Vortec Heads Suck...
 

oil past the valve seals?

Here's the deal:

Noticed a misfire at idle. Started pulling plugs to look for clues. #1=good. #3= oil fouled! Bingo. But the question is why?
This is a new gm crate motor with about 2k miles on it. I swapped new GM Vortec heads on it 1000 miles ago.

So I cleaned the plug with acetone and a wire brush. Swapped plug #1 with plug #3. Drove it for two days. Today I pulled the plugs and #3 is getting oil fouled again (originally plug #1).

Concluded it's not the plug. Inspected and ohmed the plug wires (new Moroso 8 mm low ohm). Wires are good. Swapped in a brand new spare cap, rotor and coil.

Gonna drive it a few days and pull the plugs again. If #3 us going south again I can conclude it's not the ignition.

Therefore, I'm assuming it can only be the valve guide seals or piston rings?

What say you all? I never even looked closely at the valve guide "umbrella" seals. I'm just assuming they have them?
Am I missing something here? I'm having a hard time believing that a new engine would have this condition.

I was hoping I just had a plug go bad but the problem didn't follow the 1-3 cylinder swap.

Re: Vortec Heads Suck...
 

Vortec heads are a great bufhet option. But you could have a cracked guide or umbrella seal.

The only inherent weakness Vortecs have are they are on a bit of an thinner casting.

This a bit of a oem cost savings vs aftermarket bragging on thickness

Re: Vortec Heads Suck...
 

Could be a bad or damaged during install or even missing seal from the factory.

Is the leak enough to be causing exhaust smoke? Any oil in the coolant? Or coolant in the oil?

PCV system installed and working?

#5 plug OK?

Re: Vortec Heads Suck...
 

Oil level changing?

Re: Vortec Heads Suck...
 

I understand your frustration but your title is misleading. You don't even know the problem yet but you are trashing vortec heads.
It may be the heads but still what caused the problem. Could be a lot of things including the head gasket. Even if it is the heads it doesn't mean all vortecs are bad, just that the ones you have are bad.
Maybe you should check the compression on that cylinder.
How much h lift does the cam have?

Re: Vortec Heads Suck...
 

After swapping plugs 1-3 around and driving it for 2 days, the plug is beginning to foul again...so I can rule the ignition system out. I'm left to believe that the only way oil is getting in the cylinder is the rings or valve guide. I will pull the valve cover and see what I can. I'm assuming that these OEM GM heads use an umbrella seal? I doubt they would be machined for the posilock type seals?

I also pulled all the plugs to see if any other plugs are oil fouled. One thing because obvious quickly- carburetors on Vortec intakes do a lousy job when it comes to air/fuel distribution! The outer cylinders are a little lean while the inners are a little rich.

To further back up that statement, the temp dropped to 38 degrees here last night. I had a hell of a time getting the truck started this morning. I know the 160 t-stat needs changed out for at least a 180. I was just surprised how lousy a combination of the intake/carb was in the cold.

There is no smoke out the tailpipe and no oil in the coolant.

The ME Wagner PCV is working great. 20 inches of vacuum and a smooth idle...except for the occasional miss due to the fouling plug that just cropped up.

Re: Vortec Heads Suck...
 

What carb and intake setup are you running? I've never had any issues with fuel distribution on Vortec heads and carb setups. I've used Q-Jets, Edelbrocks, and Holleys. Cold start issues can be fixed with correct tune and choke settings. That's definitely cold for Yuma. I lived there 86ish-92, saw it snow once.

I understand being frustrated with an issue, but sometimes you have to step back and take a look at the whole picture. You never did mention if it is smoking...on startup? under a load? when letting off the throttle?

Re: Vortec Heads Suck...
 

Never liked the 'vortec' castings from the factory-- light weight and prone to cracking. Cheap bolt on power, but I was never really impressed with them. One of those too good to be true things

Re: Vortec Heads Suck...
 

