Today's Message Index:
----------------------
1. 04:44 AM - Balancing Connecting Rods (Hopperdhh@aol.com)
2. 05:37 AM - Re: Balancing Connecting Rods (Archie)
3. 04:52 PM - Re: Balancing Connecting Rods (Hopperdhh@aol.com)
4. 06:00 PM - Re: Balancing Connecting Rods (John Grosse)
5. 06:59 PM - Re: Balancing Connecting Rods (Archie)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Balancing Connecting Rods |
--> Engines-List message posted by: Hopperdhh@aol.com
I made a search in the archives and couldn't find anything on this subject.
Is is safe to remove metal from a Lycoming rod to match up a set of 4? The
worst one is 9 grams heavier on the big end. That is quite a volume of
metal, and the rods don't look like they have that much to spare. One option
is
to do it on the crank. Is it safe to remove metal from the crank.
I'm concerned about the nitride coating layer, mostly. Is there any advice
that anyone can give me about what to do or not do.
The engine is an IO-360-A1A. The rods are LW10646.
Thanks, Dan Hopper RV-7A Flying 144 hours
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Balancing Connecting Rods |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
If you attend Oshkosh, I conduct seminars on engine balancing.
Briefly, Aircraft manufacturers balance rods in total weight.
While this is satisfactory, for horizontally opposed engines,
an improvement is to separate Reciprocating from Rotating weights.
9 Grams is doable with care and stress knowledge.
On Lyc rods, there is an area by the rod bolt that is unfinished.
This area can be taken down and polished.
Do not use a grinding wheel. Metal must be removed with a high speed
belt sander so as not to allow the rod to overheat. If this happens, the
bore will distort.
Prior to starting, you may want to check the bore accuracy. Most aircraft
shops merely
replace the pin bushings and rod bolts. I have found that most rod bores
are "not on the money", but people use them as is anyhow. (no comment on
that)
Same with crank balancing. For the most part, they are not usually too bad.
Grinding and polishing is my preference. The factory balancing is with a
fairly
coarse finish.
Also, do not forget the starter gear. It becomes part of the crank
rotational force
when attached. (as do the bolts).
Archie
> --> Engines-List message posted by: Hopperdhh@aol.com
>
> I made a search in the archives and couldn't find anything on this
> subject.
>
> Is is safe to remove metal from a Lycoming rod to match up a set of 4?
> The
> worst one is 9 grams heavier on the big end. That is quite a volume of
> metal, and the rods don't look like they have that much to spare. One
> option is
> to do it on the crank. Is it safe to remove metal from the crank.
>
> I'm concerned about the nitride coating layer, mostly. Is there any
> advice
> that anyone can give me about what to do or not do.
>
> The engine is an IO-360-A1A. The rods are LW10646.
>
> Thanks, Dan Hopper RV-7A Flying 144 hours
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Balancing Connecting Rods |
--> Engines-List message posted by: Hopperdhh@aol.com
Archie,
Thanks for your reply. I understand about the whole rod vs. big end and
small end weights. The rods are actually at a local shop which specializes in
race car engines. I think they are pretty knowledgeable, but not experienced
in Lycomings. Could you be a little more specific about where to remove
metal. The rods have quite a lot of metal already removed along side the bolts.
I say that because it looks like rough machining there. There is an area
near the nut on the rod proper (not the cap) with some to spare possibly. Or
are you talking about on the cap? Knowing what 9 grams of steel looks like,
I am worried about trying to take that much off.
I will attend your seminar at OSH this summer, but that will be too late for
this job. I have attended a balancing seminar already, there. But, they
were just trying to sell prop "dynamic" balancing equipment. Don't get me
wrong. I am a believer in doing a final balance job on the prop end of the
engine, but I think it is a good idea to match up the internal parts first. The
pistons were within a few tenths of a gram, and the crank was also very good.
But the rods were by far the worst. If there is not enough "meat" on the
rods, how do you feel about taking some off the crank? I know that its like
two wrongs making a right, but its all rotating weight, so theoretically it
should be in balance.
Thanks again,
Dan Hopper RV-7A
In a message dated 3/4/2006 8:37:44 A.M. Eastern Standard Time,
archie97@earthlink.net writes:
If you attend Oshkosh, I conduct seminars on engine balancing.
Briefly, Aircraft manufacturers balance rods in total weight.
While this is satisfactory, for horizontally opposed engines,
an improvement is to separate Reciprocating from Rotating weights.
9 Grams is doable with care and stress knowledge.
On Lyc rods, there is an area by the rod bolt that is unfinished.
This area can be taken down and polished.
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Balancing Connecting Rods |
--> Engines-List message posted by: John Grosse <grosseair@comcast.net>
Why don't you try swapping rods with someone if that's a possibility. Or
do you have access to a shop with inventory that might let you had pick
a new rod to replace the 9 g heavy one you have?
