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Re: Popping sound
Posted: 07 Jun 2011, 18:38
by john1
kevtherev wrote:Are you sure it bows the WD away?
Yip both sides mate def!
I did fear a big problem and it was a wee bit chappy the other day DOH! Tho not now strange.
worst case scenario??
Re: Popping sound
Posted: 07 Jun 2011, 18:55
by kevtherev
IF it is blowing back
and a compression test will see that
then a burnt valve(s) is/are the suspects
At worst... new or used heads, with new valves
My ten pence.. I could be wrong
Has any one adjusted the tappets recently?
Re: Popping sound
Posted: 07 Jun 2011, 19:03
by john1
kevtherev wrote:IF it is blowing back
and a compression test will see that
then a burnt valve(s) is/are the suspects
At worst... new or used heads, with new valves
My ten pence.. I could be wrong
So low compression tells all?
Thanks Kev I will put the rope away.
If thats two new heads with valves, any idea of cost and where to get them? I have never done this job on air cooled T25, can you do it without dropping the lot?
Thanks for your help mate
john
Re: Popping sound
Posted: 07 Jun 2011, 19:06
by kevtherev
That's a step to far ..get it compression tested first
did any one mess with the tappets?
Re: Popping sound
Posted: 07 Jun 2011, 19:24
by john1
kevtherev wrote:That's a step to far ..get it compression tested first
did any one mess with the tappets?
Dont worry kev test will be done this week as soon as I get a chance.
Tappets have not been touched, she was running great 2 weeks ago, then poppig sound when off the gas going down hill.
I did a wee fix with a joint blow on the exhaust at back box to heat exchanger thats why i was thinking i may have disturbed manifold.
Did notice kinda low on oil at the time, just wonder if this has been the killer for top end!!!
Thanks again Kev
john
Re: Popping sound
Posted: 07 Jun 2011, 19:28
by kevtherev
What's the mileage on the engine John?
Re: Popping sound
Posted: 07 Jun 2011, 19:33
by sarran1955
Hello,
Followed thread, still no clue as to what Aircooled engine we're playing with here
Air cooled engines popple ' going down hill in gear'.... ie on overrun,.....where the high and low pressures in a carb setup engine do all sorts of interesting things...... for 2 reasons.
1. You've got a hole in your exhaust.
and/or
2. You've got a burnt out exhaust valve/seat.
Mileage on engine......
DIY regrind,......... do all the valves whilst your'e at it...... cost pence. Plus decent gasket set £ 28.
Its what Aircooled VW is all about..
Cordialement,

Re: Popping sound
Posted: 07 Jun 2011, 19:48
by kevtherev
john1 wrote:
2L air cooled 1982
john
I assumed it was a CU would you sarran?
Re: Popping sound
Posted: 07 Jun 2011, 19:50
by john1
kevtherev wrote:What's the mileage on the engine John?
Well Kev clock says 51,900. Last 6 MOT's confirm but bus came from south Afirca in 91 so I will leave that thot open.
I have service book and sale history plus newspaper cuttings form the sale over there. it looks ok but I can't be 100% sure.
She looks clean as far as spindles on carbs and general engine appearance doesn't give concern.
Pedal rubbers and interior suggest the same.
As I say not 100%.
Im not sure what life expectancy is for one of these girls.
john
Re: Popping sound
Posted: 07 Jun 2011, 20:04
by john1
sarran1955 wrote:Hello,
Followed thread, still no clue as to what Aircooled engine we're playing with here
Air cooled engines popple ' going down hill in gear'.... ie on overrun,.....where the high and low pressures in a carb setup engine do all sorts of interesting things...... for 2 reasons.
1. You've got a hole in your exhaust.
and/or
2. You've got a burnt out exhaust valve/seat.
Mileage on engine......
DIY regrind,......... do all the valves whilst your'e at it...... cost pence. Plus decent gasket set £ 28.
Its what Aircooled VW is all about..
Cordialement,

Hi Sarran
CU engine.
Popple or popping going down hill was new then problems started after.
No hole in exhaust.
Still to test valves.
51,900.
Glad to hear its not going to cost loads of pennies,
Cheers
john
Re: Popping sound
Posted: 07 Jun 2011, 20:57
by kevtherev
52 or152,000 miles is not that bad... if it has been serviced and shows no neglect then you have something worth saving.
Re: Popping sound
Posted: 07 Jun 2011, 22:19
by john1
kevtherev wrote:52 or152,000 miles is not that bad... if it has been serviced and shows no neglect then you have something worth saving.
Def worth saving Kev, just looking for cost if what we think needs done is actually needing done.
Can you change the heads with it all in place? Or do i need to drop the lot out for easy work?
john
Re: Popping sound
Posted: 08 Jun 2011, 06:33
by kevtherev
easy work is better work I say
Don't struggle, if you have to do it, drop the engine, VW made them to be removed easily
Re: Popping sound
Posted: 08 Jun 2011, 16:46
by jason k
dont fanny around, drop it, its much easier
just to clarify the wd40 is being blown away at idle?
your not revving it at all?
Re: Popping sound
Posted: 08 Jun 2011, 16:48
by kevtherev
Ah I wondered when you might pop in Jason
