EXCESSIVE OIL CONSUMPTION on TOP OILER

[OROBBE]

Hi every body,

I'm Oliver a French Unique Motorcars Cobra owner since 1 year and a half.

My car is equipped with a 427FE Top oiler with Edelbrock performer Rpm heads anEdelbrock performer intake and a Holley 750Cfm.

My engine consumes 1qt of oil evry 125 miles...

I've checked compression I get 160 to 170 psi on each cylinders.

I've replaced the intake gaskets still the same problem.

My heads were new and have now 5000 miles.

I've got spark plug on cylinder n°5 wich is oily all others are dry.

What do you recommend to me ? One ring is faulty ?

Thanks for your replies.

OliveR

[blykins]

Instead of a compression test, try a leak down test. If you do have a cylinder with bad rings, it will make it more obvious. I would of course look to the cylinder with the wet plug. Can you tell if it's wet with oil or gas?

Do you have any leaks anywhere? Does it smoke when you drive it?

[OROBBE]

Blykins the spark plug in cylinder n°5 is wet with oil and solid black deposit.

When removing the foot of the throttle pedal and when I push down on it I've got a cloud of blue/grey smoke.

I don't consume coolant at all.

OliveR

[blykins]

I'd do a leakdown on that cylinder. Blue smoke is the result of burning oil. It's possible that you have a stuck or broken piston ring.

[RICK LAKE]

OROBBE Olive Compression test sound OK.
What oil are you running, SAE and weight?
A leak down test is only going to show if you have a compreesion leak from the valves not sealing or rings.
Does the car have a PCV valve on the right valve cover??
Does it have good vacuum?? This is basic so hang in there.
My feelings are that the valve stem seals are broken or the spring came off the top of the seals. Have you over revving this motor?? Real easy to bend a valve.
Are the intake gaskets clear of the oil return ports??
A partial block will over fill the heads and cause oil to get sucked through the valve guides.
I think you are going to have to pull the heads and have them checked at a good machine shop.
Quick check, with the motor running, pull the PCV valve out of the valve cover and tell us if it looks like a smoke stack, puffing??
If so you have bad blowby and the oil rings may have collasped on the pistons. Talk to you later. Rick

[OROBBE]

Rick, Blykins,
I'm running with 20w50 oil with Zdd+ additive
I removed the PCV valve 1 year ago and replaced it with a valve cover breather on the right valve cover meaning that I've got 2x valve cover breathers on my engine (one on both side).
Few smoke is leaving from the 2x breathers when engine is running at idle.
I've used Edelbrock intake gasket (7224) which match perfectly with my Edelbrock intake.
My heads have only 5000 miles since buy new.
OliveR

[blykins]

You really need a PCV valve on one side that's actuated by engine vacuum. I put PCV valves on the passenger side of my engines with breathers on the driver's side.

One thing you could check is to remove the valve cover and take a look at the valve seals on the #5 cylinder. They are hard to see through the valve spring, but you should be able to see if something is badly wrong.

Otherwise, my thoughts are that you have a piston ring issue on that cylinder. You could put compressed air into that cylinder (part of a leakdown) and listen for a great amount of air entering into the oil pan.

[Jerry Clayton]

there is a flowmeter guage that you can get to measure the amount of blowby---sorta like a welding gas flowmeter but different--really works well in more controlled situations--like a series of like built(spec) engines that you are keeping track of---I don't remember who sells them--

[OROBBE]

Brent,
Ok, I'm going to check valve seals on cylinder n°5.
Concerning the test with compressed air in cylinder n°5 I supposed prerequisite is that both intake and exhaust valves must be closed ??
OliveR

[Jerry Clayton]

valves have to be closed---be careful when you pressure ize it as the engine may turn over from the pressure---listen for air at carb (intake valve leak) exhaust(exhaust valve) and breather holes (blowby)

can you describe how much smoke comes out the breather holes at idle? and if #5 is always oilly, try removing and grounding that plug wire to short out the cylinder, and see if there is any change in the smoke--if there is you have serious blowby that piston/rings---


Sorry Brent---didn't mean to jump into the middle of your replies--meant some of your buddies at Ohio

[Rick Parker]

The rate of consumption would seem to be excessive for an individual valve seal (??) As others have hinted at, look to the rings or the gasket seal on the #5 cylinder.

