3 bearing engine

[Ladybird]

We have owned our 1936 Opal for just over a year, have had a lot of fun despite covid and have covered more than 1,000 local miles.  We have sorted most small niggles including a top end rebuild, however there is a persistent bottom end rumble when the oil warms up and major work is needed during the winter. Past experience suggests that engine removal, dismantling, delay awaiting new parts and the probable discovery of a cracked crankshaft could lead to the car being off the road for some weeks or months, something we are keen to avoid.  We are based in Somerset.  My question is; does anybody relatively local to us have a spare 3 bearing engine under the bench that we can borrow to swap in and keep the car running while we rebuild ours??  Obviously we are happy to indemnify the owner for wear, loss damage etc...  Can anybody help??

["Slack Alice" Simon]

Why do you need a three bearing engine in particular?

Many owners have swapped three for two, apart from the cam bearing bolt they are externally identical, I think.

It has to be the low frame crankcase to be an easy swap, though.

[Ladybird]

Good point, any engine that fits and can accept our gearbox and ancillaries...

[Howard Wright]

Hi Ladybird

If your car is still running why not start building a new engine rather than sourcing a temporary swap?

There are crank cases and blocks around for not too much money and the rest you would spend in a refurb anyway.  

Talk to our cherished suppliers they may have a suitable engine in need of refurb.

Cheers

Howard

[Ladybird]

Thanks for your suggestion Howard.  I guess my thinking is:


1.  The engine we have is running well and has been rebuilt from the cerankcase up.  I don't know the condition of the crank other than that the mains rumble badly.  I suppose I'm wary of the dreaded cracked/broken crank....

2.  In preference, I want a reliable engine so that we can do more adventurous things with the car.  A sound bottom end seems fundamental and I'd like to avoid a garage full of spare parts, I don't have the storage space.

3.  If I buy a second bottom end is there not a good chance that it will have a cracked/broken crank? The time, effort and expense of sorting the replacement engine may be wasted if all our engine needs is a set of bearings.

So, to sum up; I see borrowing an engine as an insurance against taking the car off the road for a long time if I find that our bottom end needs a lot of attention.  Can anybody help or offer a better solution??

[Howard Wright]

Hi Ladybird

I was rather thinking of you building the bottom end with a new crank and bearings.  I wouldn’t now build an engine without a new or billet crank.

If the top end is good it should only be a couple of days work to swap over the top end and reinstall the engine?

Good luck

Cheers

Howard

[Chris KC]

Chris / Hilary, I applaud you for wanting to keep the car on the road to drive. I think you should not delay investigating your bottom-end noise, whatever the rest of the plan is.

It will be great if someone is able to help you with a spare engine and stranger things have happened, but I wouldn't count on it.

In your shoes I think I would whip the sump & gauze off & take a good look - if it's big ends or centre bearing you can more than likely change shells (if applicable) with the engine in situ (I can on my car anyway). Whether shells or white metal it's not a big job to pop bearing caps off and check general condition (just replace them the same way they came off). While there you can check the crank visually for any gaping cracks, especially across the rearmost centre main circular web. The problem / solution may just smack you in the eye.

Different people have different ideas of what 'adventurous' means but if planning on 'bigger' journeys later on I'd be inclined to follow Howard's suggestion & build up a good strong replacement engine with a new crank - then you know where you are. There's no reason not to run a sound original engine but sounds like yours needs some attention before you can have real confidence in it.

[AustinWood]

A lot of people have a spare engine handy in case of problems.

[Nick Turley]

For a "bomb" proof result.
I would obtain a two bearing engine, put a new crank in it and do the top end, clutch plus all else.
Keep the engine you have as the spare.
Not the cheapest but if done correctly that should last you a good 65,000 miles plus.
Peace of mind = more fun.

["Slack Alice" Simon]

Chris & Hilary

I have sent you a PM.