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Oil Spraying from Rocker Shaft - BJ 8

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DavidThorn

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Having read about excessive oil loss from the rocker shaft I decided to check mine. One rocker (the 4th from the front) is gushing oil out of the top hole to a height of about 6 inches (on tick over). All the others seem fine plenty of oil about but no `gushers`.

Could there be any reason for this ? Presumably its due to excessive wear in the shaft but why only on No 4 ? Is it worth dismantaling or should I just leave it ?
 
Hi David,

What is your oil pressure like, both at idle and running? Depending on engine age, idle oil pressure should be in the range of 20 - 40 psi warm. Running pressure should be 40 - 55 psi warm. Besides the gusher, do you have a lot of oil running from the rocker shaft? You should have some oil dripping from each rocker and some dripping from the top of each pushrod. If you have a single gusher with good oil pressure and oil dripping from each rocker, then you may not need a rebuild.

The excessive wear on a single bushing could be coincedence or could be from an off-center alignment of the rocker with the valve stem. In any case, good oil pressure and good oiling of the rocker shaft might indicate that your rocker shaft can wait for a rebuild.

Mark
 
Hi David, I might equate your rocker shaft problem to that of a set of lawn sprinklers where one of the sprinkler heads has been broken off. That broken one will gush water while the others will just bubble. Consequently, excessive wear in your # 4 rocker may be masking the wear in the others. I would give the shaft a bit of attention .--Fwiw---Keoke
 
Having Rocker Arm Specialists rebuild it is not very expensive and turn around time is only a few days. Give them a call.
 
shorn said:
Having Rocker Arm Specialists rebuild it is not very expensive and turn around time is only a few days. Give them a call.
Click to expand...

Well OK Shorn but David is in the UK!----Keoke- /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
 
You're right Keoke, as usual, but with the current exchange rate, Rocker Arm Sp. might not charge very much at all in Brit pounds. Turn around time and shipping, however, may pose some issues.
 
David

Dismantling is a piece of cake just watch out for the oil feed into the pillar, loosen off / disconnect the connection into the nipple on the head first then undo the the gland into the pillar, otherwise threads will be damaged in the pillar. A new shaft is around ÂŁ22 - ÂŁ25, It may get a little tricky if you need to replace the bushes due to fancy drifts if you read the manuals,havn't done it myself yet but it is on the menue having just had my head converted to unleaded. Complete replacements ready to bolt on and go or yours refurbished - around ÂŁ100 ish.

Bob
 
Thanks for all the info - to start at the top my oil pressure is at the lower end of those given about 23 on tick over and 45 ish on the road.

That said I am aware the engine is worn as there is some blow past from the pistons and that oily smell after a long run, but there again it doesnt use much oil so a bottom end rebuild will probably be on the cards in few years time.

There is oil dribbling from all the other rockers as it should it just that one,and only one is gushing.

I do get a bit of blue smoke (well some time quite a bit) on start up which I attributed worn valve stem seals. I must say I had`nt thought of the fact that one gushing may be disgusing the fact that others would if the pressure was higher.

As I am in the UK I see the price of a new shaft is about ÂŁ20 and each bush about ÂŁ2 so a complete re build may be a winter project. Is the wear likely to be in the shaft or bushes,or both?

Also any tips for fitting the bushes,I dont have a press so is it best to leave that to a professional?
 
Hi David,

If you are rebuilding the rocker shaft assembly yourself, you will need to press out the old bushes, press in new bushes, and then hone the new bushes to give the correct fit to the shaft. This is something normally best left to a machine shop, unless you have your own machine shop (I wish I did...!)

You won't know if you need to change the rocker shaft until you check its diameter with a micrometer or calipers. Rocker Arm Specialist did not need to change my rocker shaft. They hard-chromed it and re-bushed the arms. They did a great job. Too bad the shipping and customs may prohibit you from using them.

Mark
 
DavidThorn said:
There is oil dribbling from all the other rockers as it should it just that one,and only one is gushing.
Click to expand...

There is an internal groove (slot) in the rocker arm bushing. This slot is supposed to be oriented (clocked) so that the groove connects the oil feed hole in the shaft ONLY to the bottom of the rocker & to the pushrod feed hole. It should NOT intersect the top rocker hole.

If the bushing has been incorrectly installed or has turned itself in the rocker arm, the oil feed slot will connect to the hole in the top of the rocker & oil will spurt out. I would carefully inspect the slot in the #4 bushing to see if it intersects the top rocker arm hole.

There have been cases where the top rocker holes have been purposely plugged to compensate for wrong or improperly installed bushings.

It's not too hard to remove the rocker assembly. Loosen the hold down nuts gradually & sequentially so that they all support the spring load as the shaft is released.

As Bob said:
When reassembling, pre-align, make very sure that the oil feed banjo bolt is threaded into the stand far enough to center the feed hole in the rocker shaft BEFORE retightening the hold down bolts. Banjo removed for now. If the stand hole & the rocker shaft hole are the least bit misaligned, the banjo bolt will strip the stand threads before it is all of the way home.

If you decide to remove any pushrods, turn, twist, jiggle them first to break any hydraulic suction. If a cam follower sticks to the end of the push rod, it will be raised out of it's hole & you will need to remove a side cover to get the follower back in it's hole.
Good luck,
D
 
Dave T

For a press you could use a large vice at a push - no pun intended, but they say that the re-installation tool is recessed to hold the end of the split bush to prevent it opening up when pressing it home. I guess that it could be manufactured on a lathe if you have access to one. Or, if John Chatham is still in business, he is over towards Bristol, or Pete Farmer down in Dorset, they may just sort the rocket bushing out for you and you do the rest.

Bob
 
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