Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic
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> compression on my 383
User Name
Password
lost password?   |   register now

Thread: compression on my 383 Reply to Thread
Title:
  
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :

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:
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.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
02-19-2003 09:05 PM
dk01_99 ya thats the thing, im not sure what exactly my compression ratio is.....i wasnt smart when i built my motor (still aren't ) so thats the only number i recall the guy saying about compression, i could be wrong.....damn i wish i knew
02-19-2003 04:41 PM
trees My 383, with 76 cc heads and TRW forged flat tops had 9.4 to 1 compression so 8.8 to 1 with dished pistons would be reasonable. Had no problem with pump gas but was not running that big a cam.

Trees
02-19-2003 02:49 PM
MI2600 I've got a 383 with a Comp Cams XE268 and I'm running close to 10:1 with flat tops. The cam lift is in the .490 range for the intake and a little less for the exhaust. The only problem arose when a valve guide seized and held an intake open, but that's a freak accident. I have to use premium gas. As above, I would recheck your compression specs, 8.8 sounds a bit low.
02-19-2003 02:40 PM
nickel333 with that little cam dont get compression too high or youll detonate. The only real way to check actual piston to valve clearance is to clay the pistons and do it manually. You must have a huge dish and some 76cc heads to get 8.8:1 man, are you sure about your current compression?? I have a calculator if you give me you head cc and the piston dish cc ill figure it out for you
02-19-2003 11:31 AM
dallam1 Is this a Chevy small block that you've stroked to a 383? If so, then where did you get your 8.8 to one compression figure from? I very cheaply built up a 383 using cast flat top pistons and smog big chamber heads. The compression is 9.4 to one. My cam is a SSI 214/224 which does not have as much duration as your Comp Cams(?)268 cam does. I cannot run the auto on regular gas but it will run fine on medium grade. So I would say you are safe with at least as much compression as I'm running. However, it's important to note that I live at 2000' above sea level so that will make a modest difference in the true compression ratio. Incidently, how are you planning on modifying your compession ratio? In reality, a 8.8 to one 383 small block can be made to run just fine. A high lift short duration cam is just the ticket that will turn that old Chev into a barn burner that will run on regular gas and you won't have to worry about piston to valve clearance and all of the trouble of changing the compression ratio. Good luck
02-19-2003 09:43 AM
dk01_99
compression on my 383

i have a 268 cam in my 383 with about 8.8:1 compression. im not so sure on all of the specs but i think the cam is the "comp cams" and if i was smarter when i got my motor i would have gotten all the specs to go along with it. but do you guys know what compression ratio i could go up to safely (pump gas) without running into valve clearances? would upping compression be wise to get more power right now? im sure you need to know everything else my motor has but i'd thought i'd ask first before listing....thanks in advance

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


All times are GMT -6. The time now is 09:56 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.