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Jun 25, 2018 11:00 am
Jun 25, 2018 11:00 am
Subject: Re: 4.5 litre pushrods
I wondered if that was what you intended. The guiding factor would presumably be whether there is excessive wear otherwise occuring to the lower end of the pushrod and/or tappet. In service these areas are normally fairly flooded with oil. Drilling the upper pushrod cup could be detrimental: the cup would be an oil reservoir; drilling it would transform it into an oil drain, possibly to the detriment of the ball and cup bearing surfaces. More care, thought and science went into the design of engine components in period than we appreciate today. That doesn't mean they always got it right, though!
My LG6 has an S4 engine; no pushrod trouble so far, but then I've rarely approached max. revs. Did once get it up to 105mph on the original 3.58 cwp, which must have been thereabouts. Doubtless the fastest the car had ever gone, given the wind resistance presented by its original saloon body. Higher revs in the lower gears appears to be pointless performancewise, the complete opposite to driving the V12.
Laurence
I wondered if that was what you intended. The guiding factor would presumably be whether there is excessive wear otherwise occuring to the lower end of the pushrod and/or tappet. In service these areas are normally fairly flooded with oil. Drilling the upper pushrod cup could be detrimental: the cup would be an oil reservoir; drilling it would transform it into an oil drain, possibly to the detriment of the ball and cup bearing surfaces. More care, thought and science went into the design of engine components in period than we appreciate today. That doesn't mean they always got it right, though!
My LG6 has an S4 engine; no pushrod trouble so far, but then I've rarely approached max. revs. Did once get it up to 105mph on the original 3.58 cwp, which must have been thereabouts. Doubtless the fastest the car had ever gone, given the wind resistance presented by its original saloon body. Higher revs in the lower gears appears to be pointless performancewise, the complete opposite to driving the V12.
Laurence