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Connecting rod bolts

mojobaby

mojobaby

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Has anyone got a set of con rod bolts for me? I think that they're also called big end bolts. They're for my 845cc that I'm rebuilding.
I put the old ones back in place, but when I re-torqued them, the very last bolt just turned and turned. The spec calls for 26 ft/lbs of torque but for some reason I tightened them to 30. So it was probably my fault entirely. I just hope I haven't stripped the female side!
No one in town has them in stock and Renault wanted to charge me 8.50Euro EACH!. Franzose also does not stock them.
Please help!
 
I can send you a complete connecting rod if you like. Than you are sorted
If you send me your address and E-mail we'll get this done for you.
I need some time to strip my donor 845

Grtz Robert
 
Thank you! I'm very grateful for your help. I am somewhat surprised that no one stocks the bolts as my manual recommends that they be replaced.
I will PM you my details
 
If anyone is looking for connecting rod bolts, R-Quatre has them, and I've ordered a set. Neither Franzose or Melun Retro stock them.

I'm having a really bad week with bolts. Today when I put my flywheel back on, 3 out of the 4 bolts stripped as well:( They are supposed to be torqued to 30ft/lbs, but they only got to 25ft\lbs.

Apparently my bolts have "neck-stretch", where the part just below the head thins out do to metal fatigue or over-torquing.

When I disassembled the engine, most bolts were fused into their cavities and I had to use excessive force to loosen them, so I'm thinking that they have been over stressed and weakened.

Can anyone tell me if the bolts are specifically made only for cars; how are they graded for strength and do they have to be a certain type of steel?

Here is a photo of the head of my bolt. Any idea what those symbols mean?

DSCF6569.JPG
 
Is your torque wrench properly calibrated? A friend of mine had a torque wrench that was inaccurate and all his engine bolts came loose! If yours is inaccurate in the other direction it might account for all these stripped bolts.

You can test them by clamping the socket end in a vice and hanging a 25lb weight 1 foot from the end. That's 25lbft.
 
Thanks for suggesting that, Malcolm. Since doing the test I have realized that I have been the one at fault. I was setting the gauge at 25lbs and then screwing in the tightening nut at the back of the handle. This pushed the grip about 10lbs higher before it finally gets tight. So my 25lbs was actually about 35lbs.

I used the formula; TORQUE=LENGTHxWEIGHT
I chose a point half way up the handle at 14inches or 1.17 foot
My weight was 9 liters of water which weighed 19.8lbs.
Multiplying the two together, I got 23.4 torque

I set the wrench to 23.4ft\lbs and at first nothing happened until I realized that I was reading the tool incorrectly, but when I moved it back 10 points, the wrench clicked.
So i would recommend to anyone using a torque wrench for the first time, to do this test to make sure the it is calibrated correctly and also that you know where to take the reading.

It's now cost me a lot of money and headaches and wasted time. Here are a few photos of the test
DSCF6572.JPG DSCF6574.JPG
 
mojobaby said:
If anyone is looking for connecting rod bolts, R-Quatre has them, and I've ordered a set. Neither Franzose or Melun Retro stock them.

I'm having a really bad week with bolts. Today when I put my flywheel back on, 3 out of the 4 bolts stripped as well:( They are supposed to be torqued to 30ft/lbs, but they only got to 25ft\lbs.

Apparently my bolts have "neck-stretch", where the part just below the head thins out do to metal fatigue or over-torquing.

When I disassembled the engine, most bolts were fused into their cavities and I had to use excessive force to loosen them, so I'm thinking that they have been over stressed and weakened.

Can anyone tell me if the bolts are specifically made only for cars; how are they graded for strength and do they have to be a certain type of steel?

Here is a photo of the head of my bolt. Any idea what those symbols mean?

View attachment 13233
Click to expand...
Hi, I have looked on the R-Quatre web site and Connot find the con rod bolts do you by chance have there part number from when you ordered them. I am looking for eight of them.
Thanks
Richard.
 
Hi Richard
At the time I didn't know what the part number was, but you can see from the attached photo from my manual that it is 7700 509393.
When I wrote an email to Jan-Willem at R Quatre I just asked for the con rod bolts for 845cc engine, He didn't stock them but he found them from another source.
He's always been really helpful

Screen Shot 2024-07-18 at 23.47.39.png
 
Indeed Jan-Willem is the best Renault parts source in The Netherlands. He is running towards 90 years but still full of life and knowledge.
Started with R-Quatre now known as https://www.renault4onderdelen.nl/ you can always get in contact and just ask.
 
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