Board index Flathead Power-Technical Questions, Answers, and Suggestions K-Models Head Bolt Torque...

Head Bolt Torque...

Moderators: Curt!, Pa

Post Thu Nov 27, 2008 3:31 am

Posts: 121
Gentlemen,
putting my heads back on... now WLA heads are torqued to 65 lbs, are KH tensions the same?

Now the obvious question, other than the K/KH riders manual and parts list why was there never a proper K series work shop manual. I've got the old Shop Dope Book with all the specs but what of a full rebuild manual – I can't believe there was never one, what did the dealers/service shops use?

Best,
Nick.

Post Thu Nov 27, 2008 9:29 am
Pa Site Admin

Posts: 5799
Location: Ohio USA

I've asked that question many times before. The early ohv Sportster service manual has a clause on the cover, which states to use it for K model also. But this manual was printed 5 years after the fact. What did the service personal do until then ? I mean, even the bottom end would be a challenge to a service person. Though simuliar to the 45, it is the differences that would puzzle one self. How about timing ? Points settings ? Torque specs ? The list can be lengthy. All done by ear and assumption ? I really don't think so. There must have been a printed document. Was the MoCo mindset.....Let us build a model and keep the specs to ourselves ! Let us not provide the dealships with anything either ! The assembly line had to have some other data. But...where is it ? What was it ? Pa

Post Thu Nov 27, 2008 10:34 am

Posts: 42
Location: Sylacauga, AL. USA
Checked my Model K Riders Hand Book. No torque specs listed for anything. Very strange!

Anybody got a set of KH upper motor mount spacers they will part with? PM me with details.
DLM32

Post Thu Nov 27, 2008 10:52 am

Posts: 976
Location: Markt Einersheim, Germany

What is the bolt size, thread size/pitch for a tap on these.

And I will look up the torque range from my Standard Aviation Handbook's Torque Chart.... on Monday (cuz it is at work).

Would that suffice???? And be within an acceptable range??

George

Post Thu Nov 27, 2008 5:38 pm

Posts: 1671
Location: Interlaken, NY USA

I think back in the day when these bikes were new, the dealers serviced them in a more rough and ready manner. The factory tool boards had a "torque amplier", a cut off fork leg, that slipped over factory wrenches so you could torque down nuts,bolts. I think the spec was "good and tight". I know the dealer I learned from practiced this. He'd been to factory and army schools and was renowned for his rebuilds lasting the distance. Just as the Lap wasn't the accurate tool a Sunnen is, in trained hands, it produced servicable results. Likewise, I think they didn't use torque specs, just the given tools and a feel for "good and tight".
George probably has the right idea for us present day folks. Look up the spec for the bolt type and go with that. In the old days.
DD

Post Thu Nov 27, 2008 6:24 pm

Posts: 2687
Location: Los Angeles, CA
Frankenstein wrote:
I think the spec was "good and tight".

Back in the '60's the mechanic at Santa Monica Harley-Davidson was Earl Kellerman. When I asked him the tourque spec. for Knuck headbolts he held up his genuine H-D headbolt wrench and said, "Tight is tight and too tight is broken".
Earl is still wrenching today and is the oldest factory trained wrench working at any dealership. These days he spends his time playing,,,,er, working on the race bikes for Bartells H-D.

Post Fri Nov 28, 2008 8:46 am
panic

K/KH is unusual at 7/16-14NC, and would need more torque than the finer 7/16-20 OHV or 7/16-16NS.

Post Fri Nov 28, 2008 11:10 am

Posts: 541
Location: Wa, USA
Try this link: http://www.futek.com/boltcalc.aspx?mode=american
I plugged in 7/16-16 grade 5 and used A36 steel for mating part as they did not have cast iron as a choice. The resulting torque was 41 ft/lbs.
7/16-14: 40ft/lbs

Post Fri Nov 28, 2008 3:06 pm
Pa Site Admin

Posts: 5799
Location: Ohio USA

Let us not forget.....we are not squeezing iron against iron. We are sqeezing aluminum against iron. One is tougher than the other. To much torque....maybe crack the heads or break the bolts ? Could to much torque be the reasoning behind so many hairline K-model head fractures ? There must be a numeral value as a fine line. Not enough torque...leaks ! As noted already, under heat, aluminum expands much greater than iron. Thus my mention of the fracture posibilities. Pa

Post Fri Nov 28, 2008 4:54 pm

Posts: 587
Location: Crewe, Great Britain

Yes, Pa, and we're not squezzing a gasket either on Ks, just thin layer of paint!!!

