Morgana Posted August 28, 2023 Report Share Posted August 28, 2023 Previous owner installed an alloy rocker cover with a vented cap, and a spigot by the carburettor which has a press-fit little air filter on. The angled rigid breather pipe on the cylinder block is present. Despite reading a few threads on here, I'm unsure how all this interacts, and with the additional little filter looking very oily and sorry for itself I wonder if there's a better solution. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 29, 2023 Report Share Posted August 29, 2023 1200s didn't have the rocker cover takeoff, their crankcase was vented through the angled pipe on the side of the block. 13/60s have a take-off from the rocker to the air filter housing of the Stromberg Carb to actively draw the pressure out as the engine runs, so this is what the small pipe on the rocker cover is for. Is your car running ok as is? It may be letting air in but might not make too much difference, in the standard setup removing the oil cap as the engine runs increases the revs but your carb may have been adjusted to compensate for the non-standard cap and rocker cover. You have the option of blanking that take-off completely, plug the hole as opposed to having a small filter, or else get a proper 1200 rocker cover just to get things as they were originally, as long as the angled pipe isn't damaged or blocked and so pressure can escape without blowing out through seals etc. The carb mixture may require readjustment if anything is disturbed. Link to comment Share on other sites More sharing options...
Morgana Posted September 8, 2023 Author Report Share Posted September 8, 2023 Thank you. The car's been apparently fine, as it's been like this since my ownership. It was very poorly set up on purchase last year, so is now properly set with valves and timing and a new distributor from Distributor Doctor, as well as a filter-regulator to overcome the high fuel pressure even with gaskets behind the pump body. The carburettor had been overtightened so was dished on the bottom and had to be flattened back to seal to the manifold. It's been reliable, and has made it around Ireland and been my only daily car during this time, but has needed quite a lot of carburettor tweaks which I've put down to unreliable fuel pressure and probably worn carb parts. Another thread on here has suggested I check the slow running jet for the lumpiness I was experiencing just before it went up on stands to sort the handbrake, where it remains as I take the bus... As I've got it in my mind to fix things, the little filter on the breather hole is now very blackened and oily and if it doesn't even need to be there I'd rather put the original rocker cover back. It may even be in the spares that came with the car. I guess the PO decided the shiny new one was more appealing. Does the old rocker cover require a special filler cap? I seem to remember reading about one packed with gauze. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted September 9, 2023 Report Share Posted September 9, 2023 13 hours ago, Morgana said: Does the old rocker cover require a special filler cap? I seem to remember reading about one packed with gauze. No, just a flat filler. Posh cars such as the GT6 had the gauze cap but us poor folk don't need one. Link to comment Share on other sites More sharing options...
Morgana Posted September 18, 2023 Author Report Share Posted September 18, 2023 Thanks. I can't see an original rocker cover so I guess I'll be on the lookout, and will probably plug the hole for now. Is the cover shared with any other cars so I can cast my net wider? Is there anything I can do to the angled pipe to check it's OK, apart from poking it? Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 19, 2023 Report Share Posted September 19, 2023 you could just remove the small filter and add a length of hose to breather lower below the engine there is an advantage with an alloy cover in that it takes on engine heat and doesnt get cooled by the fan so it is far less likely to generate hair cream/mayo that you will get with a tin cover and short runs Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted September 19, 2023 Report Share Posted September 19, 2023 https://www.ebay.co.uk/itm/145294894783?hash=item21d44026bf:g:URUAAOSwfLdkvDm0&amdata=enc%3AAQAIAAAA8LMqTMheFJ1PW5pUdAB3xHZiS%2BiXmSxMWnEr4vi77uzaT%2F031Ian13ec178bGEuyyHjTA%2FrWf7%2B4IE6xRw%2FNOnwEFgex0ApA77Ku9j%2Bsp%2B03adeuUfMyD8QyRj8ZSHg18Vuo1qd9kPLtmepKude2%2F5ugscIwmLAgGtKdF967NsImTLS%2BbVqoq1DU6q%2BgivIb175WhK66ftBQ2vYnzOrPdKiCPt8iX7pIrOAfl4dCKH8C84j7vjYF3vk%2FwNBr%2F%2Fic%2B6NFdby3Wm5rDbdKNMYPXlnHtcgk%2BHFigIKtggoLTVYCXa2BnKT5JDVzNevsYixcUg%3D%3D|tkp%3ABk9SR7qjv-DVYg One at eBay for £15, needs a sandblast. I see a 6 cylinder SAH rocker also for sale... £550? Mon joo... Link to comment Share on other sites More sharing options...
