Early TR4 Rocker Cover

CT1547 (engine CT1639E) has the rocker cover without the brass plug.

To make this conversation even more interesting, note that the first edition of the TR4 SPC lists only rocker cover 302610, which is the exact same rocker cover fitted to TR3’s after engine TS18230E. I do not recall ever seeing any photographic evidence of this, but I suppose the possibility could exist and this is mentioned by Bill Piggott on page 202 of The Collector’s Originality Guide TR2-TR8.

gary

There was an early TR4 for sale on e-bay a few weks ago, CT4736L.  It has a brass plug on the rocker cover.  I believe that perhaps only the very early TR4's were w/o the plug?????
Darrell

My former TR3B very close to Darrell's, TCF 2654 L, with its original 2138cc TR4 engine, also had the brass plug in the rocker cover.

It's odd that TR3A rocker cover 302610 is listed in the SPC for TR4 engines, as the oil filler was moved down the back on the TR4 for bonnet clearance.

Happy New Year to all,

Viv.

I have a brass plug on CT611L, w/ the correct engine number (which escapes me right now).
Mark

I need to check the engine number, but I recently acquired an early style TR4 cover along with a disassembled engine and the cover doesn't have the brass plug.  I'd be very surprised if the commission number was earlier than what Mark notes.

I think the SPC (first edition) is in error on the TR3 rocker cover. I have looked through my entire library and the web for any photos of an early TR4 with the TR3 rocker cover and the only photo or illustration I found was the lubrication chart in the TR4 glovebox Owner’s Manual.

The SPC calls the brass plug a Breather Pipe Adaptor Plug applicable after engine CT14234E. Due to the apparent scarcity of the non-plug rocker cover (in the US), I really doubt that this is entirely accurate. The plugged rocker cover must have been available much sooner as evidenced by Marks’ early TR4.

In 1961 California passed an emissions law requiring 1962 model year cars to have a PVC valve installed to control emissions (although it was not 100% mandatory until the 1963 model year). New York passed a similar law in 1962. PVC valves were typically installed on the top side of the rocker cover, which seems to be what our plugged rocker covers were designed for.  So the two questions I have are: 1) Were the plugged rocker covers meant only for the US market, making the un-plugged covers more common in the UK?, and 2):  Is there any evidence that a PVC valve was used on the early TR4’s, especially in California?

 
gary

I have the brass plug on my '62 TR4, #3559, engine #CT3147.

Rich W

I still haven't check the block number I have, but I think Gary's note is fitting with the other pile of parts I acquired with my engine and valve cover - included was a domed speedometer, km/h version - likely not from a US bound car originally.

There is a 1964 TR4, CT16824L, posted on e-bay currently that has a Rocker cover without the brass plug.  Item # 130479882294.  Nice CA, Wedgewood Blue one!  Dang, I wish I could have them all. Everything else looks sort of real.  Is this one of those "Just because it's on the car doesn't mean it is  original?"  It has a long neck radiator as well which goes against the TRA judging guidlines on that component. More on that later.

Darrell

I have the brass plug on both CT 3995 L and TCF 839 L.
John

For what it's worth, here's my thought on this subject.

The Vanguard Vignale and Ensign Deluxe were the only two Standard-Triumph cars that used the 4 cylinder TR engine during this time period and both of these had different rocker covers, although I believe that some late Sportsman models used the same chrome cover. The TR engine was also used in the Morgan Plus 4 and Peerless at this time, but it is unlikely that S-T would go through the expense to manufacture a different rocker cover for the competition.

The brass plug was likely meant in anticipation of the 1961 law enacted in California requiring a PVC valve to be fitted. This requirement was followed by New York in 1962 and by 1964 became a federal standard. There was a brief period when the standard was strongly encouraged, but with voluntary compliance. The original GM patent was designed to have the PCV valve installed in the rocker cover and through agreement was distributed royalty-free to other manufacturers. It is highly probable that the plug was fitted to valve covers prior to CT14234E for selected anti-smog markets and became standard for all markets at CT14234E until S-T developed their closed circuit breathing which resulted in another valve cover.

Gary

Both of my two early 4's (CT288L and CT611L) have correct engine block numbers and brass plugs in the rocker cover.  What are the chances that both cars needed a rocker cover change at some point?
Mark

Brooklands' "Triumph TR4-TR5-TR250 1961-1968" has reprints of eight articles on the first tests of the TR4, ranging up to July, 1962, including both US and UK tests. There are number of pictures of the rocker covers, and in all the ones taken from the carb side, there is no brass fitting on top. This includes the famous "white car" that was used in the Road & Track and Car and Driver tests, plus in the first ads: it clearly does not have the brass fitting. There are a number of pictures taken from the oil filter side, and these are ambiguous: there may be a brass fitting, but it's difficult to tell. David Phipps' road test for Canada Track and Traffic (September 1961) clearly shows the lack of the brass fitting, while John Blundsden's for Motor Racing (October 1961) may have it, but it's difficult to tell. On the basis of this evidence, I would submit that either type - with the brass fitting or naked - is probably correct for early cars. My car, CL2966L, does not have the fitting, but was delivered in Paris with what appear to be US specs. The choice of rocker cover may have depended on the shipping destination.

Although not a TR, I thought the attached photos might be of interest. These are the Engine of a 1951 Triumph Renown with the Vanguard engine. It appears that the initial stamping of the rocker cover is the same as the TR with additional brackets attached. Of interest is that the engine has the center stamped for a threaded banjo fitting. I don't know the purpose of this fitting, but it does indicate that the stamping for the rocker cover with the brass plug existed as early as 1951.

Gary