I am looking at a 74 CSi engine, for parts, and noticed the two halves of the intake manifold (plenum chamber?) were welded all the way around in a manner which definitely is not factory. (The owner doesn't know why it was done but claims the engine is a factory re-build anyway.) Anybody care to hazard a guess why it would make sense to do such a weld instead of buying a new manifold?
FI intake manifold weld
- Thread starter bill
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MMercury
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Doing a limited search I was unable to locate a picture of the so-called welded log or Sasquatch manifold but I know several exist. I have personally encountered them and long ago had one on an engine stand. I don't think they were stock to any E9 though. Instead, I believe the factory used this type manifold in North America on later models also using the M30 block e.g., 5, 6 and 7 series // E24 or E23.
The cast manifolds were certainly more ubiquitous. Exactly why the factory may have used this stamped-welded-shell variant is a mystery. Not having one in front of me it is a wild guess but the decision could have been economic or even a short term design accommodation for North American models.
I would not be too quick to dismiss the stamped design as being less than the cast model's equal. Sasquatch may appear cosmetically less appealing but both logs can use the same intake runners. I understand the entire induction system can be designed as a package including the air filter but from personal experience those runners probably have more direct effect on engine operation.
