Author Topic: New engine rebuild smoking and oil fouling plugs  (Read 7546 times)

cob4ra

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New engine rebuild smoking and oil fouling plugs
« on: August 03, 2019, 12:47:55 AM »
My good friend Bill just had his numbers matching engine ď professionally?Ē Rebuilt by a company in California! $10,500 later plus r&r cost  itís smoking on acceleration not as much on deceleration has been Fowling 4 to 5 plugs and itís gone a quart low !! They ran it on their Dyno and did a break-in procedure! He is up here in Idaho with me and now having this engine in his shelby ;  heís looking for help!!  Iím thinking they misaligned the rings or during the break in procedure on the Dyno something was damaged but your opinions are very needed here !  We have not checked the compression but it cranks over evenly with each stroke and it runs With acceptable power ! Changed oil twice with recommended oil and two sets of spark plugs and they are still fowling with oil on them!?
1966 Shelby GT350 Hertz 1680 ( previously 6s1842;6s1818)                                                  2000 Saleen S281 Speedster.                              Previously two sunbeam tigers and have owned 24 mustangs ; 4 Mercury Cyclones and one 1960 Fiat 600!

Bob Gaines

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #1 on: August 03, 2019, 01:03:53 AM »
My good friend Bill just had his numbers matching engine ď professionally?Ē Rebuilt by a company in California! $10,500 later plus r&r cost  itís smoking on acceleration not as much on deceleration has been Fowling 4 to 5 plugs and itís gone a quart low !! They ran it on their Dyno and did a break-in procedure! He is up here in Idaho with me and now having this engine in his shelby ;  heís looking for help!!  Iím thinking they misaligned the rings or during the break in procedure on the Dyno something was damaged but your opinions are very needed here !  We have not checked the compression but it cranks over evenly with each stroke and it runs With acceptable power ! Changed oil twice with recommended oil and two sets of spark plugs and they are still fowling with oil on them!?
If you open up the engine then the company that rebuilt it may use that against you. What does the company that charged all of that money have to say about the problem? They should be the first to call.  The engine needs to go back to them so that they can make it right. If they are a honorable company then they will take care of the problem . If they are not and you are stuck with it then start looking for another rebuild company as most likely some one is going to have to do a tear down to determine what the problem is . Remote diagnoses will not help much because it will still need to be torn down regardless to confirm any diagnoses. Just my opinion. Others may have different. 
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

jerry merrill

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #2 on: August 03, 2019, 01:07:16 AM »
Could be one of several things, warped or misaligned intake manifold that is sucking oil or I had a new engine that had several bad valve guide seals or worst case broken or incorrect installed rings. I have had all three of these happen to me over the years. Good luck!

69 GT350 Vert

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #3 on: August 03, 2019, 02:53:12 AM »
I had the same exact problem happen to me.  I ended up giving the engine to a different shop to fix since I did not have confidence in them any longer.  Turned out my cylinder hone was too smooth,  and the intake was sucking oil at bottom due to inadequate gasket pinch. 

I feel the 1st shop would have duplicated the same errors a 2nd time. 

shelbydoug

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #4 on: August 03, 2019, 06:47:13 AM »
I would look for something simpler first. My first reaction is that this is a pcv issue

I first would disconnect and plug the pcv, then run the engine and see if the issue is still there.

Ford pcv connection designs were always questionable and were one heartbeat away from dumping oil into the intake manifold.

Right now, I'm a big believer in installing oil tank/scrapers into the pcv plumbing.

Sometimes big things get blamed on little things especially if there is a novice involved somewhere in line between the shop and the installation.
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Re: New engine rebuild smoking and oil fouling plugs
« Reply #5 on: August 03, 2019, 06:54:31 PM »
How many miles? Do a leakdown test - better than compression to see how much is getting past rings.
Previous owner 6S843 - GT350H & 68 GT500 Convert #135.
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s2ms

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #6 on: August 03, 2019, 10:07:59 PM »
I would look for something simpler first. My first reaction is that this is a pcv issue

I first would disconnect and plug the pcv, then run the engine and see if the issue is still there.

