Oil leak at head joint

[Brian]

I guess its my turn. I have been using thread inserts for about as long as they have been around, must be about 30 years now, and I reckon they are wonderful. I have never had one fail. They are easy to use and give a stronger thread than the original. They are available in just about any thread including cycle thread. I have never and would not put a insert inside an existing insert, in this situation I would make up a oversize sleeve or if its a stud make a stepped stud. I have used inserts in iron barrels many times. Like dpaddock I torque to 40lbs with just a flat washer under the head but must say I prefer the solid copper gaskets. The only head gasket I have ever had leak was a compound one. Its important that the solid ones are annealed before use, especially new ones as they are as hard as rock when you buy them. I anneal them then clean them up with hydrachloric acid [wear gloves and eye protection], give them a good wash, dry and its ready to use. I put a very slight smear of grease on both sides and thats it.   Brian.

[RichardL]

Not to be a trouble maker, but I just discovered a product called "Twinsert" from the makers of Helicoil. These are, effectively, Helicoil-in-Helicoil, but are only available in metric sizes. I realize this is off the point, but I found it interesting.

Richard

[Brian]

Thanks for that Richard. I had never heard of them but will head off down to my local engineering place and ask.    Brian.

[RichardL]

Twinserts

http://www.boellhoff.de/web/germany/en/web.nsf/HTML/hcr_twinsert.html

[groily]

Loads of lovely stuff here - thanks guys! Re copper or composite, have to say I prefer copper with a smear of grease myself, but agree composite squishes better. Just needs more check-tightening I have found in the early miles - and boy do I hate rocker shafts which gave to come off to do it. (Discreet plug for AMC machinery here, with cast lugs on head to carry the gubbins, lovely little domed individual covers, eccentric spindle adjusters for valve clearances, straight-through studs from c/cases to head, and all nuts accessible without dismantling anything.) Since the demise of asbestos, some of the composite gaskets I've had for some other vehicles have been very sensitive - as in 3 or 4 retorques necessary to get them finally settled.
I'm never going to even think about the applicability of the helicoil ever again - shall use with impunity if necessary! Point about annealing well made too dp, shall be playing with fire as soon as bits arrive! Not sure if French pharmacies will sell me hydrochloric though . . . Could have annealed and reused the old one I suppose, but somehow thought a new one might be better, as they're cheap enough. If an alloy head is comfortable with 40 lbs . . . that should suit me fine with iron. Mine'll be better with the proper washers than with the soft things that were under the heads of the cheese-bolts. And breathing issues I am not going to think about for the time being as I don't reckon I'm suffering in that department any more than normal! Groily

[Brian]

Groily you should be able to get Spirit of Salts at your local hardware store which is used for soldering and its mainly hydrachloric acid. There are probably other chemicals that will clean up copper, maybe someone else on the forum will know.   Brian.

[groily]

Ta muchly, I'll get the thing clean one way or another! Groily

[groily]

Well, I now know what proper head bolts and washers ought to look like, as a new set came today. Less than 72 hours to a furrin country, not bad. Very different from the scrapyard weirdies that were in there. Am awaiting partial set of 3/8 drive BSF sockets (from A&R Sheldon if anyone else is interested) as all my existing WW/BSF sockets are 1/2 inch. With luck they'll arrive asap, and the thing will be back on the road for its habitual Saturday 200 kilometres - just enough to get me to take-it-apart-and-check-the-torque time. And the new tappet adjusters have natty little allen-key heads - prettier and better than the square jobs on the originals, as it'll be possible to hold the screws while doing up the locknuts a lot easier. Think I'm going to be very happy. Groily

[LJ.]

I quite agree how so much better it is to adjust the tappets with the allen-key heads. The key being a right angled shank holds the adjuster in precise position while then it is easy to get at, and tighten up the lock nut. The old square head makes things difficult with two spanners side by side.

[dpaddock]

In my 1957 Spitfire, a 3/8-24 UNf Helicoil fits the barrel just fine. I used 3/8-in HoloKrome socket head cap screws in bolt holes #8 and #9 and torque all bolts to 40 ft-lb. (Alloy head with 3/4-in OD X 25/64-in ID X 1/8-in thick hardened flat washers under the bolt heads); 9.1:1 CR, composite gasket. No oil leaks or evidence of blow by. Most satisfactory.
Solid copper gaskets are difficult to anneal; the composite does a better job of sealing.

