1914 turbo bug

[bazibbo]

Thanks Bill, I'll get that looked at when it goes back for the boosted map. I did wonder if it shouldn't be a looped system, I'll get some pictures of the regulator / filter setup too. I suspect the way that works has something to do with it.

Do you think not using the top air valve (ralenty valve?) is going to an issue in the long term or just something nice to have?

[Steve Arndt]

People have problems getting enough air past the throttle plate at idle without the valve. The solution is to do some light porting in the throttle body to help it flow when almost closed.

It is no problem running without the idle air valve, but you may want to incorporate it later.

[CobraJet]

Actually, that unplugged port would make a good place to add the idle valve.

[billz60vw]

There is no port on the manifold!the tb has been ported and idles well without the idle air valve.i ran that system for a long time before shipping it to the U.K.barrie you need to make sure you have no intake leaks.

[bazibbo]

It's all to bits again this weekend, so I'll concentrate on getting it leak free and improve wiring and plumbing layout a bit. The main aim is to get it running so it's mostly a case of getting what's there running.

I made the big mistake of letting my wife find the bill from the rolling road

Here's my fuel regulator...



It's a BMW standard item, and comes with a built in filter. From my untechnical outlook it appears to loop the fuel internally, sending a single line out, rather than being the 'dam' at the end of the fuel line. There is a pressure referancing pipe, that's just visible as a grey blur.

I've also got the rear rhino mounts in place, as well as a single mid strap, that doesn't fill me with confidence as it only appears to touch the gearbox at two points on the sides rather than be neatly wrapped around it.



Budget issues are stopping mid mounts, frame horn trusses and uprated boxes.

[bazibbo]

Heads are off and I'm beginning to think I've sussed out why I'm always having valve related problems on my 700 mile engine...



what do you think?

[Clonebug]

That would do it !!!!

[Wally]

More interesting: Why do YOU think the seats fell out?

Cool pic btw

[Clonebug]

More interesting: Why do YOU think the seats fell out?

Cool pic btw

Interesting that it was the intakes that fell out..... those are the cooler of the two valves.

[Wally]

More interesting: Why do YOU think the seats fell out?

Cool pic btw

Interesting that it was the intakes that fell out..... those are the cooler of the two valves.

Yes indeed, its also a bigger seat.

[bazibbo]

no.3 inlet valve had touched the piston at some point, there's a little tell tale mark. I didn't realise no.4 was lose until I tilted the head and it fell out..... they really are lose! no cracks that I can see either.

I'd suspect that the valve hitting the piston on no.2 last year could have been the very same issue. I've only done about 700 miles in it, 600 were running it in with no boost .... oh joy. Still, this could be a good explanation as to whats going on.

[Wally]

I think its a clear case of too high head temperatures in relation to the (press) fit of the seats. The hotter exhaust valve seats expand a little more and are only second to fall out. The head overall gets about the same temperature, thus the intake seats usually fall out first when heads get too hot.
The really interesting thing is what caused the too high head temps. Besides cooling efficiency and everything that contributes to less optimum air cooling (tin sealing and such), tuning can play a major part in this as well. You'll have to do some soul searching as only you know what you've assembled and how you tuned it

Valves hitting pistons (resulting in a bend valve) usually cause the valve to break at one point due to overheating of the valve as it can't properly transfer its heat to the seat anymore, but there much less correlation to valve seat loosing their press fit imo.

[bazibbo]

ta Wally. I'm taking the heads to see my engine builder this weekend, hopeing to get some clue as to why it happened, but more importantly, to find a 'cheap' fix so I can get the car back on the rollers and finally get the mapping sorted and for the first time! have a fully running turbo bug.

I'll keep an eye on cooling issues, I am aware that my ignition leads don't sufficiently fill the tin holes but most other things are covered, I'm using a working thermostat and blocked heater outlets.

One thing that does confuse me slightly is the fact that the current inlet valve seats do not fit and are too small. So whilst excessive heat could have lifted them out, they should still be a snug / interferance fit when cold.. unless my head's cracked or grown 2 sizes. They literally slip in and fall out with gravity. Possibly expansion damaging the surrounding alloy.

Anyway I'll report back after the weekend and I'm guessing I'll be looking at new larger seats pressed in.

[Clonebug]

Air follows the path of least resistance so any opening in the tin is an outlet for air to escape.

You might not realize how important those spark plug wire seals are but they are an integral part of the cooling system.

It takes pressure to force the cooling air through a hot head and you are giving it an easier path to escape by not having those holes sealed.

I would think there is a very real possibility that those leaks are a significant contribution to your hot heads. If you have non stock tin it could be even more probable.

[bazibbo]

Over two months since I've posted.

I've spent most of that time waiting to get my heads sorted, but I've basically given up as summer is passing and I want to get onto the road! General consensus is that the heads were either faulty from day one or that they got damaged in the first gentle 8 mile (over rich with zero boost) trip to the rolling road, or whilst there. There's also enough damage to need a bit of welding before new seats are machined in.... not ideal so I've taken a different route.

It would certainly explain why I was getting a slight pinking / detonation noise evenb though I was assured the AFR was spot on... I'm guessing it was the seats rattling around... and its sad that the second rolling road session, where they couldn't iron out some irrational weak spots, could well have been head related and not carb related.


Anyway, I'm not bitter and twisted... lets crack on.


While everything's been in bits, I've bought and half mounted a wideband sensor, an Innovate MTX. Just needs a bit of wiring and cable routing. At this point I don't know if I'll be running it as part of my EFI or just as a tuning tool, it's a big jump for me to get my head around closed loop systems.... though that might happen soon.

Found a decent old laptop that I can dedicate to the bug and ban all family from using it.

And lastly I've got hold of (or will do shortly) a pair of 044 cnc roundports. They're used but tidy, and have been taken out to somewhere between an oval and wedge, 42 x 37 valves and I think they're 63cc but I'll check. I'll get a few pics when they arrive.

Need to start thinking about writing maps...