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MG TD TF 1500 - Adjusting valves with engine running, Who else?
|Am I the only one who has been adjusting valves using no measuring device of any sort? Concerned and well meaning folk often insist on telling me my valve lash it too tight, they know it, because my top end is not tick tick tic ticking away when they hear it running.|
My grand dad taught me how to do it 60 years ago, but Al Moss is usually given credit for coming up with the idea. My grand dad said that was simply how he was taught how to adjust, so I guess everybody who knew anything used to do it that way, eh? At least people in the MG world know who Al Moss is, so when I tell them where they can easily find a reference to this technique they finally leave me alone. Works on any engine with valve lash you can adjust with the engine running. Dont even need to know what cam is in there or what the hot or cold lash is supposed to be. Helps if you can get sorta close first. Obviously it is intended to do when the engine is warmed up fully, not cold. MGexp threw me off their crap site for mentioning this technique on the MGB forum. Gotta love those little know nothing babies over there. Here is his quote exactly:
I am always getting comments from other owners about how quiet my TC engine is. I have always set the tappets by the following method: I have a banjo bolt brazed shut and install this in the oil line running to the cylinder head. It is now possible to check and adjust the clearances with the engine running. This takes a bit of practice but it can be done. Once set with the proper clearances, there will probably be one or two (usually the same ones, by the way) that still click. This is because the end of the rocker is slightly cupped, giving a false reading with the feeler gauge. Now, carefully tighten that rocker screw until the clicking stops. This will give the proper setting. If you doubt this, check it out with a dial indicator or, better still, with a vacuum gauge.
|Is it April Fools day already? |
|Well I see Tim has never heard of it. Check out the mg-tabc.org website technical articles some time and you will find it there. At the very bottom, below the white page.|
Really, nobody knows about this?
|I think pre war Vauxhall tappets were set with the engine running but you had to use hardened feeler gauges. I am pretty certain normal ones would be pounded to death.|
|OK, Jan may have heard of it but does not understand Al Moss was talking about adjusting the valves on his XPAG engine. No feelers get used during the running adjustment, Jan. What happens is you loosen the 8mx1.0 adjuster nut just loose enough to allow movement with your perfectly fitting screwdriver, and adjust it until you hear a little tick produced from that one and then tighten it (adjustment not nut) up only enough to make the tick just go away. Viola, tighten the nut, and after all 8 done your lash is perfectly adjusted and no clatter. When I check them with a feeler afterwards, for laughs, it is surprising the variation from what your feelers or other measuring technique would tell you is correct. Measuring the lash on a used engine like this is pretty much useless, except to get the lash in the approximate ballfield. It is good to have them as close as possible before doing this running process. Makes it quicker.|
|Presumably the guy that designed the cam did so taking account of the required clearance, so that the valves open and close as planned. So what is the clearance for, if its measured when the engine is fully up to temp? |
Is it just to allow for exceptionally high temps if something fails, so that any potential damage is reduced?
If so, you might lose a little power without valve clearance, but everything will otherwise be fine until that day arises.
|Because of wear in the system I final set my clearance with a Mercer gauge (dial micrometer). This give me a quiet engine with accurate gaps. You can pick them up at autojumbles for pennies, a mag mount helps as well.|
Vauxhall 1960/70 OHC engines were set with throwaway strips of feeler.
There again memory is failing,it could have been Ford.
Ray TF 2884
|I had an old 37 Chevy, "cast iron 6", that I adjusted the valves that way. They were also known for loud tappets. Holding your fingers on the rocker arm while the engine was running, you could actually feel the change taking place as you tightened or loosened the adjustment along with the tappet sound. Not crazy at all, were just getting a little too technical on these ancient horse and buggy engines, JMHO. PJ|
|In high school autoshop back in 1963 we had a tool that was a hex socket with a thru hole for a screw driver. |
|Many-many moons ago I had a tool to adjust OHV while running. It had a spring loaded screwdriver like stalk and the working end was like a screw driver with extended ears along the sides of the blade. This was to keep it centered on the adjusting screw.|
I seem to remember that it was a KD tool with a blue plastic handle. The blade had a total movement about 3/4 ".
