Author Topic: Main/case studs? (Read 2308 times)

Don R · « **on:** January 15, 2014, 11:03:26 am »

I'm putting the 11xx whatever cc engine back together and thought it may want lower studs in addition to the heavy duty upper ones. On car engines you shouldn't change to studs unless your machine work was done with them. I'm assuming this doesn't apply to our application.
Any issues with re-assembling using main case studs with used bearings? (They look new)

How big a deal are main studs in this application?

TurboD · « **Reply #1 on:** January 15, 2014, 11:18:47 am »

Don I have built many race car and bike engines over the years that I changed or added different bolts or studs later without any problems, I can't see the old Honda's being any different.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #2 on:** January 15, 2014, 11:24:26 am »

I'd Plastigauge them and I'm sure you will too since you'll be torqueing tighter.

MRieck · « **Reply #3 on:** January 15, 2014, 01:11:50 pm »

You won't have problems with the studs and bearings....upgrade those nuts they give you with the studs.

bear · « **Reply #4 on:** January 15, 2014, 05:00:20 pm »

Quote from: Don R on January 15, 2014, 11:03:26 am

I'm putting the 11xx whatever cc engine back together and thought it may want lower studs in addition to the heavy duty upper ones. On car engines you shouldn't change to studs unless your machine work was done with them. I'm assuming this doesn't apply to our application.
Any issues with re-assembling using main case studs with used bearings? (They look new)

How big a deal are main studs in this application?

Don,

The weak link in our big displacement, high cylinder pressure sohc motors are the top case studs.
Because the top cases are bored to accommodate larger sleves, some of the stud hole threads have very little "meat" to support them.
They tend to either strip or stretch.
This problem is the primary cause of head gasket failure in our motors.
Best you check it out.
I think I have a couple of pictures if I can find them I will post them.

Cheers,
Brian

Don R · « **Reply #5 on:** January 15, 2014, 05:41:14 pm »

The top has aftermarket studs, I did that in my 836. I'll check them carefully, so it's a go on the lower case studs but re-check the bearings. Thanks.

Big Jay · « **Reply #6 on:** January 17, 2014, 09:13:39 pm »

http://cbrzone.com/sohc.html

Don R · « **Reply #7 on:** January 17, 2014, 09:32:51 pm »

Quote from: Big Jay on January 17, 2014, 09:13:39 pm

http://cbrzone.com/sohc.html

Thanks Big Jay, I'm a big fan and previous customer, today was payday for the Funny Car job we did so I'll be ordering soon. Gotta measure my copper head gasket first.

MRieck · « **Reply #8 on:** January 18, 2014, 05:39:28 am »

Quote from: Don R on January 17, 2014, 09:32:51 pm

Quote from: Big Jay on January 17, 2014, 09:13:39 pm
http://cbrzone.com/sohc.html

Thanks Big Jay, I'm a big fan and previous customer, today was payday for the Funny Car job we did so I'll be ordering soon. Gotta measure my copper head gasket first.

Gotta love those days Don. Everybody goes out for dinner!

Don R · « **Reply #9 on:** January 18, 2014, 07:30:39 am »

The good news is the customer is so pleased with the front half job he wants us to start building an entire new TAFC chassis for next year.

johno · « **Reply #10 on:** January 19, 2014, 03:00:00 am »

Hi guys,
Any you guys had a hiccup putting in the APE main bearing studs $:-\$

I used the standard install procedure from their web site, long thread end oiled and into the case, tension to 15 ft / lb
with two nuts, then final assy tension to 35 ft/lb using good nuts.

I noticed all the short studs were no problem spot on in length with the honda washer under and a full purchase on the nut, BUT with the two longer centre studs I have to leave the honda washer off and still one or two treads shy of getting a full purchase on the nut thread.

APE goodies should be spot on, been around for years, leaves me confused , do I shop for two longer studs , say 4 or 5mm longer , mill 4mm off the case flange around the stud hole, I dont like the idea putting up with 3/4 thread purchase in the two nuts.

Any ideas ? cheers johno

bear · « **Reply #11 on:** January 19, 2014, 03:38:03 am »

Bugger

Makes using HD studs a pointless exersice if you can't get a full nut on them.
Sorry mate I'm no good to you, I've allways used the Honda studs.

