Engine rebuild questions and important ramblings...

[Dave M]

I've posted a few times about my tiring M50 non-vanos bottom end (pardon the pun). Cylinder 5 is dragging it’s ass by @ 20lbs, when compared to the 175lbs to 180 lbs in the remaining cylinders. Administering the 'wet test', cylinder #5 picks itself up to 210lbs along with the rest. The car still drives great, burns oil under vacuum conditions (in gear, coasting on long downhills), gets @28-30 mpg highway (7.9-8.3L/100km). I wouldn’t think twice about driving it for another summer (stored winters) and wouldn’t mind learning how to rebuild a used bottom end in the ‘off-season’. I’ve located a bottom end with @180,000km on it in the Toronto area and could get it shipped for @ $150. A rebuilt cylinder head was installed less than two years ago, so I’m not interested in an entire engine (the seller doesn’t mind keeping the head). I figure, this way I may get a rebuilt bottom end, with a fresh head, do the clutch (maybe flywheel) and learn something next winter.

So my questions are:

Is $500 Can ($360 U.S.) sound reasonable for a M50 bottom end with 110,000 miles?

What might a rebuilt by an indy cost if I handed them the bottom end?

What might parts and tools cost? Are parts available from sources like BMA?

Is it a ridiculous undertaking for someone with almost no internal engine experience to attempt the rebuild? Remember, I’ve got the time.

Thanks for reading my ramblings. I’m mainly thinking out loud at this point, but would drop the money in a second if I knew the project was realistic. I’m just looking for opinions.

[Kalevera]

Heck - I have no internal engine experience...and little external experience, but I'd still do it :) You'd, no doubt, learn a lot...but I'd think it'd get expensive if you needed to pick up special tools/more tools (in general) to machine parts and reassemble.

I'd do it!

Good luck!

Best, Whit

[Dave M]

Thanks fro the support, it may be all I need to take the plunge

Dave M

[winfred]

if it was me and theres no rust on the cylinder walls of the "new" short block id slap that head on it and roll, rather then possibly screw up a good to go short block. i've freshed up a few m50s and m52s and can give you a few tips if needed based on my observations

[Kalevera]

That's an even slicker idea...and probably about 75% less work. But then Dave wouldn't learn anything besides how to swap the head :)

[Dave M]

if it was me and theres no rust on the cylinder walls of the "new" short block id slap that head on it and roll, rather then possibly screw up a good to go short block. i've freshed up a few m50s and m52s and can give you a few tips if needed based on my observations

I've been told the engine has been stored inside. In a PM, Mark D'Sylva said the seller is reputable, so I would like to believe it will arrive rust free. I thought about the 'easier' straight swap, and it definitely appeals to me, but don't want to go through all the work to swap in a dud. I'm just not sure how (yet) to gauge the condition the block (sight unseen) without something like a leak down test done by the seller with the head on. The Bentleys doesn’t seem to have a great section on engine internals, but I have both the Chiltons and Haynes, which have such info. Would a measure the “Piston Clearance” and taper be good enough? Would it be a lot of Work? (removal of pistons). Would new rings a good idea? Honing......? So many questions.
Anyhow, glad to know I have the wealth of knowledge available to tap into. I'm sure I'll use it.
I will make my decision on the block next week and it should be on a pallet shortly after. Now that you’ve offered the freshen-up tips, prepare for some questions :D. This project may cut into my hunting next fall though.