This is a collection of notes on the G60 rod bearing replacement
procedure. Many have done this modification to eliminate the metallic rattle
between 2000-3000 rpm under no load conditions (ie, just cruizing). Note
that many 8V VW engines exhibit the same problem, and it has often
been attributed to wrist pin slap (correctly or not). It's also covered
under a VW TSB,
which recommends replacing the entire crank shaft,
To some degree this is a risky procedure because if you don't do it right, you may end up with a spun bearing, a rod sticking out of your block, or whatever. Shops that do this modification typically will NOT garantee the work. So be forewarned.
This is also the reason why I waited a couple of years to see what the long term effects are:
Here are a couple of statistically insignificant data:
| Name |
(approx) |
|
|
| Matt Heffner | May 1997 | 40k miles |
|
| Thorsten Allers | May 1997 | 25,000 miles |
|
| mega0019 | 160000 km |
wear while the rest seemed quite ok. (copper colour shining through) after consulting VW I replaced them with the standard size ( oversizing they said is only needed when the axle is revised.) |
Good Luck, Jan
Copyright (C), 1997, All Rights Reserved.
From: Thorsten
Allers
Date: Thu, 22 May 1997
A similar article can be found at: http://www.corrado-club.com/faq/detail_faq.CFM?FAQID=27
Ok, first I'd like to acknowledge Matt Heffner for telling me how to do this.
Then I have to get the standard disclaimer out of the way: use this
information
at your own risk. My employer has nothing to do with this, and I am
not
associated with any of the companies and products mentioned. I disclaim
any responsiblity for any mishaps that may occur as a result of this
procedure.
So, first check out the symptoms to see if you have connecting rod rattle
in
your G60 Corrado. It will sound like knocking (a metallic sound) but
occurs
only under partial load and especially between 2-3000 rpm. It can seem
to come from the right side of the engine. It is often loudest when
the engine
is slowing down through 3-2000 rpm. It will only be apparent when the
engine
oil is warm (>180F). Make sure the noise can also be heard when the
car is
not moving, as you don't want to misdiagnose it for something else.
Now go and buy the parts. You will need:
8 connecting rod bearing shells. Make sure
you get the revised set which
have a central oil hole. I threw away the box so I don't have the part
no.
They will come as a set and cost about $30. Get the standard sized
set,
as most of the wear will be on the bearings and not the crank. The
original
bearings were much too soft for the G60 engine.
8 connecting rod bolts and nuts. They will
also come as a set. They need
to be replaced because the stock ones are stretch bolts and cannot
be
reused. You can opt to buy the OEM bolts from VW, or for about the
same
price you can buy a set of Raceware
bolts.
The Raceware part no. is RTE-4002 and they cost about $120. They ARE
reusable.
One oil pan gasket, cost around $10.
5 quarts of synthetic oil (eg Mobil 1 15W50),
an OEM oil filter and
the small
copper washer for the drain plug, which should always be replaced.
Total cost
is around $25.
I bought everything except the oil from Velocity
(310-643-0005) because
they were the cheapest. The dealer wanted 3x as much as them for each
part (eg the bearings would have been $100 for the set). [Jan:
See the part numbers
as a reference in Thorsten's write-up].
Next check if you have all the tools:
Now get ready to spend most of your Saturday under the car.
First drive it around to get the oil warm, then drain out the old oil.
Meanwhile take out the spark plugs (you will need to rotate the crank
later) and cover the holes with clean rags.
Jack up the car and make sure it is safe on the stands.
Now get ready to take off the oil pan. For this you will need the 10mm
1/4" socket and flex extension. But first you may need to remove a
silver metal piece that is bolted onto the trans at the engine side,
which
obscures the oilpan bolts in that area. I don't know what it is for.
Take off oilpan (careful to keep all the bolts) and old gasket.
At this stage a lot of old oil will drain all over the floor.
Now remove the oil pump by undoing the larger 2 bolts which hold
it in place. The black baffle with also come away. If you want to
check/replace the oil pump, now is a good time.
Once the oilpump is out everything should become much clearer.
First put a wrench on the crankshaft pulley bolt (I found a sparkplug
socket ideal) and rotate until the crank journals are at the bottom
of
the stroke. Work on one connecting rod at a time, as you don't want
to mix up the rod caps. Undo the nuts and remove the cap. The
bearing should slide out easily. To get out the bearing shell from
the
rod itself you need to push up on the rod (but not too far in case
you
hit the valves), reach in and remove it. But first you may want to
remove
the old bolts. You will need patiently to hit them will a small hammer.
