Shrapnel in Exhaust Valve Inspection Cap?
- Thread starter Rob H
- Start date
As those two little weeny holes are blanked of by the tappet clearance and spring pressure.
Ask Bill Easter how many miles he has on a pair of heads done back in 1987 ? I had to put some new guides in after 125,000 miles and that was maybe 15 years ago. Oh, one thing, I don`t put those two little weeny holes in the bush.
Bill Easter is a hero of mine. I remember him dismantling his primary drive inside a motel unit at the 1983 Australian International Rally. My pal AJ, who built up the freakishly good "D" Comet replica had two bearings fail within 200 miles through not having these two holes drilled. I suppose it only shows that all motors are different in terms of how much oil mist is wheezing about internally, and how much clearance within the dark declivities of the gubbins. I respect your knowledge too much, Trevor, to contradict you. I only offer observations, as I am totally unqualified save in my quirkish experience and elephantine memory. Cheers mate.
The amount of time these holes are blanked off is only while the valve is held of its seat no more than the oil feed holes on the cam spindles are blanked off in exactly the same way by each cam shaft. It is more likely that when the top hole in the rocker bush is opened up to suit the ET 100/1 mod that these holes have been burred over. Until the bush assembly is removed, then the cause can be assessed. If Trev is saying these holes are a waist of time, then why did the manufacturers do it in the first place.......The entire valve train from the cams/followers up need as much lubrication as possible. The only reason why I can see that there shouldn't be a lot more oil passed through this area, is because the location of the lower guide is so low in the head, which allows the easy ingress of oil down these guides. Remembering this oil also does most of the lubrication for the cams and followers.
I remember on more then one occasion when stripping engines that had lasted through the 'dark ages' when Vincents were worth SFA some very curious wear patterns on the rocker pivot pins. The part of the pin that at rest met the hole was raised like a pimple above the worn surface of the pin yet the aluminium bush was not excessively worn.also occasionally I found pins that were solid in the bush and the rocker rotated on the pin
Morning Chankly, Can you tell us more about Alan's Problem.
Maybe there are a batch of faulty Rocker bearings out there ?.
Going back to what I said about grinding the rocker arms to get full movement after fitting locking feed bolts, If the arms are not free to move, Could it be that it is Forcing the rocker Pin Downwards ??, It would be easy to see as the wear marks would be on the bottom of the Alloy bearing. Cheers Bill.
Maybe there are a batch of faulty Rocker bearings out there ?.
Going back to what I said about grinding the rocker arms to get full movement after fitting locking feed bolts, If the arms are not free to move, Could it be that it is Forcing the rocker Pin Downwards ??, It would be easy to see as the wear marks would be on the bottom of the Alloy bearing. Cheers Bill.
AJ (Alex) had the bushes made locally by someone unfamiliar with the machine! Correct bushes fitted after second failure, no further drama.
Slide hammer with a rear chain spring link, with tappet removed put one chain link pin through the tappet with a short length of plastic to not damage thread,, the other through a drilled bolt that is then attached to slid hammer and it will come ! never had a failure yet.
bananaman
bananaman
I recently did a little job on a very pretty Black Shadow, the majority of work was well done, but then they go and fit an alloy ideler, the ATD was so slack it beggered belief, the rear brake torque arms both mounted on brake plate pins OK but the clips hadn't been pulled back to lock them ! The rocker blocks had been drilled out to take the captive feed bolts but not fitted just the standard ET/100 (never even had to look up the part number,,I must be a boring old fart) so every thing was slopping around, to get the job done I fitted some old standard rocker blocks inserted 5/16 BSF helicoils and threaded the ET100's for four threads only 2-3 threads of helicoil used, (some one told me that Bob Dunn had used this method). It works but a few hundred miles later the owner was tightening the bolt on top and the tip of the et100 snapped off, on examination the hole inside was too big and too far down, so sent him another threaded ET100 all OK again. When the mod came out in MPH 1965 or 66 I was in the factory so made a set but the holes are well above the 1/4 BSF thread at the bottom as the oil has plenty of space going down the side so can only go down the holes in the block as the nut prevents it dropping onto the rocker and the block is held up tight in the tunnel. That was bloody long winded. Sorry.