1725 Bottom end questions

[mrabody]

I recently acquired a 1967 Hillman Minx (same bodystyle as a Hunter/Arrow). It has a knock at higher RPM. I assume it is a rod bearing that is going. I have read that this isn't uncommon for the 1725 and that it may be related to poor connecting rod bolts.

Can anyone advise me if this is a common problem with these motors?

I am guessing that the engine will need to be gone through. I would like to rebuild it for considerably more power. As part of this process I plan to install longer connecting rods in order to improve the rod/stroke ratio and then fit custom lightweight pistons with more modern rings.

What I need to know is the width of the stock 1725 Connecting rods. Since mine are still in the engine I can't measure them just now. I would like this information so that when selecting the longer rods I can find some that will fit the journal without leaving to much side clearance? Does anyone know this dimension?

Also, are windage trays available for these engines? And can you get highvolume oil pumps for them?

Lastly, can anyone tell me what the deck height of the block is?

Thanks in advance.

Drew

 

[MikeP]

The 1725 engine does tend to have oiling problems with the number 3 rod bearing. One fix is to drill the crank oil passage larger. As for windage trays and high volume pumps, I've never see either for that engine. As for the measurements, I don't have anything available to me at the moment for those. YOu might however ask at www.saoca.org, there are a couple folks with a lot of experience with the 1725 in the Alpine, which is the same basic engine as yours.