Main Menu
|
Nevada Classics
|
Advertise at CC
|
April 2024
|
S |
M |
T |
W |
T |
F |
S |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
25 |
26 |
27 |
28 |
29 |
30 |
|
|
|
|
|
CC Advertisers
|
|
01-17-2004, 02:54 PM
|
CC Member
|
|
|
Join Date: Jun 2003
Location: new bern,
nc
Cobra Make, Engine: ERA 2092
Posts: 225
|
|
Not Ranked
deck height ? on 427
Looking at a 427 s/o short block, the block was decked and now the pistons come .030 above the deck, i will be putting Edlebrock heads on this motor with 72cc , any help would be great Bob
|
-
Advertising
01-17-2004, 04:20 PM
|
|
CC Member
|
|
|
Join Date: Jun 2003
Location: Freedomia,,
Il
Cobra Make, Engine: Coupe,Blue w/white stripes SB; Roadster, Blue w/white stripes BB w/2-4s; SPF installer/Hot Rod-Custom Car builder
Posts: 1,376
|
|
Not Ranked
Something isn't right, you shouldn't have any piston above the deck, it sounds like a combination for some piston and head interference. The block has obviously been decked,but that seems extreme. If all checks out on disassembly, I would have the pistons cut. The factory clearance is .018,since it is older and you'd expect some machine work has been done,it would be a little tighter. I don't think you could find a gasket thick enough to negate that much protrusion above the deck. If you're looking at buying it, I might be a little leary, if you already own it you need to figure out why the slugs come up so high.
__________________
WDZ
|
01-17-2004, 05:21 PM
|
|
CC Member
|
|
|
Join Date: Oct 2002
Location: Fairfield,
CT
Cobra Make, Engine: HM-2027 / 427 SO
Posts: 815
|
|
Not Ranked
What crank and pistons are in it?
|
01-17-2004, 09:30 PM
|
CC Member
|
|
|
Join Date: Jul 2002
Location: Portland, OR area,
OR
Cobra Make, Engine: Contemporary CCX33868 Sold. Just "playin' the boards now."
Posts: 634
|
|
Not Ranked
Good question FFR
There are several combinations that will cause this as well as a deck height issue.
It boils down to wrist pin location for the different stroke/piston combinations. IF you can, get the number off a piston and check it with the manufacturer to see what it is supposed to fit.
A little unlikely but not impossible, is that someone had the crank ground with an offset to use smaller rod journals and or change the stroke and the pistons are not the problem at all. If you can, accurately, check the stroke with a dial indicator and/or a precision caliper (they have a depth rod). It should be 3.73" (less deck material removal and bearing clearance) from deck to piston top at bottom dead center.
Hope this helps.
Al
__________________
"If some is good, more is better.
And too much is just enough."
--Carroll Shelby
|
01-18-2004, 01:31 PM
|
CC Member
|
|
|
Join Date: May 2002
Location: San Francisco CA,
Posts: 525
|
|
Not Ranked
Something is out of whack...
You will need to determine the true deck height of the block.
The stock deck height of a 427 is 10.17"
If the crank, rods and pistons are correct then that means your block has been cut .040" to .050".
If you care to use a block cut that much custom pistons will be required.
You will alsohave tons of fun getting the intake manifold to fit and of course custom pushrods will be required.
I hope your block is not cut that much and you will just need new (correct) pistons
--Mike
__________________
They bend 'em, we mend 'em.
Last edited by SFfiredog; 01-18-2004 at 01:34 PM..
|
01-18-2004, 01:51 PM
|
|
CC Member
|
|
|
Join Date: Sep 2002
Location: Hickory,
NC
Cobra Make, Engine: ERA 427SC w/427so, ERA GT #2002
Posts: 1,106
|
|
Not Ranked
Deck clearance specs are 0.0005, 0.005 or 0.018 inch depending on the pistons used. Sounds like you'll have to flycut your pistons to achieve the needed deck clearance, or 0.0005 inch minimum. Also, check valve-to-piston clearance to make sure the valves and pistons don't collide.
__________________
Tom
"If you can make black marks on a straight from the time you turn out of a corner until the braking point of the next turn, then you have enough HORSEPOWER." Mark Donohue
|
01-18-2004, 05:10 PM
|
CC Member
|
|
|
Join Date: Apr 2001
Location: Abe Lincolns Birthplace,
Ky
Cobra Make, Engine: CSX4761, KCR Shelby Alloy 496,760hp
Posts: 867
|
|
Not Ranked
I have a friend who uses copper shim gaskets to get the desired deck height,,he says the seal is better too,either way,if the short block is a good buy,you can fix it,if not steer clear and wait for a better deal.
the true nascar blocks were milled .050. before they left ford,this was to get the compression up with changing rods/pistons Tim
__________________
Tk
"this whole Adult thing just isnt working for me "
|
01-19-2004, 06:53 PM
|
|
CC Member
|
|
|
Join Date: Dec 2003
Location: Chino Hills,
Ca
Cobra Make, Engine:
Posts: 112
|
|
Not Ranked
I t seems like the block may have been decked more than 1 time or decked a bit much. eather way deck height is the amount of clearance between the top of the piston @TDC & the deck of the cylinder head. This is usually .035- .040 with steel rods. This includes the head gasket. Example, piston @ .000 deck, gasket @ .039 thickness (Fel-Pro type), would give you a deck height of .039. In times past Ford would run the piston @-.018 down the hole with about a .022 thick shim type head gasket giving a total of .040, Simple!
Hope this helps, Mike
|
01-20-2004, 05:39 AM
|
|
CC Member
|
|
|
Join Date: Sep 2002
Location: Hickory,
NC
Cobra Make, Engine: ERA 427SC w/427so, ERA GT #2002
Posts: 1,106
|
|
Not Ranked
Mike: I believe what you describe is piston-to-cylinder head clearance. Actual deck height is the distance the top of the flat surface of the piston is from the top of the cylinder-block deck with the piston at top dead center. The minimum for this on a 427 is 0.0005 inch, but 0.018 inch will surely work. Whatever deck height is, you've got to ensure there will be no piston contact with the cylinder head.
Check out how to determine deck height by clicking on:
http://www.2strokeheads.com/Deck_Height.html
__________________
Tom
"If you can make black marks on a straight from the time you turn out of a corner until the braking point of the next turn, then you have enough HORSEPOWER." Mark Donohue
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -7. The time now is 07:31 PM.
|