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What is decked???

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Old May 30, 2017 | 02:17 PM
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Default What is decked???

I'm looking at a Craigslist posting for a 1968 Stingray.

In describing the engine he mentioned that it was "decked". What is that???

The seller states:
Full disclosure: In a prior rebuild sometime in its history, the engine was decked and the VIN on the build pad was lost. Before the current rebuild, I sanded the build pad and could see enough numbers to tell the engine was a 327/350HP High Performance engine (with manual trans/PS/AC) assembled the month before the car was assembled (logical), but could not see the last 5 digits matching the VIN. Additionally, the casting code on the block and the numbers on the header indicate it is a 1968 Corvette engine. Given all of this, I have high confidence it is the original engine, but hesitate claiming "numbers matching." Take this into consideration if you are looking for a future high-end show car. It might be possible to see the rest of the numbers by some other professional method, but I have not pursued it.

Does that make sense? Is this legit?
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Old May 30, 2017 | 02:22 PM
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The engine was machined at the area where the head bolts on
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Old May 30, 2017 | 02:23 PM
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Old May 30, 2017 | 02:24 PM
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It means the block to head sealing surface on the block has been milled down to make it flat. In that process metal is removed from the same surface that the block numbers exist on.

It's a legit practice. How much was removed is important to determine the CR of the engine if you're building it and it the piston will reside in the bore, level with the bore (zero decked) or slightly above the bore at TDC.

If he can see the imprint of the numbers, then it sounds like not much metal was removed.
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Old May 30, 2017 | 02:27 PM
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and it usually means they continued the machine process and removed your VIN block numbers.
Do not allow this to happen if you are rebuilding your engine and have a numbers matching car.

Last edited by 69Vett; May 30, 2017 at 02:28 PM.
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Old May 30, 2017 | 02:37 PM
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Sounds like a fairly honest seller to me disclosing this in the ad.
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Old May 30, 2017 | 03:58 PM
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Default Kudo's to the seller.

Kudo's to the seller for a likely honest presentation.

More importantly, even if the engine is likely original, still not worth a matching number premium price, IMHO.

So, if you like the Corvette, I would buy it, just pay fair market price for it as possibly NOM.

My 2 cents

Last edited by 20mercury; May 30, 2017 at 04:00 PM.
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Old May 30, 2017 | 04:04 PM
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Honest seller disclosing facts not fiction. I would approach this as a NOM car.
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Old May 30, 2017 | 04:08 PM
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there is disagreement on if one should have the block/head mating surface done at all.. it is an expensive machine and the machine shops want to recoup their investment. some shops may insist on using it or will not warrant their work.
there is a spec for what your deck surface and head surface can be out of flat before a resurface would be required.
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Old May 30, 2017 | 04:13 PM
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Hi ICD,
"What is that???"

Originally the block was 'decked' (broached) as part of the machining process at both the Flint (sb) and Tonawanda (bb) engine plants. (Those 2 plants supplied engines for Corvettes.)
This was done on a huge machine and left a particular surface on the top of the block that is known as 'broach marks'.
The marks in the top surfaces are in a straight line and parallel with the rows of cylinder bores.
Normal machine shops have a different way of decking engines as part of a rebuild which leaves very DIFFERENT marks compared to the original surfaces at Flint and Tonawanda.
There are now several rebuilders that have obtained these original broaching machines and are broaching blocks for restorers.
People have varying opinions about this.
Here's an example of original 'broach marks'. Notice the parallel straight lines.
Regards,
Alan

A bb stamp pad showing a typical broached surface and 2 typical pad stamps. One identifying the engine configuration and assembly date and the other indicating the car the engine was installed in.
Name:  47872746d1426900860-stamp-pad-picture-with-question-image.jpg
Views: 177
Size:  32.1 KB

Last edited by Alan 71; May 30, 2017 at 05:27 PM.
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Old May 30, 2017 | 07:57 PM
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Good Head-Gaskets can make up for Minor Surface Imperfections

Good Article by Felpro

http://www.felpro-only.com/blog/gask...urface-finish/

* " A good rule of thumb for flatness is that surface flatness, measured in thousands of an inch, should never exceed the number of cylinders on each bank across the length of the block."

