304 engine noise under load - Off-Road Forums & Discussion Groups
IH Scout & Trucks Discussion of International Harvester, 4-Wheel Drive Truck and Scout Vehicles

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 04-23-2005, 03:32 PM
Posts: n/a
304 engine noise under load

I have a '74 Scout with a 304 in it. I built it about 5 years ago. Runs well. Started hearing a tapping in 3rd and 4th gear as I accelerate. Does not sound like a knock but a tap, especially when I'm cruising and then give it just a little more gas. Don't think it's spark knock. Checked and adjusted dwell a few degrees. Tried premium gas, tho I really had to bite the bullet on that one. No help. Checked the lifters for play and used a stethescope to listen for any errant noise at idle. Nothing. Only seems to tap under a load. Good compression, so I don't think it's valve train related. I'm going to try to clamp my stethescope with a long hose on it to various engine parts and listen for noise when underway and under load. Any ideas?
Sponsored Links
post #2 of (permalink) Old 05-11-2005, 09:48 PM
Keyboard Implanted
Join Date: Jan 2003
Location: Northwest Corner, Connecticut
Posts: 2,382
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 304 engine noise under load

Exhaust leak? Trans issue? Man you've tried a lot too... problem is none of it was tested under load was it?
CTBrent is offline  
post #3 of (permalink) Old 05-12-2005, 06:08 AM
Keyboard Implanted
Join Date: Sep 2000
Location: Tn
Posts: 2,200
Thanks: 0
Thanked 0 Times in 0 Posts
Re: 304 engine noise under load

If its not valvetrain related youve prolly got a cracked exhaust manifold. Theyre known to crack on the left side towards the back.

Brent, you have a heep and a zuk. What the hell are you doin here.
zukinut is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not 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