120 122s engine rebuild plus more - UPDATED 16 Sept - CC'ing the head

toddamok @todd Adelaide
edited September 2019 in RWD

I have got all of the parts together to get stuck into rebuilding the engine in my ride.


The block, head, crank and flywheel are at the machine shop, cleaned and measured. I have to drop a box of parts in the morning.


Pretty exciting!

Will provide updates.


  • toddamok @todd Adelaide
    edited July 2019
    I got my parts back from the machine shop. Quite happy with the service. Took just over 2 weeks, but I did say there was no rush.


    Today I cleaned up the garage a bit and started cleaning some of the yucky bits.




    Not sure about the little parts washer yet. For about $200 for the washer and the proper solvent parts washer fluid I could buy a lot of the SCA degreaser spray cans.

    The machining all looks really good, although I'm not sure what a "kline" is. I must call and ask. The balancing guys (sub contracted) had to really grind a lot of of the big ends to bring them down to match the lightest. I expect it will make a good improvement. Will try to take pics to show.
  • toddamok @todd Adelaide
    edited September 2019
    I got the normal home ownership chores out of the way and made it back into my garage today.

    Oh, but it seems I can't add pics. Will investigate...

    Seems edit no longer has the abilities of new comment....

    Spose this update will have to go at the bottom.....

    For 20 JUL update see post
  • toddamok @todd Adelaide
    edited September 2019
    For 15 SEPT update - Electronic Ignition, see post
  • toddamok @todd Adelaide
    edited September 2019
    For 16 SEPT update - CC'ing the head, see post
  • carnut222Greg S @carnut222 Daylesford VIC
    Nice - look forward to seeing more! :)
  • I really like the 122s coupe(?). Are there many around?
  • I really like the 122s coupe(?). Are there many around?

    I think the 2 door 122s is becoming a rare beast. I only saw a few while looking for my 4 door. Good luck.
  • Angus242164Angus @Angus242164 Western Victoria
    Looks like the ingredients for a very thorough rebuild! The costs add up fast, but it's nice knowing that you have as much power and reliability as possible under the bonnet once it's done.
  • VolDanVolDan @VolDan Launceston,Tasmania
    Hi @todd, looks like a lot of good gear there. Would be very interested in as much detail in your progress as you'd care to share!
    Looks like a steel timing gear set. Is that the one from IPD? I need to replace mine shortly and looking for suggestions.
  • toddamok @todd Adelaide
    edited June 2019
    Is that the one from IPD?
    The timing gear is the aluminium kit from CVI. I think the aluminium one should last ok and reduces rotating mass.

    I actually accidentally over ordered and have two of these kits. I would be willing to sell one for $205 + shipping, which is about cost, not including any of the cost of shipping/GST/import fees/import taxes that I paid on the order.

    Shoot me a message if interested.

    I receive my machined and balanced parts next week.

  • What engine is that?
  • toddamok @todd Adelaide
    edited July 2019
    What engine is that?

    B20E, still with HS6 SUs. Not sure where the manifold is from, seems modern. Dual exhaust outlets and no preheat system.
  • Vee_QueVee_Que @Vee_Que South Eastern suburbs Melbourne.

    Not bad, what is the compression ratio you are going with on the head and the squish volume? On my pushrod redblock builds I aim for 0.035' , makes it less likely to ping.

    What cam will you be running?

  • toddamok @todd Adelaide
    edited July 2019

    The compression ratio and squish is yet to be measured. Squish will be pretty easy to measure, I think/hope. Hopefully it comes out ok. The machine shop was reluctant to assemble to check. I have thought about custom head gasket too. Measuring the capacity of the chamber might be a bit more of a challenge. Off to ebay to see how much a pippet (I think that's what I need) is. (edit: pippette is what I was thinking of, may be able to use a syringe to get close)

    The cam is a K reproduction from CVI, says made in usa on it.

    I plan on rebuilding a second head at a later date. I have a mate that will port it. Prob don't need a better cam till that happens.

    I live in the city so I kinda want to stick with the SUs.

  • You may find the K requires a lot of rpm to deliver (that is if you've not had experience with the K). The D with an appropriate 123 programmable electronic ignition will deliver mid range power and torque.

  • bgpzfm142bgpzfm142 @bgpzfm142 Launceston TAS
    edited July 2019

    K and D cams for a B20 are very similar.


    The K was used in B20E engines. I had a K cam in my 144 years ago, and it was very good for a daily driver - there was good idle, and it wasn't a pig below 2200 RPM, like the later (bigger) cam in that car was.

  • Vee_QueVee_Que @Vee_Que South Eastern suburbs Melbourne.

    I run an aggressive cam on my 122 b20 compared to stock, and it is no harder to drive than a modern 16v s40 Volvo, I'd even say it's equal. So sure it doesn't have all it's torque at 1500rpm and you can't bog it down, but you shouldn't anyway!

  • I got a little further today.

    I dug out the engine stand.

    Got it mounted to the block.

    With some help from my better half to lift the assembly in place.

    I wiped down the main journals with acetone and blew with compressed air. The block is pretty clean as I got the machine shop to clean and wrap. Worth the sixty bucks.

    Main shells in the block.

    It came cleaned but oiled. Wiping down with a soft clean rang and acetone and blowing clean including the oil ways. the edges of the oil ways have been nicely deburred. The efforts of balancing can be seen with the linishing marks on the first counter weight and near no.4 big end journal.

    the main seal surface doesn't look great. I hit it with some 1200 wet and dry and metho.

    That's a bit better. I will have to remember to leave the main seal proud so the seal runs in the best area.

    It can be seen in the last two pics that the thrust surfaces only just cleaned up.

    On the uncleaned rear main housing where the seal last sat. It should be ok to leave it proud by a mm or two.

    Extracting the spigot bearing without a puller. Grease (or bread if the grease gets though the sheilds) and a punch works fine too.

    Giving the flywheel mounting surface a light stoning to ensure there are no raised burrs or dings.

    Giving all of the journals another clean with acetone and a soft cloth.

    Adding some assembly lube and oil to the main shells in the block.

    Gently placing the crank where it is supposed to be.

    Adding some assembly lube and oil which I mix into a slippery goop with my finger.

    All the main caps on and just nipped up. I turns by hand, which I guess is a good sign. I discussed with the machine shop if I should plastigauge it or not. The response was, if the were gong to assemble it for me the consider it fully measured and wouldn't themselves. They did assemble, torque and measure the bearings and grind to suite.

    That's it for today, back inside to find the torque settings.

    Hopefully tomorrow I will have time to get stuck into putting the rods/pistons in.



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