John Grosse
Hopperdhh@aol.com wrote:
>--> Engines-List message posted by: Hopperdhh@aol.com
>
>
>Archie,
>
>Thanks for your reply. I understand about the whole rod vs. big end and
>small end weights. The rods are actually at a local shop which specializes in
>race car engines. I think they are pretty knowledgeable, but not experienced
>in Lycomings. Could you be a little more specific about where to remove
>metal. The rods have quite a lot of metal already removed along side the bolts.
> I say that because it looks like rough machining there. There is an area
>near the nut on the rod proper (not the cap) with some to spare possibly. Or
>are you talking about on the cap? Knowing what 9 grams of steel looks like,
>I am worried about trying to take that much off.
>
>I will attend your seminar at OSH this summer, but that will be too late for
>this job. I have attended a balancing seminar already, there. But, they
>were just trying to sell prop "dynamic" balancing equipment. Don't get me
>wrong. I am a believer in doing a final balance job on the prop end of the
>engine, but I think it is a good idea to match up the internal parts first.
The
>pistons were within a few tenths of a gram, and the crank was also very good.
> But the rods were by far the worst. If there is not enough "meat" on the
>rods, how do you feel about taking some off the crank? I know that its like
>two wrongs making a right, but its all rotating weight, so theoretically it
>should be in balance.
>
>Thanks again,
>
>Dan Hopper RV-7A
>
>
>In a message dated 3/4/2006 8:37:44 A.M. Eastern Standard Time,
>archie97@earthlink.net writes:
>
>
>If you attend Oshkosh, I conduct seminars on engine balancing.
>Briefly, Aircraft manufacturers balance rods in total weight.
>While this is satisfactory, for horizontally opposed engines,
>an improvement is to separate Reciprocating from Rotating weights.
>9 Grams is doable with care and stress knowledge.
>On Lyc rods, there is an area by the rod bolt that is unfinished.
>This area can be taken down and polished.
>
>
>
>
>
>
>
>
>
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Balancing Connecting Rods |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
The area on the main rod just above the nuts is unfinished on the factory
rods.
The obvious forging mark is there, and can be taken down maintaining the
same arc curve. This area is usually good for about five grams.
I cannot go into details here, but will tell you not to try and remove too
much
from any given area.
In certain instances, have turned a couple of grams off on a lathe.(nuff
said here).
Do not remove any metal from the periphery of the bolt holes.
(Superior rods are completely finished.)
Do not try to correct a rod weight by working the crank.
Adding bob weights is not the answer.
It is either right or wrong. If necessary, and you are not comfortable
with rod correction, either obtain closer rods, leave it alone, or just
use total rod weight..
There is much more to machinery dynamics than wheel balancing,
and not worth the risk of part failure if not experienced in this area.
Archie
> Archie,
>
> Thanks for your reply. I understand about the whole rod vs. big end and
> small end weights. The rods are actually at a local shop which
> specializes in
> race car engines. I think they are pretty knowledgeable, but not
> experienced
> in Lycomings. Could you be a little more specific about where to remove
> metal. The rods have quite a lot of metal already removed along side the
> bolts.
> I say that because it looks like rough machining there. There is an area
> near the nut on the rod proper (not the cap) with some to spare possibly.
> Or
> are you talking about on the cap? Knowing what 9 grams of steel looks
> like,
> I am worried about trying to take that much off.
>
> I will attend your seminar at OSH this summer, but that will be too late
> for
> this job. I have attended a balancing seminar already, there. But,
> they
> were just trying to sell prop "dynamic" balancing equipment. Don't get
> me
> wrong. I am a believer in doing a final balance job on the prop end of
> the
> engine, but I think it is a good idea to match up the internal parts
> first. The
> pistons were within a few tenths of a gram, and the crank was also very
> good.
> But the rods were by far the worst. If there is not enough "meat" on the
> rods, how do you feel about taking some off the crank? I know that its
> like
> two wrongs making a right, but its all rotating weight, so theoretically
> it
> should be in balance.
>
> Thanks again,
>
> Dan Hopper RV-7A
>
>
> In a message dated 3/4/2006 8:37:44 A.M. Eastern Standard Time,
> archie97@earthlink.net writes:
>
>
> If you attend Oshkosh, I conduct seminars on engine balancing.
> Briefly, Aircraft manufacturers balance rods in total weight.
> While this is satisfactory, for horizontally opposed engines,
> an improvement is to separate Reciprocating from Rotating weights.
> 9 Grams is doable with care and stress knowledge.
> On Lyc rods, there is an area by the rod bolt that is unfinished.
> This area can be taken down and polished.
>
>
>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|