Cam suggestion? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 12-19-2010, 04:58 PM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Cam suggestion?

i am building a 383 sbc and looking for a good cam that will get me to 500hp of as close as possible. I've been very cost savvy and I got 1400 invested in parts that include,

1. 350 4bolt main std deck, align hone, bore and hone 30 over
2. balance Eagle 383 assembly
3. Dart iron eagle heads 64cc 2.08/160 215cc intake(former circle track heads) the springs are good for .570 lift
4. roller rockers and pushrods
__________________________________________________ _______________previously owned parts

5. Weind stealth aluminum intake
6. Holley 750 vacuum secondaries
7. Accel hi-energy performance distributor

I would like to make use of the parts I already had to keep cost low.
Now that is all out I have a four part question.

1. What would be a good cam for this set up.
2. will the head, stroker assembly work with the carb intake combo
3. What compression ratio am I looking at Ive done some calculations and
I came up with 10.427 to 1
4. what head gasket thickness can I use to bring the compression ratio to
10 to 1 or is it possible at all,
thanks in advance for any input

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-19-2010, 05:20 PM
done learning, done living
 
Last photo:
Join Date: Feb 2009
Location: Middle of the Mitten
Age: 29
Posts: 1,626
Wiki Edits: 0

Thanks: 140
Thanked 86 Times in 77 Posts
10.5 is pretty high for iron heads. What is the deck height of your pistons? You don't want to put a .051 gasket to lower compression on a stock height block your quench will be like .080" when the idea number is .041" to reduce detonation. Give us some more information about the rotating assembly. Pistons and deck height.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-19-2010, 05:37 PM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by crussell85
10.5 is pretty high for iron heads. What is the deck height of your pistons? You don't want to put a .051 gasket to lower compression on a stock height block your quench will be like .080" when the idea number is .041" to reduce detonation. Give us some more information about the rotating assembly. Pistons and deck height.
I was afraid i was going to have some issues with the head/assembly combo
deck is 9.025 and the piston are speedpro flat -5cc hypereuctectic.
the heads(2) were only 500 bucks assembled and you can get a bare casting for around 450 new so it was a heck of a deal. i dont wan to buy the cheap procomps cause ive heard more bad than good
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-19-2010, 06:04 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,599
Wiki Edits: 326

Thanks: 701
Thanked 890 Times in 757 Posts
Your static compression ratio is over 11:1. You screwed up by using a flat-top piston with 64cc heads. Change the pistons or change the heads. Your choice. 18cc D-cups will put you at 9.7:1, a very reasonable ratio with iron heads and the proper cam to work with that SCR. (212 to 222 intake duration).
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-19-2010, 06:27 PM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by techinspector1
Your static compression ratio is over 11:1. You screwed up by using a flat-top piston with 64cc heads. Change the pistons or change the heads. Your choice. 18cc D-cups will put you at 9.7:1, a very reasonable ratio with iron heads and the proper cam to work with that SCR. (212 to 222 intake duration).
how did you come up with over 11 to 1, I looked in the book from eagle and is advertise as 10.7 with 64cc heads I might wrote down the wrong info..With that info is their any way I can bring the compression ration down to use 92-93 octane or are the iron heads the issue and if that is the case

ANYBODY LOOKING FOR A SET OF DART HEADS!!!!!!!!!!!!!!!!!!!!
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-19-2010, 08:09 PM
techinspector1's Avatar
Senior Curmudgeon
 
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Hemet, California, USA
Age: 72
Posts: 12,599
Wiki Edits: 326

Thanks: 701
Thanked 890 Times in 757 Posts
Quote:
Originally Posted by kndymn73
how did you come up with over 11 to 1
You and the book are figuring on having the piston down in the bore a little (piston deck height). I build 'em at zero deck to make sure the decks are the same distance from the centerline of the crank along the entire length of the decks, front to rear. Then, the gasket thickness becomes the squish dimension, usually a 0.040" gasket.

It takes 5 dimensions to figure static compression ratio.
1. cylinder volume
2. chamber volume
3. piston crown volume
4. piston deck height volume
5. gasket volume

Here's the way it plays out in your case with zero decks....
1. 784 cc's
2. 64 cc's
3. 5 cc's
4. 0 cc's
5. 9 cc's

Add these 5 values and find 862 cc's. Now, remove the cylinder from the mix and add the remaining values and find 78 cc's. Now, divide 862 by 78 and find 11.05:1 SCR.

