..vw type 4 strange noise with removed oil cap..

Discussion in 'Mech Tech' started by areksilverfish, Jul 8, 2019.

  1. Hi
    Well another issue I’ve just found with my engine..
    After I installed dual dells on my 3ngine this year I noticed a strange sounds (goorgling souds kind of) when accelerating under load..you can’t really hear it at idle..anyway I opened the oil filler cap and found this

    It is defo something new I mean it was not there before..The bus ran abit diffrently last year on dells with different sounds and definatelly there was no such a sounds coming out of oil filler cap..tbh I dont think its anything mechanical matter (everything else seems ok) but really no clue what to looking for..carbs?..I set them up as same as last year apart from changine idles from 52s to 57s and mains from 142s to 130s that’s pretty much it..mhmm can’t sleep well at night...

    Cheers


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  2. It's possibly normal ...never listened to mine with cap off ...but you are getting all the working component noises bare .
    Can you here it with cap on ?You haven't got to much oil in have you ?
     
  3. That is...odd. Type 1s tend to gurgle underneath after they’ve been turned off after a run, as the oil drains down. Can’t think what that would be.
     
  4. You haven't run over a pig have you?
     
  5. davidoft

    davidoft Sponsor

    When you fit carbs like that they do make gurgling inlet noise
     
  6. Why should it gurgle only when he takes the oil cap off?
     
  7. I will have to compare it with mine. I would say it is normal. You are hearing the oil being slung around in the crankcase area by the crank etc. The Cam lobes rely on the oil sling for lubrication.
     
    snotty likes this.
  8. I'm with the "big carbs can gurgle" answer. However, have you tried having a listen with length of tube put to your ear? Like a stethoscope but not as expensive. Put the other end of the pipe at various places around the engine following the source of the noise until you locate the culprit. My Bug recently started making an odd noise and this technique helped locate it, the loudest was by the right hand side carb. At first we thought it was the dizzy or the alternator. But no, seems its spindle wear on the Weber. Have yet to dismantle so I can't say this for certain but it appears to be a common Weber problem and sounds like a rotational noise, similar to something catching...now you wouldn't expect a carb to make that kind of noise but there's clearly something going on in the middle where the spindle is located.
     
  9. davidoft

    davidoft Sponsor

    It’s not, just acts like a loud speaker
     
  10. ..well yes and no..Im aware about noises but it wasnt this sort of noise before..you can hear that noise at accelerating its kind of horrible noise coming out of carbs..again last year when I test fitted the same carbs it was rather sacking sound to hear..
    Oil’s spot on..


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  11. ..thanks for your input guys
    Its kind of hard to discribe but the noise was so different type of goorging before..and it seemed to pull better from the low end..been thinking about it and it colud be related to the issue with erratic idle?..it puls really low vacuum at idle (I no rings related problem but compression still at 115psi pretty much on all cylinders-average but still not that bad) and lats say after 2500/3000 it starts to pull..so something has changed oviously..
    Im gonna take the carbs off over the weekend and have a closer look whats going on..
    BTW from what revs your buses start to pull significantly? What engine/carbs combo?

    Cheers


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  12. ..would appritiate if any of you guys with type 4s and weber/dells setup could take the oil cap off and hear to the sound coming from it?
    Maybe Im overpanicking


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    snotty likes this.
  13. It sort of sounds like you have exhaust blowby. Check the compression, you may notice one cylinder is down.
    More power means more responsibility.. for watching the CHT and AFR gauges especially if your main jet changes are leaning up the mixture at heavy load..
     
  14. ..pretty sure that sound should nt b there..will recheck compession again anyway but I got an idea what it eventually could be..hard to believe but will need to confirm that at first..will let you all know..


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  15. Maybe a silly question but where have you vented the crankcase breather to?
    Oil pump or any partial blockage in the oil feed?
    I have twin dells and once I get the new hydraulic tappet back in I'll let you know if it sound like yours with the oil filler cap off. But I don't think so.
     
  16. Its vented to breather box fixed to the firewall..I just dont have much time for further investigations but been thinking about it alot and Im blaming the oil filter..just need to do few checks and oil/filter changing to confirm that..


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