Topic: Cam tower studs

[disco]

I'm rebuilding a K2 & i've just noticed that the cam tower studs are missing. This engine had been disassembled when I got it. It was literally in boxes. I've searched high & low and there no longer around. Don't know they were there to begin with! This part is no longer available. CMSNL describes it as a M6 x58lg stud. Can I just fabricate some? Any thing special about them? Your suggestions would be appreciated. What do you use to seal them? Hondabond?

[BPellerine]

as long as you have a die set you can make them,if you have some longer m6 bolts or studs cut them to size and put some thread on them,they are not a high torque item,they use a shouldered nut but maybe a nut and washer will do.bill

[markb]

I don't know why you couldn't just use threaded rod. Or a hex head screw for that matter. I've often wondered why the studs were used on one side of the tower and a screw on the other. Maybe someone will chime in on that. And yes, you want to seal them. Plain old thread sealer is all I've ever used.

[drumstyx]

If you use threaded rod, make sure you use 8.8 or better. I broke a stud and thought the same, but the local Fastenal only had something like grade 4 or 5...Nowhere near strong enough, as I found out testing with a couple nuts. Didn't even stand up to 4 ft lb

[jamesw]

PM MRieck....he always has a bunch.

OR
https://www.mcmaster.com/#standard-threaded-rods/=169axlq
PM madmtnmotors...he can direct you which bolt to buy. He buys from these guys often.

OR
http://m.ebay.com/itm/HONDA-OEM-NOS-92700-06056-BOLT-STUD-6X56-B6T-/222388807670?hash=item33c767e7f6%3Ag%3Ah1wAAOSwARZXmniD&_trkparms=pageci%253Aed73e116-eda5-11e6-b502-74dbd1807871%257Cparentrq%253A1b8ab2f215a0a6a5e3ba22f9fffdd515%257Ciid%253A1

OR....as an absolute last resort
http://m.ebay.com/itm/Honda-OEM-Bolt-Stud-92700-06056-/381388213942?hash=item58cc824eb6%3Ag%3AhRQAAOSwLVZV6d8G&_trkparms=pageci%253Aed73e116-eda5-11e6-b502-74dbd1807871%257Cparentrq%253A1b8ab2f215a0a6a5e3ba22f9fffdd515%257Ciid%253A2

[disco]

Thanks Bill/Styx/Mark/James!
Yikes on those Honda prices! I have done some measuring & have some M6 grade 8.8 bolts on order, in 55mm & 80mm lengths. I'll attempt to make some studs out of the 80mm ones with a set of dies. If they're too tough to thread, then I'll resort to using the 55mm bolts.

[slikwilli420]

I am missing the studs on my race head and think I will go all out with time serts for each hole and ARP bolts instead of studs. Should make for a substantially stronger than stock setup.

[Don R]

 Use a good die. I needed a thread on a pto type cable end and the end was harder than my cheap die. I then used a good brand die and it worked beautifully.

[PeWe]

If the threads are bad, use time serts. It shold be much better if that should been done before head was mounted, done in a real drilling machine and get the threads absolutely 90 degrees relative the surface. I have inserted time serts in 3 of them, the 4:th still a heli coil I mounted in the 80's.

Glue the thread inserts with Loctite 272 (hard and heat resistant), seal stud with teflon thread sealer also high temp.

[disco]

Thanks PeWe,
The threads in the head where the studs engage are perfect, so I don't need to repair the thread. I just need to make some studs or use suitable bolts.

[madmtnmotors]

https://www.mcmaster.com/#98867a270/=t15a10

or

https://www.mcmaster.com/#93210a017/=t19sgp

[slikwilli420]

https://www.mcmaster.com/#98867a270/=t15a10

or

https://www.mcmaster.com/#93210a017/=t19sgp

I would be worried the first on you posted didnt have enough threads on the one side. Additionally, these are not class 8.8 which I have seen suggested elsewhere. Probably better off with higher grade bolts or threaded rod.

[madmtnmotors]

https://www.mcmaster.com/#98867a270/=t15a10

or

https://www.mcmaster.com/#93210a017/=t19sgp

I would be worried the first on you posted didnt have enough threads on the one side. Additionally, these are not class 8.8 which I have seen suggested elsewhere. Probably better off with higher grade bolts or threaded rod.