* "For example, no block or cylinder head should exceed .003 out-of-flat if they are 3 cylinders, as there would be in an iline-3 of a V6 engine. Inline -4 and V8 applications should never exceed .004" out-of-flat and so on, across the Length ( front to back) on the surface. No block or head should exceed more than .002" out-of-flat across the Width (top to bottom) on the surface".

"Different surface finishes require different gaskets.

SO
The moral of all this IS :
not all head and blocks need to
DECKED or SURFACED


COPPER HEAD GASKETS
good article

http://scegaskets.com/wp_super_faq/g...r-head-gasket/

........................................ ...... tom



Attached Images  
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Old May 30, 2017 | 09:24 PM
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Here is what I wrote to the seller. Nothing back yet.

Hi, Dave here.

I'm interested in your Corvette. I live in the Indianapolis area. Within a few weeks I will be driving down to visit my family in Huntsville. I plan on mountain bike riding, so I’m waiting for when it hasn’t been raining for several days. When I do come down it would be easy swing by your way on my trip.

Until then can you get pictures of the under side of the car, showing the suspension components? Also the frame rails? How is the rust under there? Have you looked under the door sill plates to see if any rust is under there? How about at the top of the A-pillers, can you see pitting where the chrome is on the corners?

You say, "the engine was "decked" and the VIN on the build pad was lost". To be honest I had to look up what decked meant. Non matching numbers isn't a deal breaker necessarily but the price would need to reflect a “Non Original Motor”. Reading up on that kind of issue, it’s not uncommon but definitely unfortunate. I appreciate your forthright approach on calling out the issue!

I’m partial to a black car with a black interior. If I can get a solid car at a good price I could hopefully have enough in my budget to get a good, black paint job. Your car could be a good candidate! I sure have been looking all over. So far every one I’ve seen has rusted frame rails despite what they are advertising. I’m beginning to believe the don’t actually know how bad it’s gotten. My “inspection method” is pretty rigorous. I take a lot of pictures and crawl around under the cars from stem to stern. Truth be told, I’m having fun with my search. I don’t know a lot about these cars but I love learning.

Anyway, let me know if you have any other info to pass along, especially like more pictures and any other things you can tell me about the car. Putting it on a lift is probably a long shot, but it’s worth mentioning it. If you did and I didn’t buy the car, people love seeing images from under a lift. I know I take longer looks at pictures of cars up on a lift. It could pay off for you.

Cheers!
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Old May 30, 2017 | 11:22 PM
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death to a once original corvette
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Old May 31, 2017 | 07:10 AM
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Originally Posted by IndyCorvetteDave
...Nothing back yet...
FWIW: "Within a few weeks" this car could be gone.
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Old May 31, 2017 | 09:37 AM
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Here is the response I got from the seller. A lot of info!

Link to images: https://flic.kr/s/aHskXMKHcs

Dave,
Here are some pictures of the underside (not on a lift, but with my camera under the car) and the top of the A-pillars. On the underside, if I remember right, the owner before me tried to paint as much of the frame as possible without removing the body. I try to drive it weekly, so it is not perfect underneath.
You’re welcome to come by in a few weeks. Be sure to let me know a few days in advance, since I sometimes travel for work and do have some vacation planned this summer
For other issues... The car is 49 years-old and, like most classic cars, does have other minor mechanical issues and quirks, but nothing major. A big part of the reason I am selling is that lack of time to have fun with it and tinker with it to address them. I don't mind sharing these with you because you are a ways out and if I were I buying I would want to know everything. I have 16 years of history on this car. Some of these you would not find with a test drive or even with a mechanic inspection, but here they are (in addition to the major ones in the ad):

