Trying to Decide Value of my 1969 Z/28

[danachevroletfor1967]

After much work and effort I have been told by my mechanic that my '69 Z needs a complete engine rebuild. There is too much exhaust smoke, oil getting into the intake runners, and the engine cannot hold vacuum at idle, it dies. Distributor has been gone thru, new valve seals, carb work, and intake manifold resealed. No external vacuum leaks can be found. Car has 80,000 miles on original engine that nothing has ever been done to, as far as I know. I can't afford a complete engine rebuild so have decided to sell it. I've owned it for 19 years and maybe it is time to pass it on to someone else to enjoy. I know what I would ask if the engine was fine but have no idea about the value knowing the engine needs to be rebuilt.
Here are some details on the car:

Original engine and rear end, trans is not original.
All sheet metal is original as far as I know.
Car was repainted in original Fathom Green more than 20 years ago. Paint is still excellent.
I have original Protect-o-Plate and Chassis Broadcast copy and owner's manual, along with pictures of the car when it was only 2 months old from the original owner.
Original black and gold California license plates. Period correct, although not original to car, dealership license plate frames.
First aid kit from dealership.
Five correct date coded YH wheels and 5 reproduction E-70-15 Goodyear Wide Tread GT tires.
Interior is in great shape.
Everything works except clock, fan blower motor, low fuel indicator light, and headlight washers (it is a Rally Sport also).
I also have that would be included with the car:
new OEM style restoration radiator and mounting hardware, new Holley 4053 DZ carb, and new OER fan shroud and mounting hardware.

How much might my car be worth? I know it is hard to come up with a value without seeing the actual car, but I would appreciate any help you guys could give me. I am going to try to add some pics with this post if I can decipher how. Thanks again guys.

[Bill Pritchard]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: danachevroletfor1967</div><div class="ubbcode-body">There is too much exhaust smoke, oil getting into the intake runners</div></div>

Huh??? AFAIK, the only way oil can get into the intake runners is if there's a blown intake gasket or a cracked intake manifold. That could also cause a lack of vacuum and engine dying. I think I'd be seeking another opinion from a different mechanic.....don't give up on the old Z just yet. Beautiful car!

[scuncio]

Beautiful car. I know you've heard this already but you would really do yourself a disservice by selling such a nice car needing an engine rebuild. The typical high dollar collector won't want to deal with the engine rebuild so you're limiting your market pretty significantly. I'll say the car is worth $15k less on the open market needing the engine rebuild.

[scuncio]

And I agree with Bill, get a second opinion before you throw in the towel on the engine.

[GMC_Typhoon]

Just rebuild the engine?

[njsteve]

The problem you describe is exactly what just occurred with a friend of mine's 1970 Challenger R/T 440. It turned out that there was a crack in the intake manifold on the valley side that was invisible to anyone outside the engine. When the car warmed up, it ran like crap. After swapping carbs multiple times, he finally pulled the engine and that's when they discovered the crack on the underside of the intake. It caused a major internal vacuum leak that sucked the oil from inside the lifter valley into the lower runners of the intake.

Before letting go of the car I'd swap intakes out and see if that fixes it.

Otherwise my 14 year old and I would be happy to rebuild that engine. <<GRAEMLIN_URL>>/biggthumpup.gif

[danachevroletfor1967]

Thanks for your input guys. You've made me think twice about my first plans and think more about keeping her. I know I would probably feel bad and kick myself if I did sell her. I do have another question; it may sound stupid to more mechanically inclined guys than myself but I honestly don't know the answer. How do you know when or if your car needs an engine rebuild? Mine does not use any oil where I have to add any between changes. It doesn't produce blue exhaust, black or gray, yes, but no blue. It runs great and is not down on power that I can notice. It just wants to die every time I slow down to a stop. Are there different levels of engine rebuild, such as just needing new rings, or a new cam and lifters, and not always needing complete machine work such as reboring, decking, etc.? I read that the compression in a 302 should be 190 per cylinder. Mine has between 160-170 in each one. Good or bad? No problem or too low for such a high compression engine? Thanks again for your input.

[SuperNovaSS]

My diagnosis is you need a new mechanic. If the engine has an erratic vacuum signal you could have a vacuum leak somewhere. An intake valve being to tight will also cause this symptom since it will produce a vacuum leak to the intake which will cause 4 cylinder to be effected on a dual plane intake and all 8 on a single plane. Silly question, has the PCV valve been replaced? It sounds like you need to start with the basics like a compression or leakdown test. Also, finding the source of the oil getting into the intake may point you in the right direction.


I hope you can get it sorted out.

Jason

[Salvatore]

Try rebuilding the carb. Contact Eric Jackson on this Site for help.

[sixt9rsx33]

I agree find a new mechanic. My friend had a similar problem on his 67 Vette small block, and it ended up being that the intake manifold was not torqued down on the engine. I agree with Super Nova SS, start with the simple stuff and work from there.
Regarding your compression in each cylinder, I would think given your engine had 80K miles on it and all the cylinders are within 10 pounds of each other you are fine. But I am not an engine rebuilder.

[chevelleheart]

Don't sell ,.......beautiful car ,....needs minor medical help !! Let us know how it turns out!

[PeteLeathersac]

Jason's diagnosis is spot on and back to the basics also a good physical inspection necessary first!
It's such a cool car you'll no doubt kick you azz for setting free forever after...especially if taking the loss for it going away in an undiagnosed state.
If you need help but are willing to do some wrenching, please speak up as I expect the group here would love to help you go through a few basics and try to pin down what's happening yourself?
Whatever you do, it's a beautiful car and best of luck diagnosing the real problem!
<<GRAEMLIN_URL>>/beers.gif
~ Pete

[Charley Lillard]

What part of Ca. are you in ? Maybe someone can point you to a good mechanic. I doubt if you need the engine rebuilt. I would have the timing gears and chain replaced though. The gears are plastic and should be about done for.

[danachevroletfor1967]

Thanks for all your responses guys; I am overwhelmed. Just to give some info of what has already been done and is going to be done. I currently have the car at a local restoration shop; he specializes in Chevys, and I have seen some of his work. Timing has been set according to specs mentioned in CRG website. Vacuum advance can is correct for this engine. New sparkplugs. Tank was filled with 110 octane Sunoco leaded, with no ethanol, racing fuel to rule out ethanol problem. New Holley 4053 DZ carb installed. I probably will ship my old, possibly original, carb to Eric for rebuilding. Carb cleaner was used to check for vacuum leaks. Anything using vacuum, such as headlight door covers, were checked for leakage. None was found. When idling though and the lights were turned on the engine would die. Timing mark on harmonic balancer was spot on, but you could turn the crank by hand 10 degrees without any corresponding movement of the rotor. Timing chain and gears are going to be replaced as is water pump. Valve seals are also going to be replaced. That's all I can think of at this time. I'll keep you guys posted. Thanks again for all your comments. I am glad I decided to keep the car.

Charley, I live in Nevada City. It's about half way between Sacramento and Lake Tahoe.