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Triumph TR6 - Valve Stem Seals
|With all the experience on this BBB I would welcome any suggestions for the follosing.|
While doing a valve job on my 73 TR6 I discovered valve stem seals on the inlet valves, with only the outer springs installed. Original design was dual springs on both inlet and exhaust valves. My theory is that the DPO tried to "fix" a fouling plug/worn valve guides problem by installing the stem seals on the inlet valves but this required that the inside spring be omitted. There is very little information on the www about LBC stem seals, except a nice article at the Peachtree MG Registry website by Barry Rosenberg where he briefly comments that the Triumph engines were never designed to have valve stem seals. http://peachtreemg.dnnsites.com/Default.aspx?tabid=88
This oddball inlet valve arrangement may have led to my bent rocker arm shaft, caused by weaker spring and sticking valves.
After due consideration Im am planning to rebuild the head with the dual springs and leaving off the stem seals.
Any experiences or ideas on this??
TR6 engines where originally all single spring intake and exhaust valves and without stem seals. By all means go dual spring and you might consider hardened valves and seats. I did not and time will tell if this was a good or bad idea. I do add lead substitute....but that is a whole different story.
Did you get CDII Bob?...are you anywhere near Huntsville AL?
|The TR250 and early carb TR6 heads used a single spring, all PI cars and the later carb TR6 heads used dual springs. With the dual spring set up, there are no cup type valve stem seals available on the market that I am aware of that can be used on standard size outer diameter valve guides for these engines.|
Are they necessary in a TR engine? We know the answer to that one is no, but whether or not they should even be considered is related to the guide being used. If you use an iron based guide similar to those originally fitted to the engine, then by all means do not consider running cup type valve stem seals. If you use a more modern bronze guide, then you can choose to run them or not. If you do elect to run seals on bronze guides, the OD of the guide will need to be turned down at the top by either turning the guide in a lathe prior to installation or fly cut if done after installation of the guide. This will allow fitting of the cup type valve stem seals with the dual spring set up.
|I stand corrected by both Steve and Bob.|
I am now trying to decide on a cam and am pretty much sold on the new (not reground) "GP2" from Goodparts. In addition I am going with their new tappet set, high performance dual valve springs and bronze guides, to go with the Stellite exhaust valves from Moss. Goodparts website also shows the teflon valve stem seals and indicates that the guides are machined to fit the seals. I assume this means that the valve stem seals are suitable for use with the dual springs. Any comments? Also, Rick, I am going with Stellite exhaust valves but I believe from what I read that the hardened intake valves available from TRF at reasonable prices are suitable, meaning that Stellite is not necessary or an option for intake. Is this correct? I'm also assuming that if you had to do it over again you might have gone with the hardened seat inserts. I figure on doing this just once so the extra $$ now seems like a good investment. I'm not sure about those valve stem seals though. I may be tossing $$ around a bit but I also favor the more expensive Renold timing chain from TRF at $49.50 vs. $12.50 for the no-name brand and figure a new cam gear is a good investment. Any advice would be very welcome. Geez, when the wife finds out what this is costing she's gonna throw a hissy fit!
1976 - TR6
|Hey Bob. I don't understand why you'd need hardened intake valves (or exhaust for that matter unless you intend to stay above 5,000 rpm or thereabouts consistently). Both the cam chainwheel, crank sprocket, and chain should be replaced as a complete set. Personally, I'd leave the stem seals off as I'd want as much lubrication as possible there (especially with high perf springs that impart a lot of stress on the valve & timing components).|
Stellite and hardened are "kinda" one in the same thing.
Stellite is a proprietary name of grouped alloys that have high hardness and resistance to oxidation at high temps.
So Stellite is just a name for hardened particular metal alloys.
I am not a metallurgist so can not comment on if just hardened valves are OK.. To me it sounds like they are the same thing....but I have been wrong before:)
Bob, I do not know if I would go with the "Lead free" head. I currently add Lead Substitute to every tank of gas. I do not put 10,000 miles on my car every year so I thing the head on my engine will outlast the head on my shoulders. Steve covers the valve stem seals. Yes replace the timing chain and gear. Also the timing chain tensioner. I would suggest going with the VP2 bearings from BPNorthW.
Thanks for the info. Based on your advice & experience I'm looking at my order this weekend to catch TRF's sale price on hardened (not Stellite) exhaust & intake valves. On TRF's site, "stock" valves appear to be hardened anyway. Also, crank & timing gears with the Renold timing chain & tensioner, GP2 cam, bronze valve guides, hi-perf valve springs & new tappets. New valve seats do not appear to be necessary due to low yearly miles. BTW, all the rest of the restoration bits for the lower engine have already been purchased. The most important piece - a new oil pump. Have I missed anything?
1976 - TR6
You didn't mention whether the head was going to be milled to increase compression. If so, maybe new shorter push rods?
I've got the Good Pts seals and they work fine. Only really "necessary" on the suction valves, but they're fitted to all the valves. With the bronze guides (properly reamed after installation) not as much oil is req'd.
This thread was discussed between 21/09/2006 and 30/09/2006
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