dibarlaw

1925 Standard Saga Continues

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There is a slot in the connecting rod.  I was going to go thru the slot.  I found it odd that they did not put a wire on these 6 bolts when they wired all the other bolts.  IMG_5370.thumb.JPG.d35fd41af8eef29d439541fe7a14a8b6.JPG

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Hugh

 

Split lock washers are an interesting subject. Lots of information out there on their use.The science appears to run contrary to our faith based application.

The literature out there all comes to the conclusion that they do nothing to prevent loosening. Once the bolt is tightened, and the washer flattened you are simply relying on the friction on the bolt threads to prevent loosening.

Here's one of the many links:

http://hillcountryengineering.com/wp-content/uploads/2011/10/Split-Lockwashers-Separating-Myth-from-Truth.pdf

That said, I still look at them and reinstall them with the thought that they will prevent loosening .Just can't shake it!

 

On a related note, When I removed the clamp bolt, some of the bolts were damaged by the wrist pin groove being out of alignment . ( my bad, probably should have stopped when the bolt removal got tough and re centered the wrist pin.

In doing so, I damaged some of the threads. No problem I figured, I'll just chase them with a appropriate die . I know there are restoring taps and dies but I've never had a problem with using regular dies for this...until now. There is something about those bolts that just do not lend themselves to this kind of operation. Its not like I'm simply cutting too much metal, its more like everything is binding during the operation. Afterwards, the threads don't look so much recut as squished around.

I'm wondering if there was either a special steel for those bolts or a different thread depth. The diameter and pitch  appear to be standard 5/16" NF.

I'm thinking of using Grade 8 bolt,  , lockwasher and high temp Loctite if I ever get it back toigether

 

Brad

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Your original bolts may be equal to todays Grade 2 bolts. My 29 has many original bolts. They are very soft compared to todays Grade 8. If switching to Gr 8 hardware I would do a trial assembly carefully bringing torque up to recommended specs for that particular grade fastener. My concern is that the threads in the rod may not be capable of holding the torque required for proper bolt stretch. If a bolt isn't torqued or stretched correctly at assembly there is a risk or it backing out or failing from fatigue. If all rod threads hold I would definitely use genuine locktite on the threads and discontinue use of the original lock washers. Also watch for threads bottoming in the thread bore.

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Going back to the offset piston pin for a minute. I did a search "why offset wrist pins" and it appears there are two reasons. One was to reduce piston slap by introducing lateral forces pushing the piston against the cylinder wall. The other was to change the angle of the connecting rod to the crank at TDC.

At the end of the article In the comments section there was this:

 

One guy said "it is like when peddling your bike and you stand up off the seat and move your center of gravity forward so you body mass is ahead of the crank spindle when you push down. It's probably not that simple but that's the general idea."

 

And another "The benefits/drawbacks of using pin offset usually makes for a lively topic of discussion among armchair engineers.  The reality is that it probably does not make a whole lot of difference unless the offset is huge.
The typical offset is usually around 1mm to 2mm.  That amount of offset can reduce the noise from piston slap, but it won't really affect combustion efficiency much.  The piston motion around TDC becomes asymmetric, with a lower initial velocity after TDC and a higher velocity just ahead of TDC.  It just becomes a trade-off."

 

And here are piston dimensions for standard engines 25 through 28 according to my Spring 1931 Chilton Automotive Multi-Guide

               Bore    Piston Height     Compression Height

1925       3"               3 13/16"                2 1/4"

1926       3 1/8"        3 13/16"                2 1/4"

27&28     3 1/8"        3 49/64"               2 3/16"

Willys      3 1/8"                                      2.167" 

 

Dave

 

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Glad you got home safely from Hershey. We did have a great time. Thanks for the info. This is what I can forward to Reeve's.

After you left the show field I talked with John Fesser as he had the 1928 in HPOF.

DSCF6359.thumb.JPG.c3ad8519cf52f23638fae574d9a93b80.JPG

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Thanks Larry. I'm sorry to have missed John Fesser and his '28. It's a great car. Love those beefy tires.

