The All New, New "What have you done to your Bay today" thread.

Discussion in 'General Discussion' started by top banana racing, Aug 27, 2015.

  1. mikedjames

    mikedjames Supporter

    No, thats quite normal. So is 120 degree oil temperature on a hot day driving a 1600/1641 fairly hard. Driving up a gentle hill at 60mph for miles can be quite hard work..
    130 degrees is hot.

    Thats why I ended up fitting an oil cooler to my 1641.. plus I get full flow filtration..
     
    Adrian1975 likes this.
  2. I suspect it might have been working itself loose for a while, but then again, I had that wheel off to renew the tyre about a month ago, it was obvious last night as soon as I looked at that side, yet I didn't notice anything untoward last month :(
     
    Last edited: Aug 23, 2022
  3. Zed

    Zed Gradually getting grumpier

    I like them. :thumbsup:
     
  4. Zed

    Zed Gradually getting grumpier

    Those compression numbers are quite high, what engine?
     
  5. Don't think I'd be going anywhere without a split pin in there, definitely saved loosing the hub last weekend, and it wasn't just me in the Bus! I don't want to think about what could have happened on the fast A roads up here.
     
  6. Adrian1975

    Adrian1975 Supporter

    Itsmy
     
  7. mikedjames

    mikedjames Supporter

    Its interesting, my 1641 was delivered with a sheet indicating 150psi /10bar compression on all 4 cylinders. Runs cooler than my old engines did.
    But generally the more compression, the more power you get.. but the relationship with heat is not so clear cut.


    I would start to look at the thermostat and flaps if its always running hot. Is the thermostat expanding properly when it is hot ?
    If the cylinder heads are not cooling as much, the oil does end up getting hotter too. On mine if the flaps jammed then I would see 130 degrees oil temperature, and I dont know how close the heads came to softening ( 150-170 degrees weakens heads) ..
     
    Adrian1975 likes this.
  8. Zed

    Zed Gradually getting grumpier

    Working out CR from cranking compression is rough to say the least but you seem to be somewhere between 8 and 9:1.
    Did you calculate it? Did you measure your deck height?
    Did you change anything like the oil pump or relief valves for so-called heavy duty ones?
    Stock cam?
     
    77 Westy and snotty like this.
  9. 77 Westy

    77 Westy Supporter

    That is true - until the point where you can increase the CR but the power doesn’t increase. The key is knowing where that point is.
     
  10. Adrian1975

    Adrian1975 Supporter

    20220823_165426.jpg
    Sorry for the delayed reply,
    See attached pic for the info I wrote down at the time, new shadek pump standard size,

    If you remember it melted no2 piston (air leak?) and destroyed the head so a replacement head was sourced , vege gold I believe,

    I covered 3000km in very hot temps in france and apart from breaking down due to the distributor she runs fine , but I worry about the temperature gauge reading 120° slowing down doesn't make a huge amount of difference

    When I replaced 1&2 head I didn't recalculate anything and just put it together I think
     
  11. Zed

    Zed Gradually getting grumpier

    It's theory for me, I've never tried to see what happens but "they" say keep your deck under 1.5mm, preferably nearer 1.1-1.2mm OR go big at 3.5mm+ for cool running.
    At the lower end the fuel/air is forced into the head chamber and burns quickly as the flame doesn't have as far to travel, you can knock a degree or 2 off your full advance.
    At the higher end (like mine) there is actually room for the combustion albeit lazy and slow.
    In between (yours) there isn't room for combustion but the fuel won't be squished into the chamber.
    Now whether we're talking small beans or if it could have a noticeable effect on your heat I don't know.
    They say a tight deck runs cool and I know my monster deck does, but in between is apparently the worst of both worlds.

    I now with ICTs people go bonkers big on the mains compared to other carbs, that would have an effect for sure but I see you followed Way out Westy and I've not heard complaints about his recommendations.

    I think it would pay you to check your maximum advance and report back. I expect you've invested in a timing gun by now :D
     
  12. Adrian1975

    Adrian1975 Supporter

    Ironically I have 2 timing guns, but didn't have any with me at the time, I will recheck the max advance tomorrow and report back , but from memory when I checked when I returned from France and after fitting electronic ignition it was 28° and idle fell back to 7.5°btdc , but seem a bit to coinedental, as said I will rechecked tomorrow,

    As a pointer- I presume this is done at operating temp, so 20min run and then check?
     
  13. Doesn't matter. Temp won't affect timing.
     
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  14. Zed

    Zed Gradually getting grumpier

    You might be better off at 30 full advance and 9.5 idle. If it idles too fast when warmed up, back off the throttle stop screws. With your apparently inefficient deck height it might benefit from an earlier spark.
     
    docjohn likes this.
  15. 77 Westy

    77 Westy Supporter

    Just looking at the cranking compression I’d say the static CR is too high for a standard cam. And your deck height is probably in the danger zone for high temperature, but you can’t (easily) reduce the deck without increasing the CR. It would be nice to know what the actual CR is.

    Do you get any knocking/pinking under heavy engine load?
     
  16. Zed

    Zed Gradually getting grumpier

    Something is a bit strange. To have such high cranking pressure, large-ish deck and stock build 1600 seems impossible?
     
    77 Westy likes this.
  17. 77 Westy

    77 Westy Supporter

    I agree; my guess is the cranking pressure isn’t really that high.
    Or maybe he replaced dished pistons with flat tops.
     
  18. awning connected [​IMG]

    Sent from my ELE-L09 using Tapatalk
     
  19. Zed

    Zed Gradually getting grumpier

    1600's have flat top pistons.
     
    77 Westy likes this.
  20. 77 Westy

    77 Westy Supporter

    You can tell I’ve never had a Type 1 – and never will,:)
     
    Little Nellie and Zed like this.

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