Forums
NautiqueParts.comNautiqueSkins.com - Correct Craft Upholstery and Part
  New Posts New Posts RSS Feed - PCM Engine Mounts
  FAQ FAQ  Forum Search   Register Register  Login Login

PCM Engine Mounts

 Post Reply Post Reply   
Author
Greg_SA View Drop Down
Senior Member
Senior Member


Joined: April-19-2007
Location: South Africa
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg_SA Quote  Post ReplyReply Direct Link To This Post Topic: PCM Engine Mounts
    Posted: April-19-2011 at 7:33am
Hi,

I was about to align my engine, but it turns out that one of the rear engine mounts (on the transmission) are totally seized.

I removed the mount, and have stripped it completely. I am replacing all the rubber isolators, washers, etc. In the process of stripping the heavily rusted mount, the lower stud retaining nut has been damaged (item #9 in diagram).

The PCM part description says:
RS1082 Nut, Two way Locking, Stud Retaining {Special} 5/8" - 18.

Is this a normal 5/8 UNF nut? Why does it say "special"?

I sourced a 5/8 UNF locally, but it seems to get quite tight as I turn it onto the stud. Just want to be sure I don't damage the threads (which are already not in great condition).

Thanks,
Greg

1989 Ski Nautique (SN2001)
Back to Top
8122pbrainard View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: September-14-2006
Location: Three Lakes Wi.
Status: Online
Points: 39118
Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 7:46am
Greg,
I'd say the only thing special is the class of fit on the treads. It's actually good that it is tight - it should be. Can you get the nut on? In a pinch, I've loosed up thread fits with very fine valve grind compound. A thin layer on the threads and run the nut back and forth a couple times.


54 Atom


77 Tique

64 X55 Dunphy

Keep it original, Pete
<
Back to Top
Greg_SA View Drop Down
Senior Member
Senior Member


Joined: April-19-2007
Location: South Africa
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg_SA Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 8:52am
I had a better look, and it seems like the threads on the stud are higher than those in the nut - i.e. the nut threads are shallower.

So by turning the nut onto the threaded stud, the nut is squashing the top of the threads on the stud. It will probably work, but its not ideal. You can see on the photo below that the nut has squashed the first 3 threads flat.

You think it is okay?

1989 Ski Nautique (SN2001)
Back to Top
cjnovus View Drop Down
Newbie
Newbie


Joined: April-19-2011
Status: Offline
Points: 6
Post Options Post Options   Thanks (0) Thanks(0)   Quote cjnovus Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 8:57am
You think it is okay?
Back to Top
8122pbrainard View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: September-14-2006
Location: Three Lakes Wi.
Status: Online
Points: 39118
Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 9:05am
Greg,
That is tight!!!

The bottom nut doesn't carry any weight of the engine. It's just handling any torsion loading. Can you source a 5/8-18 adjustable die over there? Is the "UNF" (18 pitch) out of the book? IE: are you sure it's a 18 pitch?


54 Atom


77 Tique

64 X55 Dunphy

Keep it original, Pete
<
Back to Top
Greg_SA View Drop Down
Senior Member
Senior Member


Joined: April-19-2007
Location: South Africa
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg_SA Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 9:11am
Originally posted by 8122pbrainard 8122pbrainard wrote:

Greg,
That is tight!!!

The bottom nut doesn't carry any weight of the engine. It's just handling any torsion loading. Can you source a 5/8-18 adjustable die over there? Is the "UNF" (18 pitch) out of the book? IE: are you sure it's a 18 pitch?


I'll find out about the adjustable die... So this would be to re-cut the thread on the stud?

I checked with a thread pitch gauge tool, and they did match. I'll try and measure the threads/inch.
1989 Ski Nautique (SN2001)
Back to Top
Greg_SA View Drop Down
Senior Member
Senior Member


Joined: April-19-2007
Location: South Africa
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg_SA Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 9:55am
I just double checked, and the thread pitch is definitely 18 for both parts... I find it strange the the thread depth can be so different :( I suppose the word "special" does mean something...

Another supplier says: NUT, LOCK PREV. TORQUE 5/8-18 Not sure it "torque" refers to anything?
1989 Ski Nautique (SN2001)
Back to Top
8122pbrainard View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: September-14-2006
Location: Three Lakes Wi.
Status: Online
Points: 39118
Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 10:05am
Greg,
There are basically 3 classes of "fits" of threads. The tightest being the "interference fit" or "prevailing torque" of a "lock" nut. This is what you have but looking at the picture of the deformed threads, it looks too tight. That's why I suggested seeing if you could borrow a adjustable die. A real light pass with a die is all it would take. If too loose, then you could always use a thread locking compound on it.


