Piston id help - Pontiac GTO Forum
User Tag List

 
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old 03-17-2019, 02:20 PM Thread Starter
 
MidnightAuto's Avatar
 
Join Date: May 2018
Posts: 57
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Piston id help

Hi guys- I recently bought an endoscopic camera to connect to my iPhone. I wanted to get a view of my piston tops to see if I could surmise what the previous owner had dropped in. Snaked the camera through spark plug hole and pictures are from #1 and #6 chambers. The motor is a 1964 421 with the 77 heads. The motor seems to run fine on 92 octane. So I have two questions, (1) do these pistons look stock, or are they dished a bit to drop my cr (and why I seem to have no isssue with 92). And (2) the #1 piston looks a bit discolored at top - is that normal or sign of pinging danger? I have never heard this motor ping, although it is free flowing exhaust that is pretty loud. Thoughts appreciated, thank u.
Attached Thumbnails
Click image for larger version

Name:	8F8E61BA-0EE8-4749-8E7D-73362D336C45.jpeg
Views:	66
Size:	159.1 KB
ID:	118045   Click image for larger version

Name:	E9573EC9-629F-450A-A955-20BCB2B8966F.jpeg
Views:	59
Size:	112.3 KB
ID:	118047   Click image for larger version

Name:	4D289080-5A4E-4AA4-9345-30B622801DF7.jpeg
Views:	57
Size:	105.4 KB
ID:	118049  
MidnightAuto is online now  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 03-17-2019, 05:00 PM
 
PontiacJim's Avatar
 
Join Date: Dec 2012
Location: Gastonia, NC - Born & raised in Connecticut - 31 years
Posts: 3,451
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 347 Post(s)
Garage
Not factory and it appears they are dished pistons to lower compression. Top of the piston looks normal as you will get carbon deposit on the tops - they do not stay shiny like new for very long.
PontiacJim is offline  
post #3 of 4 (permalink) Old 03-17-2019, 07:06 PM Thread Starter
 
MidnightAuto's Avatar
 
Join Date: May 2018
Posts: 57
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 15 Post(s)
Thanks for confirming Jim. I continue to be impressed with po decisions. He had passed away so did not get to talk about the car...
MidnightAuto is online now  
 
post #4 of 4 (permalink) Old 03-27-2019, 04:53 PM
64-67 Expert
 
geeteeohguy's Avatar
 
Join Date: Feb 2008
Location: Fresno, California
Posts: 8,457
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
What Jim said. Custom dished pistons. Lucky you. Whoever built that engine built it to live on today's gas. Win-win for you!!!
geeteeohguy is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO Forum forums, you must first register.
Please enter your desired user 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:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help figuring what piston I need. (wallace calculator) RMTZ67 1964-1974 Tempest, LeMans & GTO Engine Tuning and High Performance 16 07-19-2018 12:24 PM
Piston and Bore Choices Help EdR 1964-1974 Tempest, Lemans & GTO General Discussion 9 03-18-2016 04:53 PM
Engine ID help (Help a brother out) Pontiacpurebrred 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion 6 07-02-2011 01:35 AM
Baer 11" 2-piston discs vs. stock single piston Jeff's Classics 1964-1974 Tempest, Lemans & GTO General Discussion 8 06-29-2010 07:27 PM
Camshaft ID, Crankshaft ID Help needed. Lukeduk1980 1964-1974 Tempest, Lemans & GTO Complete Engine Compartment Discussion 3 06-01-2010 10:00 PM

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

 
For the best viewing experience please update your browser to Google Chrome