Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> Thinking out loud - 1911, Found my deck height. All good?
jaredmcginness
post Jul 4 2020, 10:03 AM
Post #1


...
***

Group: Members
Posts: 501
Joined: 12-June 19
From: Baltimore
Member No.: 23,209
Region Association: MidAtlantic Region



See update and actual numbers on the added reply.


Sorry for the novel!!

Hey guys,

I'm building a 1911. I want to make sure that I have my thoughts in the right place.

-96 Bore x 66 stroke. Fresh rebuilt 1.7 heads with a 105mm fly cut register. Stock valves

-Running a .495 lift cam, lifters to match, HD springs + counter bore .630 (IIRC) extended.

I need to CC my heads first, get the volume, then determine my deck height and compression ratio? Stock 1.7 heads are 50cc. I assume mine will end up a tad larger, maybe 52cc. (will the fly cut alter the size?) But I might be off.

Is 8.5:1 a good target ratio? Ive read a few threads and this seems to be the middle ground compression. A good target DH is .045-.065? With a minimum of 0.040 to avoid contact.

A few examples - per a CR calculator:

50cc, 0.065 = 8.7:1
50cc, 0.045 = 9.2:1

53cc, 0.065 = 8.4:1
53cc, 0.045 = 8.8:1

This in mind, depending on my head volume it should be easy to narrow down where I need to be.

Am I on the right track? New to this and been digging into some old books.

Whats a good compression ratio, that should be safe for a mild carbed (dual 36) motor and mild cam. Want this thing to last more than a summer! I dont really have a target CR, because I dont know the difference of a few decimal points!

Happy 4th (IMG:style_emoticons/default/beerchug.gif) !
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
jaredmcginness
post Aug 1 2020, 04:54 PM
Post #2


...
***

Group: Members
Posts: 501
Joined: 12-June 19
From: Baltimore
Member No.: 23,209
Region Association: MidAtlantic Region



Thanks a lot everyone.

I’m expecting to have done a lot wrong, but that’s part of the fun I guess. Just want to not have a total dog on my hands and keep er cool.

I’ll keep you updated.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 28th March 2024 - 07:31 AM