4.250 + .030 = 4.280

 

.030" Over 454 Stuff

I have this REMANF. 454, 4 bolt from AC DELCO
.030" over mains, .030" over rods, .030" over bore
with .030" STAMPED in the top of the pistons w/2
relief valve notchs. Can anyone tell me the default
deck height?
I am using the "RSR Static Compression" calculation
off their website to come up with my final CR on these
101cc heads that are milled .032" which makes is 97cc
if the .008" per cc is applied. Does having the valves in
make less CC's? When Chevrolet makes these old heads
063's and cast the numbers in and then rate them for the
cc's do they calc whole chamber less valves or do they calc
with valves because if I think about it...valves IN make the
chamber smaller
Thank you

 

With the valves in normaly... Compression will be about 9.1 to 1 (rough figure)


Good place for info on pistons

 

.030" over 454 again

Thanks Bumpstick
Think I have talked to you before. I have the
65 Malibu Project.
Using the same website for CR...I came up with
9.52..
Makes a difference if I use a typical width head
gasket of .040" or the 1970 LS6 454 steel shim
gasket at .022"
Help..?
and thanks

 

Hey... Think I remember you as well... Just my opinion but for a non-nitrous street mild strip engine the Felpro blues which should be in the .040 range are the best bang for the buck...

 

CR calc Close, 97cc Flattops

Hey Bumpstick and anyone..!!

bumpstick yousaid roughly 9.1:1
I came up with 9.47:1
using 4.28 bore
4.0 stroke
.040 gasket thickness
0 deck height
4.9cc for valve reliefs
97cc chambers = 9.47:1 CR
If I am wrong please correct me..because
I need to be running on pump gas 92oct or so.
Plus hoping that taking .032" mill off 101cc chambers = 97cc
I do not have the money for all the fancy equipment to get
exact...if I had the money i would just buy this set of 1969 aluminum
corvette heads rectangular ports this guy has.
Thanks for the info and more if you can...

 

Those rectangle port aluminum heads would more than likely hurt your performance rather than help it. Aluminum is cool and might help prevent detonation a bit but the big intake runners wouldn't do you any good until you got into the 5500rpm and above range.

 

the cam you what to run is fairly big so it should handle 9.5:1 easily. Are you sure about a zero deck height???

this is the specs on the cam from your other post: 287/305 with 107 lsa.

A tight 107 lsa increases cylinder pressure but the intake should still close very late. 71 degrees according to my calculations, with the intake lobe center installed at 107. The compcam spec sheet on that cam doesn't add up (weird numbers).

Do a dynamic compression calculation using an intake closing point if 71 degrees

 

CR, cam & .032 mill off Closed heads

Thank you Double V23 & 454C10...

C10 you lost me on the calc's you want me to do....no clue.
The cam # I gave you was for those new CompCam "Thumper"
Yes it is a little strange on the #'s duration of 287 intake and
304 exhaust, 0.51 lift/0.495 lift, 107 lobe sep. Should sound pretty
beefy. BUT..! I do not know enough about the mathmatics/specs
on cams to know if they are right/wrong, benificial/bad..?? Apparently
these new cams are designed to bring back that old Muscle Car sound??
and give good performance. Grind # is "CB287T H-107 T".
454C10....no I am not sure of the 0 deck height. The piston are stock
looking .030" stamped in the top with 2 valve reliefs and a small chamfer
around the edge of the piston (small) and it looks as though the piston comes
up flush with the block deck @ TDC. On my compression calc I input
0 deck height.
Thank you guys for advice, knowledge and more answers to come I hope.

 

OK, I know you can afford a feeler gauge and a steel 12" rule. Lay the rule across the bore and insert a 0.001 blade between the rule and the piston crown at the edge of the bore. If that goes, try a 0.002" blade, then a 0.003" and so forth until you use a blade that gives you a slight drag between the rule and the piston crown. Do this routine a couple of times after bumping the crank forward and backward to change the piston position in the cylinder. It's hard to tell when you're at TDC by just using your eyeball. With the feeler gauge, it's ok to stack two or more blades together to arrive at a thickness you can't get with just one blade.

Setting the squish with the proper gasket thickness is going to be way more important for running on pump gas than worrying about a few tenths of a point of static c.r.

