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About Bfg

  • Birthday 09/01/1956

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    Suffolk, England

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  1. I suspect the timing of this new dilemma is coincidental to adding fresh fuel., not least because unless you've drawn in water with your fuel - I don't associate backfires with fuel but rather ignition. And tick-over vibration most often relates to just one or two cylinders not firing, something inside breaking or jumping adjustment, or an engine mount not being secure ..whereas generic fuel problems tend to effect all cylinders. Because 'something inside breaking or jumping adjustment ' is horribly pessimistic, and in any case often accompanied by odd noises from inside the engine (even at tick over) - my approach would be to start off by checking the HT leads and spark plugs. Indeed with any such mystery - I remind myself of the basic workings of an internal combustion engines, and systematically check (..but unless very obviously wrong - not adjust) those. Not knowing exactly how " bit of a novice under bonnet" you are - I'll explain, but my please accept my apologies if I'm teaching grandma to blow an egg. The basics are 1. spark, 2. fuel, 3. timing (of both ignition and and valve opening), and 4. compression. And each of these need to be roughly close to tolerance for each cylinder. And 'the process' is one of elimination. ie. if you check something works fine ..then you can eliminate it from being the fault. I've numbered ' the basics' in order of being most commonly at fault on an engine which was previously running normally. So, if in your situation, having already thought through the fuel issues, I would start by first checking the HT lead on each plug. So, start the engine and when warm enough to have a steady slow tick-over - pull the HT lead off just one plug at a time (wearing rubber gloves or with rubber handled grips / pliers - to save you getting a high voltage shock) ..and listening to hear for a difference in engine note. If, when you pull a HT lead cap off, there is no difference in engine speed then that plug or lead is faulty. Even if that doesn't identify the issue, because it's a quick job to do, and so quickly things to eliminate - I'd move on to systematically removing each plug to check its gap and condition. At the same time you'll be visually checking the condition of each HT lead and cap - for cracks in the insulation, security of the cap onto the lead, and for corrosion, and to check for a positive lock of the cap onto the spark plug. Also for any chafing of the lead itself along its whole length. While each plug is out, check its spark by refitting its cap and resting the threaded part of the plug against the cast iron cylinder head. When turning the engine over you're looking for a small but sharp, bluish spark across its electrodes. NB. This doesn't check the sparkplug as much as the HT leads, because a spark plug can work (just OK) at tick over but falter when engine revs are applied. Having said that, a big whitish coloured spark is likely to be faulty spark plug. Substitution with a set of known-to-be-good plugs, set to the right gap, is the easiest way to eliminate those from the list of suspects. If the spark isn't good on each plug - then go one step up-line and check the points. The contact breaker points gap should be something like 15 thou - which is much the same as ordinary copy paper folded three or four times. Prise the contacts' gap open with a small screwdriver to see if they are clean and bright, or whether they are dark and pitted. If it looks fine then don't touch or adjust things. When turning the engine over with the cap off - the points gap's spark should be a barely visible bluish crackle, not a big spark which usually indicates a faulty condenser. Also feel the distributor to ensure it's clamped securely to the engine block, so it doesn't turn. Carefully also visually check the distributor cap for cracks and cleanliness. Either might be a path to loose your spark through. Also check the HT lead between the coil and the distributor and it's connections, as well as the small wire feeding power to the points. If all that checks out as fine - great you can eliminate 'spark' from the list of being the potential fault. From the photograph I see you have fuel in the bowl. Undo the clip to drop that glass and see and smell the petrol is fresh and not contaminated with water or debris from the almost empty fuel tank. There should be a fine gauze filter on the underside of the aluminium housing. Assuming the fuel and filter is clean then carefully refit the glass, taking care to feel that it sits flat on its seal before the clip is refitted. Personally I'd think it unlike that a carburettor is suddenly at fault. So if you still have the fault, I'd not touch anything on those for the time being, aside from checking and cleaning each filter in the fuel pipe's banjo connection. If all is well there I'd go on to check the ignition timing. I'll let you breeze through the above checks, before boring you with others. But I hope it's helpful, and again I apologise if I'm explaining something that you were perfectly aware of. Pete.
