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Triumph TR6 - Valve Adjustment
|I just finished setting the clearances between the rocker arms and valves. I use a feeler guage and take my time making sure all the lock nuts are tight.|
But why, after a couple hundered miles or so, does one or two of the buggers get loose. What in the devil changes to allow a couple of rockers to start making noise.
( And I didn't drive over any railway tracks!)
73 5 speed.
|I'd like to know this answer also. Just did my valves, very carefully, and a couple of them are clacking away|
|I've only run about 200 miles since I first adjusted the valves on my (new to me) '71 TR6 and it's fine. But when I had a '64 Spit, that was monthly maintenance for the best performance out of its little 1147cc four, more often if I drove it hard.|
That's why my TR mentor taught me to use petroleum jelly as a valve cover gasket compound. It makes an adjustment a 20 minute tinker and I usually re-used the gasket.
Isn't a little clatter normal for this design?
|I THINK IT HAS NOTHING TO DO WITH RAILWAY TRACKS !|
Remove the valve cover, then the bolts holding on the rocker pedestal and lift off the whole assembly. Look at the round or radiused ends of the rockers where they hammer down onto the top end of the valve stem. If you can see wear in the center, the answer lies there. Run your fingernail across the rocker surface. Where the shiny area is worn it may be as much as 0.010"
When you gap the valves with a feeler gauge that is wider than the top end of the valve, you are gapping it between the valve stem and the "un-worn" radiused curves of the rocker end. If it is worn, say 0.010", you are really gapping the valves to what you want plus the 0.010".
I took a power file and removed the excess metal from the un-worn areas on the curved ends of my rockers. I tried as best as I could to keep the same curved radius. Then I re-gap between two smooth un-worn surfaces. I have done this at least 3 times over the life of my original rockers, ie. over 155,000 miles. They are quiet, even though I've always gapped the exhaust valve clearances at 0.012" and the intakes at 0.010". Normal for a TR3A is 0.010" for all valves.
As for the gasket for the valve cover, Wagner Sales will be coming out with a new molded silicone gasket for the TR6 in the near future.
But I've only used about 3 or 4 cork gaskets over the 155,000 miles life of "TRusty". I use goopy brown gasket goo to seal it into the TR3A valve cover and never use anything between the gasket and the top surface to the head. It never leaks.
Don Elliott, Original Owner, 1958 TR3A
|Excellent workaround Don. For those that are not yet inclined to pursue your rocker grinding approach, I'm going to instead modify the geometry of my 0.010 feeler. I'll let you know how that goes with a narrowed feeler.|
There used to be tool called a 'click adjust' on the market [at least in the UK]which compensated for pad wear on the rocker, I don't know if they are still available but you might pick up one on Ebay
|Great insight on the rocker wear issue. |
In my case I'm running brand spankin new roller tipped rockers and new valves with a Kent Fast Road 83 bump stick.
The valve adjustment spec from Kent is .020
73 5 speed.
|Well John, that proves this has nothing to do with railway crossings !|
Run your TR6 a little longer and see if it repeats. That is, see if your gap gets larger over the next 1000 miles. Maybe they need to "bed in". Usually there is no damage if the gaps are wider than the spec. It's only when they get smaller that you can have problems.
Are your new rollers worn ? Have they been properly heat-treated ?
If you put in a higher lift camshaft with new stronger valve springs, have you bent your pushrods ? Roll them across your kitchen table to check for "wow".
About 10 years ago, there was also a rash of "soft" cam followers, those cylindical parts that are lifted by the camshaft and which in turn, lift the pushrods. When they are not heat-treated, they wear and that can change the gap.
Pull them out very carefully with a magnet stick and study them. Think about this before you do it, because they are hard to get perfectly aligned to put back in, but it might be done without pulling the head using a special tool like the long magnet stick or the one with the three-jaw claw end.
Why the 0.020" valve gap ? If your new roller rockers have a different geometry giving a different front to back ratio compared to your original rockers, this may change the distance that your valves are getting pushed down to open. Could this be affecting the gap ?
Don Elliott, 1958 TR3A
|Don-Removing the lifters on a TR6 is more challenging. The opening in the head is too small for the lifter to pass through, making it necessary to remove the head. Having said that, it is possible to change the cam and lifters with the head in place by removing the pan.|
|Don your system view of the problem is usefull in understanding the many areas that contribute to wider-than-spec valve gap.|
In my case I'll offer a bit more information.
The cam followers are new original stock PIPER which I'm told are excellent quality.
The cam is new from Kent. I spoke with a Calgary British mechanic on the issue of using different vendor cam and follower and the response was no problem with Kent and Piper together in the system.
The roller rockers were purchased from the famous Mr. Ted Schumacher at TSI. Ted is a great guy to deal with at http://www.tsimportedautomotive.com/
Ted also supplied me with shortened hollow chrome molly pushrods to coincide with the dimensions of the shaved head.
The valve springs are stiffer than stock and the head was redone by a local machine shop.
When I fired the motor for the first time I'm pretty sure I didn't gall the cam as I ran it at 2000 rpm for 20 minutes much to the dismay of my non-english speaking neighbour who spent 15 minutes of that run-in period jumping up and down and waving his hands. At first I thought he was cheering me on for a job well done....;not!
After 500 miles I removed the valve train and re-torqued the head and re-gapped the valves. Also checked the roller tips on the rockers and all looked like no wear.
