virden Posted April 22, 2015 Share Posted April 22, 2015 Will some kind soul please tell me the torque setting for the Allan bolts that attach the manifold to a cast iron head. Why?... cos I have blown yet another middle gasket..Thye only seem to last 1000 miles.Thanks Link to comment Share on other sites More sharing options...
Jonathan Kay Posted April 22, 2015 Share Posted April 22, 2015 DeletedJonathan Link to comment Share on other sites More sharing options...
Gordon C Posted April 23, 2015 Share Posted April 23, 2015 Give Vulcan Engineering a ring They supplied some gaskets for me some years ago. Not sure what they are made of but lets just say they have never leaked and thats with removing the primaries a couple of times as well. I can only describe them as a laminated type of material almost asbestos like. Worked for me Link to comment Share on other sites More sharing options...
apjenkins Posted April 23, 2015 Share Posted April 23, 2015 Chris Wheeler of 'The Seven Workshop' supplied me similar sounding copper/"asbestos" gaskets that were perfect for many miles. When I reused them I added some 'copper silicone sealant' which never burnt or leaked. Torqued the Allen set screws, with spring washers under the heads to - feels tight enough - tension and checked for tightness after the first few runs.@ndrew Link to comment Share on other sites More sharing options...
Nigel Riches Posted April 23, 2015 Share Posted April 23, 2015 Check the face of the flange for flatness. If it's over about 0.5mm out of true have it skimmed and go easy on pulling the bolts tight. Nigel Link to comment Share on other sites More sharing options...
Roger King Posted April 23, 2015 Share Posted April 23, 2015 As stated, make sure flange is flat, use laminated type gaskets and tighten securely, but not too firmly, using just an allen key so you don't have too much leverage. The final job is to lockwire the allen screws so they can't come undone because, inevitably, the gasket will settle and loosen the screws.If you overtighten, you will simply collapse the gasket at each end and encourage warping of the flange again. Link to comment Share on other sites More sharing options...
elie boone Posted April 23, 2015 Share Posted April 23, 2015 Len Selby does a gasket that is 1 piece but far more superior than the OEM part http://www.historicracing.org.uk/parts/garageclearout.html Link to comment Share on other sites More sharing options...
virden Posted April 23, 2015 Author Share Posted April 23, 2015 Thanks all, the head is true and I had the flange planed, so not a gap issue. I am wondering if it is a case of the shear weight of the 4:1 and silencer which is providing a leverage to flange forcing the bottom in an dthe top out. It is always the top which blows, and I have tried several different types of gasket...but never double. Link to comment Share on other sites More sharing options...
SM25T Posted April 23, 2015 Share Posted April 23, 2015 Do you use the front mount on the chassis to help support the weight of the system ? Link to comment Share on other sites More sharing options...
virden Posted April 24, 2015 Author Share Posted April 24, 2015 SM25, I have heard that there may be a bolt hole in chassis rail but do not know where it is. My car is a 96 S3 live axle,built by Arch Link to comment Share on other sites More sharing options...
SM25T Posted April 24, 2015 Share Posted April 24, 2015 Ask them for confirmation ? Normally between 800-805mm from the centre of the rear exhaust mount hole ... at the same height from the underside. Link to comment Share on other sites More sharing options...
Nigel Riches Posted April 24, 2015 Share Posted April 24, 2015 Don't mount any bracketry from chassis to the exhaust system, mount it back to the engine block, so the engine, exhaust, and bracket, all triangulated together move as one piece,. Movement of the engine will transfer energy through the exhaust and then into the chassis / frame, which is not a good situation. Nigel. Link to comment Share on other sites More sharing options...
virden Posted April 24, 2015 Author Share Posted April 24, 2015 Nigel,If I used a rubber exhaust bobbin as used to attach the rear bracket, would this not mitigate the worst of the vibration? Link to comment Share on other sites More sharing options...
Roger King Posted April 24, 2015 Share Posted April 24, 2015 If you do that, you'll effectively be using the exhaust as an engine stabiliser which is a no-no. There's no problem with the standard mounting system provided everything is done properly. Link to comment Share on other sites More sharing options...
Drumster Posted April 24, 2015 Share Posted April 24, 2015 Just for the record, I never had any issue with the gaskets provided by Chris Wheeler on my '93 x/flow. Thus was with a 6" Techcraft silencer and 4-into-1 primaries with a single bobbin on the bracket near the tailpipe. Link to comment Share on other sites More sharing options...
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