Morgana Posted September 21, 2023 Author Report Share Posted September 21, 2023 On 19/09/2023 at 11:49, Pete Lewis said: you could just remove the small filter and add a length of hose to breather lower below the engine there is an advantage with an alloy cover in that it takes on engine heat and doesnt get cooled by the fan so it is far less likely to generate hair cream/mayo that you will get with a tin cover and short runs Pete I'm not sure what you mean, Pete. Are you suggesting to connect the hose to the angled pipe breather, or leave it dangling? Thank you, @Colin Lindsay - I'd spotted that one but didn't have the experience to know if it really were for the right engine! I thought the filler cap spout looked too tall and I imagined it punching through the bonnet... Link to comment Share on other sites More sharing options...
dave.vitesse Posted September 21, 2023 Report Share Posted September 21, 2023 The Herald 1200 rocker box has a large oil filler cap which contains oil socked wire gauze. It vents directly into the air through holes on its underside. It works in conjunction with the crankcase breather on the side of the engine. The service notes say that you wash out the cap with petrol, leave to dry and then re-fill with engine oil. If I remember every 6,000 miles. Basically you need a bigger washable filter on the end of the pipe coming out of the alloy rocker box. Dave 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 21, 2023 Report Share Posted September 21, 2023 just suggested fit hose to the rocker spout and breath it to atmosphere with a length of hose pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted September 21, 2023 Report Share Posted September 21, 2023 (edited) 6 hours ago, dave.vitesse said: The Herald 1200 rocker box has a large oil filler cap which contains oil socked wire gauze. It vents directly into the air through holes on its underside. It works in conjunction with the crankcase breather on the side of the engine. The service notes say that you wash out the cap with petrol, leave to dry and then re-fill with engine oil. If I remember every 6,000 miles. Basically you need a bigger washable filter on the end of the pipe coming out of the alloy rocker box. Dave I'd actually forgotten that!! Too much working with 13/60s has clogged the brain cells. I was picturing the large two-cap type thingie that the 6 cylinders have, and forgot all about the 1200 breather cap. Edited September 21, 2023 by Colin Lindsay Link to comment Share on other sites More sharing options...
dave.vitesse Posted September 22, 2023 Report Share Posted September 22, 2023 The Vitesse 6 (1600) has the same oil filler cap crank breathing arrangement as the 948/1200 Herald. Also early Big Saloons (2000) had the same. The 2 Litre Vitesse models have the close circuit set-up. I have the same problems with brain recall. Dave Link to comment Share on other sites More sharing options...
Morgana Posted September 22, 2023 Author Report Share Posted September 22, 2023 Some clarification there, thanks. That eBay cover would need the special filler cap, then. What's the purpose of filling the gauze section with oil? Currently, the angled pipe is present but the rocker cover still has the vent spigot. The filler cap has a small hole in so I think is vented. Won't having all these vents upset the original purpose of the setup with the angled pipe? The current filter is not washable. I've tried in various solvents, but it's all pressed together so I can't get in to get the stuff out, unless I'm just not trying hard enough. It's this type. Anything larger will be impossible to fit behind the carburettor, so the only option would be remote mounting with a hose. Link to comment Share on other sites More sharing options...
dougbgt6 Posted September 22, 2023 Report Share Posted September 22, 2023 (edited) On 09/09/2023 at 14:05, Colin Lindsay said: Posh cars such as the GT6 had the gauze cap but us poor folk don't need one. My GT6 is even posher, don't ya know. It has no gauze, but a system of interleaved plates fitted in a raised block on top of the cover. They don't need cleaning, but It's a mk dependant rocker cover. Doug Edited September 22, 2023 by dougbgt6 Link to comment Share on other sites More sharing options...
Ian Foster Posted September 22, 2023 Report Share Posted September 22, 2023 (edited) Ha ha Mines even posher than Doug's. I haven't got' a raised block fitted with with interleaved plates', but I do have a shiny chrome filtered filler cap, a Smiths valve and a catch can!! Ian Edited October 11, 2023 by Ian Foster update Link to comment Share on other sites More sharing options...
