ZZ427 issues - Team Camaro Tech
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post #1 of 7 (permalink) Old Mar 27th, 15, 12:32 PM Thread Starter
Brian
 
Join Date: Nov 2007
Location: charlotte
Posts: 4
ZZ427 issues

Guys - need some help. I've got a zz427 in my 67 Camaro mated to a tremec tko 5-speed. I've got 3000 miles on it and bought it with 800 miles. Can't get it to run consistently and need some guidance from some of the pros on here please. When I get to 160 or so, oil pressure drops to around 18-20 psi. Compression tests fine but spark plugs show burnt oil. I'm in Reading, PA and hoping to have Molly back on road for late spring / summer so, any help appreciated. Thanks in advance! Brian
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post #2 of 7 (permalink) Old Mar 27th, 15, 01:14 PM
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Matt
 
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Re: ZZ427 issues

Is that 18-20 PSI at idle? If it is then your oil pressure is fine. The safe rule of thumb is 10 lbs. of pressure for every 1000 RPM (4000 RPM 40psi., 5000 RPM 50psi., etc.) Always check the easy stuff first. Are you running a PCV valve? Do you have baffles in your valve covers to prevent oil from getting sucked into the engine? I would check those things first.On an engine with 3000 miles on it, I would then re-torque your intake manifold bolts in the proper sequence and see if that takes care of it. All engines use some oil, but it shouldn't be noticeable on the spark plugs. Then there is the million dollar question, Why did the previous owner sell the engine with only 800 miles on it? Maybe oil consumption was the issue? Maybe not. G.M. crate engines have not had the best reputation over the years for oil usage and oil consumption has been a problem, especially with the big blocks for some time. I don't know if the issue's have been resolved or not. The fact that your compression checks out is a good sign that your rings are doing their job. With only 3000 mile on the clock, I can't imagine that your engine has that much wear to cause a major oil consumption problem. Let us know if you find anything.

1969 SS Garnet Red X55 350 Factory 4 speed
12 Bolt 3.55 Posi
461 BBC TKO600
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post #3 of 7 (permalink) Old Apr 1st, 15, 11:29 AM Thread Starter
Brian
 
Join Date: Nov 2007
Location: charlotte
Posts: 4
Re: ZZ427 issues

Matt:

Thank you very much for your thoughts and insight. Given the various gremlins I am encountering with the engine, I have decided to pull it, and have it redone. I applaud the guy I bought it from as he has agreed to pay the parts.

So, if I may, I would appreciate thoughts on carb versus FI. It originally came with an 870m Holley and I put on a FAST fuel injection systems.

Any thoughts appreciated! Brian
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post #4 of 7 (permalink) Old Apr 1st, 15, 12:38 PM
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Matt
 
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Re: ZZ427 issues

Brian, MY choice would be a carburetor. I like the old school look on a big block, plus the carb. will be about a quarter of the cost of fuel injection along with the appropriate pressure pump and regulator. For the price though, you WILL get better drivability, throttle response, and fuel economy with fuel injection. You must decide what will be best for you, your budget, and your driving style. There isn't anything wrong with either choice. Let us know if you find anything out of the ordinary in your ZZ427. I am curious what the problem might be.

1969 SS Garnet Red X55 350 Factory 4 speed
12 Bolt 3.55 Posi
461 BBC TKO600
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post #5 of 7 (permalink) Old Apr 9th, 15, 07:18 AM
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Art
 
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Re: ZZ427 issues

Before you go all out and pull it, check your intake manifold sealing surfaces. I've encountered quite a few issues in the last few years with bad intake sealing causing "unintentional PCV" when engine vacuum draws oil from the valley area under the intake. Vortec headed small blocks are particularly prone to this, but I've dealt with a couple crate engines that experienced it as well. If you pull the PCV from the valve cover and feel a vacuum at the hole you removed the PCV from (with the engine running, of course), there is a very high likelihood this is what's going on. A vacuum leak at the intake can also wreak havoc with the fuel injection you have installed, particularly if the ECU learns the vacuum leak during idle and cruise. The adaptives in the fuel map cannot properly fuel the engine at higher load conditions when this occurs. What's your MAP reading at idle when connected to the FAST ECU?

Artie

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post #6 of 7 (permalink) Old Apr 9th, 15, 01:22 PM
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Dave
 
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Re: ZZ427 issues

Also want to point out that the ZZ series of big block motors all have LOW tension rings to reduce friction and free up horsepower. People expect more from a big block than it can deliver with pump gas due to the poorly designed 1962 technology heads.
The open chamber design helped (1968 technology but in order to obtain the 12.5:1 static compression (Sunoco 260 back then, race gas now) it utilized a huge hemispherical dome. Todays engines use small heart shaped chambers with flat top pistons which the 121 cc open chamber BBC head doesn't have. As a result the engineers at Chevy tried every trick in the book to free up parasitic drag, installing oil control baffles, and even reducing the chamber volume slightly to attempt to get one horse per cube to simulate a high horse motor. Of course a 406 SBC will blow it away but it doesn't have the same charisma.

I overcome the deficiency of low performance big block heads by building a BBC of around 600 or more cubes and then putting a 396 or 427 decal on it (usually I claim it is only a smog era 402 if I think I can get away with it) to get that desired torque that a SBC can not match. They all look alike on the outside if you build a standard deck height block.

Big Dave
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post #7 of 7 (permalink) Old Apr 9th, 15, 01:47 PM
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Don
 
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Location: Houston, Texas
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Re: ZZ427 issues

Quote:
Originally Posted by Larger Dave View Post
Also want to point out that the ZZ series of big block motors all have LOW tension rings to reduce friction and free up horsepower. People expect more from a big block than it can deliver with pump gas due to the poorly designed 1962 technology heads.
The open chamber design helped (1968 technology but in order to obtain the 12.5:1 static compression (Sunoco 260 back then, race gas now) it utilized a huge hemispherical dome. Todays engines use small heart shaped chambers with flat top pistons which the 121 cc open chamber BBC head doesn't have. As a result the engineers at Chevy tried every trick in the book to free up parasitic drag, installing oil control baffles, and even reducing the chamber volume slightly to attempt to get one horse per cube to simulate a high horse motor. Of course a 406 SBC will blow it away but it doesn't have the same charisma.

I overcome the deficiency of low performance big block heads by building a BBC of around 600 or more cubes and then putting a 396 or 427 decal on it (usually I claim it is only a smog era 402 if I think I can get away with it) to get that desired torque that a SBC can not match. They all look alike on the outside if you build a standard deck height block.

Big Dave
I was going to mention that myself, but I've been posting about oil control issues for some time now on the ZZ big blocks, and didn't want to bash the OP's motor choice.

But now that it has come up again, I would never buy another ZZ BB oil burner again.

And about those low tension rings, at the time I had my problems (with 2 ZZ 502 motors) there were no aftermarket alternatives available for them. They are also narrower than any other oil rings I've ever used..

I didn't want to have buy conventional pistons and rings , so I had to pay $50.00 per ring set for EACH piston.

Also the cylinder bores looked terrible, and needed a hone using a torque plate.

The heads too needed to be gone through and a decent valve job done on them.

This was on a ZZ 502 that had less than 1000 miles on it! I had to do something, it used a startling amount of oil. I'm talking over a quart in a couple of hundred miles. The whole engine got a complete overhaul.

The reason I had to pay myself instead of warranty was because it sat in the crate for a year and was out of warranty on time.

On a positive note they make great torque and are fast when they do run.

Don ~ TC Member #15 ~
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