Date: Mon, 4 Sep 2006 10:50:11 -0400
Reply-To: ROBERT DONALDS <donalds1@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: ROBERT DONALDS <donalds1@VERIZON.NET>
Subject: Re: Connecting Rod Bolts
Content-type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original
Evan
1.9 and 2.1 rods are the same casting and are interchangeable with the
exception of the bolt. The longer stroke 2.1 cranks in combination with the
1.9 rod bolts can but do not always hit the camshaft
The 2.1 rod bolt work well for 150K and I have seen these stretch to yield
bolts reused with failing.
2.1 rods distort over time by this I mean the big end is no longer round.
The cap shifts and the big end gets smaller opposite the parting line.
Another way to say that is if you draw a line down the rod from the small
end threw the beam of the rod threw the big end the circle is smaller at
that point. So just replacing the bolts is not the cure for the 2.1 rod
problem. The big end needs to be resized to do this I have a cap grinder it
trims a few thousandths off of the mating surfaces of both the rod and cap.
After deburing the hole and installing new non stretch to yield bolts and
reassembling the rod I torque the nuts and resize the big end with a sunnen
rod hone. Machine shops have spec books to provide dimensions for the
finished size.
I take the next step and that is to install rod bearings torque and measure
difference between the size of the ID of the big end with the bearing in
place The size of the rod journal this is clearance to the crankshaft. The
difference influences the warm oil pressure.
used rods with the 150K measure as much as .004ths bearing clearance this is
enough make oil light come on at an idle. My engines have a rod bearing
clearance of .0015ths. and I can say that because I have invested in the
right equipment to properly measure clearances and restore dementions.
you CANT just replace the bolts unless you only want 6k out of the engine
my rebuilt rods are $140 exchange with news bolts ready to install
Rebuilding is about restoring clearances
assembling is about adding parts
at Boston engine you get more than parts
Bob Donalds
Boston Engine
all rights reserved
----- Original Message -----
From: "Evan Mac Donald" <macdonald1987@SBCGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, September 04, 2006 8:51 AM
Subject: Connecting Rod Bolts
>I have heard that the bolts for 2.1 l con rods are not the greatest, and
>should be replaced on a rebuild with 1.9 l bolts. I don't have any 1.9 l
>engines around I could steal them out of, and would also worry about
>re-using "tired" bolts in an upgraded rebuild, anyway.
> Does any body have any suggestions? I haven't had much luck on my own,
> but I also have no idea what other bolts may be a usable substitute.
>