  2. . I apologise if I'm misreading or misunderstanding your summary, but to my mind emissions "pollution" come from the combustion of carbon fuels, and is not a factor of crankcase oil mist pulsating back n' forth at piston velocities within too tight a space. So unless the piston rings are shot or the bore is terrible condition, either resulting in massive piston blow by - next to nothing of the breather fumes are "corrosive gunge" and similarly next to nothing is (re)digested by the engine. And surely, if the majority of the breather's oil mist is separated from its air, courtesy of the PCV valve which drains oil back into the crankcase, then very little oil mist is carried into the combustion chamber to be incinerated. If this were otherwise, then it would be clearly evident in the colour of the exhaust "smoke". Certainly in my (albeit limited) experience - most of the oil in a combustion chamber comes via the lubrication of the valve guides (particularly so if they worn, inaccurately machined, or damaged) ..and from the necessary oil lubrication of the pistons in their bores. Regarding control of the fuel/air mixture.. Well, the low pressure manifold take-off facilitates a lower than atmospheric pressure within the crankcase. For that to happen - air IN to the crankcase has to be limited (because if there were free flow of air in - then it would be impossible to lower its pressure), therefore the amount of air drawn through the breather into the manifold is equally limited and reasonably steady. So with an engine, in pretty well any running condition, the ratio of fuel to air can be adjusted. The fact that some of the air is drawn in after the carburettor is incidental. It is still a measured amount. I do however accept that it may not be measured accurately enough to knock one-hundredth-of-a-second off a racer's lap time, but for normal road use I don't see it as a problem. To be perfectly honest, I really cannot speak of racing practices ..perhaps Mickey might drop in to advise us on this. But just guessing like - I suspect a large part of the reason they do not use a PCV valve is more a matter of inlet manifold design. Looking at Stuart's photo of a twin Weber setup - just where exactly would you take 'just one' manifold low pressure take-off from ? Indeed I cannot determine if the front and rear cylinder manifolds even have a balance pipe between them. And with regard to leaving you stranded should a PCV diaphragm fail. Not so.. just disconnect it. Vent the breather to the atmosphere, bung the hole in the manifold (to prevent excess air being drawn in) and drive on. Sorry I don't understand "maybe a clutch flooded in engine oil". I'm with you
  3. Roger, I'd agree - that looks to me as if the car's previous owners have operated on a zero budget for yonks and engine oil changes have been neglected. I'm sure the residue in the sump will be positively horrid. Personally speaking I'd clean that out, consider upgrading to an easier-to-change oil filter, wipe off the crud around the rockers ..followed by a series of frequent oil changes ..and I'd expect to see that much improve without disturbing anything but the sump and rocker cover. Mind you, I'd suspect finding a similar neglected situation with the cooling system. A catch tank will make absolutely no difference to the state of the engine oil or the crud it deposits inside the engine cases. A catch tank will however help keep your induction tracts and combustion chambers clearer of oil mist deposits. Although the photo implies your valve stems haven't been replaced on this engine for half a century ..so whatever mist you might have from the breather will be next to nothing compared with oil seeping passed those. What are your plugs like and do you have oil dripping from joints in the exhaust system.? If wet then I'd personally first suspect the valve guides. A finger in place of the rocker cover breather pipe will give you an indication of how much pressure is in the crankcases. If you just feel the pulsations but not a lot of pressure then your bores and piston rings are in decent condition, but if there's a build up of pressure then piston rings are due for replacement. NB. Compression tests won't tell you this because those figures are also a factor of how well the valves are seating. P.
  4. Sorry I'm just an old fart trying to be helpful, and I'm not familiar with later systems but is that not what we are considering here and the brake servo booster illustrated in the original post.?
  5. ^ why put a flame trap in the breather pipe.?
