jano Posted June 21, 2006 Posted June 21, 2006 I have just replaced cyl 2&3 gasket on my XF, a large piece of the material between the two metal sides of the gasket was completely gone. I haven't been high revving or pushing the engine (not much any how 😬) since rebuild. The engine is a 145ish HP 1600 XF with 4-1 side exhaust. So what causes the gasket to blow? Wrong torque of the manifold bolts? Bad gasket? Crazy right foot action of the driver? I have also noted that cyl 4 exhaust manifold had a very small thin hairline crack in the weld. And a little sod was visible on the edges of the crack. Do I need to get that fixed?  Lotus S3 1968, 1600 Crossflow. Just love the sound of crossflow in the morning.
Midnight Posted June 21, 2006 Posted June 21, 2006 Jano, Its not bolt torque or your right foot its a design fault. The reason these centre gaskets blow frequently is because the siamesed 2/3 exhaust ports have no room for a centre bolt. As the exhaust expands and contracts there is an area between the pipes in the gasket that lets go first. You can go two ways to make this joint (See ad in Low flying mag). Or go down the route I took which was to have the centre exhaust flange replaced with a Van Diemen Ford centre exhaust flange which is roughly twice as thick as the standard offering and therefore does not warp away from the cylinder head when it gets hot. Hope this is of use.
Midnight Posted June 21, 2006 Posted June 21, 2006 Sorry Finger trouble!! I deleted the bit about the Seven workshop who make a set of special copper exhaust gaskets which get around this problem!
MusCat Posted June 21, 2006 Posted June 21, 2006 Same problem on my 1700 xflow - central gasket was blowing so I replaced it with a Caterham gasket which has lasted next to no time. Midnight - do you know where you can get hold of the Van Diemen item you mention? Tim
jano Posted June 21, 2006 Author Posted June 21, 2006 Thanks for your replys they are very helpfull. I think I'll go for the copper exhaust gasket. Can the engine get damaged by running for a period of time with a blown exhaust gasket? /jano Lotus S3 1968, 1600 Crossflow. Just love the sound of crossflow in the morning.
Jorgen Posted June 21, 2006 Posted June 21, 2006 Hi Have send you a blatmail. Get in touch and we can discuss. Might be more easy since we are in the same part of the world.  Jorgen
Midnight Posted June 21, 2006 Posted June 21, 2006 Muscat, I took my centre pipes to an address in Croydon to a small premises recommended to me By Steve Parker (ad in Low flying) I'll try and find the address and post it up on Blatchat, The y did all sorts of specialist exhausts and a lot of race stuff maybe even a bit if F1 pipework in there as well, Watched the guy cut off my old flange and weld on the new one. Like watching an artist at work!Â
DomRees Posted June 23, 2006 Posted June 23, 2006 I too have a blow on the 2nd and 3rd, so a well worked remedy would be useful for me also...  cheers in advance..Â
eric Posted June 23, 2006 Posted June 23, 2006 same problem 4 days ago Check the pipes are not bent like a banana the flange on the centre primary pipes must be flat Sorry, I think I bought the last cooper gasket set from 7 Workshop eric
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