And by the way, in my opinion, the motor's gonna be a pig anyway with that cam. It's gonna bleed off too much compression for the anticipated static c.r.

 

CR & Milling BBC Heads

Thank you "Techinspector1"
So by doing what you suggested will give me my "deck height"?
I'll do that tonight.
I am going to use the blue felpro head gaskets .040" thick is
what they are +/-
OR
the 1970 LS6 454/450hp .022" steel shim gaskets
Still deciding, I was suprised to see how much of a difference it
made in the CR though.
Thank you

 

use this website to calculate dcr.

it is a pontiac site but just put your chevy numbers.

use 71 degrees for the intake closing point

 

Pontiac CR Site

Hey 454c10
There was not site on the reply you posted.

 

http://www.projectpontiac.com/ppsite/content/view/16/30/

sorry about that. work is distracting me a little.

 

Static/Dynamic CR -milled heads

Hey 454C10
I tried out the Pontiac CR calc site. I entered the following:
Bore = 4.28 .030" over
Stroke = 4.0
.040 = Gasket Thickness roughly Felpro Blue ?
97cc = Head cc that is .032" of alleged 101cc from GM Stock heads
.005 = Deck Height ? unsure right now 030" piston stock w/2 reliefs.
4.9cc = valve reliefs
6.135" = Rod length
71deg = Intake valve angle
COMES UP WITH 9.38 Static/7.18 Dynamic
W/0.22" gasket COMES UP WITH 9.7 Static/7.42 Dynamic

WHAT IS DYNAMIC CR ?? and does this look right?
I need to be more accurate on deck height and gasket thickness
I think. It makes a difference from the looks of it. I just do not know right
now unless I do what you guys suggested and put straight edge across hole
at TDC and start in with my feeler guage till it starts to drag. There has to be
a default number that is safe???? Pontiac uses .023" as default
Help amnd thank you for your help

 

There is no default number that would mean anything because rebuilders most often use an inexpensive cast piston which has a shorter compression height than the stock piston did. Compression height = the distance from the centerline of the wrist pin to the crown of the piston. Plus, you have no idea how much the rebuilder cut from the block decks to square them or if he did any cutting at all.

It looks to me like you are trying to "wish" your way into this build and it just ain't gonna happen until you get up off your duff and do some measuring. By the way, stand the rule on its EDGE across the edge of the bore to check piston deck height. I forgot to mention to use the edge of the rule, not lay it flat.

Your dynamic compression ratio figures prove what I said earlier. The motor is gonna be a pig. Too much cam. I think you're more worried about rump-rump to wow the zombies down at the drive-in than you are about screwing together a good combination. Again, just my opinion. Now, don't get me wrong, there's nothing wrong with a rump-rump cam, but you must build the motor with sufficient static compression ratio to support the cam if the motor is expected to pull the hat off your head. You don't have anywhere near enough s.c.r. to support that cam. If you bolt together what you have outlined and take it to the drive-in, for God's sake lie to the old guys there and tell them the motor has 10.5:1 compression ratio. That way, they won't laugh at you.

A pump gas motor should have around 8:1 dynamic c.r. With good gas, the proper cam, a good tight squish and everything in the combustion chamber de-burred and polished, you could probably get away with 8.5:1 dynamic c.r. Keep playing with the d.c.r. calculator, dropping the intake valve closing point 2 degrees at a time until you get into the 8:1 or better area. Then look up the phone number of your favorite cam grinder and call them up. Give them all your information about the motor and tell them you want a rump-rump cam.

It doesn't cost anything to talk to the cam grinder tech guy and you'll have the benefit of the entire library of knowledge that these guys have collected over the years.

 

here is website describing dcr.

http://cochise.uia.net/pkelley2/DynamicCR.html

both my bbc's have 0.015" deck height. put you never know until you measured that.

yes, your cam seems a bit big. to get the lopey idle stay with 107 LSA but drop the intake and exhaust duration by 10 to 15 degrees.

BBC's are a bit detonation prone due the the large amount of ignition timing needed for max power. Wide pistons and slow burn heads need lots of timing. Staying in the 7.75 dcr range is most likely a safer bet.

 

There is a guy in Wisconsin by the name of Big Block shawn that will tell you that you don't need a lot of compression to make power in a BBC.