With the same flat-top pistons that you now have and a set of 75 cc heads, zero deck and a 0.040" gasket, your SCR would be 9.8:1, just right for pump gas using a 212-222 intake duration cam. Also use a dual-plane, high-rise intake such as an Edelbrock RPM or Weiand Stealth and 1 3/4" long-tube headers with a 3/8" thick flange.

I'll list some heads for you to look at....There isn't much to pick through when you have to look at the larger size chambers, at least not with a decent sized intake runner. Truth be told, you'd be way better off financially to change the pistons and cut the decks while you have the whole thing apart again.
http://www.summitracing.com/parts/AFR-1050/
http://www.summitracing.com/parts/BRO-1028101/

Last edited by techinspector1; 12-19-2010 at 08:19 PM.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-20-2010, 06:00 AM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by techinspector1
You and the book are figuring on having the piston down in the bore a little (piston deck height). I build 'em at zero deck to make sure the decks are the same distance from the centerline of the crank along the entire length of the decks, front to rear. Then, the gasket thickness becomes the squish dimension, usually a 0.040" gasket.

It takes 5 dimensions to figure static compression ratio.
1. cylinder volume
2. chamber volume
3. piston crown volume
4. piston deck height volume
5. gasket volume

Here's the way it plays out in your case with zero decks....
1. 784 cc's
2. 64 cc's
3. 5 cc's
4. 0 cc's
5. 9 cc's

Add these 5 values and find 862 cc's. Now, remove the cylinder from the mix and add the remaining values and find 78 cc's. Now, divide 862 by 78 and find 11.05:1 SCR.

With the same flat-top pistons that you now have and a set of 75 cc heads, zero deck and a 0.040" gasket, your SCR would be 9.8:1, just right for pump gas using a 212-222 intake duration cam. Also use a dual-plane, high-rise intake such as an Edelbrock RPM or Weiand Stealth and 1 3/4" long-tube headers with a 3/8" thick flange.

I'll list some heads for you to look at....There isn't much to pick through when you have to look at the larger size chambers, at least not with a decent sized intake runner. Truth be told, you'd be way better off financially to change the pistons and cut the decks while you have the whole thing apart again.
http://www.summitracing.com/parts/AFR-1050/
http://www.summitracing.com/parts/BRO-1028101/
thanks, Ill be taking the advice and go with the zero deck, and a different set of pistons, and assemble the engine. I never imagine rebuilding a centrifugal chiller was easier, but then again you are only replacing parts.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-20-2010, 06:48 AM
Landshark928's Avatar
FrankenPorsche
 
Last photo:
Join Date: Feb 2010
Location: Pensacola, Fl
Age: 45
Posts: 459
Wiki Edits: 0

Thanks: 0
Thanked 13 Times in 9 Posts
Rather than buying new pistons and then decking the block, wouldn't it be cheaper and easier to swap to aluminum heads. Don't aluminum heads allow for about an extra point of compression?

Procomp heads have gotten a lot of flack in the past but they are now on their third generation and redesign. They won't keep up with AFRs or Profilers, but for $469 bare from Skip White for the CNC models, they flow 270cfm @ .600" lift. Enough to make 500HP+ with the right cam. Most of the complaints you read about Procomp heads are either 3-4 years old, folks trashing on Chinese made products, or folks who just won't let go of Procomp's original issues. I am very happy with mine so far. I went to a dyno day this weekend and hit over 450RWHP with Procomp heads on my 383. Very happy. I'm just under 11:1 compression.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-20-2010, 07:15 AM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 8,715
Wiki Edits: 0

Thanks: 17
Thanked 286 Times in 266 Posts
Those are some good heads, I would look into different pistons to lower your static compression, shoot for about 10:1-10.3:1, for a cam I am planning on running the Howards 180325-08 cam in an LT1 I am building with 1.6:1 rocker arms, 226/234 duration and near .570" lift with 1.6 rocker arms. If you get all of your engine specs together someone here can run a desktop dyno to give a rough simulation of the power curve it will provide in your engine. I have an old copy of desktop dyno 2003, but that thing is about as accurate as throwing darts.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-20-2010, 09:18 AM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by kndymn73
I have a four part question.

