4.2L clatter or NOT? - JeepForum.com
 
LinkBack Thread Tools
post #1 of 5 Old 09-19-2020, 09:09 PM Thread Starter
gunny40
Junior Member
1982 CJ7 
 
Join Date: May 2013
Location: San Antonio
Posts: 95
Garage
4.2L clatter or NOT?

I bought a '85 cj7 which has 105,000mi on it. Not sure if original. Bought from someone who received it as partial payment for worked performed. It belonged to a one star general retired. It appears to be well taken care of. I do not know if engine has ever been rebuilt. I started hearing some clatter noise when under load and RPMs rise ( not sure of RPM range, i do not have a tach), I switch gears and no clatter until RPMs rise. I disengage clutch and rev engine (no clatter), release clutch pedal and engage clutch and begin accelerating and once RPMs begin to rise I have clatter. No clatter at low RPMs when accelerating, just as RPMs begin to rise to point of needing to shift to next gear. I drive 20 miles to work and the noise seems to have gone away by the time I reach work. Also, the clatter seems to be absent if in neutral or clutch disengaged. Any suggestions.
I recently changed valve cover to aluminum and torqued all rocker arms to spec. Performed oil change with 10w30 oil and wix oil filter, added 1 qt of Marvel Mystery Oil. No change in clatter after oil change.

gunny40 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 09-19-2020, 09:30 PM
JEEPFELLER
Registered User
 
JEEPFELLER's Avatar
1977 CJ5 
 
Join Date: Dec 2015
Location: GREENWOOD
Posts: 379
Garage
Kinda sounds like "castanets"? (Spanish finger instrument?)

Might be that your timing is off (set wrong) Or maybe something happened with the distributor's advance?

Do you have a timing light and a dwell/ tach to use to set it correctly or check it's operation?

----JEEPFELLER
JEEPFELLER is offline  
post #3 of 5 Old 09-20-2020, 04:35 PM Thread Starter
gunny40
Junior Member
1982 CJ7 
 
Join Date: May 2013
Location: San Antonio
Posts: 95
Garage
I should be kicked in the seat of the pants. I did not think to check timing. I can almost bet it is a timing issue. I have a fast idle. Vehicle seems to run fine down the road, but does have a fast idle. I was trying to buy a used timing light off craigslist, but will bite the bullet and pay $50 for the cheap light at my local parts store, or splurge for the nice $120 one. I will also need one once I put my AMC 360 in my 1982 CJ7 I am building. I will buy the light, adjust timing and let you know. Thanks.
gunny40 is offline  
 
post #4 of 5 Old 09-21-2020, 05:32 PM
JEEPFELLER
Registered User
 
JEEPFELLER's Avatar
1977 CJ5 
 
Join Date: Dec 2015
Location: GREENWOOD
Posts: 379
Garage
Cheap stuff is fine---bells and whistles make it more confusing.

Yard sales and pawn shops ae good places to look.

See me in this link https://www.jeepforum.com/forum/f8/c.../#post41071725

---JEEPFELLER
JEEPFELLER is offline  
post #5 of 5 Old 09-22-2020, 05:57 AM
NormWild
Registered User
1985 CJ7 
 
Join Date: Sep 2017
Location: Lehigh Valley
Posts: 319
I don't know, typically timing valve chatter would be under load at lower rpms, and goes away at higher rpms. Consistent clatter as rpms climb sounds like a bad lifter/valve spring.

1985 CJ7- 4.5" BDS/Fiberglass Tub/33s/Many Mods
NormWild is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com 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 e-mail 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



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 Off
Pingbacks are On
Refbacks are On

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