Cheers,
Brian

Jerry Rxman Griffin aka MuthaF'er · « **Reply #12 on:** January 19, 2014, 08:44:09 am »

35 ft lbs? Last I saw it was 22 ft lbs..... Same as the cylinder studs.

johno · « **Reply #13 on:** January 19, 2014, 01:22:07 pm »

Jerry I got the numbers from APE web site from their install specs for the head studs.

Also The stud kit was sent to me with the same head install instructions hand written on the back of the main bearing studs blister pack ! where did you come up with your numbers ?

cheers johno

bytio · « **Reply #14 on:** January 19, 2014, 01:33:56 pm »

I got the same APE studs, and no probs with length, also instructions show 22 lb torque , 15 also seems very tight to go in cases, those higher values you mention appear on other models studs, are you sure you have correct ones for CB 750?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #15 on:** January 19, 2014, 06:02:45 pm »

I'm not at home close to my stuff. Couple places actually. Big Jay in a phone conversation then I found the info that came with them. Jay even said they are the same as the cylinder studs. I won't be able to get to my stuff until weekend after this coming one. I believe the KPM studs take more torque.

Edit you are saying you installed the studs into your cases at 35 ft lbs, not torqueing the cases together at 35 as I first thought. OK but the figure for that is even less and I don't have access to that figure. Wish I was close to my stuff! I have a figure in mind but I can't back it up now - 8 ft lbs.

Big Jay · « **Reply #16 on:** January 19, 2014, 06:08:29 pm »

8 lbs in the case and 20/22 on the nut. 8mm main stud inst. http://www.aperaceparts.com/tech/mbskaw.html

I looked all through our site and looks like you picked the one for the generic 10mm cylinder studs.

johno · « **Reply #17 on:** January 19, 2014, 07:13:42 pm »

Thanks Jay,
Straight from the horses mouth !

Thats exactly what I done, used the generic specs from all other studs section, I didnt double check as someone had written the cylinder studs specs on the back of the main studs blister pack, so presumption being the mother of all #*#* ups

Still reckon the two long studs are 4 to 5mm short , but if that's the go then the boss the hole is in can be milled 4mm easy to get a full thread on the nut. just more cleaning again !
Thanks guys ,
johno

Kickstart · « **Reply #18 on:** January 20, 2014, 04:29:09 pm »

I had the same problem with the APE main bearing studs. The two longer ones were not quite long enough.

On my build, I flipped the two longer ones around (so the shorter end was in the case)... this gave me enough thread height on the nut side to have complete thread engagement with the nut.

I somehow convinced myself this was ok

I think I might have looked at the threads on the original bolts and decided the length was about the same as the shorter side, so it should be OK... I don't really remember though... it's possible I'm taking a big risk only having the shorter side in the case.

I don't really need them... my build is just 61mm (1+mm) pistons, but my old bolts were pretty rough and I figured, what the heck the HD ones must be better.

I did 8lbs in the case (even that made me nervous) and 17.5 lbs on the nut (with locktite - so equivalent of 21-22 dry?)

Also, make sure you run a thread restorer/tap on the threads. I found that the longer threads on my APE studs were a little off (it took considerable force to run the thread restorer tap up and down the threads at first). The shorter side threads were fine.

I don't mean to complain... I'm very happy with APE.
APE balanced my crank and back cut my transmission - excellent work and always a pleasure to talk to on the phone (both Jay and his guys had a lot of patience for all my newb questions).

Big Jay · « **Reply #19 on:** January 20, 2014, 10:54:07 pm »

The thread pitch diameters on all studs that screw into the case, either top or bottom, are larger than the net ends.

Kickstart · « **Reply #20 on:** January 21, 2014, 08:02:08 am »

Interesting... why is that... and what part of the thread pitch is larger (just the major or the entire pitch diameter overall)?

The original main bearing bolts seem to be standard thread pitch diameter. At least my restorer tap spun up and down them with no resistance.

Big Jay · « **Reply #21 on:** January 21, 2014, 11:52:08 pm »

Because they are designed to be a tight fit so they don't unscrew upon disassembly.

Kickstart · « **Reply #22 on:** January 22, 2014, 08:59:51 am »

Ah... makes sense.

I guess mine will probably unscrew upon disassembly now

Thanks,
Chris

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Author Topic: Main/case studs? (Read 2308 times)