• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

To b18 or to b20... That is the question.

Which motor option for my 65' 122s

  • Rebuild stock b18. Add better cam and exhaust.

    Votes: 6 33.3%

  • Swap a b20 from an early 70's boat into the car.

    Votes: 8 44.4%

  • Find a b20e head and install that and a new exhaust on the b18.

    Votes: 0 0.0%

  • New exhaust and drive as is.

    Votes: 4 22.2%
  • Total voters
    18
Cams are def. the B18/20 weak spot. The lobes aren't really well oiled, nothing direct anyhow, I guess they get some of the oil draining back down from the rocker shaft, and crankcase windage. But that's about it.

That and apparently there was a long period where replacement Volvo lifters were not quite up to snuff.
 
The cam I pulled out of my 142 had one exhaust lobe with little more than 0.120" of lift. The rest of the lobes were trashed but much better off. I was surprised how smooth the engine actually ran like that.
 
Ok guys I think I have a plan now that I've heard some solid input. I'm going to put the 4-2-1 manifold and head pipe on my b18 and run a 2.25" exhaust.
Meanwhile I'll pick up the $250 b20 and put it in the garage. For the rest of this year I'll just run the heck out of the b18 and slowly collect a cam, lifters, and a few other odds and ends for the b20. Then do a partial build over the winter and put it in sometime next spring. That way I'm not rushing or without my fun daily driver for the summer. Time to research b20 motor parts!
 
Get some B21 pistons and a Cometic 93mm B20 HG...

If you need to replace pistons anyhow, it barely costs more to go to B21 pistons, Which are (maybe?) easier to find now anyhow. The cometic costs more, but is in theory reusable.
 
I've got a set of early (pre 73) standard pistons for 6 bolt cranks. Or if you swap cranks and roids with your b18 theyd work in an 8 bolt block. They need new rings but otherwise they look good.
 
I think the pistons should be fine. I'd like to leave the pistons, rods and crank alone if possible. I'll know when I open it up though.
 
Got the boat b20 tonight. No starter, cracked dizzy cap and rotor, some silicone around the freeze plugs. Compression test, then the Valve cover and head will come off Friday for a more detailed inspection. Ended up getting it for $200 so I think that's a decent price even if it needs a little work.

Also the carbs said solex I think... What's up with that?
 
Last edited:
Every boat engine I got my hands on was solex. B21 also had a solex
 
That's pretty awesome!
Sprayed the cylinders with Pb blaster tonight. It wasn't seized but I figured it would be a good measure. Hope to check compression tomorrow.
 
Awesome, is it a better starter then the old ones from the b18/b20? Also would the head from this motor need hardened valve seats?
 
You must log in or register to reply here.
Back
Top