4. what head gasket thickness can I use to bring the compression ratio to 10 to 1 or is it possible at all,
thanks in advance for any input
Assuming 5cc reliefs, 0.025" in the hole, a 0.030" overbore, and 64cc heads, it'll take a 0.058" head gasket thickness w/a gasket bore of 4.100" to get 10.02:1 CR.

Problem w/that, is the quench goes to hell- at about 0.083".

Your plan to zero deck it and to use D-cup pistons w/the correct volume is the right way to go.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-20-2010, 04:41 PM
done learning, done living
 
Last photo:
Join Date: Feb 2009
Location: Middle of the Mitten
Age: 29
Posts: 1,626
Wiki Edits: 0

Thanks: 140
Thanked 86 Times in 77 Posts
Quote:
Originally Posted by cobalt327
Your plan to zero deck it and to use D-cup pistons w/the correct volume is the right way to go.
I have to go with cobalt on this one, keep the heads and swap the pistons, zero deck the block or deck it to 9.10 (to allow for an oops) and run a .035 gasket +/-. Are the pistons pressed on or floating? Are they brand new? Can you return them or exchange them?
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-20-2010, 07:26 PM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by kndymn73
thanks, Ill be taking the advice and go with the zero deck, and a different set of pistons, and assemble the engine. I never imagine rebuilding a centrifugal chiller was easier, but then again you are only replacing parts.
I run into a set of pistons from speed pro part#L2403NF-30 for $200 the only info I got was that it had a 1.562 dish design and are forged pistons. Would that be equivalent to 25 cc, cause that would put me to 9.03 to 1 with std deck height(.025) and .015 head gasket to get total of .040 that is one of the cheapest routes, or I can go with speed pro 12ccfor $170 .025 deck and a .031 gasket and get 9.93 to 1 compression ration. Will this be the correct ratios and is 9 to 1 to low and 9.93 to 1 too high, any other piston with a range of 14 to 20 cc will cost me another $300. Any input on this two set of pistons will be appreciated.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 12-20-2010, 07:36 PM
How fast is fast enough?
 
Last photo:
Join Date: Jun 2005
Location: St. Louis, MO
Age: 29
Posts: 8,715
Wiki Edits: 0

Thanks: 17
Thanked 286 Times in 266 Posts
9.93:1 is perfect, get it decked to true up the surfaces and run a good thin steel gasket.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 12-20-2010, 07:40 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 59
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by kndymn73
I run into a set of pistons from speed pro part#L2403NF-30 for $200 the only info I got was that it had a 1.562 dish design and are forged pistons.
That compression height and piston diameter is for a 3.48" stroke crank.

Last edited by cobalt327; 12-20-2010 at 07:46 PM.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 12-20-2010, 09:00 PM
Registered User
 
Join Date: Dec 2010
Location: omaha, ne
Posts: 8
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by cobalt327
Assuming 5cc reliefs, 0.025" in the hole, a 0.030" overbore, and 64cc heads, it'll take a 0.058" head gasket thickness w/a gasket bore of 4.100" to get 10.02:1 CR.

Problem w/that, is the quench goes to hell- at about 0.083".

Your plan to zero deck it and to use D-cup pistons w/the correct volume is the right way to go.
let me run this by u 12cc reliefs, .025" in the hole, .030 overbore, 64cc heads, with a .031 head gasket and a gasket bore of 4.100 will give me a 9.91 to 1 will that be a .056 quench? and is that acceptable.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Would this Isky Hydraullic roller cam work good for my combo eric32 Engine 9 06-18-2009 04:36 PM
Cam break-in and zinc Frisco Engine 34 03-13-2007 08:22 PM
Comp cam suggestion is whack??? BigTex88 Engine 9 02-20-2006 04:42 PM
IGNITION and CAM TIMING sum87mustang Engine 3 07-11-2003 07:52 PM
cam suggestion for DD with 1.74s COCHEV Engine 2 02-25-2003 11:22 PM


All times are GMT -6. The time now is 12:40 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.