It's Adventure Time! My '72 88"

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Originally Posted by JDNSW

Not normal. The Series 3 should have a positive crankcase breather system, and strictly speaking, needs this to be roadworthy. System has a hose from the cap on the top of the rocker cover to the elbow on the air intake above the carburettor, and a pipe from the oil filler pipe to a positive carncase ventilation valve sitting next to the carburettor and connected to a vacuum port under the carburettor.

There are three likely scenarios in your case - clearly the original is not in place because there is no elbow to plumb the top cap to. The correct way to deal with this would be a connector on the underside of the air cleaner to connect this hose to, and leave everything else as is.

The second way of doing it would have been to replace both the rocker cover cap and the oil filler tube cap with the caps from the earlier models, that incorporate oil wetted air cleaners. While this is mechanically satisfactory, it is not legal, although very unlikely to be picked up.

The third, which is the most likely to have happened, is simply to remove the pipes and hoses from the crankcase ventilation system. Apart from being illegal, this means that unfiltered air is allowed to enter the crankcase, but at least it is ventilated - expect excessive engine wear due to intake of dust. A variant on this would be to replace the top cap with the earlier one, and block off the oil filler breather connection. This will at least keep the dust out and allow some crankcase ventilation, but with no circulation of air through the crankcase, expect a sludge buildup. Another variant would be to leave open the top cap hose connector but leave the PCV and plumbing to the oil filler. This is probably the worst, as it will suck dust in rather than just allow dust in. Yet another variant would be to block both breathers. This is going to lead to a buildup of pressure and will result in oil leaks and quite possibly failed crankshaft seals.

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Thanks John. I'll have a look for the pipe off the oil filler pipe - i haven't noticed it yet.

At the moment I will put filters on them to keep the dust out. If/when I go back to a factory carb and air cleaner I will reinstall the hoses. Not sure when that will happen though as I realised today the original air filter location is right where the brake booster has been placed.

Quote:

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Originally Posted by JDNSW

Not normal. The Series 3 should have a positive crankcase breather system, and strictly speaking, needs this to be roadworthy. System has a hose from the cap on the top of the rocker cover to the elbow on the air intake above the carburettor, and a pipe from the oil filler pipe to a positive carncase ventilation valve sitting next to the carburettor and connected to a vacuum port under the carburettor...

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John, I've checked and my car has the brrather pipe off the oil filler pipe, running to the vent valve which is connected to the port under the carby.

Can I tee the rocker cover vent into this pipe or is it important that its before the carby?

I figure after the carby you could get fuel travelling back into the oil, which is why the vent valve is there. Both areas would be under vacuum, and I can't see why it wouldn't work, though my knowledge and experience is very limited (in case you hadn't noticed :D haha)

A filter is easy but a bit of pipe to a tee would look way more period correct then an anodised aluminium filter!

Cheers

Dan

If you tee the pipe into the other pipe, there will be no circulation of air through the crankcase. This is needed to prevent sludge buildup. The original system has a vacuum feed via the PCV valve from below the carburettor, with the rocker cover getting filtered air from before the carburettor - no vacuum.

Thanks John, it appears I have incorrectly assumed that the engine sucking in air would create low pressure behind the air filter?

I'll stick a filter on it for now. Thanks for all your help :)

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Originally Posted by Disco-tastic

Thanks John, it appears I have incorrectly assumed that the engine sucking in air would create low pressure behind the air filter?

I'll stick a filter on it for now. Thanks for all your help :)

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No, while there is some inescapable pressure drop across any filter, any properly designed aircleaner will have a barely measurable pressure drop even at full throttle and maximum rpm.

On the other hand, the manifold below the throttle plate will have an inescapable pressure drop from the venturi and drag of air passing the throttle shaft and other obstructions in the carburettor, even at full throttle and low rpm. With the throttle closed, and high rpm, there is quite a respectable vacuum below the throttle - which we use for brake assist on many cars. The PCV valve closes to only allows a small amount of air to be drawn through at high vacuum, and opens up at full throttle when there is not much vacuum.

Hi all,

Well I finally did something with Finn (still not locked in, though I haven't thought of a better name), even if it's only writing a list...

Attachment 138059

I've since added a couple more items (steering arms and tie rod ends) and there's gotta be a stack more I'll find along the way.

I also managed to pull the front wheels off and take out the brake shoes in order to roll him about - as it's been sitting still the brakes are dragging on crud in the drums. The shoes look good, dry and clean with plenty of meat on them - I've tagged and boxed them. I didn't get any photos of the pads (I'll try and get one when I do the rears) but I got a photo of it with a wheel off, just to prove I did something :)

Attachment 138060

I will try and do the rears Easter Weekend, but we'll see how I go - can't move too quickly [thumbsupbig] (My wife even made the comment that at this rate I might have the car complete for my 4 year olds 30th birthday!)

The plan is to free the brakes to roll the Finn out so I can concrete the carport, before blasting everything with a high pressure wash.

Until next time (don't hold your breath)

Dan

A little bit more progress, though not on Finn himself. He was moved out though, and was enjoying the sunshine.

Attachment 140051
Attachment 140052

As I got sick of lying down on quarter minus gravel and having it stick to me, plus the thought of trying to clean up an oil or fuel spill, I decided to concrete the carport. Finally got it done and I think it came up alright, considering I only had a lump of 4x2 hardwood and a 900mm long level to screed it, and a broom to finish it.

https://www.aulro.com/afvb/images/im...018/05/133.jpg

Once the concrete has cured, Finn will be moved back into his home and I will start getting everything working. First item on the list is the fuel system - I need to make a new in tank pick up filter and clean the tank out. I've also noticed the outrigger holding the tank is rusted through in some spots, so I'll be practicing my welding in order to fix that too. Plus a half decent paint of the chassis, diffs and suspension after I remove all the surface rust. Can't wait to start crossing some things off that list!

Cheers

Dan

Bolt some 4x2 to those poles and put some tin up.

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Originally Posted by loanrangie

Bolt some 4x2 to those poles and put some tin up.

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I have thought about doing that but the concrete is only 3.2m square (10 square metres) and I think the space to move around Finn will be necessary.

A couple of sides might be feasible, and would make life a lot more pleasant in some weathers, as well as helping to protect the vehicle. A further thought would be a wall at the end, and opening doors on another two sides - roller doors would be most elegant, but just hinged doors could work. Open them only when needed.