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B20 block and head choice for performance build 120-130

Hey, All. I've searched the archives on here and have found some good technical info about build of 'peppy', or greater, B20 engines. I have a '65 122 wagon and I am interested in building (mostly myself, except for the machine work) a performance B20. I'm looking for probably one step lower than race, so a hot rod or fun street engine I guess it could be called. It seems that other than the 6 bolt/8 bolt crank thing that the lower end of these engines are generally the same. It also seems that the later, fuel injected B20s are desireable because of their larger intake valves. If I don't care too much about 6 or 8 bolt crank and if I'm willing to have the head machined for whatever is necessary to bring it to the spec that I'm looking for, then won't almost any usable B20 block do the job? This engine will not be abused or raced, and will be well maintained.

Please let me know what you think.

Thanks.

Deluxe





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    B20 block and head choice for performance build 120-130

    I have a B20F head at a guys shop right now. He is porting the valves for me and is milling it down for a better CR. So far he has kept the stock valves, intake and exhaust, and it getting GREAT numbers off of his bench flow tester. I think that I am going to hold off on putting in larger valves until I see what it feels like after the porting and milling.

    His pricing is also very favorable.





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    B20 block and head choice for performance build 120-130

    Thanks a bunch for all of your help! There is a lot of good info here!

    Deluxe





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    B20 block and head choice for performance build 120-130

    Use a '75 B20F FI block and a '72 carb head and intake which has the bigger valves and doesn't have the secondary throttle valves in the intake, optimally the best choice, if you can find these. A '71 B20E block is also a good choice, but good luck finding one.
    Things to note, the '72-74 B20F has the same bottom end as the 75, but the 75 has an improved forged crank and cam. The early B20F has cam problems as well as connecting rod/wrist pin is weak. I think the '74 B20F has the improved D cam and better bottom end, but has the 6-bolt crank.
    Note that all B20E/F blocks have a slightly different bore/stroke geometry (more square, shorter stroke) than the B20B and will be a better hi rev motor with a B20B head and high compression.
    --
    '89 245 sportwagon, destroyed by hit & run driver, RIP. '04 V70 2.5 T Sportwagon, 12k mi and '91 245 5-speed, 209k mi, replaced the '89





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      B20 block and head choice for performance build 120-130

      First off, let's assume we're talking about US market cars, in which case the chronology is quite a bit different from what you describe:

      The B20B came out in 1969. It had twin carbs and 10.5 compression, and was rated at 125HP SAE gross. It was used until the end of the 1972 model year.

      The B20E came out in 1970 (in the 1800E) and was also used in 1971. It had, compared to the B, larger valves and improved porting, as well as the D Jetronic injection. These engines used a D cam. They were rated at 130HP SAE gross. As far as stock engines are concerned, this is the one to have.

      In 1972, the E was superseded by the F. The B20F (72-73) had slightly lower compression, a different head with more restrictive porting, and minor modifications to the D Jet system. These engines still had the D cam and 6 bolt crank. They were rated 125 HP, and are also good ones to work with.

      The 1974 model year is when the major changes took place. The engine was still designated B20F, but very little remained the same about it. This is where the 8 bolt crank came in, as well as hardened valve seats. Also, all the threads in the block were changed to metric. Previous versions had been SAE. The 74s had K Jetronic (CIS) fuel injection, and to go with it, a K cam. Compression was reduced still further. 74 was not a good year. These were the engines with the porous blocks and wear-prone camshafts. I refer to 74 as "the year of round cams and oval cylinders" In my opinion, they are best avoided, except that the head is a quick, easy way to get hardened seats, if you can find one.

      The 75 is pretty much identical to the 74, but with most of the quality control issues resolved.

      To answer the original question, if I were looking to build a carbureted performance street engine, I would look for any 6 bolt bottom end in good condition, and top it with, ideally, a 71 E head (with the injector ports plugged) or, as those are very difficult to find, a 72 or later F head, perhaps with a bit of port work to bring it up (more or less) to E spec. Don't go too high with your compression--10.5:1 is a reasonable upper limit.

      As for the camshaft, I have often heard that not all D cams were created equal, and that those in the 70-71 Es were more equal than the others, but have never seen any kind of official confirmation of this.





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        B20 block and head choice for performance build 120-130

        Nearly all the '74 motors I have seen here still use UNC threads in the blocks combined with the 8-bolt metric crank.

        I've only seen one with metric main bolts, but it still had UNC everywhere else on the block.

        I agree that a lot of '74 blocks had soft blocks, but that was the year they started using CWC cam cores which solved 90% of the previous cam problems & it's still the core that you get today.





