Please Help servo vacum pipe blowing off 2lt air cooled

Post by **horizontal kipper** » 07 Aug 2006, 16:43

Was having problems with sticking tappets removed and cleaned and repumped as best as can also leaking head gasket on 3 and 4. So removed head and replaced worn exhaust valves lapped them in on 3 & 4 have finally managed to rebuild it and fitted new exhaust system. When started the van runs but the servo pipe keeps blowing off under anything more than tick over. Blows off from below carbs at 3 & 4 then when you hold that on it blows off 1 & 2 side. Why is it doing this never had servo on split or bay so in the dark please help any advice gratefully received. At wits end with it. engine is a 2ltr cu 1980 westy joker

Post by **Mocki** » 07 Aug 2006, 16:51

must be something quite amiss there, because there should be suction there not blowing.......

cant be anymore help from here i dont think.....

Post by **OLD ONE** » 07 Aug 2006, 17:02

Have you got HT leads on correctly. Over adjusted tappets It is something producing pressure in inlet manifold. Hate to say ,did you check head for being flat?

Post by **horizontal kipper** » 07 Aug 2006, 17:03

Thanks moki, As soon as it pops off the engine just stalls. It first did this after i started it up after standing for 2 weeks then was ok till now.

Post by **Mocki** » 07 Aug 2006, 17:17

are you sure it is blowing off, rather than falling off?
you need to check if there is any suction there........

Post by **horizontal kipper** » 07 Aug 2006, 17:27

have leads on corect, checked head with rule, torqed head in sequence in manual also followed bug me type 4 rebuild dvd. there is defo pressure. ran another compression check all are reading around 145 psi. now im lost.

Post by **OLD ONE** » 07 Aug 2006, 17:36

To get proof. Stick you comp tester on vac pipe on manifold. Just an idea

Post by **toomanytoys** » 07 Aug 2006, 18:30

if there was that much blowback then the thing wouldnt run surly.. would be hellish rough if it did... must be spitting back like a bstd..
Hydraulic tappets? back them off to no preload see if that helps
oh and check the timing, duel vac dist has an odd set up...

Post by **horizontal kipper** » 07 Aug 2006, 23:06

Thanks, going to set my tappets at 0.6 the same as ive always done on vans before this one tomorrow and see what it does then. Are hydraulic tappets known for giving these problems then? it had stood for a couple or so weeks and did make a right clattering before it blew the pipe off first time.

Post by **SplendiferousII** » 08 Aug 2006, 09:22

This is just a thought.

When I rebuilt a 2 ltr Aircooled engine a couple of years back, I found my Cam shaft to be very very very badly worn. The hydraulic tappets which actually follow the cam shaft if I remember correctly? had worn the cam shaft so much so that it was all but round.
The engine actually ran very well, funny enough!
Maybe your cam is worn to a simular state and the exhaust valves are just not opening enough to allow time for the gases to get out.
I would imagine the only way you could check this apart from a full strip down, would be to remove the rocker covers and measure the stroke of the push rods.

Post by **Tex Ritter** » 08 Aug 2006, 10:36

When starting my van up after it came out of hibernation it backfired badly and blew the hose off.

TR

Post by **HarryMann** » 08 Aug 2006, 10:58

The inlet valves are sticking open when running but not when doing a comp test?

Did you have these out and re-grind them in also? Is there a lot of play in the valve guides?

Oil pressure OK?
Crankcase breathing?

Weird

Keep in touch when fixed please - for the archives - not a common problem.

Post by **horizontal kipper** » 09 Aug 2006, 18:36

I seem to have sorted the problem I found a link on Boston Bobs problem with Hydraulic Tappets, it said to set them all at 0.6 thousand, ran it on the drive for around half an hour pipe popped off once on starting the motor but after a couple of mins the tappet rattle almost stopped and the vacum is now sucking not blowing. So can only guess that it was still a sticking tappet. despite removing them cleaning them and repumping them. Have now run an oil flush and fillter change etc. Took it for a drive today fingers crossed all seems well again. Thanks for all your help everyone much appreciated.
Harrymann yes i did re-grind the inlet valves in, valve guides didnt have a lot of play in them. I am now begining to think i took the head off for no real reason but with the noise it was making i thought a valve was about to go through the piston!

Post by **toomanytoys** » 09 Aug 2006, 20:29

glad to be right sometimes

Post by **HarryMann** » 10 Aug 2006, 10:05

Tops!

You might have to do the valves in other head now, if the exhausts were burnt on the one you took off - to get it running just perfectly

Only joking

Thanks for letting us know the resolution, will Wiki this when I get a minute - complete with Simon's lucky guess