[Zoom This]

I went through all the problems of oil consumption that oliver is dealing with, with my first 418W and found out during tear down that my rings were not installed properly by the first engine builder that went out of business shortly after completion of my motor. The rings were improperly installed and the ring gap was way too narrow and they would touch after the engine warmed up. This wound up destroying the ring lands causing ring flutter. I had replaced the intake gasket which also was installed by blind monkeys during the first build. Didn't stop the oil consumption however. After building a new motor by a master engine builder and over 8k miles on it to date, I only burn a quart of oil every 2-3k miles. I hate to say it but I think a rebuild is in your future.

[OROBBE]

JERRY, smokes that come out the breathers is poor at idle. When I revove the breathers on each side, I just can feel very few air pressure from the holes.

RICK, some friends in France told me the same. They think that oil consumption is too excessive for a valve seal problem.

ZOOM THIS, what do you mean by "a rebuild" ? check the rings and if needed replace them ? Do you think I need to replace too the rods and the main bearings ?

For information the engine had been rebuilt by Southern Automotive 5000miles ago.

OliveR

[blykins]

Oliver, have you contacted them yet?

[FatBoy]

Oliver,

I also have a 427 in my Cobra from Bill at Souther Automotive. I know that some people have had problems with SA built engines, but Bill is an honourable guy and he will stand by his products. Give him a call and see what he says. If there is a problem, he will amost certainly put it right for you at his cost.

Paul

[Zoom This]

ZOOM THIS, what do you mean by "a rebuild" ? check the rings and if needed replace them ? Do you think I need to replace too the rods and the main bearings ?

I did a complete rebuild of my motor since I was so pissed about only getting 6k miles on a motor that burned copious amounts of oil since it was built. Rings, pistons, new block, heads rebuilt, etc done. You'll need to check the bores of all cylinders for exact roundness if you change rings. Some of my cylinders in the old block were out of round. Just another layer of bad engine work the first time. I gotta say that I find it hard to understand how Chevrolet, Ford, Toyota etc. can get oil consumption under control 10k times out of 10k times and so many after-market motors struggle with heavy oil consumption.

[OROBBE]

Do you know if I can remove pistons/rings from bottom of the engine (to avoid removing intake and heads) ?

I sent an Email to Bill Parham but no news at the moment.

I've checked again my spark plugs yesterday and I confirm that only N°5 is oilly. All others are grey and dry.

I've got a question: I've seen that I've got 6005 Edelbrock heads on my 427 (I thaught I had 6007) but these heads are designed for 390 or 428. Do you think that these heads are OK for my engine or there is a wrong assembly ?

OliveR

[Jerry Clayton]

Question---do you have a cross bolted main 427 block???or possibly a stroked 390 block?? the stroked 390 block won't clear the 427 valve sizes

and you can't remove pistons from the bottom

[OROBBE]

Jerry, my block is a 427 Top Oiler stroked to 454 by just replacing the crankshaft (428' crankshaft).

What do you mean by cross bolted main 427 block ?

Any answer about my previous question about the Heads ?

OliveR

P.S.: please tell me that I can remove the pistons from the bottom

[Mike Huddart]

Oliver,
the 6005 (9) head IS for 428 and has the smaller valves, also a smaller (72cc ) combustion chamber. The 6007 is the complete assembled version of the bare 6008 which has 76cc chambers and can be machined for the larger 427 valve size, the 6005 cannot.

Cross bolted mains means the center three main caps have extra, external , horizontal bolts to add strength, you can see three bolt heads at the bottom of the crankcase on either side if the block is crossbolted. Some 427 center oilers and late 406s where crossbolted, most not.

And NO, YOU CANNOT remove the pistons from below.
Mike