1) When the engine is completely heat-soaked (after running about 30 minutes or more, depending on outside temperatures), if you floor it and open the carb secondaries the engine will bog down or may rarely backfire. I haven't researched this in depth but think it is a carb or timing issue, not a major repair.
2) Also when heat-soaked, there is sometimes a clicking from the front that can be heard when coasting about 40 mph, but not when idling. Haven't figured this one out, but performance is not affected and it has done this for many years. Sometimes I think the fan is barely hitting the radiator shroud, but don't know.
3) The transmission has a very small fluid leak. Figure about one drop an hour. After driving about an hour it will drip onto the exhaust and you can smell the fluid burn for a bit, then won't smell it again--but I haven't driven more than two hours in a long time. After driving, it may leave a couple drops on the garage floor (maybe quarter-size spot).
4) The rear-view mirror is loose. It rests in a good place for me, but does occasionally need adjustment during a drive.
5) The driver-side power window is functional, but needs some help getting the window to the very top.
6) The fiber optics all work, but a couple are a little dim.
7) When not driven, the battery will run down in a few days. I have a quick-disconnect on the battery terminal. Always start with a fully-charged battery to avoid burning out the regulator (which I have done before).
8) The original radiator expansion bag is still in place, but not in use. Any coolant overflow goes to the ground, but after it reaches a certain level it stops and I never have to top it off.
9) I would be hesitant to drive it in a parade or stop-and-go traffic on a hot (90+) day because it may stall due to fuel vaporizing. This might be solved with an electric fan or aluminum radiator, but I like the engine looking stock so I never added either. You might consider something like that for a true daily driver in any weather.
10) I sometimes think I hear a small exhaust leak up near the manifold, but haven't tracked it down.
11) I believe the exhaust pipes hang a little lower than normal. If you hit a good dip too fast, they will scrape the road. Suspension could be a little soft and contribute to the issue, but it rides and handles well-enough.
Another note on the engine. It is bored 0.060" and stroked with a 350 crank. The builder lowered the compression slightly from original 11:1 spec so it would run better on pump gas. I always use non-ethanol premium. I do have the original 327 crank to give the new owner.
I’ll send a few more pictures in a different email.
I'm not sure what to make of this car!
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Old May 31, 2017 | 10:14 AM
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Originally Posted by IndyCorvetteDave
...I'm not sure what to make of this car!..
It isn't black.
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Old May 31, 2017 | 10:20 AM
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Originally Posted by Easy Mike
It isn't black.
That's what I was missing!!!

Seriously, though. I'm wondering if is a good candidate for a professional paint job.

I keep looking at this online: http://www.gatewayclassiccars.com/fo...ette-S414.html


It's black!
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Old May 31, 2017 | 10:46 AM
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Originally Posted by IndyCorvetteDave
...Seriously, though. I'm wondering if is a good candidate for a professional paint job...
Also seriously. Why buy a color you do not want and immediately pay out the butt for new paint?

...I keep looking at this online: http://www.gatewayclassiccars.com/fo...ette-S414.html...It's black!...
According to the trim tag, it's the real deal. Based on what you've posted, it's the color combination you want.

Last edited by Easy Mike; May 31, 2017 at 10:47 AM.
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Old May 31, 2017 | 01:57 PM
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Default Much Thanks Alan!

Quote from Alan:

There are now several rebuilders that have obtained these original broaching machines and are broaching blocks for restorers.
People have varying opinions about this.


Wow and this is good to know. Somebody must think there is a significant return on investment to buy an original broaching machine and set it up. Only seen photos but understand this machine was huge and as big as a railroad engine. Paying a premium for matching numbers will get more interesting.

I saw this one too:

https://nashville.craigslist.org/cto/6094319916.html

Pretty nice 68 Corvette, little too high, IMHO, maybe just wanted room to negotiate?

Worth a premium though if you get that cool front license plate with it!

Last edited by 20mercury; May 31, 2017 at 02:16 PM.
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Old May 31, 2017 | 02:02 PM
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Something like this would not be worth it for me. Sounds like it's going to be a work in progress, and lot's of it. If that's what you want, then buy it and good luck.
The bored out to 60 thousands would explain a bit of the overheating issues IMO. I had a 77 T/A bored out to 40 thousands, and it ran much hotter than before.
Depending on the issues, it could be costly, so you may want to look some more and get something that's already good to go.

Good luck with whatever you decide.

Last edited by 4SUMERZ; May 31, 2017 at 02:10 PM.
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