saturn sohc piston rod bolt

[spasm3]

I had a rod bolt snap while assembling the engine. This bolt is 37lbs torque spec. I now want to change them all as i don't trust them

I can't find any on rock auto or ebay. It is head stamped 9.8 has 10mm head( don't know the thread size yet). If i match the threads , will any 9.8 bolt of the correct thread and length work? Or is there something special about rod bolts?

The rod is threaded and the bold goes through the cap and threads into the rod.

Thanks

 

[HerrStig]

That's something the dealer should supply, it's a critical area.

 

[eljefino]

I also snapped one of the stupid things. I think technically it's a splined stud.

I had the torque wrench on it and for whatever reason the fastener turned to butter and the wrench never clicked. Hint: Wasn't a top-tier tool.

 

[Trav]

Originally Posted By: HerrStig
That's something the dealer should supply, it's a critical area.


+1 Torquing the clean dry threads in multiple steps is a good idea. Torque all to 15lb then 30 then final spec.

 

[The_Eric]

Originally Posted By: Trav
Originally Posted By: HerrStig
That's something the dealer should supply, it's a critical area.


+1 Torquing the clean dry threads in multiple steps is a good idea. Torque all to 15lb then 30 then final spec.


You sure? It was my impression that the torque specs for head, rod and main fasteners were typically quoted as with engine oil on the threads.

 

[punisher]

Yup, unless otherwise specified, internal fasteners are torqued with clean oiled threads.

 

[eljefino]

You're supposed to have oil (or assembly lube?) on the con-rod bearing shells which I can imagine dripping on the stud threads below.

When you torque 'em if the little tabs in the bearings aren't lined up right they'll either go, or jam, and wreak havoc. But hope they go.

 

[spasm3]

Originally Posted By: eljefino
I also snapped one of the stupid things. I think technically it's a splined stud.

I had the torque wrench on it and for whatever reason the fastener turned to butter and the wrench never clicked. Hint: Wasn't a top-tier tool.

Originally Posted By: Trav
Originally Posted By: HerrStig
That's something the dealer should supply, it's a critical area.


+1 Torquing the clean dry threads in multiple steps is a good idea. Torque all to 15lb then 30 then final spec.


I was using a click wrench, i think i'll switch to the craftsman beam wrench, its just harder to read.

I did sneak up on the torque values, evenly on each nut before the final torque. The threads were clean and lightly oiled then wiped. The manual calls for oil under the cap of the bolt.

It felt spongy then just snapped, fortunately i was able to get it out of the rod. The torque was 33 ftlbs.

After much searching i finally found a GM part number for them and i found them at a GM parts outlet.
Some saturn parts are not easy to find anymore, like the pickup to block sealing ring.

Since one broke, i don't trust any of them so i'm replacing them all. I'm also going to loosen and re-torque the mains with the beam wrench just to make sure .

Thanks

 

[bdcardinal]

I have only ever used ARP rod bolts on an engine I assembled that mattered. You always use liberal amounts of the ARP lube and use a bolt stretch gauge when tightening.

For OEM style bolts you make sure the threads are cleaned thoroughly and then lubed with motor oil unless the OEM specifies something different.

 

[spasm3]

Originally Posted By: bdcardinal
I have only ever used ARP rod bolts on an engine I assembled that mattered. You always use liberal amounts of the ARP lube and use a bolt stretch gauge when tightening.

For OEM style bolts you make sure the threads are cleaned thoroughly and then lubed with motor oil unless the OEM specifies something different.


Thanks, i actually checked and arp does not make rod bolts for the saturn, they do have head stud kits.

 

[spasm3]

Originally Posted By: eljefino
I also snapped one of the stupid things. I think technically it's a splined stud.



I don't know about all years but for the 01 sohc the gm part number is;

21008005

I think the 98 and older had a shorter connecting rod. Mine is a fractured cap designed rod.

 

[Trav]

Originally Posted By: The_Eric
Originally Posted By: Trav
Originally Posted By: HerrStig
That's something the dealer should supply, it's a critical area.


+1 Torquing the clean dry threads in multiple steps is a good idea. Torque all to 15lb then 30 then final spec.


You sure? It was my impression that the torque specs for head, rod and main fasteners were typically quoted as with engine oil on the threads.

Your right.

 

[bdcardinal]

Originally Posted By: spasm3
Originally Posted By: bdcardinal
I have only ever used ARP rod bolts on an engine I assembled that mattered. You always use liberal amounts of the ARP lube and use a bolt stretch gauge when tightening.

For OEM style bolts you make sure the threads are cleaned thoroughly and then lubed with motor oil unless the OEM specifies something different.


Thanks, i actually checked and arp does not make rod bolts for the saturn, they do have head stud kits.


The key, even with OEM bolts, is to minimize friction when tightening. With the ARP lube you have to apply it anywhere the fastener touches, even under the head of the bolt and on the washer. The friction of the bolt rubbing against the surface will cause an inaccurate reading.

 

[Trav]

True, I forgot to say put a drop of oil on the clean, dry (blow with air to evaporate the solvent) threads. The threads should always be cleaned because sometimes loctite is used on them.

 

[spasm3]

Originally Posted By: Trav
True, I forgot to say put a drop of oil on the clean, dry (blow with air to evaporate the solvent) threads. The threads should always be cleaned because sometimes loctite is used on them.


Thanks, i did clean the threads on the main and rod bolts. I cleaned the the bearing seats so that no oil or anything was behind the bearing shells.

I washed the block until i could wipe the bore with a white towel and it was clean, i didn't want any remnants or boring to kill the rings. I cleaned the crank and ran long pipe cleaners through the oil holes as well, stuff came out of them on the pipe cleaners.