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Exhaust Manifold Identification


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Hello,

Whilst separating the downpipe from the manifold a bit fell off the manifold - old and cracked a long time ago (bit like me these days)

Exploring the options of cast Iron welding or replacement I have discovered that there are two exhaust manifolds in existence - one for 907 and 912 Standard engines and one for HC engines. As I have an HC cylinder head (A912E 0311PK - which car did that come off - Esprit? - as not in Excel parts list) I need an HC exhaust manifold - A912E 2005K. As my cracked manifold doesn't have any part number on it as far as I can see (Mr Magoo has better eyesight) how do I know which one I've got - sneaking suspicion it's off a 907 Engine. As far as I can tell looking at the parts list the only difference is the diameter of the studs that hold the downpipe on - 8mm for Std, 10 mm for HC. Is the difference to suit the exhaust downpipe connection on different exhaust makes rather than the exhaust pressure at the head? Or it doesn't matter, because it is in reality the same thing.

Also (what now?) can I fit a good exhaust system from a 907 Elite to my 912 engine - again a pressure query - if I alter the geometry?

 

Brian

 

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the difference is visible by looking at the three bolts that secure the downpipe to the manifold. Orientate the manifold to it's normal position. Single bolt at the top (and so awkward to get to when in place) = LC/907, single bolt at the bottom (and so easy access) = HC/912

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To put my post in context,  it's so that @Grizzly can determine which type he has and so get a like for like replacement. Yep, the later ones will help remove a possible restriction to gas flow, even if not give a noticeable increase in power on earlier engines.

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Andy,

Thanks for the way to identify which manifold is which - so simple when you know the answer. Why didn't I try it against the cylinder head which was the obvious thing to do now I think about it - except my engine is away being rebuilt, so i don't have it.

My luck holds - I've got the wrong exhaust manifold - anybody got one for a 912 HC engine complete with exhaust?

 

Brian

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There is more than one version of the exhaust, the tubes that pass over the driveshafts etc are different between different manufacturers. So, if your exhaust fits together and doesn't knock, I'd say do a little mix n match.

You can probably get a decent secondhand manifold and downpipe from Lotusbits then get a flexi joint, and take the front of the replacement manifold, and mate to the rear section of your existing downpipe. That  gives a decent flowing manifold plus an exhaust then you know fits without knocking.

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I've just had two quotes for repairing the 907 exhaust manifold

           "We can weld the crack/missing piece and machine up with a grinding to shape and bead blast, then VHT black paint, just need a pattern for the holes.

            Estimate for the welding repairs £415 ex vat/transport (based upon picture sent)

            Delivery time 3-4 weeks standard."

or

          "I see no problems with repairing your manifold ,

           Approx. cost will be around £280+Vat including machining of the flange , with 12 months warranty"

 

I don't think so

 

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Have you tried SWLC?

they have remanufactured the LC one, but not sure about HC status

Phil strongly advised against welding due to concentration of impurities in a cracked/holed manifold preventing a good repair.

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