DZ Block - Team Camaro Tech
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post #1 of 15 (permalink) Old Apr 21st, 15, 11:32 PM Thread Starter
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Ray
 
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DZ Block

I am restoring a 69 Z28 which has a CE stamped block. Assuming the original motor was blown and replaced with the counter engine. Long story short, last summer I finally got the car rolling out of the garage, but started to hear a knock in the motor. The knock was light and didn't seem to change when I pulled the plug wires one at a time. The knock seem to be in time with the cam, but doesn't sound like a top end issue.
I started to tear into the engine and pulling cam next.
I am probably looking at pulling the engine if I don't find something obvious soon.
The crank, rods and pistons are the correct components for a Z28. Trying to decide on building up another motor or locating a DZ block since my current block has the correct components.

Thanks for reading.

I am located in N.E Ohio.
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post #2 of 15 (permalink) Old Apr 22nd, 15, 05:16 AM
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Brian
 
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Re: DZ Block

Since you already got the have the CE block, I'd rebuild it if you don't find the problem. A CE block would be closer to numbers matching than a DZ block from someone elses car.

Experience...... It's what you get when you didn't get what you wanted.
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post #3 of 15 (permalink) Old Apr 22nd, 15, 06:50 AM
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MIKE
 
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Re: DZ Block

Have you adjusted the rockers arms first before taking everything apart, if that did not change anything I would take all the internal parts to a reputable machine shop to check all the parts for correct tolerance.
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post #4 of 15 (permalink) Old Apr 22nd, 15, 10:49 AM Thread Starter
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Ray
 
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Re: DZ Block

Brian and Mike,

I pretty much performed the usual diagnostics in trying to isolate the origin of the noise. I have 20 lbs of oil pressure at idle. The noise is a light knock and when I hook up my timing light the noise is in sync with flash of light. So this pointed me to the top end. As mentioned taking the load off each cylinder by pulling each wire one at a time didn't make much of a change. I have so far pulled the manifold, and lifters. Lifter wear looks OK and lifters came out of their bores easily. Here again I figured if a cam wear issue I would see some evidence of this on the lifter face. The noise did not change when I did a hot lash adjustment. Next I will check for unusual cam walk before pulling the cam to inspect the lobes. One other note. The engine when running was smooth with vacuum around 18 and steady. Dry compression average at 209. Wet 211 to 215.
__________________________________________________ ____________

OK, I purchased the Z after it sat in a garage for 20 years. I have had it 12 years. I have slowly gone through the car starting with the suspension. The engine was not my focus since it was said to have had few miles on it since a rebuild. I should have dug into the motor when the rest of the drive train was out. OH well.
The CE stamped engine is a 010 four bolt and verfied correct crank, rods and pistons years ago when the motor was down to the short block. I did not pull crank or pistons at that time. I just replaced the pan and oil pump.
I will keep pulling the engine apart and maybe I will stumble on something. If not, out she comes. The only reason I mentioned finding a DZ block is since it seems to be the first thing most focus on when looking under the hood. Bottom line, I do not have the numbers matching engine and the cost of a DZ motor is out of the budget for this guy.
Happy to have a Z whatever pushes it down the road. Not getting any younger. I grew up in the sixties dreaming of a Z28. Remember the DZ motors at the local swap meets complete for a under a grand. Yea! I am getting old. 472 manifolds for $50. Where is that time machine :=)
__________________________________________________ ___
Thanks for the reply guys. Typically, post and get no responses.

Ray Mentor, Ohio 440-953-9425
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post #5 of 15 (permalink) Old Apr 22nd, 15, 01:18 PM
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Gary
 
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Re: DZ Block

As someone said earlier, a CE (warranty replacement) block with all correct Z28 components is preferable (more likely to be correct) than a DZ stamped block which came from another car (or which may be a restamp). Address the noise problem with your engine, make sure it's good.. and leave it alone stamp wise. Unless you have information stating otherwise, I'd assume that the original shortblock was damaged during the warranty period and was replacement under warranty with that CE shortblock (by Chevrolet).
PS. check the oil pump push rod as a potential source for the noise...

Gary
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post #6 of 15 (permalink) Old Apr 22nd, 15, 03:24 PM
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Tim
 
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Re: DZ Block

Good time to pull it apart and check for wear, 20 lbs at idle is low. IIRC, the low oil pressure warning light is triggered at around 15lbs.