 

Dave

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On ‎10‎/‎5‎/‎2017 at 4:09 PM, Hubert_25-25 said:

The wrist pin bolts on my car are only held with a lock washer.  Larry mentioned that he has known someone where one of these came loose.  I would like to wire mine.  I have ordered 6.  I also plan to get 6 grade 8 lock washers to replace the existing lock washers as one I have is already missing a piece.

 
AN5H-12A  5/16-24 x 0.813 Grip Airframe Bolt, 1.34 UHL, Drilled Head  $0.79 
 
 
Hugh
IMG_5371.thumb.JPG.134d5973c7a4a4c0bac4901ab03e0100.JPG

 

I am one of those persons that had the bolt break and I lost a cylinder and piston when the top of the rod broke on a tour.  Needed to sleeve the cylinder and replace the rod.  The good and bad of that experience is that I ended up putting aluminum pistons in the engine since it was out.

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As I just wrote in another posting, split lock washers have no place inside an engine. The above photo is exactly why.

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Jerry

 

Buick thought one needed 6 of 108579 5/16"  lock washers  to make the engine operate correctly but I take your point. Times have changed and the evidence is clearly against split 'lock' washers.

Your suggestions for an alternative for this application? 

1) Just the bolt?

-2) bolt + loctite?

-3) bolt + internal or external toothed lock washer?

-4) bolt  + above lock washer + loctite?

-5) bolt + lock wire  ( Hugh has a lot more patience than I do !!!)

 

I'm thinking 3) as the Loctite would be a bit of overkill .

 

If your post had more info, could you provide a link?

 

Brad

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The 1928 Riley Nine engine I have nearly finished assembling has only loctite. I have used it before on engine assemblies amongst other things and believe it is superior to mechanical means such as lock washers etc. I recommend to just go with loctite, no need for the washer, which could fail like you have experienced.

Matthew

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What great responses!  Thank you. 

It's not normal anymore to see broken lock washers given current manufacturing controls.  I always see this kind of broken stuff on vintage fasteners, but I think rare on modern parts.  Especially if buying graded fasteners.  Tolerances and metallurgy are vastly improved since 1925. 

Since I bought the exact size drilled bolts as were in the engine originally, I may send them back and get a shorter bolt as I am leaning toward leaving the lock washer out.  If I stay with this length I may just use an improved lock washer.

 I made the same mistake as Brad did, and buggered up the threads on most bolts with the wrist pins being slightly misaligned and that flattened the threads on removing the original bolts.   Brad knows me too well now.  He is correct on my plan to do #5.  I have had some loctite failures where the loctite never dried.  I can't afford a failure here.

Not a rocket scientist, but what would NASA do?  Probably all of the above, and wear a hair net in the process to prevent contamination. 

 

Hugh

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3 hours ago, Hubert_25-25 said:

 

It's not normal anymore to see broken lock washers given current manufacturing controls.  I always see this kind of broken stuff on vintage fasteners, but I think rare on modern parts. 

 

Especially if buying graded fasteners.  Tolerances and metallurgy are vastly improved since 1925. 

 

Hugh

 

I agree with this.  A lot of original lockwashers break when I remove them from the Buick, they snap right in half. 

 

New hardware, I have never experienced it. 

 

Loctite is amazing, but always do a test piece on the bench from the same batch you use on the car, to make sure it cures. 

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I don't know if your rods do fit or not but in cases where conrods use pinch bolts and when the rod doesn't fit down the bore, I fit the rod to the piston and bolt it together, then fit the piston from the bottom leaving the task of fitting the rings till last. A lot easier in my opinion than trying to fit the piston to a rod in the block.

Matthew

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I did not have time to read the whole post so if you still need the pipe from the rocker to the heat, I have one off a 28 Master that looks like it is the same as yours.   It is yours if you want to risk the postage.   fred.rawling@live.com   562 644-4670 are the surest ways to contact me.

 

Fred

 

 

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