|Here's my problem with the method described by G Gilly. If you adjust the valves so that there is no clearance (no noise from the tappets clicking against the top of the valve stems) there is little opportunity for the valves to transfer their heat to the head. Also, at high RPM you will have valve bounce allowing leakage. Additionally, restricting the oil to the rocker shaft while adjusting the valves is potentially very harmful. I understand the problem with the oil splatter while adjusting valves on a running engine but depriving the rocker shaft of oil for any period of time is foolhardy. My father, an auto mechanic for 40 years, always adjusted the valves on a running engine. But he used a feeler gauge on a solid lifter engine and the lack of tappet clicking on a hydraulic lifter engine. I seriously doubt if there is one automobile manufacturer in the world who recommends no valve clearance on a solid lifter engine.|
|G Gilly, the MG-TBAC article you reference says nothing about adjusting the valves on a running engine without a feeler gauge or tappet clearance. In fact the article recommends against a running engine adjustment.|
|Maybe my age is showing, but that technique, with the use of an appropriate feeler gauge, was SOP for adjusting the valves on Detroit Iron engines for years. You turned the adjusting screw until you felt drag on the feeler gauge. Then you tightened the lock and went onto the next one. Did clicking go away when the feeler gauge was in the gap? I guess so, but that wasn't the criteria. Bud|
|Bud, I adjusted many valves while the engine was running at my dad's garage when I was a kid. Using the feeler gauge the clicking did go away when the feeler gauge was in the gap. The proper setting was a drag on the gauge not a complete stop when moving it. It was a very messy job with oil flying everywhere. But the mechanics at the time (late 50s early 60s) thought it was the only way to adjust the valves. Certainly with hydraulic lifters it is the only way to adjust the valves on older cars. But adjusting valve clearances without a feeler gauge is a good way to burn a valve of degrade performance. And stopping the flow of oil to the rocker shaft while adjusting valves on a running engine is just nuts.|
I am regressing back to the 1960s and can remember my father setting the tappets on a neighbour's car whilst the engine was running. I can clearly recall the workshop manual being referred to and to the bonnet having flutes where the sides joined the top. The clincher though is the engine was a OHV which was unique to Vauxhalls, apart from some exotics.
|Wow, utter confusion (Tim) from a few. Who on earth said anywhere, ever, about no lash clearance?? The Al moss comment was copied and pasted directly into my first opening comment, and then the link was provided a few posts later, instructing that the quote was below the main article, at the very bottom. NOT THE MAIN ARTICLE! |
I also said that (for laughs) I have checked my engine running adjustment with feelers and said that due to wear (just as Al Moss described in his comment at the bottom of my first post and bottom of the link) it was obvious feelers only gave an approximate setting, knowing what the manufacturers of the cam intended on a brand new engine with no such wear.
Now, you can go verbatum on the AL Moss instructions and temoralily go no oil flow when adjusting, or you can make up a different method like I did where I temp. install a different pipe to oil head with a ball valve installed that can be set to allow just a trickle of oil. This eliminates oil splatter while adjusting the valves with the engine running, yet keeps a little oil flow going. tHE al mOSS METHOod cuts off the oil. No I am not advocating shutting the valves to zero lash nor cutting of oil to top end.
This method will work on every real M.G. made since the TB through the last MGB. No, it won't work on a jet engine or many lawnmowers with non adjustable valves or on an engine that uses shims to adjust valves. I dont think listing every exception is very productive, so lets not.
|G Gilly, You said, "Who on earth said anywhere, ever, about no lash clearance?" In your OP it says, "Now, carefully tighten that rocker screw until the clicking stops." If you think there is lash when the clicking stops then you don't understand how a valve/tappet/lifter system works. If there is no noise there is no clearance. Al Moss probably meant to say that if you have an especially loud tappet then use his method. He certainly didn't mean when there is no valve lash noise at all. But he says, "Once set with the PROPER clearances.." he is not saying, as you indicated,, "Dont even need to know what cam is in there or what the hot or cold lash is supposed to be." You misunderstood what he was saying.|
In the article you supplied Moss says, "I do prefer setting the .012 cams at .015, however." Well how on earth would he set the lash at .015 if he, "...[Didn't]even need to know what cam is in there or what the hot or cold lash is supposed to be."?
|Sorry to hear you have no idea what you are talking about Tim. Maybe you should take it from the top and re-read every single post here so you can confuse yourself even more. Why the need to act like you know what you are talking about when obviously you barely know what century it is? I have been adjusting XPAG, MGA and MGB and midget valve lash like this for over 40 years and people pay good money to get their valves adjusted by me. Bring your car to my shop and I will do your valve adjustment to perfection for $400. It will take about an hour after the payment clears. I can also tell you if your top end needs rebuilding, and specifically what is wrong with it. Adjustments using this method last for much longer that the measurement method which leaves your lash sloppy and all over the place due to wear. When they are adjusted to perfection they stay in adjustment much much longer and reduce valve train wear considerably.|
I can fit you in sometime in 2019 around March. Let me know.