I don't use a torque wrench anywhere on me bikes, don't have one, just follow simple rules, like don't put a 2 feet tube at the end of a 7/16th spanner, tighten a bit at a time and come back to it later!!!

Patrick

Post Fri Nov 28, 2008 8:34 pm
Pa Site Admin

Posts: 5799
Location: Ohio USA

Precicely Patrick ! That is exactly what I am getting at. :D Pa

Post Sat Nov 29, 2008 4:05 am

Posts: 587
Location: Crewe, Great Britain

Pa:
Could to much torque be the reasoning behind so many hairline K-model head fractures ?


I've had some thoughts about these cracks over the years, I've got about 7 heads, only 2 are not cracked... Upon inspection, the 2 uncracked ones have had the KR radiused pocket relief done in the past...

The std casting has quite a brutish and squarish transition between the roof and the vertical side on the outside of the valves, this surely must promotes cracking along the transition. But not explain why the cracks appear in the 1st place... It's also quite a complicated casting to make, having a core unlike most other sv heads I know of, so I'm quite sure they experienced a lot of casting rejects as well as ending up machining some which were not as perfect as they seemed.

I came to the conclusion it's the double decker fin that promotes cracking. It's further away from the primary heat, and when the engine is stopped, it's the 1st one to cool and contract, hence internal casting stresses that will result in std heads cracks at their weakest point.

The raduised KR type has a smother transition, stesses are still there but the crack having no starting point does not appear. Late 60's racers often got rid of the double decker fin as well by cutting it on a miller...

Patrick

Post Sat Nov 29, 2008 5:20 am

Posts: 121
Patrick/all,
still can't figure how/why there is no detailed manual, was this common for HD historically?

Between us is there some way of getting this issue to someone who was involved in the company back then? How do HD manage records nowadays – is there a technical PR rep. that can be contacted?

Best, Nick

Post Sat Nov 29, 2008 6:36 am

Posts: 587
Location: Crewe, Great Britain

Hi Nick,

I suppose, in the old days, all the mechanics were trained "in house" under the supervision of an "old foggie" both in dealerships and factory mech. school, experience was the game, people were more mechanically minded, designs from one bike to the other were similar, hence I don't think there's any official records for that sort of things. Things went slightly different in WW2 when distance from dealers/factory was huge and loads were conscripted, not necesseraly with knowledge, hence a bit more details in the WLA/WLC manuals...

As far as street bikes are concerned, the 1st ever H-D Service Manual as we know it is in 1959, and as they say in the front page, "most" herein can be applied to earlier designs!!! Before that, the "Shop Dope" sheets were all that was available... A loose collection of new or improved things the factory thought might be of help to the dealerships.

Most spanners and tools have a restricted lenght designed into them that should prevent overtorquing when used with std hands.

Patrick

Post Sat Nov 29, 2008 11:27 am

Posts: 2687
Location: Los Angeles, CA
thefrenchowl wrote:
1st ever H-D Service Manual as we know it is in 1959, and as they say in the front page, "most" herein can be applied to earlier designs!!!


I guess you are forgetting about the Knucklehead/UL Service manual.

Post Sat Nov 29, 2008 11:43 am
Pa Site Admin

Posts: 5799
Location: Ohio USA

I'm sure he meant the Sportster/K-model service manual Chris. Pa

Post Sat Nov 29, 2008 2:04 pm

Posts: 1050
Location: Greenbackville, Virginia, USA
I torqued my KH to 60 ft/lbs. Had to make sure the head bolts didn't bottom out first, though. 2 did, corrected with a grinder. Aluminum paint on both head and barrel gasket surface, heat soaked 3 times. No leaks, No problems.

Post Sun Dec 07, 2008 5:20 am

Posts: 240
Location: Kirkland, WA, USA

I run KR heads, and set the torque at about 40 to 45 ft lbs. That seems to keep the compression in there...

Barry55KH

Post Sun Dec 07, 2008 7:24 am

Posts: 587
Location: Crewe, Great Britain

Chris/
I guess you are forgetting about the Knucklehead/UL Service manual.


Well, as you should know by now, I'm stricltly a K/X man and a little bit W as well!!! So I wouldn't know about existing manuals for other models...

Indeed, the 1st ever Sporty service manual is in 1959, with that note on the front page... Shows you H-D probably thought at the time that, not being "proper" bikes, the K and early XL did not deserve a service manual :evil: :evil: :evil: !!!

Patrick

Post Sun Dec 07, 2008 8:20 pm
Pa Site Admin

Posts: 5799
Location: Ohio USA

Yeah !! And great bikes to boot !! What is the deal ? ! Pa


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