I say patiently because you don't want to screw anything up, but
really a hammer is the only way. Once the old bolts are out I would
think about putting in the new bolts first. Lubricate them with some
clean oil first (this also applies to the new bearings), then attempt
to push them in all the way. If they won't go try using the small clamp.
(It will work eventually, and if you replace the rod cap you can
draw the bolts into the holes by tightening the nuts.)
Now replace the bearings with the new ones (with central holes)
which you have lubed. You will see a small tab that will fit into
a notch in the rod or cap. Make sure this happens. Replace the
rod, making sure it is back on the same way you took it off: the
markings on the rod and cap should be adjacent to each other,
and the side markings should point to the timing belt side of the
engine. Now lubricate the nuts and tighten up the bolts. If you
have OEM bolts follow the torquing procedure in Bentley.
If you have Raceware bolts follow the torquing procedure
that comes with the bolts. I tightened up the bolts once,
undid them and relubricated, and retorqued them as they
recommend. Pay close attention to your torque wrench technique.
Now carry on and replace the other 3 sets of bearings. You will
have to turn the crankshaft after your second one. And it will
become much easier as you get some practice. Once you have
finished you may want to recheck the torque on the bolts, if you got
Raceware. If it's OEM, then leave them be.
Replace the oil pump and torque its bolts according to Bentley.
Wipe clean the oilpan flange and make sure all the old gasket
is off. Now comes a difficult part: you have to hold the new oilpan
gasket in place while you get the oilpan back on. You may
find a hose is the way. I got assistance at this stage; it's amazing
how much more you could do if you always had 4 hands.
Do up the bolts in a roughly cross-wise fashion and check them
all one last time for tightness (don't want any oil leaks). Replace
the mysterious silver thing on the trans, and replace the oil drain
plug, using the new copper washer. Take out the old oil filter
and replace with a new one (not much more than hand tight).
Recheck you replaced everything and take the car off the stands.
Pour in 4 quarts of oil and let it drain in. Meanwhile replace the
spark plugs.
Now start up the car. Let it run for a minute or 2, then stop the
engine and let the oil drain down again. Check with the dipstick
and add oil until it looks good (you will need around 1/2 quart more).
Do NOT overfill with oil (just thought I would get that one in).
Once the oil looks good start up the car again and check underneath
and around the oil filter for leaks. If all looks good, go for a drive
and then have a beer (in that order).
If this did not cure the noise then I'm afraid the problem lies
elsewhere (such as wrist pin rattle, which will be more difficult
to repair). If this is the case, then you can console yourself
with the knowledge you have a change to bond emotionally
(if not physically) with the insides of your Corrado.
However, in my case the noise completely disappeared.
I did the first oil change after the bearing swap at 1000 miles.
Quite a few metal shavings, but none at the next oil change.
I considered this normal.
Good luck, and if I missed anything let me know.
Thorsten
Apologies for the long message, but quite a lot of people
with G60s may be interested (I hope).
<snip (a lot of stuff about G60 rod rattle etc.)>
>The VW rep also said that bearing failures almost always occurs due
>to inadequate lubrication.
This is interesting. Seems as though VW are trying to claim
it is one kind of rattle that isn't serious, when it most probably
is another, more serious, thing. I refer to the mirror finish
I found on my old bearings, which is a good sign of
lubrication problems. The sides of the rods looked fine.
>OTOH, Randy Walterz with his 86 gTI, has been racing it every weekend
>with this problem (230k miles) and the engine has not blown yet.
>So I am not too worried.
Yeah, I know, I could have lived with it and not suffered at all, apart
from the embrarrasing noise. To tell the truth, at least part of the
reason
I did the repair is that I am not going to hang on the my Corrado for
ever (I am only in the US for a few years). If I try to sell it with
that kind
of noise I risk being sold short by far more than the repair cost me.
>The rattle (at least in my case) only occurs under no load or very
light
>load conditions, it promptly goes away under load.
>If there was something really wrong with your bearings, you'd hear
it
>especially
>underload (so I thought).
This is how mine seemed as well. However, it is possible that you
would not hear the noise under load because of increased engine
noise. I may have only started noticing my rod rattle after I had the
motor mounts replaced and the whole car became quieter.
>> wear, it was all on the bearings. Some of them had worn
>> to a mirror finish! The replacement bearings have a central oil
>> hole for lubrication and will therefore go a long way to
>> alleviate the real problem here, which is one of lubrication
>> and preventing metal-metal contacts, which will wear out the
>> bearings and lead to rattling.
>
>Well, this is indeed interesting.