  6. . Roger, I'm glad you're managing to get you head around crankcase breathers. Your previous post imply concern about moisture inside the crankcases, to which I simply ask - how does that moisture get in there ? And that would be through a non-regulated (by one-way valve) crankcase breather system allowing atmospheric humidity to be freely drawn back into the crankcase. The early TR's with an open vented breather system were like this, and so your experience was to see a lot of creamy coloured condensation goo dripping out of the end of the breather pipe, and so quite understandably are now keen to extract it. But pressure regulated (one-way valve) and closed breather systems are quite effective in preventing that humidity from getting inside in the first place (the inside of your oil filler cap for example should be clear of any such creamy coloured residue). Aside from that, the everyday practical advantage of a closed breather system is to provide negative crankcase pressure which helps avoid crankcase oil being pushed out of the engine seals. A brake servo maintains the vacuum until the brakes are released (.. note the characteristic hiss of articulated lorries when they stop), but 99% of the time its valves are closed, ie. whenever the brakes are in use or not in use - it's only the very short time-span of brake release where the vacuum is lost, and that soon recovers even though the engine is just ticking over. So what I'm saying is that Y or T connector from the inlet manifold connector will all but maintain the partial vacuum of the original closed crankcase breather system. However if you Y piece connect to an open vented system (either just a drop pipe or via a catch tank) then the vacuum in the brake servo is compromised, and a one way valve in line (see Stuart's photo) to the breather is necessary to prevent air coming back in through that pipe. Should the one-way valve, or the Y connector pipe to it, fail - then you loose your brake servo. So as Malbaby suggests "a dedicated single vacuum source for the booster to operate efficiently" and is the safer option. Regarding the twin cylinder engines. The 2cv has a boxer engine where the crankshaft is a 180 degrees - so the pistons go the opposite direction at the same time (ie. both simultaneously going away from the crankshaft, or both coming towards it). And yes these masses tend to balance each other out. However their firing is one side and then the other so they still rock. Four and six cylinders are naturally very much smoother. Parallel twin motorcycle engines were at one time commonplace. Most had a 360 degree crankshaft (both pistons go up and down together) - primarily because a top-hat shaped crankshaft is easier (and therefore cheaper) to make, and it's stiffer (for the same weight) than an S-shaped 180 degree crankshaft. Drillings to feed oil to the big ends is also much easier, and less oil pressure was needed. And then, although the reciprocating mass of the pistons and con-rods needed counter balancing with bob-weights on the crankshaft, the engine's secondary balance (felt as sideways rocking on a motorcycle) was much better. .
  7. A crankcase breather is simply to accommodate the change in internal volume of that crankcase when there are reciprocating parts. So for example with a 500cc twin cylinder engine, where both pistons descend the cylinders at the same time, compresses that 1/2 ltr displacement into exactly the same crankcase space (volume) as when the pistons are at TDC. And that crankcase pressure is enough to blow passed oil seals. So breather vents and pipes are added to let the air pressure out. Many such engines have a simple one-way flap valve on this vent, so air doesn't come back in again ..not least because that outside air can contain dust and pollen, outside humidity and road spray, and perhaps even the occasional insect. But with crankcase air being pushed out by the descending pistons and then only a small amount of air coming back in (when a one-way OUT valve is fitted and the pistons ascend) results in negative crankcase pressure . This (partial vacuum) inside a small engine ..such as a Citroen 2cv 600cc flat-twin or a larger twin cylinder motorcycle engine, has the benefit that on the piston's power stroke (descent) there is less air pressure to resist its descent. On such an engine that resistance is said to absorb 2 or 3 bhp of power (..so almost 10% of the Citroen's 33bhp). The 2cv has a one-way vent breather designed into its engine oil filler tube. This negative crankcase pressure also helps reduce engine oil leaks. NB. larger capacity but compact-in-size parallel-twin cylinder motorcycle engines have the worst ratio of displacement to crankcase internal volume.. which is why they are notorious for leaking. Naturally on a four cylinder engine, where two pistons are ascending as the other two are descending, there