That fuse block with the raised rib is kind of a terrible design for long-term durability, surprised the screw terminal block isn't moved up further on the frame where the connector is less likely to rub to shorting.
I guess strain relief was an unloved science in 1970.
Keep up the good work!
Lucas gets a lot of bad rep for crappy electronics but I've seen my share of bodged electricals on Volvos as well. Most of it comes down to the cars being old, so the wiring is old, and they've been through a lot of owners, of generally decreasing ability in terms of making good repairs.
If you decide to keep the stock fuse block, a good first step is simply replacing all of the fuses with new in-kind. You'd be surprised at how many issues that clears up. I just replaced all of the fuses on my Jaguar and was surprised to now have a functioning heater blower fan!
Clean off the fuse contacts with electrical cleaner and cloth. Use dielectric grease.
If those are the same fuses as Mercedes used for much of the 70's/ 80's I have a huge box of new ones. PM me your name and address, and how many of what size you need, and for the cost of a shipping envelope I'll send you some.
I have a box of new fuses ready to go, thank you for the offer though. I'll continue to run the stock fuse block for now, but it will come out for a light pass with emory cloth and some light dielectric grease.
volvoclearinghouse wrote: Lucas gets a lot of bad rep for crappy electronics but I've seen my share of bodged electricals on Volvos as well. Most of it comes down to the cars being old, so the wiring is old, and they've been through a lot of owners, of generally decreasing ability in terms of making good repairs. If you decide to keep the stock fuse block, a good first step is simply replacing all of the fuses with new in-kind. You'd be surprised at how many issues that clears up. I just replaced all of the fuses on my Jaguar and was surprised to now have a functioning heater blower fan! Clean off the fuse contacts with electrical cleaner and cloth. Use dielectric grease. If those are the same fuses as Mercedes used for much of the 70's/ 80's I have a huge box of new ones. PM me your name and address, and how many of what size you need, and for the cost of a shipping envelope I'll send you some.
On startup the engine races for 2-3 seconds then dies out. I've replaced all vacuum lines and double checked connections. It's not a fuel starvation issue, plenty of flow there. I went ahead and ordered the weber DGEV rebuild kit because who knows how long that's been sitting there or what's clogging it. Any other suggestions?
Timing is at 10° and feels spot on. I rebuilt the carb but it's till spitting like it's lean when I try to start it. I pulled the carb apart again only to confirm there's no fuel blockage. Jets, air correctors, emulsifiers, filter, everything looks good. While going through the Weber diagnostics it says no more than 3.5 psi to the bowl. I'm using an aftermarket pump with a longer arm so it's quite possibly putting out more pressure. I'll get a regulator today and see how it behaves.
nharperc wrote: Timing is at 10° and feels spot on. I rebuilt the carb but it's till spitting like it's lean when I try to start it. I pulled the carb apart again only to confirm there's no fuel blockage. Jets, air correctors, emulsifiers, filter, everything looks good. While going through the Weber diagnostics it says no more than 3.5 psi to the bowl. I'm using an aftermarket pump with a longer arm so it's quite possibly putting out more pressure. I'll get a regulator today and see how it behaves.
Yes, SUs are quite particular when it comes to fuel pressure. 2-3 psi is ideal. I've taken to installing an adjustable regulator and gauge into my SU equipped cars. Even with a "stock" type fuel pump. You can plumb in such a setup for quite inexpensively.
Big engine updates tonight.
I had a friend come over to help diagnose the issues. There are big problems.
Step 1: Fuel Pressure Regulator
I added an adjustable fuel pressure regulator after the pump, before the filter. Cranking the car and no fuel was making it to the filter. I thought for sure I just bought a bum regulator but quickly realized the gas tank was just empty. Another gallon of gas in the tank and things were better. Fuel pressure set to 3.5psi…things were looking up.
Step 2: Solve the Lean Condition
With fuel to the carb it was still having trouble starting, and the Weber DGEV was spitting. Everyone says ditch the Weber and go back to SU's, I get it, but I don't have SU's laying around so I'm working with what I have. I opened the Weber up and adjusted the float height to the correct specification. This definitely allowed the filter to fill up faster and fed plenty of fuel to the carb. The car started right up and idled pretty well until we noticed fuel dripping from between the intake manifold and the head–straight on to the exhaust.
Step 3: Intake Gasket
Realizing the intake gasket was shot, and having a spare on hand, we removed the intake/exhaust and pulled the old gasket. It was in pretty bad shape, but bigger issues were appearing. A few of the intake studs were sheared off before we touched it. I think the lack of clamping proper force lead to early failure of the intake/exhaust gasket. If the gasket was shot enough to let fuel drip out, that means there was a massive vacuum leak which also helps explain the lean condition I saw. We put the new gasket on but with crummy studs and closed hardware stores we weren't able to make a permanent fix tonight. So, we did more diagnostics.
Step 4: Compression Testing
Cylinder 1: 149
Cylinder 2: 140
Cylinder 3: 145
Cylinder 4: 50
fcuk.
Cylinder 4 (with a splash of oil): 100
fcuk.