Colin Lindsay Posted September 22, 2023 Report Share Posted September 22, 2023 3 hours ago, Morgana said: Some clarification there, thanks. That eBay cover would need the special filler cap, then. What's the purpose of filling the gauze section with oil? Currently, the angled pipe is present but the rocker cover still has the vent spigot. The filler cap has a small hole in so I think is vented. Won't having all these vents upset the original purpose of the setup with the angled pipe? The current filter is not washable. I've tried in various solvents, but it's all pressed together so I can't get in to get the stuff out, unless I'm just not trying hard enough. It's this type. Anything larger will be impossible to fit behind the carburettor, so the only option would be remote mounting with a hose. The oil traps dust and small particles so they don't enter the engine. It was the best solution back in the day, same as the oil-bath air filters. You can buy those caps new, they're used on the TR range as well. Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 22, 2023 Report Share Posted September 22, 2023 the small hole in the cap it to allow atmospheric pressure changes from not making leaks when left staic only of use in sealed/semi seal breathers of no consequence when used with open breathers like the herald of the day the alloy cover is better at reducing tappet noise and mayo /condensation problems so just fit a small filter as you have (keep it clean ) or just tube the fumes to below the engine zone its simple and get some sleep , its not something you need to worry about Pete Link to comment Share on other sites More sharing options...
Morgana Posted October 11, 2023 Author Report Share Posted October 11, 2023 Thanks all. I wasn't able to find a hose of the right diameter or a filter before a few days of several hundred miles, so it's just been venting from the spigot with no ill effects. I'm on the lookout for a plug or washable filter, as routing a pipe down past all the exhaust bits might easily end up with a melted hose. Saying that, I've just noticed in the workshop manual that the picture of the original rocker cover has the filler cap at the front of the engine. My filler is at the back. Is there anything preventing me from flipping the rocker cover end for end so the filler is at the front, and then the spigot will point out to the left, leaving plenty of room for a filter, hose or what have you. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 11, 2023 Report Share Posted October 11, 2023 yes swap it around the only restriction is if the filler may be too close to the bonnet pete Link to comment Share on other sites More sharing options...
Morgana Posted October 24, 2023 Author Report Share Posted October 24, 2023 Alas, the holes are off-centre so it can't be mounted back to front. On with the plug, or I get good at TIG welding and cut it off. Although. Canley have original secondhand covers listed... I noticed a lot of oil covering the bottom of the engine (more than the usual 'rust prevention system') when replacing the exhaust downpipe gasket, and realised the rocker cover gasket wasn't sealing properly (as well as the continuous leak behind the fuel pump). The gasket is a thick, yet narrow, cork one which I think is not suitable for the alloy rocker cover as far as the parts advice on the supplier websites goes. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 24, 2023 Report Share Posted October 24, 2023 Most of the alloy rockers come with a purpose-made seal, as the originals usually have rounder corners and so the profile is slightly different. You can buy silicone versions, or else just holdout for either a period-correct rocker cover, which the gaskets will fit, or the correct alloy cover gasket. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 24, 2023 Report Share Posted October 24, 2023 club shop sell the flat neoprene gasket for alloy rocker covers (and they are everlasting ) you wont get a cork one to work well as there is no register to hold it in place as they are just flat faces on alloy covers Pete Link to comment Share on other sites More sharing options...
Morgana Posted October 26, 2023 Author Report Share Posted October 26, 2023 Yes, the faces are the problem. The alloy's flat and the tall, narrow cork one on there has been bent over the inner edge of the cylinder head so it's not sealing square around the flat mating surfaces. I read on here some disappointed experiences with the club's neoprene one, so was considering Rimmer's thin rubber/cork offering for alloy covers which is also cheaper. I'm also a sucker for cork as it's a wonder material. Perhaps an autojumble will throw up an old undistorted rocker cover for the future, though the alloy one feels quite robust. If it weren't for that silly spigot... Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 26, 2023 Report Share Posted October 26, 2023 ive used a club one ( we were part of the idea to get some made ) for years on two cars they are problem free if they get adhered and you rip it off then i guess it will stretch or worse they are quite thin but mine have been reused a good few times without issue club shop are half the rimmers £28 6cly £14,40 4cyl £12 inc vat Pete Link to comment Share on other sites More sharing options...
Dick Twitchen Posted October 26, 2023 Report Share Posted October 26, 2023 My experience, on this topic(!), is the same as Pete's and the only time I could not re-use a gasket was was own fault. Dick Link to comment Share on other sites More sharing options...
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