Thread: blow by and swirly port heads.

Tweet

Originally Posted by 36 sedan

What's your fuel pressure? Does your oil smell of gas?

36 sedan asked a critical question. I don't see that you mentioned what fuel pump you're using but your Edelbrock carb calls for 6.5psig (MAX), and most folks recommend keeping it below 5psig.

Originally Posted by rspears

36 sedan asked a critical question. I don't see that you mentioned what fuel pump you're using but your Edelbrock carb calls for 6.5psig (MAX), and most folks recommend keeping it below 5psig.

sorry for my ignorance this is my first real ground off restoration and i am learning the more advanced things the expensive way. anyways its a mechanical fuel pump a factory replacement would be my educated guess( it came when i bought the engine) but i believe they put out something in the range of 5-8psi am i right? anyways i have both bowls set at maybe 1/4 or a tiny bit less then 1/4 in the sight glass, ive played with it when i was tuning the engine and it can fill them or keep them low. so correct me if im wrong but i should be in the correct range of pressure?

i am a little bit worried the cylinders where not honed properly for moly rings? what is the correct grit/stone for this i want to ask the builder what he did now i have learned the leak down tester is misleading giving a green "good zone" up to 40%. i am at 20%(seems a bit much as someone else mentioned) on each cylinder i preformed the test cold not sure if it would be better hot?. i could hear what sounded like a balloon filling during the test but could not pin point it at the spots to check i thought that may be a normal sound. should it be silent during the test?

if it does end up being rings have not seated properly. what do you guys think about putting in some SAE 30 non detergent and driving the piss out of it for a while? maybe moly rings need extra time to seat, again this is still new under 50 miles on the vehicle. in the past ive just had cast iron rings and never noticed any smoke ever on a new engine they seem to break in pretty much instantly.

I have experienced stock mechanical replacement pumps that push more than 10psi. I have experienced stock mechanical replacement pumps pushing fuel past the needle seats in my Edelbrock carbs. I have a pressure gauge and a regulator on all of my carburetors, Edlebrock's are set at 4-5psi, Holley's are set at 4-5psi. SMELL YOUR OIL for fuel.

YES, both my Edelbrock and Holley carbs are set at the same pressure. Carburetors fuel supplies DO NOT operate by high fuel pressure, rather by gravity, atmospheric pressure (differentials of) and fuel VOLUME.

IMHO, no carburetor needs more than 5psi. If you need more than 5psi, you have a supply volume problem (fuel line and/or pump rating is too small), not a pressure problem. The carburetor only needs enough fuel pressure to overcome gravity and atmospheric pressures, SUPPLY volume (Gallons Per Hour) is what keeps the fuel bowls full.

And, JMHO, if you think the rings are not seated, TRY what JERRY said, use BonAmmi and see if it seats the rings. BonAmmi is a mild abrasive that will break the cylinder glaze and allow the rings to seat (in most cases).

However, if you have a ring gap or misalignment problem, BonAmmi will be no help at all..

P.S. as Denny says, always use DETERGENT oil.

With ONLY 50 miles on it, it's to early to tell. And does it have more time on it idling than driving?
Run it down the road / highway and at a bunch of different rpms. Then change the oil and re-evaluate.

Again, just my opinion.

Denny, I respectfully disagree with the float weight and length being a factor in figuring fuel pressure.

JMHO, the float operates the needle and seat valve by a fulcrum (leverage), and the float itself is a buoyancy factor (moved by the fuel). When fuel is used from the float bowl, the float drops opening the needle valve allowing fuel to enter and refill the bowl, as the fuel fills the bowl it raises the float pushing the needle shut stopping fuel entry. While inertia may play into the weight and length factor, I can not see how either float weight or length would dictate the minimum fuel pressure required.

And, while most carburetor manufacturers will specify a maximum pressure, it should not be confused with normal operating pressure. Though, I have seen manufacture’s tech support tell people to raise their fuel pressure, usually it is due to a poor fuel supply system and a tech trying to make it work with what they have, seldom with optimal results.

Excessive fuel pressure is the number #1 cause of carburetor troubles. High pressure will push fuel past the needle seat and flood the motor.

Again, no disrespect is intended, I truly respect your knowledge and experience. Simply want to clarify and help avoid problems and misunderstandings about carburetors.

I’ll modify my original comment to; “no STREET operated carburetor needs more than 4-5psi.”

BTW, excellent breakin procedure.