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          B20 block and head choice for performance build 120-130

          Hello,

          The 1974 & 1975 Volvo B20 & B30 engine blocks have all US coarse and fine threads for the fastners, including the head bolts EXCEPT FOR THE FOLLOWING LOCATIONS:

          Bellhousing bolt holes at the rear of the block
          Transmission brace bolt holes near the oil pan bolts as well as the threads in the aluminum brace itself
          Crankshaft main bolt caps

          I think that the connecting rod nuts and studs, the crankshaft pulley bolt and the flywheel/flex plate bolts also go metric.

          I know that the exhaust flange studs and the clutch bolts are metric as well.
          --
          Eric
          Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
          Torrance, CA 90501





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        B20 block and head choice for performance build 120-130

        D cams can be very different. The lobes on the came D cam can be very different.

        Get a quality after market cam





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          B20 block and head choice for performance build 120-130

          The lobes on the same D cam can be very different.

          More likely is that the lifter bores are very different, there's not much you can do about that without boring & sleeving each lifter bore.





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            B20 block and head choice for performance build 120-130

            I had an immaculate, barely broken in early 70's vintage D cam that I got from a retired Volvo regional service rep. A "Cam Doctor" showed more nearly 10 degrees difference between the best and worst lobes as measured at .050 lifter rise. The person who did the test was shocked at the poor quality control on that cam. I read somewhere that the d cam is a duel pattern design, but these variations didn't correspond well with intake or exhaust lobes.





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              B20 block and head choice for performance build 120-130

              It's not possible to grind a cam that badly, it's not like a 1960's cam grinder is that much less accurate than the latest available equipment.





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        B20 block and head choice for performance build 120-130

        This is awesome info! I'm in Maryland, so the US info is good. It seems to me that if I'm willing to pay a machine shop to work the heck out of the head to make it produce great flow, then couldn't I use almost any B20 head while steering clear of a '74?

        Thanks!

        Deluxe





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          B20 block and head choice for performance build 120-130

          The 74 head is OK, (and has hardened seats as original equipment) it's the bottom end you want to avoid, as they are prone to problems. Any B20 short block with a 6 bolt crank is a better choice if it's in OK shape to begin with.





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          B20 block and head choice for performance build 120-130

          No. Not all B20 heads are the same, and if performance and high compression along with the larger valves are important to you, the only one's to work with are the early B20E heads and the one and ONLY US carb head that had the bigger, same size valves used on all the E/F heads as well as 10:1 compression is the '72 (up to '75 in Canada and Europe) B20B head. This head was only used on US wagon models and came with the HIF6 carbs, as all other models came with FI as standard, and the wagon was opt FI.
          If you take any of the later B20F heads w/larger valves, you would need to block off the injector ports and shave the head to up the compression, and do some porting to open up the flow. Just using a thinner head gasket is not enough to get it to 10:1 or greater.
          --
          '89 245 sportwagon, destroyed by hit & run driver, RIP. '04 V70 2.5 T Sportwagon, 12k mi and '91 245 5-speed, 209k mi, replaced the '89





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            B20 block and head choice for performance build 120-130

            From '73 onwards, all B20's got the 44mm inlet, even the B20A's, they also all have the added material in the ports & water jackets.

            '70-'72 B20E heads are the ones that flow the best standard.

            '73-'75 heads of B20A,B,E & F are the ones that are better when ported.





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            B20 block and head choice for performance build 120-130

            Well, I'm thinking that a block won't be too difficult to find, but a specific head will be. I think a lot of people will know that their head is a B20 head, but they may not know the exact year, specs, etc. I've been cruisin' eBay for 122 stuff for at least a few months now and haven't seen a head or engine on there. There's a B20 on eBay right now in Tenessee, a little far away for a block that I can probably find locally, and I think it is a '75 or later. Where do I go to get a desirable head? I can probably get a block here in my state.

            I have a 95% complete running and driving '65 wagon that I'll trade for a good B20 engine. The car is about what you'd expect from a person who is willing to trade it for an engine, but it is a cool, nearly complete, '65 with a B18.

            Deluxe





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              B20 block and head choice for performance build 120-130

              If you can't find a head locally, I can help you with a B20B head--the earlier carb type with the 42mm intakes. I have a few of them. You can have one cheap. Compression on those was not 10:1 as stated elsewhere--9.3:1 and rated at 118hp SAE. I used a carbureted head (unknown year) that had 44mm intakes, same as the FI heads, on my 1969 140 B20. I originally had it on a screaming B18 and had milled the head .125" to get a ratio of over 11:1--but that was before oxygenated gasoline and I had to devise a water/alcohol injection sytem to keep it from pinging. I've used the same K cam in both motors and on the B20 the ratio is a more managable 10:1, runs good on what passes for premium these days and doesn't need the water injection, even on occassional track days. The first of the FI motors had 10.5:1 and very good porting but that was only for a year or so. Later FI heads had a much lower compression ratio. You need to measure the deck height of any head and compare that to the specs in the "green book" to see what you've got (I think mine started off at 87 or 88mm). Volvo really got the intake porting correct, there's not much you can do to improve it, especially for a street car. The exhaust side can benefit from some cleaning up and port matching. I have a B20F (1975-8 bolt crank) you can have (if you come and remove it) but the hood of the parts car rotted and let water drip down so I don't know what the internals look like now. I sold the head many years ago. I have a complete B20B in a 1969 parts car--I'm almost afraid to ask (in fear for my life-wife can't know kind of deal) to see pics of the 122 if you're interested in the '69 motor.