So I'v done most of the right things - the car goes like a bat - but just clacks a but more than I think it should.
I'm driving it like I stole it and slowing down for railway crossings only if possible!
I'm off for my annual 1000 km cruise in a couple days through the great Canadian Rocky Mountains that split British Columbia and Alberta and won't be taking anything appart till the snow flies!
Thanks all for your help.
73 5 speed.
I hope you don't have the same problem I had with my "new" two years ago Kent cam, lifters and springs.
The cam has 7 very badly worn lobes and 10 of the lifters are shot.
If you have cam wear this would be the cause of the adjustment changing.
Does anybody have any ideas on a cam regrinder, new cam or where to get a cam and lifters hardened?
|Brent - Most heat treat shops will tell you which is best. I suggest nitriding crankshafts because that's what "they" said about 35 years ago. As for smaller items, they can be "Tuff Trided" which will make them last longer than you or me.|
See you at VTR and Roadster Factory Party ? Wil you have an experienced navigator you could loan me for the gymkana ?
Don Elliott, Original Owner, 1958 TR3A
Reed Cams (Stockbridge GA) will do regrinds, but there is a distinct possibilty that the Kent unit may be too far gone to regrind. They do not like to do weld build ups on Triumph cams when I have discussed this with them. They have done some rather wild grinds for Fletcher Williams on his old GT3/E Prod TR6. I have always had good dealings with these folks.
Paeco (Birmingham AL) will do weld build ups on worn cams for grinding to one of their specs. Bring money though, it was something like sixty skins a lobe if I am remembering correctly. I have gotten mixed reports on dealing with PAEco from folks, but my dealings with them have been OK.
APT (Riverside CA) uses an ion nitriding process on the cams they sell which should give a nice hard wear surface. While I am using a cam from Reed, many other components in my valve train and induction system came from these folks. Service has been very good. The only time I had a problem, I called them up told them that 5 of the 6 air horns shipped were for a 40 DCOE and 1 was for a 45 DCOE. I had the right 40 DCOE bit delivered to me at no charge before I had a chance to get the wrong bit in the mail back to them.
There is also Ted Schumacher mentioned a few posts above.
|For anyone aeeking info relating to the stock valvetrain, I'm up to nearly 1,000 miles since adjusting and all appears well. I plan on another 1,000 before Labor Day and will update the BBS then.|
Charlie & his original '71 TR6 @ 93,500.
|I asked this question at the Roadster Factory Summer Party and VTR last week. (There were 101 TR6's lined up side by side on Philadelphia Street in downtown Indiana, Pennsylvania, last Saturday evening) Many have hotted up their TR's and run the autocross, the hillclimb and the dragstrip. A "non-stock" TR8 hit 112 mph in the 1/4 mile and a TR6 with a hot huge Ford V-8 hit 109.|
John, several said that it is normal that a new set-up like what you have done needs to run-in or bed-in. It's not unusual for the first few times. But if it persists, check out all the things mentioned above. They talked of brand new cams as well as new roller rockers which had not been hardened and other horror stories.
Don Elliott, 1958 TR3A
|Don you are quite right about the fact that if the valve gap becomes larger over time, there must be some wear in the system - that is after the engine has broken in and the wear patterns between the components have been established.|
In my case - and sure enough - I have a big problem.
I removed my fancy-dancy roller tipped rockers and installed the old stock steel rockers. The roller tipped rockers suffered a major failure of the brass bushings through which the rocker shaft is located.
Seems the manufacturer made an omission and forgot to drill the oil holes through the bushings!
I won't mention the vendor - he seems to be a good guy and hopefully will make good on the warranty. Will post further when all said and done.
Goes to show that all this high performance jazz is not an easy road. It's a challenge though. Had I known, I'd have inspected the rocker arms prior install.
Regards and thanks all for the replies.
73 5 speed
|One of the horror stories I was told at VTR last week was about this very problem you have described. But it was the other way around. The bushes were just fine. It was the rocker shaft that the bushes rock on that was worn. Seems the rocker shaft was so soft that even the bushes wore the shaft oval - hence the rocker gap noises tapping more and more.|
Don Elliott, 1958 TR3A
|Don, In my case I had some shaft wear as well as the bushing wear - everything was wearing. |
I will say one thing - for what it's worth to the vintage "tuner" crowd - going from the 1:55 roller rockers back to stock feels like I just neutered the poor car - definately less breathing, less jump - feels dull! The rollers really are a treat.
Having said that - I think the needle bearing roller rockers combined with the hardened shaft is really what a person should do. (sucker for punishment... but as my wife said "that's why it's a hobby...")
73 5 speed.
If the 8 ponnied TR6 was red in colour then it was a member this BBS ....Chris Trace.
Chris took me for a spin in the "red rocket" last weekend. Like the song goes..."what a rush". When the rear 2 barrels kicked in, it was like going into after burner mode.
|John--What lubrication requirement changes are needed for a needle bearing rocker setup? I mean it seems that the needle bearings would offer way less resistance to oil flow which could result in oil starvation in the rocker box? Would the external oil feed be a necessary mod then?|
|I believe there are spring loaded washers on each side of the rocker to offer some resistance to oil flow. And the external oil line is a "must". I've had a set of of 1:1.55 RR's (Good Parts) & external line for 5 years with NO problems.|
John, I've got to ask - was the failed set from Swarthout?
This thread was discussed between 29/07/2003 and 20/08/2003
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