Ford pcv connection designs were always questionable and were one heartbeat away from dumping oil into the intake manifold.

Right now, I'm a big believer in installing oil tank/scrapers into the pcv plumbing.

Sometimes big things get blamed on little things especially if there is a novice involved somewhere in line between the shop and the installation.

+1. Especially if there's been any messing with the valve cover baffles to accommodate roller rockers.
Dave - 6S1757

cob4ra

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #7 on: August 04, 2019, 01:15:54 AM »
Thanks to all; tomorrow Iím going to block off his PCV. Valve and drive it some? How far to realize if itís changed? 3 miles? or? ; I wish I had leak down tools but I will run his compression in each cylinder and hopefully not any too different or low ! After all weíve read here; the third will be an inspection of the intake manifold gaskets if the others check out ok ? Opinions??!
1966 Shelby GT350 Hertz 1680 ( previously 6s1842;6s1818)                                                  2000 Saleen S281 Speedster.                              Previously two sunbeam tigers and have owned 24 mustangs ; 4 Mercury Cyclones and one 1960 Fiat 600!

shelbydoug

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #8 on: August 04, 2019, 07:40:40 AM »
Thanks to all; tomorrow Iím going to block off his PCV. Valve and drive it some? How far to realize if itís changed? 3 miles? or? ; I wish I had leak down tools but I will run his compression in each cylinder and hopefully not any too different or low ! After all weíve read here; the third will be an inspection of the intake manifold gaskets if the others check out ok ? Opinions??!

It should show up vertually immediately.

You could get an inexpensive clear case fuel filter. Plumb it into the PCV hose and see if it is filling with oil.

Sucking oil into the intake manifold through the original pluming set up is very common. My parents had a new 76 Granada. It was completely stock with a 302. It was very similar to what I had in my 68 GT350. Sort of a generic Ford PCV set up.

They took it on a 500 mile trip new. When they came back, they had completely sucked the oil pan dry. How they survived and not have blown the engine is beyond me?

That original Ford molded twisted s shaped pcv to intake manifold hose IS part of the issue as is the connection point on the intake manifold.



You may not like the idea of an oil scrapper but here is a picture of what I did.

Early owners (64-5) don't like the idea of a closed breather system. In a sense they are right because of this issue BUT there is lots of data around that shows that they are giving about 25hp away by running open breathers.

IF you look for it, you will actually find a bunch of Shelby Comp cars with open breather systems that have arrived at the point of putting a very similar tank in line to their breathers.

I recently saw an S/C with one plumbed in and it dates from it's original comp days. This is not a rare and unusual solution or condition.

The siphoning is caused by the connection to the intake manifold being lower then the connection to the valve covers and the really bad, cheap quality of the pcv themselves.



Sure it's cool to run the Shelby Comp design of tall filler tubes on the "Comp" valve covers BUT that was done for racing reasons on Comp Cars that didn't have to go 10,000 miles without any kind of service. Rebel against the US Fedral and California emissions rules if you like but it just is foolish to do so. The closed design is just better all around.

You can always go to the head Priest for the Shelby Secret Police and confess that you have sinned and ask for absolution? Maybe for penance they will just make you talk nice to Corvette guys for 10 minutes or so?  ;D


Try one of these spiffy pcv's. They are better quality (the best I can find) and the adjustability may help you out some?

http://mewagner.com/?p=444
« Last Edit: August 04, 2019, 08:54:18 AM by shelbydoug »
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69 GT350 Vert

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #9 on: August 04, 2019, 10:09:42 AM »
Thanks to all; tomorrow Iím going to block off his PCV. Valve and drive it some? How far to realize if itís changed? 3 miles? or? ; I wish I had leak down tools but I will run his compression in each cylinder and hopefully not any too different or low ! After all weíve read here; the third will be an inspection of the intake manifold gaskets if the others check out ok ? Opinions??!

