Very basic donor motor question

pieterk · 10-09-2007, 06:45 AM

Okay, this is probably the most rudimentary of questions, but as I've been looking for a 7R case or core to start with, I realized (duh!) that if I bought only a case, I'd still have to buy the myriad of other small parts--cam chain housing covers, intermediate shaft, oil pump, tin, fan, valve covers, etc., and that's totally aside from the, err, sexy parts, like crank, P&Cs, rods, etc.

So it occurred to me: as a general rule, is it more economical to buy a full core?

I'm looking at pictures of different motors for sale, and suddenly, the idea of buying just a case and then having to chase down all those parts doesn't seem so fun.

So maybe it's worth an extra grand or so to get it all in one fell swoop. No?

Of course, all appropriate machining would be done once it's taken apart.

Or is there a really strong argument for starting with just a case first?

Thoughts?

304065 · 10-09-2007, 07:32 AM

Depends. If you just want to drive it for a while and then move on to another project a core is OK.

If you are like me and are restoring the engine to go another 40 years then you end up replacing a lot of stuff with brand new parts because the hassle of teardown AGAIN to fix a marginal part just isn't worth it.

pieterk · 10-09-2007, 07:49 AM

Hmmm. Good point about fixing marginal parts. I guess I was thinking more of the external parts: covers, fan housing, fan, some tin, etc. I know I said intermediate shaft and oil pump, but since all the other internals will be new, or magnafluxed/machined, I will make sure those too are the best possible parts I can find.

It just struck me that having to source a myriad of low-wear parts might become a drag. Then again, all or mostly all new parts would also give me an aesthetically superior motor, and that is also a part of this whole R replica project.

ischmitz · ischmitz's Garage

It all comes down to your budget and how much time you want to spend. If you buy a naked case and have to buy all internal and external parts new or used in seperate deals it will be a lengthy process. Buying them used doesn't really get you any advantage and buying them new will be $$$$.

I would always get a complete core engine to start with. Everything, that is either marginal or does not meet your aesthetic criteria can be replaced in the process. You will quickly realize where to put your threhold.

In other words if someone is parting out an engine and could sell every part he will likely make more money compared to selling it as one piece. So go figure.....

pieterk · 10-10-2007, 05:55 AM

Thanks Ingo (and thanks for the inserts too!).

That makes sense. I forgot too that with a complete core, you can make a little bit of money back on parts that you don't need.

As it happens, I followed up on a candidate yesterday for a motor which meets pretty much everyone's suggestions for the ideal core for this project: 1973.5 2.4T. It's complete, although apart (which is fine). The heads have already been reconditioned with all new guides and springs, there are new rings on the pistons, crank is std/std, the case has been case savered and is clean and free of any damage, the tin is clean; in short, it's a pretty tidy package, and it can be delivered free of charge to boot. No induction or exhaust, which is fine. Anyone could put it together tomorrow and have a complete, running 2.4T that meets spec.

So this seems like one to go forward with. Sell the parts I don't need, send the case off to have all the correct machining done and forget about it for a couple of months!

In the interim, collect parts.

When it comes back, slowly start putting it together, and have fun!

More and more it's looking like I'm going to be building a 2.8S by the way. Aside from street tractability, it'll save me a little (only a little) bit of money in not having to buy a new crank, and, should I elect to use the stock rods rather than exotics, the cost of a set of rods.