Going nuts engine - 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 07-21-2004, 09:23 AM
strikingthematch's Avatar
Pure American Muscle
 

Last journal entry: Still Going
Last photo:
Join Date: Mar 2004
Location: VA
Posts: 688
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Exclamation Going nuts engine

Well as the subject states im going nuts here. I have a 1971 Chevelle the 307 in has been swapped out for a 355 that I had. The guy I got the engine from said it had only been rebuilt a few years ago and from looking at the heads and oil it is super clean so I believe that. He didn't know what went into the rebuild so it is a pain not knowing whats in it. Anyways I believe it to have a stock bottom with stock pistons and such (never had the heads off) the heads are stock too. It has a freshly rebuilt turbo 350 trans with shift kit the stall is at 1200 (I know that has to go up) and the newer items that have been are the eldebrock per. intake and holly 750 dual pumper with K & N air filter. It has a full MSD ing. system with the rev. limiter. ALso hooker headers and a new 2/1/2 flowmaster American thunder kit. It of course has power but I wouldn't be much of a muscle car guy if I didn't want more

Now after that large report here is my problem. I am replacing some of the top end. I am going to replace the head and cam from what I understand the rest of the top will be fine for now.
This car is an almost daily driver in the summer never in the winter but it's often out to just ride around and some fun street racing. As many people know ryans engine combo for pre dyno tested engines. Combo 14 combo # 14 is what im looking for from my engine I know a lot of other factors play a roll in HP and TQ but in that area and driveablity is what im going for.

My problem he is that I know i am getting AFR 195 street ported heads with the 74 combust. chamber. As for a cam it is either a competion or crane. I think i am going to stick with a flat tappet if I can mainly because hyd rollers are so expensive.
Im thinking this cam

113801 would work really well. I think I would get the kit that comes with that with the timing chain and such.

Im so confused with stuff though I have been looking through these fourms finding out info on cams and heads and it seems cam choice is always the hardest I plan on calling both cam co. and seeing what they say.
My question to all of you is do you think with those items installed I would be ok? As in it will run on pump gas and not blow out my bottom end? Also can I even use a flat tappet cam or do I need to go with something else. Mind you this has to stay streetable.

Im just going nuts because there is to many things to consider im hopeing someone can either tell me that that is close to what I want or point me in the right direction. Thanks everyone all your post have already helped get me this far!

    Advertisement

Last edited by strikingthematch; 07-21-2004 at 10:03 AM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-21-2004, 10:52 AM
blndweasel's Avatar
paints everything flat black
 

Last journal entry: September 2005 - Current
Last photo:
Join Date: Mar 2003
Location: San Diego, CA
Posts: 363
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
The most important thing so far that you haven't figured out is what your compression is, and that depends on what pistons are in there. Besides that, you don't know the condition of the bearings, and the tolerances on the bottom end.

My advice would be to pull one of the heads off and get an idea of what pistons are in there. The cam companies will have trouble recommending a proper cam if they don't know what the bottom end will support.

Once you know what's in there, and can purchase the parts you need for the top end, I'd figure in the possibility of having to do more work on the bottom to make sure you have a solid setup. If you're investing the sort of money you're planning on a set of AFR heads, then I can't see why you wouldn't also be willing to put the appropriate amount of care (read: $$$) into the bottom end.

Speaking from experience, it's always easy to speculate about one or two things then come up with a plan for what you'd like to do to an engine. But you won't ever have the peace of mind you're looking for until you've been through every bolt and every clearance and know for yourself what the tolerances are. If you have the sort of money it sounds like you have, invest $500 in precision measuring instruments and a book on "how to blueprint a small block chevy". Go through the entire thing tooth and nail. Don't move forward from one step to the next until you're absolutely certain you completed the last step sufficiently. That's how you build reliable power. That's how you build a motor, that when you stomp on the gas, you know what to expect, and when something breaks you generally know what it was without even taking the engine apart.

The question is how much time and money you're willing to invest to gain the knowledge necessary to build reliable power.

good luck man!

tbw

oh yeah.... one more thing. I had an engine like that before. guy i bought it from said whatever he felt like about what was in it, how it was put together, etc. but what it comes down to, is NEVER trust another builder's word on how something was done. this deserves repeating. NEVER trust another guy's word when it comes to engines. it's just too easy to lie about something you know the other guy's not gonna figure out until months down the road when he's finally got the whole assembly apart.

solution: take it apart yourself. measure everything accurately. reassemble with confidence.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-21-2004, 10:53 AM
gpeak's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: Kansas
Age: 42
Posts: 384
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
As far as i can tell you have answered your own question. Best bet is to call Comp Cam and tell them your EXACT set up and they will give the right cam. And no, just putting heads on and a cam won';t blow your bottom end.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-21-2004, 11:01 AM
blndweasel's Avatar
paints everything flat black
 

Last journal entry: September 2005 - Current
Last photo:
Join Date: Mar 2003
Location: San Diego, CA
Posts: 363
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I'd tend to disagree with you. If you put on heads that have too small of combustion chambers, you will cause unreasonably high compression, capable of destoying even the stoutest of bottom ends.

same thing for a cam, if you throw something in with too much lift, you can have piston to valve contact which will damage the new heads you just bought, and could damage the pistons.

don't do anything until you know what compression those pistons are producing.

good luck

tbw
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-21-2004, 11:36 AM
strikingthematch's Avatar
Pure American Muscle
 

Last journal entry: Still Going
Last photo:
Join Date: Mar 2004
Location: VA
Posts: 688
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Should I check the compression on the pistons now? With the stock heads on? The problem is that im not sure what exact compression im going to get by putting that cam and the heads on. hopefully be around 9.5:1. Would it be better with the 64 combust cahmber or a 74. Would the larger chamber lower compression? The cam im looking as says it works within the 9.5 to 11 or whatever compression so of course I need enough to get that to work of course I will call and maybe they will recomend something else. Im just worried that it will blow the bottom end buy putting on a bigger cam I mean it has one as is but again I have no idea what it is. It sounds like a very mild one.

As for taking it apart I was thinking it would be a good idea to take a head off too and see what pistons are in there if I can. Problem of course is money that i do not have much of however in making upgrades I get my money worth best heads and a good cam. If possible I did want to keep away from doing the bottom end just yet. Of course as you said you never can be sure what is in it till you have done it yourself. I agree 100% sadly though money dosent always let me have those comforts. Of course all the heights will be checked before the heads would go on and make sure it would work im just worried that the bottom end will go before I can replace it.

Last edited by strikingthematch; 07-21-2004 at 11:36 AM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-21-2004, 12:45 PM
gpeak's Avatar
Member
 
Last photo:
Join Date: Oct 2003
Location: Kansas
Age: 42
Posts: 384
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Since i read his post, i already knew that with 74cc heads, the compression wouldn't be unreasonable. Furthermore, i am assuming a not too radical cam since it is pretty much a daily driver that he wants streetable. That being said, if he said he wanted a bad*** radical engine, then yes you need to do bottom end work.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-22-2004, 06:58 AM
Member
 
Join Date: Feb 2003
Location: North Carolina
Posts: 454
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
One thing to consider when changng heads and cams is the changes on the cylinder pressure and how that's going to effect the rings if the engine has alot of mlles on it. Also make sure you get valve springs to match the cam you end up using so the opening and seat pressure is correct.
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



All times are GMT -6. The time now is 11:05 AM.


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.