Threaded cylinder head

[macmattom]

<font face="Comic Sans MS"></font id="Comic Sans MS"><font size="5"></font id="size5"><font color="blue"></font id="blue"><b></b>Hi, another question.

One of the threaded holes in the cylinder head for the inlet manifold bolts has threaded. Does anybody have any good ideas? I was going to use some of that chemical metal to fill the hole and then re-thread it the same size, but should I just drill the hole out larger and the rethread to suit? If so, what is the smallest diameter bolt I can use?

Thanks again,

Mac

The pheonix rises from the ashes - just give it time.

[Cobber]

<font face="Comic Sans MS"><font size="2">What you need is a helical thread insert like Helicoil or Re-coil (brands available here in Oz, other brands my be available in other countries) available from industrial tool suppliers and bolt merchants.
http://www.emhart.com/products/helicoil.asp
http://www.engineproblem.com.au/helicoil.htm
http://www.youtube.com/watch?v=RFYa6sjhh_E
http://www.alcoa.com/fastening_systems/ ... cat_id=685 </font id="size2"></font id="Comic Sans MS">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100
I sold the '61 International AA120 to a mate.. he hasn't paid for it yet!
Sold the Jag XJ12 too

[Rich in Vancouver]

Cobber is right. A Heli-coil will allow you to use a fastener of the correct size into steel threads. They are inexpensive and easy to use. I have used them on my FHC to repair stripped spark plug threads and have had absolutely no problems.

Rich

1975 TR7 ACL764U

[cliff]

Mac, another option is a threaded key-locking insert also known as locksert inserts, as Heli coil insert have a tendacy to back out.
http://www.bikudo.com/product_search/de ... serts.html If you search on <font color="red"><b>key locking threaded inserts </b> </font id="red"> you should be able to locate a vendor in the UK.[8D]

Cliff in SoCal

Don't use force, get a bigger hammer!!

[Marko]

Cobber's right works great on any ruined thread including spark plug threads

[Cobber]

<font face="Comic Sans MS"><font size="2">The trick to using helicoils on spark plug threads is when you re tap the hole fill the flutes of the tap with grease this causes the swarf to stick to the tap and not fall down the hole into the bore. </font id="size2"></font id="Comic Sans MS">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100
I sold the '61 International AA120 to a mate.. he hasn't paid for it yet!
Sold the Jag XJ12 too

[Hasbeen]

You blokes are better than me. When I bought this 7, one of the
plugs brought the thread out with it.

With all the right gear, I tried to put one in, but a rough point,
about half way in stopped the coil, & it just unwound, every time,
no matter how I tried to tap it.

I had to get a mobile bloke to come & fit a solid sleeve.

Hasbeen

[macmattom]

<font face="Comic Sans MS"></font id="Comic Sans MS"><font size="4"></font id="size4"><font color="blue"></font id="blue">I've decided to take it to a pro and swallow the cost. No point trashing the head beyond repair trying to be a clever-clogs. I have a spare head I'll practice on, but need to get the engine back in the car. Thanks for your help.

Cheers,

Mac.

The pheonix rises from the ashes - just give it time.

[jclay (RIP 2018)]

OK, whats a " clever-clogs"?

jclay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]

[Rich in Vancouver]

as the swarf was just alloy I let it fall into the cylinder and get blown out the exhaust. Mind you, at that point I was in no mood to get fancy. I had been crossing a long bridge in heavy traffic when the engine started making a horrendous noise. I struggled to the far side of the bridge, and when I opened the bonnet saw a spark plug hanging by it's wire. I drove into a nearby parking lot and called my wife to take me to the auto parts store. I picked up a Heli-coil kit and had the plug back in place in no time. Heli-coils have come a long way. The kit I bought had a 2 level tap that follows the remains of the old thread to tap the new hole. That was a life saver with the TR's angled plug holes. They also require that you Loctite the insert into place, so no problems with it coming out or leaking.
I would recommend them highly!

Rich
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Cobber</i>

<font face="Comic Sans MS"><font size="2">The trick to using helicoils on spark plug threads is when you re tap the hole fill the flutes of the tap with grease this causes the swarf to stick to the tap and not fall down the hole into the bore. </font id="size2"></font id="Comic Sans MS">

80'Triumph TR7, , 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
85'Alfa 90, 69'Ford F250.
76' Ford F100
I sold the '61 International AA120 to a mate.. he hasn't paid for it yet!
Sold the Jag XJ12 too


<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

1975 TR7 ACL764U

[macmattom]

<font face="Comic Sans MS"></font id="Comic Sans MS"><font size="5"></font id="size5"><font color="blue"></font id="blue">Well, that's another job ticked off the list. It was expensive, but still cheaper than a trashed head. Sometimes I just can't be bothered.

The pheonix rises from the ashes - just give it time.

[macmattom]

Clever-clogs is a phrase for a know-it-all, a smart alec (don't know if I'd get away with the common phrase, but didn't want to offend, just in case).<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by jclay</i>

OK, whats a " clever-clogs"?

jclay

[url="http://web.mac.com/jclaythompson/iWeb/Site/Welcome.html"]My Triumph Site[/url], [url="http://web.mac.com/jclaythompson/iWeb/Technical/Intro.html"]Technical Stuff[/url], [url="http://homepage.mac.com/WebObjects/FileSharing.woa/53/wo/HJMTK8gsojtwKleP.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]Download Page[/url]
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

The pheonix rises from the ashes - just give it time.