Notices
944 Turbo and Turbo-S Forum 1982-1991
Sponsored by:
Sponsored by: Clore Automotive

Rod nuts replacement

Thread Tools
 
Search this Thread
 
Old 08-19-2004, 02:27 PM
  #1  
alexands
Pro
Thread Starter
 
alexands's Avatar
 
Join Date: May 2004
Location: Dallas, TX
Posts: 537
Likes: 0
Received 0 Likes on 0 Posts
Question Rod nuts replacement

The thread on head nuts reminded me of my issue. My machinist just got my block, head, and crank done yesterday. He balanced all rotating assemblies and everything. He did so with the old rod nuts. I was under the impression you should never re-use them. When questioned he said put two drops of Loctite on them and they will be OK. BTW: He does many Porsche engines for the local shops around DFW, so he's got some experience with these cars.

What do you guys think? Should this be OK?
Old 08-19-2004, 02:59 PM
  #2  
tommo951
Burning Brakes
 
tommo951's Avatar
 
Join Date: Jul 2004
Location: Kent, UK
Posts: 1,096
Likes: 0
Received 0 Likes on 0 Posts
Default

Well if you are going to use locktite why not just get the mig out and weld them properly.......
only joking. Do you really want to trust your rebuild to what could be a potential weak link in the chain? When I am building engines for race or performance, if I am re-using the roads I always take 10thou off the caps and reline bore the complete big end bearing housing. I also do the same with the main bearing caps. What is the point in having a crank knife enged if it is going to run tight in its caps? In essence what I am saying is don't sink the ship for the lack of a coat of paint. You don't need to go to the extent of buying race hardware but new OEM would be a distinct benefit. You can locktite those as well if you are not going to lock wire them.
Old 08-19-2004, 04:24 PM
  #3  
Matthew West
Instructor
 
Matthew West's Avatar
 
Join Date: Jul 2002
Location: Carnation, WA
Posts: 200
Likes: 0
Received 0 Likes on 0 Posts
Default

My understanding is that you should replace them AND use loctite.
Old 08-19-2004, 04:50 PM
  #4  
hosrom_951
UAE Rennlist Ambassador
Rennlist Member
 
hosrom_951's Avatar
 
Join Date: Jan 2004
Location: UAE & Germany
Posts: 9,142
Likes: 0
Received 2 Likes on 2 Posts
Default

Here is a tip, replace them with the raceware kit (?)

The stocks ones are plastic? I read that they are in the 911&Porsche World Magazine.

Since the bottom end rods are critical, go and upgrade the rod bolts.....i would.....
Old 08-19-2004, 04:56 PM
  #5  
Ski
Addict
Rennlist Member

 
Ski's Avatar
 
Join Date: Nov 2001
Location: Heber Springs, AR
Posts: 7,897
Likes: 0
Received 2 Likes on 2 Posts
Default

I've always replaced them and NEVER used loctite, torque to spec. IIRC the only loctite used or specified is blue medium on the rotor screw(just a dab'l do you), red loctite, high strength, on new factory head studs and ARP studs - (Raceware specifies pipe dope), and loctite 574 on the girdle, oil pump, and balance shaft covers. Of course, experience and past proven history for trusted people and what they have done is up to you.

Last edited by Ski; 08-19-2004 at 07:01 PM.
Old 08-19-2004, 05:52 PM
  #6  
alexands
Pro
Thread Starter
 
alexands's Avatar
 
Join Date: May 2004
Location: Dallas, TX
Posts: 537
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for all of the input. My only hesitation to just picking up new ones is that the motor has already been balanced and I don't want to throw anything off. So, maybe the question I should be asking is - if I replace the nuts how much do you think it will affect the balance job?
Old 08-19-2004, 05:56 PM
  #7  
adrial
Nordschleife Master
 
adrial's Avatar
 
Join Date: Jun 2001
Location: Northern NJ
Posts: 7,426
Likes: 0
Received 1 Like on 1 Post
Default

Nuts I do not think would effect the balance job at all.

Factory rod bolts definetely are not plastic...
I have never seen loctite recommended for rod nuts. ARP recommends their assembly lube on the bolts, thats it.

ARP recommended red, high strength loctite for the head studs I bought from EBS.
Old 08-19-2004, 06:02 PM
  #8  
hosrom_951
UAE Rennlist Ambassador
Rennlist Member
 
hosrom_951's Avatar
 
Join Date: Jan 2004
Location: UAE & Germany
Posts: 9,142
Likes: 0
Received 2 Likes on 2 Posts
Default

Adrial: That is why i said "The stocks ones are plastic? I read that they are in the 911&Porsche World Magazine" coz i KNOW that it couldn't be
Old 08-19-2004, 07:40 PM
  #9  
Laust Pedersen
Addict
Rennlist Member

 
Laust Pedersen's Avatar
 
Join Date: Sep 2003
Location: Menifee, CA
Posts: 1,357
Received 8 Likes on 6 Posts
Default

Plastic?
In engineering terms you distinguish between plastic and elastic deformation.

Plastic deformation is a permanent deformation (such as a stretch bolt) and elastic deformation is a reversible deformation (like a spring used within its design limits). Maybe that was the reference rather that a material description.

If the stress on a part at any spatial point exceeds its Yield Strength (material property) then that region will be plastically deformed.

… Compare changing the nuts to knife-edging the crank, which certainly affects the local dynamic balance a lot more.

Laust



Quick Reply: Rod nuts replacement



All times are GMT -3. The time now is 03:13 PM.