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- เผยแพร่เมื่อ 5 ส.ค. 2021
- #HindustanAmbassador #HM #AmbassadorMark2
This video demonstrates how we inspected, tested and measured the cylinders on the 1970 Hindustan Ambassador Mark 2 BMC petrol OHV engine. First we visually inspected the cylinders. All cylinders were scored/scratched vertically, with Cylinder 3 being the worst. Then we checked the pistons for side play within the bore.
Next we tested the piston rings for leakage using Petrol/Gasoline. This was an experiment to check if the petrol leaking down the cylinder is a reliable enough gauge for piston ring health. The results seem satisfactory and we think that this is a good method to check piston ring condition with the cylinder head off the engine. The logic being that the cylinders that do not seal well will leak off before the ones that do. Like the compression test, this is also a comparative test where the time taken to drain is compared to the other cylinders.
Finally we took to measuring our bores for wear, taper and out-of-round (or ovality). All bores were slightly tapered with the top being larger than the bottom (un-worn region) and slightly out of round (thrust sides wearing more than the perpendicular sides). Cylinder 1 was the worst having a taper of 0.065mm and an ovality of 0.04mm. Surprisingly, the max taper was observed between the non-thrust sides of the piston (along the axis of the crankshaft). Maybe that's why Cylinder 1 performed the poorest!
Overall, since the goal of this build is to get this 1970 Hindustan Ambassador Mark 2 back on the road without undergoing a complete engine rebuild (re-boring, oversize pistons etc.), we are going to work with theses numbers for taper and out of round (and they are not bad TBH). Many forums for Chevy and Ford V8s quote as much as 0.005 inches (= 0.125mm!!) of taper being okay for rebuilding without re-boring the engine! So, we think we should be fine. Also, its only Cylinder 1 that's a problem, the others are well within 0.03mm and 0.01mm taper, ovality measurements.
The only problem we see is the scoring on the walls and any new problems that the pistons will throw at us when they come out of their bores! For the scoring we will try and hone them out using a three-leg drill hone.
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History of the Ambassador "king of Indian roads": The roots of the Amby can be traced back to the Morris Oxford Series 2. In the late 40's, Hindustan Motors or HM entered an agreement with Morris Motors to manufacture and sell the Morris Oxford, Morris Minor etc. as the Hindustan 14, Baby Hindustan etc. With the passing of time, came the Morris Oxford Series 2 sold as the Hindustan Landmaster and eventually the Morris Oxford Series 3 that became the mighty 1957 Ambassador (unofficially called the Mark 1). The Amby in this video is a Mark 2 which was a facelifted version of the Mark 1 (with a Mini like front grille) and in our opinion, the first desi Ambassador (cause it was not a through and through copy of the Morris). The engine however, was the same up until Ambassador Mark 3 and Mark 4 (we believe): inline 4 cylinder petrol BMC B Series.
The BMC (short for British Motor Corporation) B Series, also known as the MG B Series engine powered a LOT of cars back then, including sports cars: MGA, MGB, Morris Mini, TVR Grantura, and a few Austin and Wolseley cars too.
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Nice
Can tell which make of electronic ignition system available in ebay is suitable to replace contact breakers and condensers of Mark IV petrol Ambassador as the points and condensers available from Lucas - TVS is of very low quality which may go faulty within a travel of less than 100 km.
I am not sure. This car retains the points and condenser system. I do not know which electronic ignition conversion would work on the BMC petrol Amby. The only conversion kit I have heard of is the Pertronix but I do not know if they make one for our engine and they tend to be expensive. Sorry I have no knowledge to offer in this case 😅
You could try to research what kind of electronic ignition conversion kits are used by MGA, MGB, Morris Oxford or even by Mini owners abroad. That might help you find a good kit.
@@fixpaana Thank you
What would be the average expense of petrol ambassador engine rework namely replacing pistons liners etc?
It would depend on who you get to rebuild the engine, which machine shop you get the work done from and what all parts need replacing/machining. Reputed mechanics and machine shops will be more expensive but worth it in the long run as once the engine is done right, it will last a very long time. So it's a lot of variables that come into play. It's not super expensive to rebuild these engines as the parts are more readily available compared to other classic cars that need the parts to be imported. So it's difficult to estimate costs but a rebuild would easily be over 30k, again depending on the condition of the engine, availability and cost of parts (pistons, bearings, bushings etc) other difficult to predict factors