They are both in in excess of class 8.8...

[slikwilli420]

https://www.mcmaster.com/#98867a270/=t15a10

or

https://www.mcmaster.com/#93210a017/=t19sgp

I would be worried the first on you posted didnt have enough threads on the one side. Additionally, these are not class 8.8 which I have seen suggested elsewhere. Probably better off with higher grade bolts or threaded rod.

They are both in in excess of class 8.8...

Dug up a chart, yes, they are class 8.8

[madmtnmotors]

https://www.mcmaster.com/#98867a270/=t15a10

or

https://www.mcmaster.com/#93210a017/=t19sgp

I would be worried the first on you posted didnt have enough threads on the one side. Additionally, these are not class 8.8 which I have seen suggested elsewhere. Probably better off with higher grade bolts or threaded rod.

They are both in in excess of class 8.8...

Dug up a chart, yes, they are class 8.8

According to McMaster-Carr a class 8.8 with a 6mm diameter has a tensile strength of 110,000 psi. The first one (57.5mm long) has a tensile strength of 116,000 psi and the second one (65mm long) has a tensile strength of 125,000 psi...

[flybox1]

This is a known leak point.  Dont forget to seal them as the ends are exposed. 

[drumstyx]

I'll just chime back in and say I didn't end up using threaded rod...MRieck sent me a few studs for a very *very* modest price. This forum's full of great people with great parts.

[madmtnmotors]

I'll just chime back in and say I didn't end up using threaded rod...MRieck sent me a few studs for a very *very* modest price. This forum's full of great people with great parts.

Mike is definitely the man! The links I provided are "studs" and not threaded rod. The first one (57.5mm) is definitely short on thread on one end having only 5mm of thread. The second one (65mm) is better suited with 12mm thread on one end and 20mm thread on the other. I use the 65mm long stud and cut 5mm off the end with 20mm thread. 

[PeWe]

Mike is a great helper! I have got cam studs from him too!
Make sure to not over torque those M6. I apply 10Nm (7.4 ft lbs) with a good torque wrench. All M6.
I think I have read higher torque somewhere

Here are more torque numbers from Hondaman
http://forums.sohc4.net/index.php/topic,57279.msg619457.html#msg619457

[drumstyx]

Mike is a great helper! I have got cam studs from him too!
Make sure to not over torque those M6. I apply 10Nm (7.4 ft lbs) with a good torque wrench. All M6.
I think I have read higher torque somewhere

Here are more torque numbers from Hondaman
http://forums.sohc4.net/index.php/topic,57279.msg619457.html#msg619457

Yeah, I ended up putting it down to 6ftlb, while the book said 8 or 9. I snapped one like it was butter well under 8 ftlbs, so I figured I'd play it safe with the new ones

[madmtnmotors]

I use the 65mm long stud and cut 5mm off the end with 20mm thread. 

Or you could flip it over, install the 20mm thread into the head and probably not have to cut anything... 

[drumstyx]

I use the 65mm long stud and cut 5mm off the end with 20mm thread. 

Or you could flip it over, install the 20mm thread into the head and probably not have to cut anything... 

+1, looks like there's loads of room in that through hole.

[PeWe]

I did not torqued the cam studs into the head by 10Nm (7.4 ft lbs) (only nuts later on). I did it with my small 1/4" socket wrench, by my wrist. Maybe 5-6 ft lbs
Nuts and the other bolts torqued when cam is mounted. Then the rockers on with shafts and the otrher bolts. 7.4 ftlbs again... Check all again since they will flex down due to the ruber coins under the cam towers. M5 bolts keeping the rocker shaft by half torque of the M6.

Seal studs with something like this:
https://www.permatex.com/products/thread-compounds/thread-sealants/permatex-high-temperature-thread-sealant/

[markb]

So can anyone explain why screws are used on the back side of the cam holders and studs are used on the front side?

[disco]

Hi Mark,
Here's my take on it. Screws have been used on the the back holes because they are 'blind' ie they don't go all the way thru. The front holes are thru holes, because the casting is thinner at this point. By using studs on the front holes, each time the cam or cylinder head is removed, it saves having to go thru the process of re-sealing these. If a bolt is used at the front you have to be careful the clean the hole out, get new sealant into the hole etc.