My 496 is proof, 284/296 dur .660/.660 lift 9:1 compression, 550hp and almost 700 ft/lbs of torque.

There are videos of it running and idling in my gallery. You want to talk about rumpity rump check those out.

I got the Cam from Bullet racing/Ultradyne cams, and I couldn't be happier. It runs great around town but when you stand on it, it is like flipping a switch. There is nothing like Big Block Power but you have to get it just right or like stated above it will be a pig.

 

CR, Flat top & Cam Inquiry

Thank you "454C10", "Double_v23" & "Techinspector1"
I measured deck height last night and came up with .040"+-
I do want the beefy cam sound, but that is not really my goal.
When you build right with good combo's that just automatically
happens. I ended up with the CompCam #11-601-4 after talking to
CompCam tech..telling him what I had. I told him I wanted alot of low
end out of the hole in your seat torque and rough idle is possible, but
wanted it to perform as good as it sounded and was more in desire of
torque than sound. "F-BIRD'88" suggested that Isky #396245, z45 grind
solid lifter cam and I was almost there and didn't really think the solid would
be as maintenence free and drivable a lot as the hyd. cam.
I just wanted to use these milled 101cc heads with .032" off them creating roughly 97cc to increase CR without going through the whole thing with a small dome piston etc....if I had the money that is what I would be doing, but I do not. I am kind of hearing..I should just use my BBC 049 heads to get rid of V/P clearance issues and just go with a suggest cam by one of you guys
with the flat top pistons and just be happy with that. I have had a lot of BBC
most resently in my 67 GMC 4x first a 396 10.5:1 close chambers w/292, bent a valve and found a 454 to throw in while fixing the 396 and that stock 454 w/049 heads had tons more torque that my built 396.
Anyway I appreciate your help cuz apparently I do not know everything.
So should I just save my 063 heads that are done and go with the 049 heads
with say...just a RV cam???
Thanks

 

never seen a 0.040" deck height! are you sure?

 

Deck HT, Flat-top, 2 reliefs

454C10
Hey again
I set a square edge along the block deck (on edge)
and started out with .005" and there was tons more
room. I increased slowly till .040" was squeeking under
the edge and top of piston. This sounds like a lot from
what I understand. I rocked the piston back-forth to assure
TDC with a 3/4" socket on the balancer bolt.

 

If you have a dished piston you are going to want to check it at the edge of the piston (raised edge closest to the deck). Then you have to calculate the volume of the dish. Unless you have a bent rod or somebody put the wrong piston in when they rebuilt it. But the .040 is really going to hurt you,

 

Deck Height - CR

Double v23
I measured with feeler guage in the center of piston. I am pretty
sure rods are straight. When I bought the engine I ran it and pulled it same
day...had a miss and I put my stethascope(sp) all over the top of both
valve cover and #2 was loud. Got home on stand popped oil pan, popped a couple caps (4 bolt) crank is clean smooth, bearing are through first layer
and just into the brass color. Pull heads the other day to get ready for these
mill 063's and as I thought #2 had an issue. It had those lousy emisson heads
on it with the tooth pick size pushrods and one a the pushrods was broken. I looked at the top of the piston and she looks unscaved, not a scratch. Top of that piston
was darker than the rest so it had been broken for a while and run with a dead cyl. Everything is very tight and clean though, can still see cross hatch
pattern on the cyl walls. The deck measurment ws done on #1. As I said I
ran it before I pulled it and the oil preasure was up at almost 50lbs and beside
that #2 miss she ran pretty beefy.

 

So THere is no dish whatsoever in the piston? Just flat all the way across with no raised edge on the outside diameter of the piston?

 

Deck HT vs Dish/no dish

Double v23
That is a fact. No noticable dish..she looks totally flat except
for 2 valve reliefs. I can try another straight end tonight. the one
I used was my carpentry big L shaped one. The engine as I have
said before remanf. According to the metal tag still on side of block
which reads "AC DELCO" REMANUF for GM made in USA .030" over
bore, .030" over mains, .030" over rods.
The top of pistons has .030" stamped into everyone one of them.Around
the end of the pistons is a chamfered edge (45 deg) about 3/32" wide
from outside edge of piston where she meets the cyl wall.

I can't say enough to all you guys who are helping me out with project
and engine issues.
Thank you...!!