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1963 PV544 rat rod

Yeah, I worded that awkwardly. The B18 and 6-bolt B20 rods are dimensionally the same, although the B18 rods are lighter and weaker.

They changes the bottom end bearing sizes for the 8-bolt B20's. The 8-bolt B20 rods are dimensionally the same as B21 rods. basically Volvo redesigned the bottom end of the motor a few years before they redesigned the top end for the B21.


I bought a set of B20E rods. I'll have the same thing done with the wrist pins as I had done with the B18 rods - press out the brass bushing, and ream it lightly for an interference fit on the 24mm wristpins.

Good move getting the B20 rods. When compared side by side the weak spot in the B18 rod becomes obvious.

B20Rods1.jpg


B20Rods2.jpg
 
That pic of them side to side makes me think its a no brained to source out an 8bolt b20 when choosing an engine.
 
Good move getting the B20 rods. When compared side by side the weak spot in the B18 rod becomes obvious.
The weird little marks inside the big ends were *right* on that weak spot.

Either they happened when the big ends were machined, or it's been happening in sue (although the bearings themselves don't have anything odd on them).

But yeah, I think I rolled the dice long enough on the B18 rods, with the heavier B21 pistons and the 7500 revving.

I'd like to make a super light weight rev machine, but there's other things do to right now (second daughter is starting college this fall, first one isn't done yet).
 
Just for the record, this is a GREAT thread for those of us planning B18/20 builds.

Was it ever determined if a B20 8 bolt rod will fit on a 6 bolt crank?
 
Are those yours? If so, I guess I bought the set that just arrived in the mail from you as well.

If I need spares, a rod probably broke, and I'll need a whole donor motor.

Actually, I have a set of B20 rods around somewhere in the basement, one of the big ends got scuffed when I spun a rod bearing (no clue why, it was full of Mobil 1 and no issues with the oil system) in the previous motor. I didn't want to reuse the scuffed rod, so I got the B18 rods.

The B20 rods and pistons came in the mail, I'll yank the pistons off and wait for the set of new B21A pistons to show up. Then off to the machine shop to have:
- the pistons balanced
- the wrist pin bushings pressed out and the rods lightly reamed for an interference fit on the 24mm wristpins
- the rods big/small end balanced
- the wristpins installed
 
My projects always take forever.

The pistons showed up long time ago. Then I took the rods and pistons to the machine shop to be balanced and assembled. They needed a bit of work on the small ends to fit the 24mm wrist pins in.

Then we went on vacation for two weeks right as the machine shop was done. Then I decided to get some new rod bearings - even if the old ones seem perfectly fine, it's still silly to put used bearings back in. So those finally came in the mail. Time to do a little reassembly.

The old cracked B21A piston on a skinny (but light) possibly fragile B18 rod, and the new B21A piston on a sturdier B20 rod.
P7163556_zpsd487684f.jpg


Does this pic show the way the 22mm rods were worked to fit 24mm wrist pins? No. This picture sucks. I've just wasted valuable interWeb packets posting this pic. Ah well. The bronze bushing is removed, and the steel just needs a *tiny* bit of metal removed. Then they chill the pin, and heat the rod, and it all slides together. As soon as the temps equalize, it's all locked in place. No circlips needed on the pistons. OMG saved .025 grams of reciprocating weightz!
P7163559_zps20e12aca.jpg


I'd only take two pistons out so far, the busted one, and a 'good' one. I decided to go with 4 new pistons, along with the B20 rods.
P7163560_zps4046a3ff.jpg


Some torque wrenching, some STP used as assembly lube, and a break to go pick and eat blackberries (they're in full gallop right now, about 2 quarts a day, sofa king delish), and all 4 are in.
P7163583_zps60ed707d.jpg


And.... yeah, I don't have an oil pan gasket. Why don't I order this stuff ahead of time? Dunno. It's part of why my projects take so damn long.
 
Is your crank rotated so all cylinders are at the middle of their stroke, or did you modify your crank to fire all four cylinders at once? :lol:
 
Oil pan is on. Head is on. Lifters are... yeah, I had to take the head off and put the lifters on. Wasn't paying enough attention to the order things need to happen on a pushrod block. too much 16V nonsense over the last few years. It's a Cometic HG, it will be fine with a re-installation.

Roller rockers are back on, valve cover is on. And I didn't as much as look at it over the weekend. Went to Cars & Coffee Saturday morning, then we went home and loaded up the backpacks for a short overnight backpack at Hawn State Park.

But it's about ready to go back into the PV again.
 
