![]() |
|
|
|
Registered
Join Date: Oct 1998
Location: Denver, CO
Posts: 1,335
|
Rod Bolt Choices...
I'm gradually gathering parts for a 2.8S build and have to decide on a set of rod bolts. What's the concensus here? Are the Raceware or ARP worth it? What are the advantages over factory bolts? I searched the archives and came up with -nothing-.
If it helps, I'll be running 10.5:1+ (maybe 11+) compression, but intend to keep the RPMs down to S specs.
__________________
- '72 911T - '81 911SC Euro |
||
![]() |
|
Registered
Join Date: May 2004
Location: Boulder, Colorado
Posts: 7,275
|
![]()
Josh
If you plan this 2.8 to be anytning other than a mild street motor with a conservative redline, like 7,200 or so on a pre-3.2 crank, and lower on the 3.2, you are flat out nuts if you don't use Raceware or ARP rod bolts. They are significantly stronger than stock - 220,000 psi steels. Additionally, they can usually be reused several times before they are stretched too far. That is a good thing for a race motor, because those tend to need to come apart more often than motors used in less stressed applications. Less of a consideration in a street motor you hope to run for 100,000 or more miles before. I sure wish bolts of this sort were available when I built my 2.3 motor, because a stock rod bolt failure (not clear if the fried bearing was cause or effect here) destroyed it. Equally bad problems with the 2.7 (I think that was the piston that pulled in half) that had Racewares left me with a bent end cap, and of course two bent rod bolts, but the bolts prevented the big end from getting loose. I doubt you will find any of the guys who make a living doing this using stock rod bolts in engines built to anything other than stock specs. I don't know what bolts Porsche used on their 2.8 race motors, but those motors got torn down between races typically and stock bolts I suspect are up to that number of fatigue cycles. Walt Fricke |
||
![]() |
|
Registered
Join Date: Oct 1998
Location: Denver, CO
Posts: 1,335
|
Thanks Walt -- that's exactly what I needed to hear.
__________________
- '72 911T - '81 911SC Euro |
||
![]() |
|
up-fixing der car(ma)
|
ARP are really not much more in the scheme of things, maybe $100 or roughly double stock rod bolts.
__________________
Scott Kinder kindersport @ gmail.com |
||
![]() |
|
Moderator
|
I used Raceware on my 3.8
__________________
Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
||
![]() |
|
Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
|
$185-205 (depending on who's supplying them) for ARP rod bolts inside a case that you don't want to have to open up again.... not a hard decision.
|
||
![]() |
|
up-fixing der car(ma)
|
Quote:
__________________
Scott Kinder kindersport @ gmail.com |
||
![]() |
|
Registered
|
What's the stroke of your engine? Here's a link to a thread that discussed the merits of some rod choices for 66 mm stroke engines, and that thread links off to a discussion of the merits of the different bolt choices.
__________________
John '69 911E "It's a poor craftsman who blames their tools" -- Unknown "Any suspension -- no matter how poorly designed -- can be made to work reasonably well if you just stop it from moving." -- Colin Chapman |
||
![]() |
|
Registered
Join Date: Oct 1998
Location: Denver, CO
Posts: 1,335
|
I'm using a 70.4mm crank with 92mm JEs.
__________________
- '72 911T - '81 911SC Euro |
||
![]() |
|