If you have someone follow behind in another car, you should know right away.  If you smell oil in exhaust or see smoke, it will be easy to detect.  It is possible the compression rings are sealing pretty well so your compression and leak down results could be ok, and it still may smoke.  I did all of these tests, and paid for a borescope test as well.  All were inconclusive, but it kept smoking and consuming oil.  I also pulled and resealed my intake, but that wasn't the main problem.  In the end, the engine came back out for re-hone and re-ring.  Good luck.  I hope you fare better than I did. 

Dan353

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #10 on: August 04, 2019, 11:12:55 AM »
I had a similar problem found out it was my valve covers.  Bought a tall set from Branda the baffle was too small the oil would get sucked straight into the PCV and into intake it would smoke badly on acceleration and when deacceleration.  I used spacers and the original valve covers havenít had a problem since.

Dan

cob4ra

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #11 on: August 04, 2019, 11:45:04 AM »
Bills coming over at 10 am and I will let everyone know ď blow by blow ď !
1966 Shelby GT350 Hertz 1680 ( previously 6s1842;6s1818)                                                  2000 Saleen S281 Speedster.                              Previously two sunbeam tigers and have owned 24 mustangs ; 4 Mercury Cyclones and one 1960 Fiat 600!

cob4ra

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #12 on: August 04, 2019, 03:58:11 PM »
I removed the PCV and blocked it! Compression is high and fine! Number five spark plug looked like a coal factory in a oil storm ? Yuk! Still smoking like this picture; mostly drivers side
« Last Edit: August 04, 2019, 04:11:58 PM by cob4ra »
1966 Shelby GT350 Hertz 1680 ( previously 6s1842;6s1818)                                                  2000 Saleen S281 Speedster.                              Previously two sunbeam tigers and have owned 24 mustangs ; 4 Mercury Cyclones and one 1960 Fiat 600!

shelbydoug

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #13 on: August 04, 2019, 05:31:00 PM »
The next stupid thing that needs to be eliminated is a blown power valve in the carb.

IF this engine backfired even a little bit, just one time starting it up, you could have blown out the power valve and the smoke can be from excessive fuel.

The current valves are more delicate then fairy dust on a snowflake in summer. A strong running engine will run under those circumstances but dumping raw fuel into the intake manifold doesn't necessarily run equally to all cylinders. It might like #5 the best?

It's also going to do a job on cylinder washing which means flinging a mix of oil and fuel all over.

Make 1000% sure that the power valve is ok. Usually the only way you can verify that is with a power valve tester. I had six out of twelve NEW in the package bad valves. Just putting in a new valve doesn't guaranty it's ok.


While the carb is out check stupid thing number three. Your float levels. The Holley procedure for setting them dry is wrong. You will flood.

Two things add to the delema of fuel level. Too much fuel presuure, like adding an electric fuel pump in line with the mechanical and unleaded gas.

If you are using a carb with sight plugs in the bowls, you need to set the level down lower then "a trickle out".

If you are using a high pressure pump or dual pumps you have to limit pressure to under 5-1/2 psi otherwise the float levels are wrong.


I can't think of stupid thing number four yet, but I will.  :)
« Last Edit: August 04, 2019, 05:36:58 PM by shelbydoug »
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cob4ra

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Re: New engine rebuild smoking and oil fouling plugs
« Reply #14 on: August 04, 2019, 06:08:33 PM »
Had to ad a quart of oil again; and it still wasnít at full ď line! The smoke is a real pretty light blue like the lighter blue on my rear Gabriel shocks! And those plugs; wet with oil and black !
1966 Shelby GT350 Hertz 1680 ( previously 6s1842;6s1818)                                                  2000 Saleen S281 Speedster.                              Previously two sunbeam tigers and have owned 24 mustangs ; 4 Mercury Cyclones and one 1960 Fiat 600!