|G Gilly, so you stand by your statement that, "Dont even need to know what cam is in there or what the hot or cold lash is supposed to be."? No need for insults by the way. |
What's the name of your shop?
|Turns out G Gilly is a troll who was kicked off of the MG Experience web site yesterday under the name grantgillyTD. What a waste of time. Sorry everyone.|
|Tim it is quite obvious you are the only TROLL around here anywheres.|
I asked you to go and re-read this whole topic but obviously you DID NOT. I stated in the first post, you know at the top, that when I posted this same topic on MGexp I was thrown off that mindless site, because they only want to talk about what some MGB workshop manual states from 30 years ago. They want people to be ignorant and buy their crap services people advertise there.
What is wrong with your brain that you began the replies with first calling it (my question) an April Fool joke, then proceeding to call be completely ignorant on how valves area adjusted. Tim the TROLL.
And you have the audacity to accuse me of calling you names! Nobody is buying the nonsense you are trying to peddle tim the troll.
How on earth do you suppose an engine can possibly run with the valve lash at zero? It cannot Tim the Troll, because that is not what I do, nor what I described in quoting MOSS and you have not bothered to read anything so that you might understand.
Tim the troll needs needs to move over to the mgexp where people are more like himself and leave normal people alone.
|You have my support Tim. Your contributions over the past few years suggest you are anything but a troll. I note that G Gilly has the same offensive tone & disregard for common courtesy as the recently banned S Cole, both of whom exhibit behaviour & express themselves in a manner that is anything but normal. Hopefully the administrator will step in & again take action. Cheers|
Peter TD 5801
|It is a pity we get into these situations because G Gilly does know what he is talking about (generally).|
|Given that setting the tappet clearance is so mind-numbing easy the 'right way', why would anyone do it any other way?|
I've set mine in as little as 5 minutes. And I KNOW they're at factory spec because I measured the gap.
C,mon.... no feeler gauge, no measuring? That's not accuracy, that's guessing.
|Many of Gilly's posts have been removed from various sites because of the same intemperate and offensive language and attitude shown above. There is no room for short tempers on this or any other MG site.|
Gilly - if you cannot be civil, please don't post.
|" Bring your car to my shop and I will do your valve adjustment to perfection for $400."|
WOW $400 per hour. Talk about getting ripped off..
And the name of the shop is ??? in Hawaii ??
|Things have escalated rapidly BUT G Gilly was correct in saying Al Moss did recommend this method. The article referenced above (http://www.mg-tabc.org/library/valve_adjust.htm) was written by Jerry Austin but if you look below the article there is this note:|
and some comment by Al Moss
I just finished reading your article about valve adjustment and will pass on a few comments.
First, I don't agree with you about the .019 camshafts. These were fitted to TCs and early TDs. There are probably very few of these left running today as they were prone to wear. I did prefer leaving those at .019". As there were no factory markings of any sort on the (4) various MG factory camshafts, it was difficult to determine which was which and what the setting was to be, I have a method but it isn't worth going into here. I do prefer setting the .012 cams at .015, however.
Now, the crux of my message. I am always getting comments from other owners about how quiet my TC engine is. I have always set the tappets by the following method: I have a banjo bolt brazed shut and install this in the oil line running to the cylinder head. It is now possible to check and adjust the clearances with the engine running. This takes a bit of practice but it can be done. Once set with the proper clearances, there will probably be one or two (usually the same ones, by the way) that still click. This is because the end of the rocker is slightly cupped, giving a false reading with the feeler gauge. Now, carefully tighten that rocker screw until the clicking stops. This will give the proper setting. If you doubt this, check it out with a dial indicator or, better still, with a vacuum gauge.