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                B20 block and head choice for performance build 120-130

                Thanks for the info. I'm not sure if I am willing to pull my parts car to NY, then remove a B20, then drive home. Definitely if nearby, though!

                Thanks again!

                Deluxe





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                B20 block and head choice for performance build 120-130

                Ooops! I mispoke regarding the compression ratios between my B18 and B20 - reverse the figures.





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              B20 block and head choice for performance build 120-130

              I believe the later B20F head from the '75 is stamped with an 'F' betw #2&3 on the top of the head. The early B20F heads are stamped with a 'D'
              I can't recall what the B20E has stamped but IIRC the B20B head with the larger valves was a D stamp also, but the injector ports were not drilled.
              --
              '89 245 sportwagon, destroyed by hit & run driver, RIP. '04 V70 2.5 T Sportwagon, 12k mi and '91 245 5-speed, 209k mi, replaced the '89





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                B20E head on eBay - $15 120-130

                Looks rough, but if you're planning on a rebuild:

                http://cgi.ebay.com/ebaymotors/Volvo-144-145-1800-P1800-ES-E-S-B20E-Cylinder-Head_W0QQcmdZViewItemQQcategoryZ6755QQihZ004QQitemZ140210498718QQrdZ1QQsspagenameZWDVW

                Paul





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                  B20E head on eBay - another one 120-130

                  This going off today->$90

                  http://cgi.ebay.com/ebaymotors/B-20-LARGE-PORT-INJECTED-HEAD-VOLVO-1800-E-S-ES-122_W0QQcmdZViewItemQQcategoryZ33617QQihZ018QQitemZ280203507062QQrdZ1QQsspagenameZWDVW





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                  B20E head on eBay - $15 120-130

                  Here's a general guide to what sort of head it is (I wouldn't trust the eBay descriptions on most parts, even if it cam off a '71 1800E there's no guarantee it started off on one).

                  First look for injector pads - the raised, machined areas over the intake ports. If it doesn't have those, it's either a B18 or carb B20 head, and you can discriminate between those by weird 'umbrella' valve seals at the top of the stem (B18) (I'm not sure how those work, even in general theory) vs. the 'real' seals, inside the springs on the valve guide (B20).

                  If it has injector pads (even if not drilled out) then it's a later head, and should have the bigger valves of an injected head. Next, look at the center head bolt on the manifold side. There is a little raised, machined surface for the bolt to torque onto. If this is completely surrounded bu lower, rough cast metal, it is a B20E head. If it is connected to one and only one of the nearby raised machined injector pads with a little strip of raised machined metal, then it is an early B20F head. If it is connected on both sides to both nearby injector pads with raised machined metal, then it is a late B20F head.

                  If you get an injector head with undrilled injectors, it might be something interesting (like an R-sport head) or it may have just been a late production carb head replacement from the parts department. R-sport heads will generally have a stamped part number on the upper surface, in the same general area as the center head bolt, on the manifold side. They sold different flavors of the heads too, so I'm not sure what differences there would be on all of them.

                  From what I understand the late B20F heads are the ones with the most potential for improvement, because they used different internal casting cores, and there is more metal in the places it needs to be ported more for better flow. Try to port an earlier head as much and you'll hit air in the ports.
                  --
                  '63 PV544 rat rod, '93 Classic #1141 245 +t





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                    B20E head on eBay - $15 120-130

                    The real late B20 heads from K'Jet cars have hard seats in the exhaust. This is convenient for a street buildup. However if you try to install bigger valves, or do an aggressive porting job the hard seat insert can get gets too thin so it can work against you.

                    Choosing a head with minimal (or favorable) core shift should also be given consideration.





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                      B20E head on eBay - $15 120-130

                      Oh yea. Check for excessive core shift, along with well positioned cylinder bores and head bolt holes in the block too.





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      B20 block and head choice for performance build 120-130

      "Note that all B20E/F blocks have a slightly different bore/stroke geometry (more square, shorter stroke) than the B20B and will be a better hi rev motor with a B20B head and high compression."

      I may or not necessarily agree with your other points. But I'm going to have to clearly challenge your statement quoted above. Every stock B20 (and for that matter, every stock B18) I've ever seen, had a 3.15" (80mm) stroke.
      --

      Gary L - 1971 142E ITB racer, 73 1800ES, 02 S60 T5
      BlueBrick Racing





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