Not sure why you'd think ignition issue for oil on plugs. Ignition or not there isn't supposed to be any oil on the plugs.
Yes, vortecs have a normal umbrella style valve seal. Its never been an issue and your the first person I've heard complain about them failing so quickly. They are just normal small block heads like any other except the intake bolt pattern is different. That's literally it.

Re: Vortec Heads Suck...
 

First off-

No "noticable" smoke from the exhaust. It's true duals so it's a little easier to know which bank it's coming from.

Intake is Edelbrock Performer for Vortec heads.

Carb is Edelbrock 1406.

I wanted to rule out the ignition system as I wasn't sure if a dead plug, wire or otherwise would cause oil to accumulate in the cylinder.

Regarding the distribution, let me ask a question:

Did the Vortec heads ever come factory with TBI?

Lacking a heat crossover, the air/fuel mixture hits the bottom of the manifold, comes to a sudden stop, tries to change direction, falls out of suspension and puddles. The colder the temp, the worse the problem. In summer, when it's 110, it's a benefit. If it were a dry manifold, e.g. TBI, this wouldn't happen.

Moving on. Tonight I did a compression check on cylinders 1,3 & 5.
All were right at 120 psi. I tested the suspect #3 cylinder wet and dry. NO change in psi between dry and wet so I conclude it's not a ring sealing issue.

I appreciate the feedback.

Re: Vortec Heads Suck...
 

No the Vortec heads did not come on any TBI engines. A TBI would still have fuel in the intake manifold. The Vortecs were only used with CPFI in automotive applications. The Performer RPM Vortec has provisions for running coolant under the carb for cold climates with a carb.

If you have a L31 crate engine, why did you change the heads 1K miles ago? What was wrong with the original heads?

Re: Vortec Heads Suck...
 

It's not an L31. It's a Goodwrench gen 1 crate engine. I was less than impressed with the power so I swapped heads and put in a 448 lift comp cam.

Re: Vortec Heads Suck...
 

I have heard rumors of 1996 GM Vans with TBI on Vortec engines. Whether this is true or not, I'm not sure...but they were never in the mainstream vehicles for sure.




Sunsoaked...the 1406 comes tuned fairly lean from Edelbrock. Have you had the top off and made any adjustments? They will run out of the box, but perform much better when they've been calibrated better.

My biggest gripe with the Edelbrocks is they love to boil this garbage ethanol fuel off, that doesn't help with starting period, cold or hot.

Re: Vortec Heads Suck...
 

Since 88 GM's gas truck engines in the gmt400 series have been called Vortec. So people see the tbi trucks and think they have the "Vortec" heads.

Re: Vortec Heads Suck...
 

The oil can be coming from the intake gasket, a weak spark from a bad plug wire can give you the oil issue. Based on dyno results on circle track crate engines with that head and a dual plane intake the vortec head engines suffer from some lean holes. My race engine builder used to do a lot of em and when I was having a lot of vapor lock issues with my L31 and the same intake and carb you are running he suggested a change based on dyno results. We switched to a Super Victor intake and a Holley 670 street avenger carb. The intake is not huge and the runners are a perfect match for the heads. Vapor lock gone, better all round performance and the vapor lock issue is gone.
Jimmy

Re: Vortec Heads Suck...
 

I don't know where you are coming from but Vortecs work, they are not a too good to be true thing. There are many many thousands of them on the road right now running great. I have seen quite a few with 250,000 or more miles and still running good. Being light is a good thing as long as they work.

Re: Vortec Heads Suck...
 

120 Lbs compression seems pretty low to me even if they are even. Normal is at least 150 lbs.

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Exactly! I agree with what you're saying 100%.

IMO, if the outer cylinders are lean while the inner ones are rich, that is NOT a tuning issue you can adjust out of the carb. It's poor design characteristics of mismatched parts. I firmly believe that Vortec style intakes were designed to be used with port injection not TBI. That's why I asked the question regarding GM using TBI with Vortec manifolds.