|Can I raise a number of points. First what is a Troll. I have heard of them but don't know what or who they are. Second I have been a "victim" of contentious comments on a site for pre war MGs and enjoyed the on line sparring so providing it doesn't get out of hand let it continue. Finally having been an engineer for 50 years I believe the best way of setting the valve clearances is to use Ray's suggestion of a DTI. This will take into account any pocketing of the rockers and ensure there is a sufficient gap to prevent burning of the valve seats.|
|Gene, I don't think there is any doubt that Al Moss recommend adjusting the valves while the engine was running. That is certainly how US cars' valves were adjusted for decades. I've done it many times myself. The issue of contention for me is the statement that, "Dont even need to know what cam is in there or what the hot or cold lash is supposed to be." In the Al Moss quote he says, "Once set with the proper clearances,..." The obvious point is how could you set the valves to the proper clearance without knowing the cam and the manufacture's recommended clearance. I believe Moss was referring to an especially loud tappet after an adjustment with a feeler gauge. I think his method of adjusting a tappet until the click (clack?) went away was for that one or two especially loud tappets, not the entire set.|
|Regarding the article referred to, it says set the valve clearances hot, then let the engine go cold and reset the clearances. This advice is obviously conflicting, so I hope no-one does reset their clearances cold.|
|R A WILSON|
|I certainly hope an unassuming, or uninitiated owner will not feel that his engine isn't properly set up if he hears the valve train.|
Quite the opposite is true.
A healthy valve train has it's clearance set - not to keep it quiet, but to allow for proper operation which includes leaving an appropriate gap. If the gap called for makes a little noise, so be it. Its based on old engineering, its sometimes a bit noisy.
While I agree with you that that may have been what Al meant I hate putting words in his mouth. I'll continue setting mine the way you, I and most everyone else here has for years...this was simply an additional bit of info.
|Jan T, a person who is intelligent, knowledgeable and insightful is someone who agrees with you on the Internet. A troll is someone who does not. :-)|
|It is a shame this thread ran off the rails. That type of behavior is very rare on this forum. It had to stop, and I am glad it was dealt with. |
A number of people adjust their valves to .019" as per the tag on the valve cover, despite having the newer camshaft. This makes for a lot of noisy valve trains. When properally adjusted, the valves are quite quiet.
This thread had my attention, and I was looking forward to the discussion. Pity.
|OK, so I'm still confused. It seems to me that if you adjust your valves so they make no noise you don't have ANY clearance (lash), right? How feeling and listening for a tick possibly more accurate than a feeler gauge, as the OP suggests? As long as the engine is as hot as it can possibly get without boiling over, maybe no lash is OK, but no margin for safety? Then why do different camshafts have different lash recommendations, if they all work without any lash under that scenario? I never had the experience of adjusting lash on old American iron, so maybe something about that would be revealing?|
And how in the world does one check valve lash with a vacuum gauge as Al Moss apparently suggests?
This is all academic to me. I've had my rockers resurfaced and I'm going to continue to use the feeler gauge method as I'm not concerned about cupping. However, I might check it with my dial gauge just to be sure. So feel free to ignore this post if the issue is already worn to a sensitive nub.
|David,the biggest problem with having no lash is that the valves don't sit on their seats long enough to transfer heat properly to the head. That can result in burned valves.|
"The intake and exhaust valves rely on physical contact with the valve seat and guide for cooling. About 75% of the combustion heat that is conducted away from the valve passes through the seat, so good seat contact is essential to prevent burning. The remaining 25% of the heat is dissipated up through the valve stem and out through the guides."
The other problem with having no lash is that the valves will open too soon and degrade performance. Cam manufactures recommend a certain valve clearance to correspond to the duration of the lift of the cam lobes.
Note: all of the above applies to solid lifter engines. Hydraulic lifters have no lash.
|Tim - "a person who is intelligent, knowledgeable and insightful is someone who agrees with you on the Internet. A troll is someone who does not. :-)"|
I hope that you wrote the above with tongue firmly planted in your cheek (as I assume that you did). Knowledgeable people can have a discussion over different opinions and not be trolls. A troll will always resort to demeaning verbiage when someone disagrees with him/her. Thank goodness we have a moderator on this forum (as does MGE in Skye) who will step in and toss the trolls. Cheers - Dave
|Dave, your right, just an attempt at humor. Didn't you see my little smiley face? If people didn't disagree on a myriad of subjects these forums would be a pretty boring place. In the time I've been hanging around here I've been impressed with both the tenor of the discussions and the knowledge imparted. I, and I'm sure you, have seen how a lack of proper moderation can turn a forum toxic. Mr. Plumstead does a great job without intruding upon the conversations. Just so we are all on the same sheet of music:|
Merriam Webster Dictionary: troll - a person who tries to cause problems on an Internet message board by posting messages that cause other people to argue, become angry, etc.
to antagonize (others) online by deliberately posting inflammatory, irrelevant, or offensive comments or other disruptive content < … trolls engage in the most outrageous and offensive behaviors possible
|I thought I read somewhere, "a noisy valve is a happy valve" :)|
|Thanks, Tim, for the explanation on heat transfer and why there may be different lash requirements for different cams.|
|Here's a really good, if low tech, video from the 50s that explains hydraulic lifter operation but also has some good info on solid lifters. It shows why there is no valve lash with a hydraulic lifter. Be sure and turn the record over when you are half way through. :-)|
|I recall that quite some time back I had a SIMCA with noisy tappets. These cars were known for this. So I took off the rocker cover and found that a few tappets were causing this. I then adjusted these very slightly tightening them up just a little. Noise much better and the car ran for many years with this approach. I owned that car 14 years in total from new and this worked fine for me.|
It is important to not that this slight pulling in did not remove the clearance it simply set it correctly where a feeler gauge fails due to a slight dent in the push rod top caused by wear/use over time.