is not nearly so much difference (puffing) of crankcase air pressure. But there is always some.. because air is pulsating ..at piston speed, from under one piston to another (in effect from one end of the engine crankcase to the other, and this pressure wave pulsates all the way up to the rocker cover). Added to this is a little more pressure thanks to combustion blowing-by piston rings. (Tip.., condition of piston rings and bore might be assessed by feeling what comes out of the crankcase breather). Long stroke engines have a worse situation than those with a short stroke, even though their capacity might be the same, simply because long stroke engines tend to have higher piston speeds. Therefore the air being pushed around inside that crankcase is having to also move faster, which in turn increases the pressure at the air wave front. So.. crankcase air pulsations + combustion blow-by fumes puff out of the breather, and this carries with it oil in suspension (ie., a mist or perhaps even a fine spray of oil, plus any humidity that is trying to escape the hellish environment inside an engine !). On a worn engine, or one put together with loose tolerances, there can be a lot of oil mist - with some engine bays being clear witness to this. What do you do with it (the oil mist) ? ..Well suck it back in to engine and let the oil get burnt up with the next cycle of combustion, and any moisture will turn to steam and is ejected through the exhaust. In short ; the inlet manifold connection is a low pressure connection to take these fumes, without their being sucked actually through the carburettor. And., serving the same function as the one-way valve on twin cylinder engines, its low pressure works to create a negative crankcase pressure (partial vacuum) to the benefit of both performance and engine oil tightness. And yes., upper cylinder lubrication is good (..in moderation). A hotter grade of spark plug will keep cleaner with such 'closed' systems, conversely if you were to switch to an open vented system - then a cooler spark-plug grade may be fine. So Roger, you can remove the manifold breather pipe and use that connection for your brake servo, and then your crankcase breather can be to the atmosphere via a simple rocker-cover cap ..such as on the earlier cars, or via a pipe to under the engine, or to a catch tank ..which is then vented to the air, or else via pipes to the air-filter side of the carburettor. The latter will give you some degree of lower pressure but (assuming your air filters are not under size then) not nearly as much as the connection from the air intake manifold. An in-line one-way valve in the breather pipe (leading to a catch tank or atmosphere) will possibly catch some of the pulsation, but I doubt if it will be particularly effective on a four cylinder engine. As to your conundrum regrading catch tanks with air filters.. Perhaps the easiest way to appreciate this is to think carburettor venturi ..where the pinching in of the cross-sectional-area causes the air to accelerate through the carburettor - so that when a jet of fuel is injected into it - that fuel 'mist' stays in suspension all the way through the manifolds, passed the valves, into the combustion chamber, and then swirls around inside to thoroughly mix. With that understood - just think exactly the same principle but the other way round - where the cross-sectional-area doesn't decrease - but instead is increased to perhaps fifty or a hundred times as big. Then the air flow velocity slows right the way down ..and the (crankcase oil ) mist drops out of suspension. The air filter on a catch tank is intended to do just that : so many times larger than the cross sectional area of the rocker's breather pipe. Oh yes, some oil mist will stick to the wires within the filter and this in turn acts as air filter to help prevent gritty dust, pollen, bugs, etc, from going back up the breather pipe. Hope that helps, Pete.
  8. Looks suitably evocative to me , and likewise the idea of a pre-dawn drive in a TR up to your own cabin sounds a truly excellent quality of life. I hope you had pre-laid the ..fireplace ready to make it almost immediately cosy. Thanks for posting.
  9. Out of interest can stainless steel bumpers not be chrome plated ? I also had the impression that the SS was of thinner gauge, perhaps it's metric rather than imperial and a decent layer of chrome over copper will add to the feel as well. Personally, I very much prefer the warmer softer look of chrome plated rather than stainless, but perhaps after 20 or more years of polishing the stainless likewise becomes rounder.? Certainly the stainless steel bumpers on my 'other car' is less bothersome to live with. I am always a little anxious not to scratch my chrome bumpers whereas, as previously remarked ; the stainless are fit n forget, to the point of being disposable ..or sacrificial.!
