Torque Value Carrillo Rod Bolts on Hi-Cam Engine

[Old Jock]

I know stretch is the correct method to get the required tension on the rod bolts, but I don't have a stretch gauge

Until I remove the bolts I won't know their size but the manual quotes values of approx 61.5 to 67 lb ft. I think this might be too high as the Carrillo sheets I've seen for an M10 (they look about that size but I could be wrong) a do not exceed torque of 55 lb ft (for the multiphase bolts) and if they are M10 I'd be scared to go above that as I could place the bolts into yield

Anybody any idea or what they did, if they have experience with the Carrillo rods in the Daytona RS/Centauro engines?

John

[dxhall]

Are the figures you’ve quoted dry, with oil, or with moly?  Carrillo usually gives the figure with moly.  Those are high numbers for lubricated bolts.

[guzzisteve]

Found this John----------

https://www.cp-carrillo.com/files/steel-bolt-instruction.pdf

Pete R had a set of those for sale so he most likely knows.

[Old Jock]

dxhall

The manual makes no mention of dry or lubricated (in usual Guzzi form). But from what I've seen Carrillo recommends that the bolts are pre lubed prior to install

Thanks Steve these numbers are higher than the sheet I seen, looks like more conflicting information (SIGH)

I'm doing this to split the rods inspect the shells and plastigauge the bottom shell to journal to get a rough idea of the clearances, since I'm in this far. TBH I don't think I'll find anything but unless I do I just won't know for sure

Yeah Pete has probably installed a good many of them and will know, I'm hoping he pops in to share his wisdom with this dullarrd

Thanks for the replies so far

[5154guzzi]

John,
 I`m not sure which size bolts were standard on the Daytona engines, I believe it was the 5/16ths.  I`ve always gone the spendy 3/8 Carr bolt route which takes a higher torque to get to the recommended stretch. These rods are good for 150 hp per cylinder, which is a bit overkill, but it`s a high winding race engine and worth the peace of mind.  If you have a decent micrometer , that can be used to measure the bolt stretch in a bench vice.  Use a small ball bearing in the recessed area of the bolt head to get accurate before and after measurements.   With the larger 3/8 bolts, I found 55 Ft LBs got me the correct stretch, which was still a few pounds under the maximum torque. That's with Carrillo bolt lube lube on the threads and under the bolt heads.  I know the rod manager at Carrillo and can pass along any questions when you know what you have .

 Bill R

[Old Jock]

Thanks a bunch Bill that's really useful information

To measure bolt stretch I not need to remove the whole rod, which I'm loathed to do as stretch vs torque is going to be based on both components and the friction required as they mate?

Also wonder now many mechies have just read the Guzzi manual and whacked them up to Guzzi's recommended torque value.

I'll certainly take you up on your offer of advice one I get the bolts out, and I've found a store in Germany selling the bolt lube

https://www.fvd.net/us-en/FVD10397599/fastener-assembly-lube-carrillo-1-oz.html

Perhaps try to remove the bolts today. TBH I'm crapping myself knowing that somewhere in excess of 60 lb ft will be required to remove the bolts (perhaps more) and I'm loading that through an 11mm socket.

It all sounds like a recipie for things to get really bad really really quickly and if it does God help me at the price Carrillo want for rods 

[weevee]

TBH I'm crapping myself knowing that somewhere in excess of 60 lb ft will be required to remove the bolts (perhaps more) and I'm loading that through an 11mm socket.

It all sounds like a recipie for things to get really bad really really quickly and if it does God help me at the price Carrillo want for rods 

I recently had to remove/replace a couple of these small-headed bolts on my Roadster, John - and they're torqued to 95 lb/ft.  They came out easily enough, despite their poor quality (..relative to Carillos) - and the dodgy Halfords socket I was using.  Maybe you can take heart from that!

Steve
https://www.smarttune.co.uk/product.php/598/smart-car-hub-stretch-bolt-front-fortwo-up-to-07

[5154guzzi]

John,
     Is this an assembled motor that you are only removing the caps to inspect the shells and journal ?    I haven`t tried the rod stretch measurement on an `assembled in the engine' rod, but it should be possible if the engine is out,  face down on an engine stand. My Carrillo 3/8ths Carr bolts have a 7/16 bolt head ( 11mm ) . The install sheet states a max torque of 58 FT Lbs. To make unbolting easier, use a 1/2 inch drive adapter and a large breaker bar and for sure , a quality 12 point socket.  Have never had an issue with US craftsman sockets , but could see a cheap socket possibly be not up to the task.  If you have moly based paste on hand, you can use that mixed with engine oil as per Carrillo.    Is this the engine in your 4v Magni ?

 Bill

[Old Jock]

Yes Bill

It's the Magni Australia (RS Hi Cam engine, which in Europe at least has the full 'C' kit, including Rillos and Wiseco pistons I believe). I've been chasing a low oil pressure problem with it for some time.

The engine is assembled, I was doing exactly as you suggest with a breaker bar and an 11mm socket but was wondering if the socket was the correct size. It fits (I'm using a Craftsman socket) but it's awkward and at an angle so I'm wondering if it really is worth all the trouble. Could I really be losing 10 psi or more from the big ends personally I doubt it. I've had a couple of goes but these bolts just don't seem to want to move and I'm afraid I do more harm than good.

I was getting a little movement between socket and bolt and that has scared me of for the moment and wondering if it was an imperial size. If I do decide to do it I think I'll purchase a decent brand 7/16th socket.

Spot on it was just to check shell condition and gap (with Plastigauge), seeing I'm in that far

To do it properly I'd need to remove the engine, which is a chore. I had the engine separated from the frame recently, when replacing the rear mains (no difference to pressure) and total removal is not much more work, but depressing all the same

I've got Molypaste but I'd probably just purchase the correct grease the cost is not that great, although probably but a rip off

Steve

Thanks for the encouragement, although it's more courage than en-courage I think I need

John