I sort of felt like using a light new style starter on it, instead of the large, heavy old style. So this morning I went by the PnP and pulled a starter off a '94 940.

Ready to put the motor back in finally.
P7264001_zpsa152e477.jpg


Taking advantage of slave labor. Pull that lever! Just like manning the oars in Greek times.
P7263999_zps2c0cc162.jpg


Almost high enough. I have to jack the car up in the air too, the legs of the lift are too wide and too tall to fit under the PV's front ent.
P7264002_zpscd1dba23.jpg


About 10 minutes of wiggling, raising, lowering, tilting one way, tilting back, and the motor slips into place. An unflattering pic of my ass working away at those bellhousing bolts:
P7264018_zps18fc2e37.jpg


The new starter is half the size. From 2150 lbs down to 2142!
P7264045_zps6166a0d7.jpg


I'm lazy. This is as far as I got today:
P7264047_zpsd1981efa.jpg


I need to weld on the exhaust header a bit before I put it back on. There was a small gap on #3 where a welding error wasn't sealing properly, it was a bit sooty around the area. I'll weld it and grind it smooth again. The rest of the work will go quickly. Exhaust header, v-band clamp to the exhaust system. DCOE's go on in one large chunk - a throttle push rod pops on, one fuel line, two choke lines. Then the distributor cap and wires/plugs. Crank crank vrooom.

I haven't driven it since last fall, and really, it's been sitting since last spring.
 
Finished up the rest of the installation process yesterday. Easy as pie on such an old car.

Then I tried to start it. Nothing. Crank crank crank crank (hey, at least the new starter works great!).

Nothing. Messed around with the carbs, thinking they were gummed up from sitting around for so long, even though I'd turned off the fuel pump and let the car suck them dry prior to taking them off. Nope, they were getting fuel, bowls were full, plugs were damp. Hmm... ignition? Pulled the coil wire off and cranked it some. Holy hell that MSD 6A box and the Blaster coil make some wicked sparks. They'd jump about an inch, 4 sparks per fire (?), made a wicked sizzling sound when it went off. No problem there. Did I get something clocked wrong putting it back together? Shouldn't be off, I left the dist drive gear in place the whole time, dist only goes on one way. Broke out the timing light and..... weak and sporadic sparks going to #1. Put it on the coil wire. Yeah, that's firing off nicely every time. That narrows it down a bit.

I took off the cap, it was fine, but the rotor had a little burn hole near the center. Apparently the sparks were jumping through it into the distributor shaft. Not sure why this decided to manifest itself right now. *frown*

It's an old Mallory Dual Point distributor body, not stock Volvo parts. So I ordered a new cap and rotor for what I think will fit - seems as though Mallory made a wide variety of fitments for the distributors, but all of those tended to use a fairly small number of common caps and rotors.

In the meantime, I dremeled out the hole in the rotor and filled it with JB Weld, I'm not sure if that will work or not. I'll try it when I get home.
 
but the rotor had a little burn hole near the center

1981 VW Rabbit Pickup - Bought discount rotor...within 1,000 miles, it too failed, same location. Then, I bought a Bosch, problem solved.

Hence, there is also heat that travels thru, and "cooks" it.
 
I've been using that cap/rotor/distributor for probably 30K miles prior to this. Never an issue. The MSD 6A box has only been on for about 5K miles though. Prior to that the Crane optical box was driving an old square Mallory coil directly. powerful - but nothing like the lightning bolts the current setup is tossing out.

I think perhaps the issue was that the cap/rotor had been off and sitting around for a while on the work bench while the motor was apart, it had a little oil in it. I cleaned it out with a shop rag, but it might have been enough to get a carbon track started?
 
In the meantime, I dremeled out the hole in the rotor and filled it with JB Weld, I'm not sure if that will work or not. I'll try it when I get home.

Might work, I filled one with the POR epoxy putty and put a pad of solder on it to connect to the contacts.. worked for 3 days while my new one shipped out.
 
I've been using that cap/rotor/distributor for probably 30K miles prior to this. Never an issue. The MSD 6A box has only been on for about 5K miles though. Prior to that the Crane optical box was driving an old square Mallory coil directly. powerful - but nothing like the lightning bolts the current setup is tossing out.

I think perhaps the issue was that the cap/rotor had been off and sitting around for a while on the work bench while the motor was apart, it had a little oil in it. I cleaned it out with a shop rag, but it might have been enough to get a carbon track started?

5k is about right for a 6a box to start eating caps and rotors.
 
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