Like you, I believe a weak plug or wire can cause oil buildup and eventually lead to a misfire. That's why I went thru the ignition system first.

Regarding the 120 psi readings. I thought that was low too. I don't know what my compression ratio is (Goodwrench engine with Vortecs)? I'm guessing somewhere around 9:1? However, I only pulled the plug on the cylinder I was testing. Had I pulled them all and cranked it over 4-5 revolutions, I suspect it would be up in the 150+ range. Since all three had the same reading, I'm not concerned with the numbers.

A leak at the intake manifold is plausible. I had not thought about that.

Re: Vortec Heads Suck...
 

I'm not a Holley fan at all, but switching to the 670 Street Avenger probably solved 95% of your vapor locking problem. Look at how the two carbs store fuel and you'll see why.


Your cold start issue is definitely in the tune, this is fact. All intakes carb'd or otherwise will have lean/rich spots. If you put individual O2 sensors on the headers of my Z28(LS swapped), you could see that even the LS6 intake will do that.

What is your max RPM? You could probably get by with a smaller carb, have better velocity for fuel distribution, and a crisper throttle response.

Not trying to split hairs with you on this one, but comparing a max effort circle track engine to a DD isn't even in the same ballpark. Single and dual plain intakes work better at different RPM ranges.

Re: Vortec Heads Suck...
 

I think the point on the heads was that yes they are cheap power ladders that they really arnt. Heads are cheap but the intakes are not. Add the costs and you have a decent factory head but you are now getting into the lower end costs of aftermarket. These will outflow the vortec and have a better deck surface. Vortec have raised ports on the intake and exhaust sides. I have tried to hook them to rams horn manifolds and that is a no go. There is not enough material to actually make the ports match even though they can be bolted on. Then you have the cam limitations. Valve spring swap helps this but still not great. After all that you end up with a thin deck, 170cc runner head, that doesn't accept alot of cams. Am I against them, no, but there are just better options out there.

Now if you are going to run them i say go with the autolite 606 plugs. I had the best luck with them and they are cheap. 605s are hard to find but a slightly colder plug. I too liked the victor over the performer intake for them. As mentioned there is no heat crossover so there is your cold weather issue for puddled fuel. Double check your exhaust manifolds/headers. I had about an 1/8 " lip on the manifold side. Nothing kills performance like the outgoing exhaust gasses hitting a wall of cast iron.

Re: Vortec Heads Suck...
 

Just sharing a quick observation. When a cylinder isn't firing the ring pack doesn't work properly and crank case oil comes up past them into the cylinder. Have seen this on the dyno.

Re: Vortec Heads Suck...
 

:ennyd:

Exactly!

Followed by a compression test to rule out damaged or broken rings. The oil scraping rings are there for a reason.
Thanks for the info.

Re: Vortec Heads Suck...
 

Yes the vortec motor came with TBI in mexico only.

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Lol. Go figure.

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Where is the PCV hose connected? The carb should have a dedicated port for it. If it is connected somewhere else it will screw the fuel distribution all up.

Re: Vortec Heads Suck...
 

The PCV is hooked up correctly.

This whole issue is about to become a moot point as soon as the big brown truck delivers my order.

After dealing with my Holley Sniper ( hurts just saying those words ) disaster, the carb was just to get me by until I could go back to my beloved Pro-flo system.

Although it ran decent with the carb, I was quickly reminded of what a headache they are.

No more starting issues everytime the weather changes, dieseling after shutdown, spark knock...

I ran the original Pro-flo for 15 years with absolutely zero issues.

The swap will rule out everything regarding the fouled plug issue except a bad umbrella seal which I can address while I got it all apart.

Re: Vortec Heads Suck...
 

Very cool, that should definitely make a difference.