Take a Vote
Cylinder 4 gained pressure with oil added, so I'm in ring territory. Now I need your help in deciding what to do next. Should I rebuild the B20 and keep it stock or start considering a swap?
Get it to run for a while, then check the valve lash, and recheck the compression. Might be a leaky valve and running it might make it a little better. If it sat a long time, running it a little might help...
I set the valves before I started it, they're at spec. I can't really run it because there's still fuel dripping out between the head and the intake manifold. The studs all need to be replaced. The splash of oil definitely indicates rings. A leak down test would have been ideal, but cylinder 4 is definitely hosed.
TED_fiestaHP wrote: Get it to run for a while, then check the valve lash, and recheck the compression. Might be a leaky valve and running it might make it a little better. If it sat a long time, running it a little might help...
Oh no!
Depending on a lot of variables, I'd be inclined to pull the head and check the cylinder bores for obvious signs of deadness.
If the bores are clean I would probably do rings and bearings and run it to death while I sort out the rest of the car.
If I could get the pan off with the motor in place I'd almost assuredly go that route.
Then decide on motor swaps later.
Is it smoking at all? Could be stuck rings. I'd fix the intake and assorted other issues and see if the compression improves after some spirited driving. The pan won't come off with the engine in place so you're talking a full engine-out dealio to do a re-ring. The bearings are likely fine, as they're tremendously oversized for this engine.
Also, not to sound condescending, but are you sure you did the valve lash set correctly? I've seen more than one engine (and yes, I've done it too, no pride here) with a seemingly "dead" cylinder that just had a bad valve lash done on that cylinder. Check the procedure for setting lash, and try again.
You make a fair point about double checking the valves, but I went with my gut and pulled the head.
Piston 4 is two halves.
volvoclearinghouse wrote: Is it smoking at all? Could be stuck rings. I'd fix the intake and assorted other issues and see if the compression improves after some spirited driving. The pan won't come off with the engine in place so you're talking a full engine-out dealio to do a re-ring. The bearings are likely fine, as they're tremendously oversized for this engine. Also, not to sound condescending, but are you sure you did the valve lash set correctly? I've seen more than one engine (and yes, I've done it too, no pride here) with a seemingly "dead" cylinder that just had a bad valve lash done on that cylinder. Check the procedure for setting lash, and try again.
Jb weld!!!!!
Or, you know, later model Volvo swap.
nharperc wrote: You make a fair point about double checking the valves, but I went with my gut and pulled the head. Piston 4 is two halves.
So, does that make it a 5 cylinder?
I wonder if there're any small diesels that would fit. That would be a neat swap...
I believe swaps on these aren't all that straightforward - compared to later 240 Volvos. If I remember right the front double wishbone suspension makes things a tight fit with a V8, and the transmission tunnel is much narrower. I recall someone mentioning that a T5 or even a later M46/M47 trans does not fit without widening the trans tunnel.
Wow, I was really just suspecting a collapsed/broken ring.
Was it even making any noise?
It's a really tight fit for anything besides a B18/B20.
I've never seen a B20 piston do that. 
If you want to cheap and dirty it back on the road, I could ship you a used B20 piston with rings for $50, including shipping. It will be used, but it won't be cracked, so a quick dingleberry hone and a piston swap and you could be back on the road with at least some compression.
My! What a unique piston failure!
I've never seen a piston fail like that.....
It's perpendicular to the pin, did the pin break?
This sounds like the most affordable questionable idea I've had this year. I'm in.
volvoclearinghouse wrote: It's a really tight fit for anything besides a B18/B20. I've never seen a B20 piston do that.
Well that is unexpected, seems like a odd failure for a street car engine. But if you replace the piston with a used one, it should work. It won't be like a true rebuild but it should run!
An interesting development: Volvo B20's came from the factory with single valve springs. This head has double valve springs, which means it's seen machine work to accept the wider outer spring. Additionally, the pushrods are .75" longer than stock, and it has Isky lifters instead of OEM lifters.
I haven't pulled the cam to verify the lift and duration yet, but all signs are telling me this has an IPD cam kit (street torque or street performance). I'm taking that as a signal that I shouldn't half-ass the rebuild.
In reply to nharperc:
Or you could look at it this way. It was probably rebuilt when all that machine work was done. Replace the #4 piston and check the other bearings while you're in there. If they look good and clearances check out, just put it back together and enjoy your already-hopped-up Volvo wagon!
Or at least should probably check to make sure the bores are factory spec before buying anything.
What's the proverb? The least expensive rebuild is a complete rebuild, cut a corner and you'll pay for it twice. You get the idea. I dropped the head off this morning for some love. The crosshatch on the block leaves a little to be desired. I'll get the block checked before making a decision.
In reply to nharperc:
Very true, and I'm one to talk. I half-assed my $2016 Challenge Roadmaster wagon rebuild. No machining, no proper cleaning, just dingleberry hone on a drill, re-ring, fresh bearings, and 600 miles later got some rod knock after several low oil pressure warnings. Should have replaced oil pump 
But you live and learn. Yours should be a fun one!
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