OK Thanks Mike .................. I've tried that and as far as I can tell it seems to be working. I'll get the oil bath filter off tomorrow, re-drill the blocked up holes. fit the thermo valve, hose it up and give it a test drive. I'm using the van daily during the week at present, going up and down from Banbury to Leamington (so plenty of cold morning starts), helping my lad restore his T25 so it will get well tested and I'll post back on here what I find!!
Right then, sorry for delay but only just got around to this job and it took a bit longer as some previous tinkerer had welded up the two holes in the top of my air cleaner doh!!
I had to grind the welds off with a finger belt sander top and bottom, redrill the holes and then repaint the bare metal. I took the opportunity of soaking the hair filter in fuel while the paint was drying tho. Surprising how much gunk comes out!
Got the new thermo valve in, refilled the air cleaner with fresh oil, put back together and hosed up the vacuum flap side.
Job done!!! I've got another three days of 60 mile round trips in the van this week so I should be able to tell if this makes any difference. I will let you know.
@mikedjames how did you test yours ? I've got a new valve but with it all linked to the carb it still doesn't open , you can feel a small amount of vacuum but not enough to open the flap if you put the pipe straight to the flap form the carb it opens... any help much appreciated Mike
Sounds like you have an air leak downstream of the valve or maybe in the valve itself.. The air feed actuator plus its hose should be air tight: suck on the hose, block it and the flap should remain in the 'hot' position until the end of the hose is unblocked. I once had a hairline crack in some crummy hose and it stopped it working. On mine it was obviously working. Cold engine, flap moved with throttle open/ close. With a hot engine/ warm air cleaner it stayed in the cold air feed position. It was easier to see because I sawed a bit off the cold air nose of the air cleaner in a fit of "making it go faster". Factoid .. the oil bath air cleaner drops about 50mBar pressure...
Thanks Mike. On further investigation last night I think the actuator is leaking ! Couldn't hear it with the engine running Sent from my SM-G973F using Tapatalk
Maybe it can be unclipped and the diaphragm replaced or patched. Otherwise back to Midland prototype bay for that air filter assembly ;-) The other thing I had was that there is a notch in the top of the bar coming out of the actuator, and the top of the notch had snapped off with the actuator slamming down. So I made a scissors spring, drilled across the bar coming out of the actuator, and the end of the flap, and reattached the two.
Just a quick report on situation so far. I've done about 250 miles now but a little inconclusive. To be fair my bus was starting and running really well previously. It's definitely not running any worse and there may be a slight increase in power and she may be pulling a bit better up hill. I'm not really sure what difference it should make ???. Im assuming that now I have everything hosed up that if the thermo valve or the vacuum flap wasn't working properly that I would see some sort of worse running???
The difference will be when you have been about three miles and you accelerate from idle and there will be less hesitation. And when driving around slowly it will tend to run a bit better.
Thanks Mike Yep, I think its definitely got rid of that flat spot in low gear when trying to accelerate and she definitely feels a bit more responsive around town so looks like it has had the desired effect. I even took over someone today !! (OK, OK, she was about 93 tootling about in her Micra LOL!!) It would be great if you could have a drive of my bus at the next Techenders to see what you think
The GOOD, the BAD and the downright IRRITATING!!! I've done around another 400 miles since the last post with quite a bit of pootling around town and through traffic, cold morning starts and wet afternoon driving, etc so a pretty good test. The GOOD : the old bus is definitely more responsive around town at slow speeds and drives almost like a normal van (as long as no one gets in your way on the hills LOL). This has really made a BIG and very noticeable difference and I'm very pleased with the outcome. The BAD : it seems to me that, if you get a decent run for the first couple of miles, everything is fine. However, if you have to stop within that first couple of miles, she seems to struggle to tick over and will stall on occasion (something that definitely wasnt happening previously). If you then manage to do another couple of miles, she'll run lovely so not a biggy .......... however ............... The downright IRRITATING : I've had a couple of occasions where I've got stuck in stop/start traffic within the first couple of miles and this can then be real pain .............. really difficult to keep her going as the minute you let your foot off the gas to hit the brake, she cuts out so you are left with the option of holding the revs on and slipping the clutch or trying to use the handbrake, and this can go on for quite some time until she warms up. (This was definitely not happening before I fitted the thermo valve thingy). Tonight, I was stuck in a long line of traffic queuing to go around roadworks and going UP HILL, which was particularly perilous LOL!! As soon as we got through and travelled a couple of miles, she was fine and would run and tick over as normal. Hopefully, this will just need a few tweaks to settings, e.g. the choke mechanism. I'm loathe to change tickover setting as she ticks over fine 90% of the time. I'll have a go but might have to disconnect again and wait for this to be my little job for Techenders ;-)
Its probably something else you knocked, or there is actually still a vacuum leak, or now there is no longer a leak and its now too rich at idle. See if the idle changes if you clamp the vacuum hose from the carb.
Tried to clamp hose with a welding clamp but didnt seem to make any difference to the idle. However, on adjusting the choke screw, I noticed that the large rubber air inlet hose wasnt seated properly on the carb, so looks like you were right again Mike, I must have not seated this properly the last time I had it off. I wonder if that was letting cold air into the top of the carb and so preventing the choke from working properly?? The tickover seems much better now and I've got 4 runs to Leamington and back next week so should be able to give it a good test