[PBMW]

Not to thread jack completely,  but,  a bit of info on various threaded inserts.
Helicoils are the only ones that I know of that require the use of an STI Tap.  (Special Threaded Insert)
Keencerts and Time Certs both are installed using a larger normal tap.  They are both much stronger than a Helicoil as they are an actual cylinder threaded internaly and externaly. 
I drag race a big block Suzuki and every threaded hole in the cases are Keen Certed.  This motor makes in the neighborhood of 900 hp and I've never had a failure due to a threaded fastener.
I would however not use a Helicoil in a Helicoil.
I believe some of you gents are in Europe and as such I may not be entirely familiar with the various typs of threaded fasteners that may be available in your specific area....

Now,  back to your regularly scheduled conversation....

[groily]

I think these 'certs' are the sort of thing I was thinking about when I was worrying needlessly about whether a helicoil was up to the job. However, 900bhp (my gawd!) ain't on my agenda and I'd have been happy with a helicoil after learning what I have learned here and elsewhere. . . also a cert needs a bit more metal all round maybe?
In the event, the problem that initiated this particular thread refused to go away as quietly as planned . . . my salvaged barrel thread turned out not to have been as reclaimable as I'd cheerfully stated here the other day. . . took test torque of 30ft/lbs+ once - but it didn't want to do it twice. So a Saturday morning run was a fanciful notion and the thing is only together this evening. Solution for the time being has been to take the bolt hole in the barrel out to 9.7mm (whatever that is in real money, sorry, I've gone native), tap 7/16th BSF and make a stepped stud from a car head stud plus a deep sleeve nut made from round stock with a solid top section milled to same size as other bolts - ie 5/16BSF, 1/4 Whit. A standard BSF 3/8 by 20 won't give spanner clearance (although a 3/8 by 24 UNF 9/16th AF nut would go on . . .  but I'd made the stud by then). Not 100% pretty, but tested to 50 ft/lbs and 100% not going to break, no way.
When the motor finally flings the rest of its innards down the street, I'll think of a neater way of doing the job, although I may be stuck with a stud on this one application: the outer thread of a helicoil is weird, as PBMW confirms, and there's a limit to how much cast iron one can steal.
We'll see whether the carefully annealed copper gasket seals, or if a composite would have been a better idea . . . hope I'll also be able to say 'most satisfactory', like dpaddock.

BTW, am I the only person who thinks the whole BSA rocker box / pushrod arrangement was devised by a man, possibly an accountant, with triple-jointed fingers and the ability to see round corners and through solids? Even with the famous comb, these are infernal things to align and it's very hard to prove to oneself that everyone is sitting comfortably. I have a nasty feeling I'm going to get more practice though over the coming years.
Groily

[Joolstacho]

On my Velocettes and japanese bikes I've worked on, rocker box drain holes include a hollow steel spigot insert that spans the head/rocker cov joint, making oil leaks much less likely.
That's sensible eh?
-Jools

[MikeN]

 Helical inserts are great on stripped threads but whenever Ive encountered threads that have been stripped and tapped oversize I never contemplate tapping them out again to acept a helicoil. I much prefer to fit a threaded  plug and drill and tap out to the original size.
  I would not turn down a stud to make a stepped stud (especially on a cylinder head) no matter what material its made from .
Mike

[chaterlea25]

Hi All,
To clean the annealed copper gasket why not give it a bath in Coca Cola??  It shines up pennies real well
I am now going out to try this, and will report back ????
I have also found a product for sale in the Aldi supermarkets that cleans brass and copper, Havnt tried it tho!

I am also a believer in real washers under the head bolts and turn my own from SS stock,
When I built my SR engine I used stainless head bolts from Andy Molnar,
At the time there were bad stories going round about using SS bolts, I fitted them and torqued them down to the standard settings and a solid gasket,
10,000 miles later no leaks and I never re torqued the head, but have checked one or two of the outers once or twice!!

Cheers
John O R