  10. .. If asked how old I am - I now reply 56.. which is perfectly true as it's the year I was born But I'm in the process of selling up my bikes (was 14 and I'm now down to 4 ) not least because I know it will hurt a hell of a lot the next time someone pulls out in front of me ..and my reactions (as much because I now don't ride frequently) are not as sharp as they were ..to avoid it. It used to be old fella's in cloth hats that didn't see bikes, now it seems it's as much young mothers eating biscuits, texting or on the phone, and at the same time shouting at their rampant kids who don't see beyond the confines of their cosseting glass box. Half a dozen years back, I scared myself going into a corner too fast on my BMW K75 Ultima, so I signed on for the IAD rider's course. The issue turned out that I was used to big twin cylinder motorcycles and rode fast using their engine braking combined with balanced front & rear braking. Conversely, the BMW triple was half as heavy again with hardly any engine braking, and most of the braking force was through the front wheel. I altered my riding style, firstly by riding in the next lower gear (as the man says what's 500rpm matter, when the engine is designed to take much more) so that when I shut the power off - the bike slowed very much more rapidly. And I also slowed further in advance of corners (to avoid front suspension pitching of this fully dressed cruiser) before powering more progressively through bends. These two things mostly resolved the issues I had. But after a lifetime of riding more powerful and taught bikes, you would have thought how to ride a relaxed cruiser would have been obvious. That IAD course of course also emphasized reading the road well ahead and anticipating other road users, which I was already doing pretty well. It also updated my older knowledge of road regulations. Darn 30mph speed limits are everywhere now ! ..except in town where the inner ring-road is 40 ? Ironically, I had an minor fender bender just a couple of months later, while driving my Chrysler Grand Voyager. I drove according to the road regulations, but the other chap didn't and clipped my rear quarter. Oops perhaps he didn't see this huge people carrier in front of him ? The claim was a small figures insurance annoyance ..on that occasion, but it could have been nasty had I been on a bike. That aside, I guess the honest reason I'm moving towards hanging up my silk scarf is that I've gotten soft and lazy sitting behind a computer desk 9 hours a day. The wet and the cold are now particularly uncomfortable ..so to be avoided. And all the cumbersome gear is a p.i.t.a. It's just so much easier and just as much fun to drive a TR. !
  11. .. Just in case someone here might be interested, I've recently been recommissioning my Norton Commando 850 Interstate (1973) with the view to selling her. I restored and semi-customised her in 2011. The style I sought was of an update to the original 750cc fastback model. . The seat and fastback tail are interchangeable with the standard seat, and of course the BMW Touring panniers fit with either. . There are dozens of changes, which if you're interested are surmised in my for sale advert on Car & Classics < here > Pete. p.s. I'm selling because I want a TR4A ..hint ..hint .
  12. Bfg

    car cover

    ^ Personally I feel that's your best option. I don't have a car port but have a raised hard standing for air to flow under the car, and I have 6ft fence panels on two sides to prevent driving rain. Previously I had a polytunnel over it but the sunlight's UV and wind shredded it. Instead I'll be erecting a simple ridge pole over it - to cover with a tarp (cheap enough to replace every year or two) ..so in effect a poor man's car port. But because I live on a farm, which is often dusty &/or has more than its fair share of flies, I'll then use an old car cover (no longer waterproof after just one year's UV) under this to keep the car cleaner even with the car's window open on very hot and otherwise good drying days. Naturally the bottom of the cover is open, so air flow might come up via the gaps between the bumpers to around the car. The arrangement then is rather like a tent's flysheet with a dry(ing) tent inner. If I lived in a town I'd use the cover to lessen prying / nosiness and possibly the interest of the wrong sorts. The removable fabric side screens suggested, or in my case 6ft fence panels, lessen the flapping of the car cover on the car ..which in turn would reduce the possibility of dust under the cover scuffing the paintwork. I also use a few of the dark grey coloured insulating pipe-wrap polystyrene tubes under the car cover, to lift it up those two inches and provide an air space between the cover and the roof (see piccie). This gap helps avoid condensation. Pete
  13. IJ, sorry but I was looking as chassis reinforcements so did a bit of web searching which led me < here > ..but then I found it again on Bullfires excellent website < here > which I think may answer your query.
  14. . I believe the "absolutely not" refers to grinding the pin off flush to the top before fitting a reinforcement plate. Because doing so means that the pin may possibly pull out from underneath the reinforcing plate, but by poking the pin through, and then welding it there too is much stronger.. Here are three more TR6 chassis likewise done. The body mounting brackets are a little above the level of the reinforcement plates, and then they have the rubber body mount pads sitting on top of them. I didn't do the job so cannot say what thickness the plates are, but clearly the studs protruded through and then were also welded on top. Likewise another . . arrow points to a split along the front edge ..which I've seen a few times, so worth checking for. And this one too, the pins poke through and are also welded to the reinforcement plates. Here the restorer used thinner plates with up-turned edges ..like a shallow channel sections. I understand the very top corner of those upturned edges (..those on the main spring hanger, but not those on the damper's bridge) were subsequently trimmed back to the horizontal ..to avoid their contact with the body tub. . .
  15. Great progress Jon Not necessarily for you Jon but for anyone having problems with their mig welding < this > Youtube might be helpful. Pete.
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