>Is it possible that we may have a combination of problems (bad
>lubrication and rod
>slap?) Did you mic any of the bearings to measure wear?
No, I didn't have the time and energy to do that. I should have.
>What oil did you use in your engine?
This is an important point. I bought the car over 1 1/2 years ago
and it had slight rod rattle. I had the oil changes and service done
at one VW dealer, and they put Mobil 1 in. But the mechanic
changed and I went to another dealer for the next oil change.
I don't know what they used, but their price per qt was much
lower, leading me to suspect it was conventional oil. Anyway,
the rod rattle was really bad not long after that (but I also had
the mounts replaced). So, it would seem as though running
conventional oil in a G60 with rod rattle does you no favours.
>Could you send us more info on the part #s, where you bought them,
$,
>and what exactly you did to replace the bearings? Any Gotchas?
>I'd love to solve this problem with such an easy fix.
Bought every thing I needed from Velocity @ (310) 643-0005
Total cost was $200 including the oil etc.
Make sure you ask for the revised bearing set with the central oil
hole. Their item no. is VLK-05-300-2500, $29.95
As far as the rod bolts (which need to be replaced),
I went with Raceware rod bolts. Velocity sell them as well.
They are much stronger than stock and I think they cost about
the same. They are NOT stretch bolts, so they can be reused.
They are on the net at
http://www.wwnet.com:80/~raceware/
Follow the torquing instructions that come with the bolts,
NOT then ones in Bentley (these are for stock strech bolts).
(Make sure you have a good torque wrench.)
The Velocity no. is VLK-05-352-5100, $121.95
You will also need an oil pan gasket, an oil filter, the
copper washer for the oil drain plug, and 4.3 qt of oil.
All of these (apart from the oil) can be obtained from
Velocity much cheaper than a VW dealer.
As far as tools , you need a standard 3/8 socket set,
a 3/8 to 1/4 adapter, a 1/4 drive 10 mm socket and 1/4
universal joint (both to get at the oil pan bolts) and a
light hammer to knock out the old bolts.
As far as procedure goes, I should leave that for another
message. I have to credit Matt Heffner <bad90g@epix.net>
for all this info.
Sorry again to ramble on.
Thorsten
Jan,
Don't take any of this the wrong way, but why do you trust VW on this
issue? I mean, they never own up to foglights on SLCs cracking
with heat, do they?
It just seems to me that if something is rattling around in the engine,
then parts will wear out sooner, and the knock sensor may be fooled
into thinking there is knocking, thereby retarding ignition.
Furthermore, this is one of the areas of the engine that has the
greatest load placed on it.
I replaced the rod bearings on my G60 a few weeks ago, and
I did not have to remove the crankshaft. The bearings can be
changed with it in place, and it is relatively easy. As for the
wear, it was all on the bearings. Some of them had worn
to a mirror finish! The replacement bearings have a central oil
hole for lubrication and will therefore go a long way to
alleviate the real problem here, which is one of lubrication
and preventing metal-metal contacts, which will wear out the
bearings and lead to rattling. As far as the rod rattle, it is
now completely gone, so I suppose my wristpins are still fine,
and the crankshaft does not need to be replaced.
Of course, if the whole engine blows up in a few 1000 miles
then I will look really foolish...
Thorsten.
Hi Jan,
Yes, I changed the bearings myself. It's a good Saturday morning
project...
> which bearing did you replace (all?)
Yes, I replaced all the bearing shells with the revised bearings.
The bearings at the #1 and #2 cylinder (right at the knock sensor)
were the worst out of all of them, since they are farthest down the
lubrication circuit.
> DId you just drop the oil pan
> and worked from the bottom?
Yeap. Drop the oil pan and oil pump (inspect the pump's backlash
and
axial play while it is out). I removed my spark plugs also so
no
compression would build in the cylinder, and allow me to position the
crank in such a way that the journal of the bearing I was working on
was
at the bottom of its stroke. I then removed the rod cap nuts
and
rod cap, and pushed up on the rod to gain access to the bearing shell
in the bottom of the rod. Tap the old rod bolts out with a
lightweight brass hammer, and tap your new Raceware or new stock rod
bolts in. Put the new shells in the bottom of the rod and rod
cap,
and make sure you replace the cap so the markings on the bottom of
the rod and rod cap are aligned properly.
> Part numbers???
As Thorsten suggested in another post, Velocity is the best place to
call for your new bearings, bolts, and gaskets. Just make sure
you
are getting the revised bearing with oiling hole, and not a solid
shell.
Hope this helps,
Matt
'80 mkI Golf GTi
'86 mkII Golf GTi
'90 Corrado G60