )..

GT

« **Reply #15 on:** July 21, 2016, 02:59:52 AM »

Platiunum plugs are not what you need in the olds...try using the autolite AR-72 or 73. also I would goto an HEI ignition...do that make sure youve got it timed correctly...if it continues youve got a carb issue in my opinion... keep us updated...

« **Reply #16 on:** July 21, 2016, 05:00:34 AM »

Quote from: billymachete on July 21, 2016, 02:59:52 AM

Platiunum plugs are not what you need in the olds...try using the autolite AR-72 or 73. also I would goto an HEI ignition...do that make sure youve got it timed correctly...if it continues youve got a carb issue in my opinion... keep us updated...

No Autolites in a Oldsmobile lol... It's not a ford

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« **Reply #17 on:** July 21, 2016, 05:59:19 AM »

Quote from: 69kona on July 21, 2016, 05:00:34 AM

No Autolites in a Oldsmobile lol... It's not a ford

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It for sure isnt a Ford. Lol

« **Reply #18 on:** July 21, 2016, 06:28:54 AM »

Quote from: jfs.welding.fab on July 17, 2016, 12:00:33 PM

So I rebuilt my 455 olds and got it back in the boat, but around 4k rpm it sputters. It has a brand new edelbrock 750, all new valves, valve guides, and springs, offy tunnel ram, newer holley fuel pump, new coil, mallory single point distributor, brand new autolite platinum spark plugs. Any help would be appreciated

I hope all this advice answers your questions.

« **Reply #19 on:** July 22, 2016, 06:30:31 PM »

If you havent tried the autolite ar72 or 3 in your olds youre short changing yourself...ford gets lucky every once in awile and makes something worth a shit LMFAO!!

« **Reply #20 on:** July 22, 2016, 06:48:12 PM »

Quote from: billymachete on July 22, 2016, 06:30:31 PM

If you havent tried the autolite ar72 or 3 in your olds youre short changing yourself...ford gets lucky every once in awile and makes something worth a shit LMFAO!!

Except Ford has absolutely nothing to do with Autolite.

You are thinking Motorcraft.

Autolite is Fram garbage and I wouldn't run them in a lawnmower.

JMHO, you should be using a plated plug.

Nippon Denso, NGK, Campion, Marine AC Delco, just to name a few...

They won't rust like a standard plug.

JMO

« **Reply #21 on:** August 08, 2016, 07:13:25 PM »

Quote from: GT Jets on July 18, 2016, 11:11:53 AM

Which carburetor?

Your fuel test is worthless (sorry).

What fuel pump?

When you say sputters, how? Carburetor, exhaust?

Just misses?

What exhaust?

How are you cooling it?

Compression test?

Timing test is worthless too... What is the timing at over 2,500rpm?

Vacuum advance?

Why points?

How much voltage on the coil with the engine running? What coil? ....

Sorry. Had to.

GT

Thanks for all the advice everyone. And sorry for the late reply, I've been busy with work. Anyways I ordered a mallory unilite electronic distributor and put that on and a new alternator since the old one was bad, and I still had the sputtering issue. So I threw on an old holley 600 cfm I had laying in the garage (looks like it was pulled out of the ocean it was so dirty) and it ran great on the hose. So I took it out and ran the boat in the water for awhile and it did good but still sputtered a bit once the engine had warmed up. And by sputter I mean when I get on the gas it hesitates and doesnt pick up speed. And to answer a few of your questions GT; the exhaust I have is Hardin logs and snails, 150 compression in all cylinders, and the coil is a mallory electronic ignition coil. That's all the answers I have as of now. Thanks for all the advice and anymore advice will be appreciated. And another thing, I don't know if I should get the holley 600 rebuilt or if the issue could be something else? Thanks in advance

« **Reply #22 on:** August 08, 2016, 07:20:58 PM »

I also forgot to mention that I have a really bad exhaust leak at the flange that bolts to the head, does anyone know if I can get a thicker gasket or double up on gaskets? Or maybe the flange on the exhaust is bad?

« **Reply #23 on:** August 08, 2016, 08:04:42 PM »

Quote from: jfs.welding.fab on August 08, 2016, 07:20:58 PM

I also forgot to mention that I have a really bad exhaust leak at the flange that bolts to the head, does anyone know if I can get a thicker gasket or double up on gaskets? Or maybe the flange on the exhaust is bad?

Have them milled flat and use high temp rtv, I have had good luck with Ultra Copper.

« **Reply #24 on:** August 08, 2016, 08:51:14 PM »

Quote from: bahner80 on July 18, 2016, 10:51:35 AM

Ditch the mallory single point and go hei or electronic,had the same problem years ago with a dual point mallory,it was on a bbc 461, I know it's not the same motor but symptoms are similiar

X2 on that, had the same problem and went to HEI and cleared it up

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