54 Atom


77 Tique

64 X55 Dunphy

Keep it original, Pete
<
Back to Top
Greg_SA View Drop Down
Senior Member
Senior Member


Joined: April-19-2007
Location: South Africa
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg_SA Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 3:16pm
Pete, thanks for all the advice, once again

I put some metal polish on the thread of the stud, and worked the nut a little back and forth, and it ended up hardly wearing the stud thread much at all (much less than the first 3 threads) - so it fits great.
1989 Ski Nautique (SN2001)
Back to Top
8122pbrainard View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: September-14-2006
Location: Three Lakes Wi.
Status: Online
Points: 39118
Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-19-2011 at 3:27pm
Greg,
Fantastic!


54 Atom


77 Tique

64 X55 Dunphy

Keep it original, Pete
<
Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 12:00am
I'm replacing my engine and transmission mount isolators. When I removed my old rear (transmission) lower isolator (part 29 in the diagram above), it was installed upside down from the diagram. Has anyone else seen that? I'm guessing the diagram is correct and mine was installed backwards in its previous life.

Thanks! -Rob
1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
TRBenj View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 20504
Post Options Post Options   Thanks (1) Thanks(1)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 7:50am
Diagram looks correct. That lower isolator does mushroom on the lower side once installed.

Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 10:28am
Thanks Benj!

It's also interesting that the ring at the top of the bracket is closed on yours, like the diagram shows. Mine are open, much like a flarenut wrench. Same functionality, just not an enclosed circle.
1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
TRBenj View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 20504
Post Options Post Options   Thanks (0) Thanks(0)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 10:33am
Have definitely seen that open top on the earlier Waukesha mounts. What year boat (engine)?
Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 10:50am
1975 or 1976 (I can't quite determine for sure) with PCM 351. However, a previous owner had, at least, rebuilt the engine, which doesn't have an engine tag anywhere. So for all I know, it could have been swapped from an original Waukesha 🤷🏼‍♂️
1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
TRBenj View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 20504
Post Options Post Options   Thanks (1) Thanks(1)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: April-13-2020 at 10:56am
That’s early enough that the open tops wouldn’t surprise me... last year for Waukesha was 74ish... typically see the PCM name used instead soon thereafter. By the 80’s, the tops seem to be closed, typically.
Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: May-20-2020 at 11:21pm
I just replaced my rubber isolators. How much torque do I need to use to tighten down the nut ( #9 in the diagram) to properly compress the rubber bushing and get it to the correct snug-ness?

And how about the equivalent nut on the front (engine) mount?
1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-21-2020 at 7:46pm
Originally posted by robdubbleu robdubbleu wrote:

I just replaced my rubber isolators. How much torque do I need to use to tighten down the nut ( #9 in the diagram) to properly compress the rubber bushing and get it to the correct snug-ness?

And how about the equivalent nut on the front (engine) mount?


Here's a picture of a 76 PCM transmission mount and that nut on the bottom is threaded on to have about 1/16 inch of threads showing to have the proper amount of "snug-ness".

No torque value needed

Same open C shaped top as what you're talking about



Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-21-2020 at 8:06pm
Originally posted by robdubbleu robdubbleu wrote:

1975 or 1976 (I can't quite determine for sure) with PCM 351. However, a previous owner had, at least, rebuilt the engine, which doesn't have an engine tag anywhere. So for all I know, it could have been swapped from an original Waukesha 🤷🏼‍♂️


So far your boat has taken turns being a 74 then a 76 and now a 75 or 76

Why don't you post the HIN and it should be relatively straightforward to figure it out.
Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2020 at 11:23am
Originally posted by KENO KENO wrote:

Originally posted by robdubbleu robdubbleu wrote:

1975 or 1976 (I can't quite determine for sure) with PCM 351. However, a previous owner had, at least, rebuilt the engine, which doesn't have an engine tag anywhere. So for all I know, it could have been swapped from an original Waukesha 🤷🏼‍♂️


So far your boat has taken turns being a 74 then a 76 and now a 75 or 76

Why don't you post the HIN and it should be relatively straightforward to figure it out.