I've read nothing but good things about the Edelbrock system. Fitech and the Holley Sniper have had very mixed results based on my research.

Re: Vortec Heads Suck...
 

Some one mentioned intake to head gasket,which I think is a good possibility.One thing I haven't seen mentioned is if the heads you bought have screw in studs & guide plates and the studs aren't sealed like head bolts would be,you can be sucking oil down the stud hole into the intake port.I built a 450 HP 383 for a friends jeep similar symptoms you describe.Only upon taking the heads off,did I noticed the oil trail from the stud holes down the runners.These were Edelbrock aluminum heads.The vortec heads may have blind holes anyway,so wouldn't be the problem.Just another thought.GOOD LUCK

Re: Vortec Heads Suck...
 

Well I feel like an idiot.

Not sure why I was using the Accell plugs other than they were the shorty version for header's.

Didn't realize the threaded side was about a 1/4 short. To add insult to injury, the porcelain side is less than an 1/8th inch shorter.

Go ahead, flame me. I'm an idiot.

Re: Vortec Heads Suck...
 

That doesn't explain why just one cylinder.An old trick to keep plugs from fouling on an oil burning engine was to install anti foulers.All they were was a short threaded extension to move the spark plug back out of the combustion chamber,which is basically what the short plugs were accomplishing for you.

Re: Vortec Heads Suck...
 

The Delco plug is also a 100% better spark plug. Delco has a much better QC process!

Re: Vortec Heads Suck...
 

Awesome that you found the problem. And respect for having the guts to share and help the rest of us.

Re: Vortec Heads Suck...
 

The mystery has been solved! A bit of a head scratcher, but it makes sense now.

I pulled the intake off last night in preparation for the efi swap. This is what I found.

My first thought was how the hell could I have put two gaskets on? Impossible. I only had one set and I'm not that stupid normally. After staring at it for awhile, it started to make sense.

The gaskets delaminated and shifted causing the intake ports to leak. The cylinders with the fouled plugs coincided with the intake runners having an oily film in them.

Pulled the valve covers and the valve stem seals are just fine.

This was likely caused by my failure to follow directions included with the Edelbrock intake gaskets. It says to apply Gaskacinch gasket sealer on the head side and a thin coat of rtv around the water jacket ports on the manifold side.

I did NOT use gasket sealer. However, I did not expect this to happen.

Re: Vortec Heads Suck...
 

NEVER USE THOSE GASKETS. There is a reason oem's are o-ring gaskets on steel. Its only matter of time until fiber gaskets fail. Stop using them.

Re: Vortec Heads Suck...
 

I have been using felpro 1255 gaskets for a few years now without any problem. When I install them though I use Gaskacench on the entire surface of the gasket. I glue the gasket to the head and then glue the intake to gaskets on the heads. I apply the glue to both surfaces let it set a couple minutes then stick them in place.
The only problem is trying to get the intake back off but I never had a leak.

Re: Vortec Heads Suck...
 

You would think a company as reputable as Edelbrock would know this...no?

Re: Vortec Heads Suck...
 

I too have blown an intake job by not following directions. I didn't have the proper torque wrench and gave it the "ol' seems pretty even and fairly tight" with a 9/16 box wrench and found my idea of fairly tight and even.... was not enough. So being cheap cost me more work, a new gasket and I still had to bu y the torque wrench.

Re: Vortec Heads Suck...
 

hay sunsoaked . did you notice any real change in the way the engine run with the comp roller tip rockers ?

Re: Vortec Heads Suck...
 

No I didn't. I kept with the stock 1.52 ratio. They are nice pieces. Roller tips reduce friction but I don't think they add any power over stock.

Re: Vortec Heads Suck...
 

You would think yes. This is a well known thing for people running vortecs. I've been using them since they came out in 96 on my stroker and I have my 98 that runs them oem. Hasn't really been brought up in the last 5yrs that I can think of though so perhaps they updated them? They updated the oem version 3 times....