So I totally agree with this post and it all makes sense to me. I have a life long Mechanical Engineering background and this basic adjustment is very logical !
|Interesting thread to say the least! I have done exactly as Mel did above. Most likely a noisy one is caused by a worn/bridged by feeler rocker tip, or pushrod or cam/lifter issue. Using a dial indicator would of course make up for the worn rocker tip. But adjusting a solid lifter engine while running in general is nuts IMHO. George|
|Mel, I assume when you say you totally agree with the post you are not including the comment, "Dont even need to know what cam is in there or what the hot or cold lash is supposed to be."|
What you call "lash" is known as clearance over here in the UK. Although I knew the manufacturers setting for valve clearance I can see that if you start with a nominal generous setting, run the engine and it will be clattering, then the procedure of very gradually one at a time tightening to a point where your senses indicate the noise is sensible should work quite well !
If unsure then once quiet you could slacken off one at a time and concentrate on each individually.
PS My old SIMCA engine did do well over 100,000 miles before I sold it on as a runner. Engine never touched - only normal services - oil etc
|If your rockers are worn, use a wire gauge. Problem solved. Or a click-adjust, or a dial indicator.|
Adjusting while running does work, but is not as accurate. Probably fine for a stock XPAG engine but for more highly tuned machinery you would not want to do it this way.
I have one highly tuned MG where opening valve clearance 4 thou makes a measurable difference in torque at the sake of high RPM power. So if you're really going for perfection then do it the common way and use the proper tool. If you just want it in the ballpark and you aren't out for maximum performance then sure, you can do it while running. I haven't found it to be easier though. Just more messy.
Do not set your valves at zero clearance! There must be room for heat expansion or you're asking for trouble. The numbers are there for a reason.
|I found this thread very interesting and although I've never considered the engineering theory, I've always assumed the cold gap allows for expansion and will close up when the engine is hot. It seems logical to me that an engine designer would wish to keep the rocker in contact with the valve stem head. Wouldn't this be the dominant mechanism for cooling the valve reducing the possibility of burnout? The valve can't be in contact with the seat for long enough to transfer 75% of the heat can it?. Also it would eliminate shock loading of the valve stem (ticking) which can't be beneficial. I've always understood that suddenly applied forces can exert twice the load of a gradually applied force. |
I don't like the idea of restricting the oil flow to the head but it does seem to me that, if you're prepared to put up with the mess doing it by ear, would be the best way. I can't imagine that the OM authors would wish to subject the poor mechanic to an oil bath or cut off the oil feed which is why they opted for the procedure of setting cold gaps.
If anyone has any experience of the engineering principles design involved here I would love to hear about it.
|A R Jones|
|AR Jones I'm starting to beat a dead horse here but maybe you'll find this useful. On the XPAG engine the cold gap is not considered since the factory instructions are to set the gap with a warm engine. Always keeping the rocker in contact with the valve stem would shorten the time the valve sat on the seat thus reducing the time for heat transfer from the valve to the seat. Only about 25% of the heat from combustion affecting the valve is transferred through the valve stem to the guides. The valve seat absorbs 75% of the heat from the valve (See this article http://www.sbintl.com/tech_library/articles/understanding_valve_design_and_alloys.pdf) So the less gap you have the less heat transfer you will have to the valve seat. Here is a pretty good article on tappets and adjustment. http://www.uniquecarsandparts.com.au/how_it_works_tappets. Google will provide you with hundreds if not thousands of articles of the how and why of valve adjustment including heat transfer. Hope that helps. I think for the sake of the other members here this will be my last post on the subject. |
|Besides my TF I have a Datsun 280Z. The site for the Datsun is a disaster and this post is a tribute to the usefulness and honesty of the people who make contributions to the threads posted. Well done.|
This thread was discussed between 02/02/2017 and 19/02/2017
MG TD TF 1500 index
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