Ok, you caught me! Forgive me, as I initially was told it was a 75 by the previous owner. Then the official title shows 74. And the hull number indicates (I BELIEVE) that it was built in December of 75 so I don't know if that was sold as a 75 or 76 model. HIN: CTC05834M75E SNK-76. And to muddy the waters further, there's conflicting and ambiguous info on the webz regarding the decoding of the HIN   


As for the mounts, thanks so much for that picture!!! That should be all I need. I took pics of almost everything but not these. Now is it too much to ask for a similar picture of the front mounts?
1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2020 at 2:49pm
Originally posted by robdubbleu robdubbleu wrote:

Originally posted by KENO KENO wrote:

Originally posted by robdubbleu robdubbleu wrote:

1975 or 1976 (I can't quite determine for sure) with PCM 351. However, a previous owner had, at least, rebuilt the engine, which doesn't have an engine tag anywhere. So for all I know, it could have been swapped from an original Waukesha 🤷🏼‍♂️


So far your boat has taken turns being a 74 then a 76 and now a 75 or 76

Why don't you post the HIN and it should be relatively straightforward to figure it out.


Ok, you caught me! Forgive me, as I initially was told it was a 75 by the previous owner. Then the official title shows 74. And the hull number indicates (I BELIEVE) that it was built in December of 75 so I don't know if that was sold as a 75 or 76 model. HIN: CTC05834M75E SNK-76. And to muddy the waters further, there's conflicting and ambiguous info on the webz regarding the decoding of the HIN   




As for the mounts, thanks so much for that picture!!! That should be all I need. I took pics of almost everything but not these. Now is it too much to ask for a similar picture of the front mounts?


As far as the front mounts go, the nut on the bottom is put on the same way and has same amount of threads showing.

2 lock nuts are used, one above and one below the trunnion stud

I'd take a picture but the fronts are in a boat and you can't see the bottom nut when it's mounted to the stringer    

That HIN says to me that it's a 75 model year built in December of 74. but I could be all screwed up.

Maybe it never left the factory that year and they magically turned it into a 76 at the factory since in some of your previous pictures it looks like a 76, especially the windshield frame

My 76 ended with SNK and no numbers after it.

Let's see a picture of that HIN
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2020 at 2:55pm
Look at the thread in the link and click on that link and go to page M1-4 and you'll see the parts breakdown of the front mounts.   

link

I just don't know what it takes to get something added to the reference section   

Back to Top
robdubbleu View Drop Down
Senior Member
Senior Member


Joined: December-26-2016
Location: Mt. Island Lake
Status: Offline
Points: 109
Post Options Post Options   Thanks (0) Thanks(0)   Quote robdubbleu Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2020 at 6:52pm
Originally posted by KENO KENO wrote:


Let's see a picture of that HIN

As requested!

1976 Ski Nautique (PCM 351) - Currently under major renovation: floor, carpet, interior, gel coat, engine overhaul
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-22-2020 at 9:27pm
Originally posted by robdubbleu robdubbleu wrote:

Originally posted by KENO KENO wrote:


Let's see a picture of that HIN

As requested!



With all those numbers, you can call it whatever you want..........or talk to the factory and see what they tell you
Back to Top
Wilhelm Hertzog View Drop Down
Groupie
Groupie


Joined: June-14-2014
Location: Cape Town
Status: Online
Points: 67
Post Options Post Options   Thanks (0) Thanks(0)   Quote Wilhelm Hertzog Quote  Post ReplyReply Direct Link To This Post Posted: May-23-2020 at 8:50am
Originally posted by KENO KENO wrote:



link

I just don't know what it takes to get something added to the reference section   



I've also found that parts manual exceptionally useful, and have also requested Keith to add it to the Reference section, but nothing so far.
1982 Ski Nautique PCM351
Do not go gentle into that good night. Rage, rage against the dying of the light.
Back to Top
KENO View Drop Down
Grand Poobah
Grand Poobah


Joined: June-05-2004
Location: United States
Status: Online
Points: 6224
Post Options Post Options   Thanks (0) Thanks(0)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: May-23-2020 at 8:18pm
Someone pointed out to me that the link to the PCM parts manual no longer gets you to the manual but through the wonders of e mail I can send a PDF copy of the manual to somebody who can put it in the reference section so it'll always be available

Back to Top
Gary S View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: November-30-2006
Location: Illinois
Status: Offline
Points: 12899
Post Options Post Options   Thanks (0) Thanks(0)   Quote Gary S Quote  Post ReplyReply Direct Link To This Post Posted: May-23-2020 at 10:14pm
Does not look like Marine Parts handles PCM parts anymore probably why the list is gone.
69 Mustang HM SS
95 Nautique Super Sport
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Copyright 2020 | Bagley Productions, LLC