Conservation and Restoration
The quest for originality can be demanding, particularly when correct detail is important. One feature of a Jensen which takes time and expertise to get just right, is the engine-bay.
Many decades have elapsed since the cars were first built, and in that time all manner of detail may have been changed. The Museum looks at the detail of a Jensen SP engine-bay.
Jensen SP Engine-Bay | Overview of the Jensen SP engine-bay
The Jensen SP was simply a modification of a standard Jensen MK.III, so the engine-bay lay out is generally the same. The obvious difference being the iconic Six Pack carburettor system, with the Six Pack specific air-can with filter.
There were, of course, less obvious differences. These included ribbed exhaust manifolds , and slightly changed lower inlets to the radiator.
Although both the engine and transmission look the same as any other Chrysler 440 engine and Torqueflite transmission, internally they were different. Both units having strengthened internals to endure race work.
For the purposes of this feature, we are concentrating on the external differences, visual within the engine-bay.
Jensen SP Engine-Bay | Six Pack Carburettors & manifold
A complete Jensen SP carburettor and inlet manifold set-up, with original specification air-can and filter. This unit was removed from a Jensen SP during the 1980s and left in storage. The set was acquired for the Jensen Museum collection in 2018.
Jensen SP Engine-Bay | SP Carburettor List Numbers
According to Mopar specialist, Duncan Watts, the carburettor list numbers found on the batch of Canadian SP units purchased by Jensen Motors, are different to all other American SP list numbers.
The images below show the list numbers on the Museum set-up, but there may be other list numbers. If one or all of the carburettors have been changed at a later date, then there could be a mix of American list numbers, along with Canadian specific numbers.
Jensen SP Engine-Bay | The SP air-filter lid
When the Chrysler SP units started to arrive from Canada, the Development Department quickly found an issue. The air-filter lid was slightly domed, and this just caught the bonnet insulation.
Development were concerned that when the car was driven, the friction of the lid against the bonnet could cause damage. They came up with a novel idea – a small circular tool, that could be fitted to a press. When pressed onto the SP air-can lid, it put a small neat circular recess.
This took off the peak of the dome. The tool only recessed the lid by few milometers, but that was just enough to keep the lid free from touching the bonnet. Undertaken carefully, the recessed circular section could be put into the lid without causing any damage to the paint.
Jensen SP Engine-Bay | The SP manifold
Jensen SP Engine-Bay | Ribbed Exhaust Manifolds
The Jensen SP had special exhaust manifolds with a set of triple ribs to each (Chrysler part number 3614295). According to Mopar specialist, Duncan Watts, Chrysler are not known to have generally fitted this type of exhaust manifold to their passenger cars with SP engines installed.
As with the carburettors, it seems these were specials made for the 200 + engines which Jensen Motors purchased from Canada. Watts states that Chrysler had their own foundry in Canada, and so it is possible the ribbed manifolds were only made there, and not in the USA. Why there was a specific manifold style for this batch of SP engines isn’t known.
Jensen SP Engine-Bay | The SP air-filter
A Fram CA332V air filter was fitted to the Jensen SP. This air filter was finished with a thin metal steel surround with a triple height of small round holes. A later Fram alternative (1980s), had a metal steel cross hatched surround.
Jensen SP Engine-Bay | The SP oil-filter
As with the standard Chrysler 440 engine, the Jensen SP had an external screw fit Fram oil filter installed at the factory. This was the Fram PH2821A, and the entire oil filter canister was finished in orange. Later versions (1980s) had a black textured finish put on to help in unscrewing the filter for replacement.
Jensen SP Engine-Bay | 131 series
Jensen SP Engine-Bay | 138 series
Jensen SP engine-bay
ACKNOWLEDGEMENTS: Brian Berkin, Jensen SP specialist |Duncan Watts, Mopar specialist
COPYRIGHTS: The Jensen Museum
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