Go Back  Offshoreonly.com > Technical > General Q & A
2000 7.4 MPI rebuild question >

2000 7.4 MPI rebuild question

2000 7.4 MPI rebuild question

Old 07-04-2009, 08:33 PM
  #1  
Registered
Thread Starter
 
Join Date: Mar 2006
Location: New York, NY
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default 2000 7.4 MPI rebuild question

I just put new heads, lifters and exhaust manifolds on my 2000 GEN VI 7.4 merc and got her started today but she is making a hell of a lot of noise. Sounds like lifters but I put a whole new set on. Is there something I am missing or may have done wrong? I'm afraid to keep running it like this. Any help would be greatly appreciated.

Thanks
Plaineman is offline  
Old 07-05-2009, 01:46 AM
  #2  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha
Posts: 17,485
Received 39 Likes on 26 Posts
Default

No way to tell without looking at or hearing it. There's about 50 things that could be done wrong.
Griff is offline  
Old 07-05-2009, 09:04 AM
  #3  
Registered
 
Join Date: Mar 2008
Location: League City, Texas
Posts: 466
Likes: 0
Received 0 Likes on 0 Posts
Default

Is the valve lash set correctly?

Like Griff said, it could be quite a few different things.
niceguy is offline  
Old 07-05-2009, 10:46 AM
  #4  
Registered
Thread Starter
 
Join Date: Mar 2006
Location: New York, NY
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default

I did all by the book and it seemed like all went well... I have been working on cars my whole life and have completed big jobs like this with great results. As for the valve lash I did find it strange that all the book said to do was to tighten the rocker nuts down to spec and it was done. The computer is not putting out any codes and oil and temp seem to be good. The water flow is fine and she even seems to be making good power. I am stumped on this... if the valve train was so far out that it was making this kind of noise would't she be running extremely rough? I have been reading some other posts and found some people complaining of a similar type of noise and found it to be the exhaust flappers. She sat all last year so maybe I have other problems all together. Wondering if maybe one of the belt driven components is shot and making noise. I'm gonna go run it for a second without the belt and see. Thanks for reading guys.... Wish me luck.

B
Plaineman is offline  
Old 07-05-2009, 11:36 AM
  #5  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha
Posts: 17,485
Received 39 Likes on 26 Posts
Default

If you used stock heads and lifters, then you should be able to just snug up the rocker bolts.

Internal Exhaust flapper noise is usually kind of inconsistent and will the noise will go away with a little more rpm.
Griff is offline  
Old 07-05-2009, 11:41 AM
  #6  
Registered
Thread Starter
 
Join Date: Mar 2006
Location: New York, NY
Posts: 119
Likes: 0
Received 0 Likes on 0 Posts
Default

Yeah... it doesn't go away and only gets more intense with RPM. I just can't see how I would have noise due to lifters or valve lash but that is what it seems like to me... Could it be that the lifters are not the right ones for my app... maybe too short? These engines have roller lifters and seem to be the exact fit... maybe my cam was shot but then again I would be having a rough running engine and she seems strong... just making a hell of a lot of noise.

Thanks for input guys... I will be at all day.

B
Plaineman is offline  
Old 07-05-2009, 05:52 PM
  #7  
Registered
 
Join Date: Mar 2008
Location: League City, Texas
Posts: 466
Likes: 0
Received 0 Likes on 0 Posts
Default

On my HP500, I had two different length pushrods for intake and exhaust.... I don't know if yours is the same, but make sure you have them in the right spot. Too short of a pushrod would cause the lash to be off making the rockers really noisy. But I would think it is was too short the motor wouldn't run very well. Just a thought.

And you're sure the noise is valvetrain related and not a lower end issue?
niceguy is offline  

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


OSO Sponsor
OSO Advertiser
OSO Advertiser

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

OSO Advertiser