1969 04A Van Nuys-built Z/28. Cortez Silver with dark blue interior and VE3. Sold Clippinger Chevrolet. Raced at Lions in LA.
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post #7 of 15 (permalink) Old Apr 22nd, 15, 09:03 PM
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Re: DZ Block

I just had to pull part our 69 L48 over the winter due to a similar condition. I found the original cam gear has plastic around it. The plastic had deteriorated and began to come apart. That was my noise. It sounded like it was coming from the fuel pump area and was best heard with a stethoscope at the fuel pump but it was the cam gear. So if yours is nylon and breaking apart that may very well be it.

1969 Camaro SS 350 LeMans Blue
2015 Z/28 - Red
2 x 1967 R/Tís
1977 Power Wagon
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post #8 of 15 (permalink) Old Apr 22nd, 15, 09:20 PM Thread Starter
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Ray
 
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Re: DZ Block

Gary,

Thanks for the reply and I have pretty much decided that if need be I will rebuild the CE motor. I did use a stethoscope when trying to pin point the source of knock and when holding end of scope right up against the distributor housing I did not hear the knock. So, I ruled out the pump drive shaft.

All good advice and I sure appreciate.

THANKS,
Ray
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post #9 of 15 (permalink) Old Apr 22nd, 15, 09:29 PM
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Garth
 
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Re: DZ Block

On mine the noise was not even exsistant at the rear of the engine.

The pump we're referring to is the fuel pump and its push rod that runs off of the front of the cam.

In my case the noise was loudest with the stethoscope at the fuel pump due to that being the shortest route that was solid.

If the noise sounded the same from either side of the car and at the front then the cam gear is suspect. If it does not have the nylon then it's probably not cam gear or timing chain.

1969 Camaro SS 350 LeMans Blue
2015 Z/28 - Red
2 x 1967 R/Tís
1977 Power Wagon
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post #10 of 15 (permalink) Old Apr 22nd, 15, 11:17 PM
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Re: DZ Block

Sorry Garth.. I had a typo (brain fart) when I typed 'oil pump'... I meant to say .. the fuel pump push rod, driven off the front of the cam, but after reading the subsequent post re the cam gear, I have to say that is also a possibility also, perhaps a better one.

Gary
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post #11 of 15 (permalink) Old Apr 23rd, 15, 11:29 AM
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Re: DZ Block

Quote:
Originally Posted by buenymayor View Post
Since you already got the have the CE block, I'd rebuild it if you don't find the problem. A CE block would be closer to numbers matching than a DZ block from someone elses car.
Especially if the block is very close to the vehicle manufacture date. I lost my orginal dz not long after I purchased new, maybe year older or so. . GM replaced with F-290 block if my memory is correct and still with me. So block is about a year older than my car which was a 12A car, early 69. Block is still in the car.
Amazing I can remember that.

Don
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Zdld17:69 Z/RS,306, NOR141111, 9N554XXX, 12A, X3G, 59/59,723, AFR 195,CCC282/290HR, TKO 600, BU1122B1E Owner since Dec 1968

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post #12 of 15 (permalink) Old Apr 26th, 15, 05:33 PM Thread Starter
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Ray
 
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Re: DZ Block

Thanks all for the helpful advice. I will continue to disassemble the engine and examine all parts carefully. Hoping to find an obvious source of the noise. I am really thinking the noise could be from a piston wrist pin. Hope not, but no real wear found as of yet. Pulling heads next.
I will need to locate a good machine shop in Northeast Ohio if it gets down to needing the current CE engine rebuilt. I plan to do the actual rebuild, but many years since I used a machine shop for block and crank work. Suggestions on a good shop is welcomed.
Thanks again.
Ray
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post #13 of 15 (permalink) Old Apr 26th, 15, 05:38 PM Thread Starter
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Ray
 
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Re: DZ Block

Wanted to also mention my Z is a Van Nuys build. A Norwood build would have been great and then I would have the X codes on the trim tag. Garnet Red, M20,BE axle.
Rolled out of garage last year and then heard the light knock. Years to get it together and now it comes back apart. Time for this old fart to get busy I guess. Thanks for the help guys.

Ray
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post #14 of 15 (permalink) Old Apr 27th, 15, 03:09 AM
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Tim
 
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Re: DZ Block

Quote:
Originally Posted by Raysdz View Post
BE axle
Ray can you please post a picture of the axle stamp?

1969 04A Van Nuys-built Z/28. Cortez Silver with dark blue interior and VE3. Sold Clippinger Chevrolet. Raced at Lions in LA.
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post #15 of 15 (permalink) Old Apr 27th, 15, 07:31 AM Thread Starter
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Ray
 
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Re: DZ Block

BE 0620G1 (June 20 )

02B Vehicle Production date (Feb)
H198
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