Mark Posted October 6, 2008 Share Posted October 6, 2008 I need to repair at least one head bolt thread in the block of my 200tdi. The only real solution to this seems to be to drill out and use a helicoil type insert. However, on looking around, there seem to be several kits available to drill, tap and then put in the insert, so I wondered if they were all much the same or if there were brands to be avoided? Looking on eBlag there seem to be several people selling differently branded kits, some including the drill and some not, so if anyone has any good suggestions on where to get a good quality complete kit for M12x1.5 then I would be grateful. Cheers Mark Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 6, 2008 Share Posted October 6, 2008 We use 'Recoil' made in Oz, they work OK. We are thinking of going to those Würth things but they are very expensive as they expect you to buy a complete kit for lots of sizes at horrendous expense. Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted October 6, 2008 Share Posted October 6, 2008 I've used a size-specific kit from Cromwell's on my thermostat housing threads. IIRC, the M6 kit was cheaper than their M12x1.5 kit i've found here but then i guess the price will go up with size. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 6, 2008 Share Posted October 6, 2008 I've done literally thousands between M6 and M12 using recoil kits and I've been very happy with them, so much so, I have my own kits for home use now. If you need any tips Mark, feel free to pm me. Mo Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 6, 2008 Share Posted October 6, 2008 I have no problem with using wire thread inserts (Helicoil trade name) in most situations but head bolts are tightened close to the limits of the bolts (and beyond in the case of stretch bolts) which is not a good place to be with an insert. You have no real choice other than to use them but I would invest a little more and fit a set of ARP studs, locking them in place with Loctite. This then moves the torque loads to the stud/nut interface leaving the insert to only deal with tension. Steve Quote Link to comment Share on other sites More sharing options...
Mark Posted October 6, 2008 Author Share Posted October 6, 2008 Thanks for the advice chaps. Mo, any advice specifically? Steve, I didn't know ARP studs were available for 200 TDI's, but it makes sense I guess... suggestions on where to acquire them? Other option would be to drill and tap to M14 or M16, but that means drilling the head to get clearance, which I really don't want to do... suggestions appreciated, keep them coming chaps. Mark Quote Link to comment Share on other sites More sharing options...
bob86 Posted October 6, 2008 Share Posted October 6, 2008 We use Wurth Timeserts in work. We've done a few blocks and never had any trouble. Quote Link to comment Share on other sites More sharing options...
steve_d Posted October 7, 2008 Share Posted October 7, 2008 ...Steve, I didn't know ARP studs were available for 200 TDI's, but it makes sense I guess... suggestions on where to acquire them?....... Sorry no. Just assumed they would be available as they seem to do studs for pretty much anything. Steve Quote Link to comment Share on other sites More sharing options...
Timmy511 Posted October 7, 2008 Share Posted October 7, 2008 have a look into getting a threadsert, its like a hollow bolt witha thread in the hole, basically a thread on the outside and one on the in. where i used to work we put them in aluminium housings for rather large missiles! so im guessing if its good enough for the MOD and at M12 size itll be plenty strong enough for a head bolt. helicoils are good, but as said previously the amount of torque your about to tighten the head bolt to will more than likely exceed the shear strength of the material used to make the helicoil. Quote Link to comment Share on other sites More sharing options...
ChrisJones117 Posted October 7, 2008 Share Posted October 7, 2008 To be honest you would be better off using Timesert inserts, buy them from the States or thru Wurth UK, we have used these at work now for several years for all sorts of high torque, load applications when repairing eg: Front and rear suspension mounts so a head boult should be no real challenge, if I remember correctly they do a kit specially for head bolts Quote Link to comment Share on other sites More sharing options...
Bobbin Posted October 8, 2008 Share Posted October 8, 2008 Timeserts really are the dogs,helicoils are nothing but trouble unless you ust the larger sizes .Wurth may be expensive but worth their weight in gold when it comes to thread repairs. Quote Link to comment Share on other sites More sharing options...
Mark Posted October 8, 2008 Author Share Posted October 8, 2008 Ok, the time-serts do look good. Thier website shows a specific head bolt kit for M12x1.5 which is what I need, but the Wurth catalogue dosn't list it... also none of them sites I have seen have any prices on, so I have no idea on cost. Do any of you guys who know about time-serts have any ideas on what they cost? Cheers Mark Quote Link to comment Share on other sites More sharing options...
steffUK Posted October 9, 2008 Share Posted October 9, 2008 You can also check with Trident Racing Suplies at Silverstone. They sell single Helicoils in all variants. Tel: 01327 857822 Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 9, 2008 Share Posted October 9, 2008 Ok, the time-serts do look good. Thier website shows a specific head bolt kit for M12x1.5 which is what I need, but the Wurth catalogue dosn't list it... also none of them sites I have seen have any prices on, so I have no idea on cost. Do any of you guys who know about time-serts have any ideas on what they cost?Cheers Mark Our Wurth salesman tried to sell us a kit but at the equivalent of 250 quid we had to decline. Quote Link to comment Share on other sites More sharing options...
landybehr Posted October 10, 2008 Share Posted October 10, 2008 I cannot tell about the Würth-set. But I do believe it´s good. But I think the Heli-Coil is stronger than a "normal" tapped thread. With a "normal" thread the force/tension is not evenly spread over the thread. The further "down" the less tension and the "outmost" thread feels relatively highest tension. Which may be the reason that you can feel the thread being pulled out of aluminium like with V8 blocks. And that´s the reason why you rip out the threads from top, one by one downwards if you overtighten. The heli-Coil can flex and therefore threads being "further down" start to take more tension than before. Thus the force is spread better over the threads than before. (hope I managed to make up my point even though the translation difficulties ). Sometimes, IIRC, threads that were suspectible to failure were supplied with HeliCoil right from the factory. BTW: Anyone renewed or helicoiled the threads for the thermostate elbow on the V8 without removing the inlet manifold ? Quote Link to comment Share on other sites More sharing options...
bluespanner Posted October 10, 2008 Share Posted October 10, 2008 My collegue has has a BMW 525i block helicoiled on every head bolt hole. Seems ok. Quote Link to comment Share on other sites More sharing options...
AD90 Posted October 10, 2008 Share Posted October 10, 2008 I have to agree with landybehr. Wire thread inserts are used extensively on aircraft engines, and not without good reason(s). One reason being; the simple fact that if you put a 1/4unf screw directly into the aluminium casing then the strength is limited by the effective diameter of the thread in the aluminum. If you fit an insert, the 1/4 screw is now in steel and the limit is now at the effective diameter of the steel insert in aluminium. Did that make sense? AD90 Quote Link to comment Share on other sites More sharing options...
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