Hey guys, I just wanted to thank you all for taking the time to give me advice. I am fairly new to the game. But !SOLVED! the problem thanks to all the input... i couldn't be happier.
I had a bit of luck and some good advice.. but if you have been following this you will know I had taken the intake off as a first step to ensure it was sealing. I also mentioned I had under 50 miles on the truck. I may have been over reacting. But the intake was not sealing properly and I was getting a small amount of antifreeze into the oil from the poor seal. I made this post after making sure I sealed the intake 100%.
From day one I had water in oil so during break in of the rings I had this issue( again only 50 miles) the rings were not seating. Here is the lucky part I think. Today I changed the oile to a 30w oil has a last resort before pulling the engine, and actually drove the piss out of it on the highway slowing down and to the floor repeat. Came home hot did a compression test 180 all around. Leak down test came in at 5% AND BEST OF ALL 0 SMOKE. plugs cleaned up basically a miracle.
Now I'm confident I'm good to go and this morning I was rdy to pull the engine. My gut told me it was going to be something simple and it was. And more bright side I learned a shit ton over the last few weeks. Thanks again!

Originally Posted by 36 sedan

I have experienced stock mechanical replacement pumps that push more than 10psi. I have experienced stock mechanical replacement pumps pushing fuel past the needle seats in my Edelbrock carbs. I have a pressure gauge and a regulator on all of my carburetors, Edlebrock's are set at 4-5psi, Holley's are set at 4-5psi. SMELL YOUR OIL for fuel.

i am taking your advice 36 sedan.fuel pressure seems too important to overlook.

Great news on the fix - and a lot of good information here too. I been building a long time but always appreciate what everyone has to say and usually learn something as well. (Oh gosh - Bon Ami! My mother used to use that stuff and I would have never dreamed of ingesting it through an engine but if Jerry says it works, then I believe!!)

Regards all,
Glenn

Denny, nice clarification.
Thank you!

Originally Posted by glennsexton

(Oh gosh - Bon Ami! My mother used to use that stuff and I would have never dreamed of ingesting it through an engine but if Jerry says it works, then I believe!!)

Regards all,
Glenn

I can speak firsthand that it works. Back in the day we used borax

Not to steal this thread, but....

Many years ago (you know this is gonna be good, right?) – I had a friend with a 1951 Pontiac that we affectionately nicknamed “the Beast”. It was a straight 8 and someone had made headers for this thing as well an adapter for a Carter AFB four barrel. This was one sweet ride, complete with a 4 speed hydro transmission and it was really pretty fast for the time.

It began to smoke and cough (likely due to seeing WOT on a very regular basis) and we somehow heard about the miracles of Rislone and Seafoam Green. We put a quart of Rislone in the crankcase and poured a bottle of Seafoam down the carb (at a fast idle of course) and within seconds, the smoke began to billow out of those dual tailpipes. We’re talking a lot of smoke – so thick we couldn’t see the end of our noses. Not to be discouraged, we got the entire can down and ran that baby at about 2,000 RPM until the smoke cleared to 10 foot visibility and then took the Poncho for a test drive. Oh my goodness, it coughed and belched for about ten miles (all the while spewing smoke thick enough to kill every mosquito within five states) and then all of the sudden, it smoothed out and we drove her back to my buddy’s house.

After a cool down, we installed new plugs/points/condenser, rotor, and cap and the Beast started with just a tap of the key and roared like a reborn lion with new life. He drove it for another year and sold it to a guy in San Bernardino as Uncle Sam called his number. Never saw the Beast again – but this smoking thread brought her to mind.

Hope you have a lot of miles and memories from your ride and remember to occasionally “… drive it like you stole it…” just because you can.

Thanks for letting me ramble a bit.
Glenn

Originally Posted by glennsexton

Oh my goodness, it coughed and belched for about ten miles (all the while spewing smoke thick enough to kill every mosquito within five states)

ROTFLMAO! I had one of those! I called it my BOND car, everywhere it went it laid an oil slick and smoke screen!

True story; we pulled into a gas station and had the attendant put 5 quarts of oil in it. Started it up, and within seconds you could hardly see us or the station, the attendant said "What happened?, it wasn't smoking when you came in????." I said, It never does when it's out of oil!!!!

Oh, and never put 90wt gear oil in your burner, it stinks to high heaven! (ask me how I know, lol)

I remember back in 1960 my dad bought a 60 Rambler at around 100K it went from good gas millage to an oil burner. we would check the gas and fill the oil. He carried a gallon can of oil in the back.