2.5 litre engine anomalies

(Ed Nantes) #41

They ae but the drive dog is a separate part, can be installed and new ones are available here.

(Peter Scott) #42

If you do want a lip seal at the rear I don’t think you need to make your own as I suspect the Triumph Herald part fits. It may be that the chain case also fits although I don’t know if these seals operate on plain sections of the shaft.


(peter balls) #43

The stem seal shown is 4 point 2 jaguar John. (see what I did there)
If your head gasket is/was composite and you intend to use a copper joint, be aware of piston crown/head
clearance. If to tight this can result in piston/head contact signald as heavy tappet noise 2000/2500 RPM
upwards. Dennis Foxley posed this tappet noise problem in Jaguar Driver 15/16 yrs ago, I suggested
a cause/remedy but am unaware of a result. Approx 1999 I fitted a recon engine (not by me) to a `37 2 1/2
First road test revealed said problem. After much head scratching/tappet ajustment I removed the head
revealing the cause. Clamping the head on a mill bed I removed approx 1mm llocal to each bore using a
ajustable cutter, problem solved.
Re cam followers, These are two part, check for hairline cracks where the pushrod seat enters the stem of
the follower.
As has been opined the drillings in the follower blocks are a carryover from sidevalve days.
Perhaps this practlce ceased when Jaguar took possesion of the Standard production machinery
post war
Peter B

(John Mellor) #44

After stripping, cleaning and inspection my rocker gear today and taking on board all the advice offered, I now understand the wick situation.
My rocker gear was found to be in a servicable condition generally, except for having 12 blocked oil feeds to the valve pad areas and also wear to valve contact pads, no doubt caused by the lack of a direct oil supply.
I will drill out what is left of the wicks and probably follow Peter B’s approach but without the valve stem seals, or would this lead to an oil burning problem?. If so, it would be relatively easy to re-fit the wick at a later date. All my vlave guide clearances are good.
The pushrod section from one of my tappets was found to be a loose fit Peter but I could see no evidence of any cracks in these areas but I’m quite sure I could find a method of re-fitting it or would it be wise to replace the whole tappet?
My original head gasket was the shim type Peter so I do not anticipate any problems here and there was no evidence of any piston to head contact. I assume the noise at 2500 rpm was due to a combination of temperature and con rod stretch but hopefully no damage to the upper big end brg’s.
I contacted Jaguar Heritage Trust Roger and they said they no longer supply the DVD’s but suggested I contact Original Technical Publications over there in the States and I checked out their website earlier. There are asking $86.00 + post and tax for their download title “SS & Jaguar Saloons 1936-1961”. which would be acceptable if I could be sure that it was good value?
Sorry about the mix up over the dizzy Rob but I will probably stick with the one I have for now and cross that bridge…



(Peter Scott) #45

If you clean out the wick passages but don’t fit new wicks you may find your oil pressure is marginal as you will get quite substantial flow down each push rod.


(Roger McWilliams) #46

John, since it looks like JDHT no longer supports the parts and service manual files, I can share the parts and service manuals with you via Google Drive if you like. My best estimate is these files no longer are copyright protected. Send an email to me at mcw3141 at gmail dot com and I will link you to the files which comprise about 222 MB in portable document file (PDF) form. It is quite useful to have a set of the manuals which cover a range of the vehicles. For example, while I focus on the Mark V cars, I use the earlier and later manuals where insights and parts were shared.

(peter balls) #47

John I do not advise no wicks and no stem seals, without one or the other the engine will likely
smoke like a steam engine. I omit the wicks prefering a good supply of oil to the rocker/valve stem
contact point. No wicks might affect oil pressure marginaly at idle, but no adverse effect on my engine.
Re the cam follower/pushrod seat, loctite methinks.
Peter B.

(John Mellor) #48

Thank you Peter S and B for the good advice about replacing the wicks. I have taken it on board and I will try to get my hands on some. I drilled the old ones out and you won’t be surprised to hear that they had become completly solidified. Why on earth didn’t they just make the hole a little smaller? Although they too would probably become blocked eventually. I am a believer in regular oil changes using a can of flushing oil in the process, which would certainly help prevents this sort of problem.

Thank you for the very kind offer to provide me with the Technical Data Roger. I will be in touch shortly. I cannot understand why JHT dont have them.


(Ed Nantes) #49

The wicks act like a little oil filter
Over 70 years the oil has passed through them and exactly like a felt elementin your oil filter, they have removed the solids out. And saved them for you.

The sockets have sometimes been found to be loose. Normally in operation they are under compression, so can’t go anywhere. When removinga push rod, it’s another story. I was told to always giv the rod a twist when lifting it to break the suction. I know there are occasional sumps with sockets at the bottom.

New cam followers are available. If you are only replacing individual followers , check that you are buying the 2 piece ones, Some repros were made solid , for economy , but this makes them heavier… Original style 2 piece are available.

(Peter Scott) #50

If you search for felt suppliers I think you will be able to find small square section of about 3mm cross section. This is what is used.


(peter balls) #51

Ed , you state that the followers shoud have a convex face of appro 2 thou to aid rotation.
As we know the followers are offset to the cam lobes, therefore the offset and the convex
face places the contact point, cam lobe to follower, more to the center line of the follower
perhaps not aiding rotation. On the other hand a concave face to the follower will place
the contact point closer to the periphery of the follower, aiding rotation.
My followers are ground flat, I reason that the offset twixt follower and cam lobe will
rotate the former. Your thoughts.
Peter B

(Ed Nantes) #52

Well I can’t claim personal expertise on cams and the like. But the people who do cams for a day job, have equipment to put the curvature on them, and from memory this was the original spec.

So I take advice and have mine done. But i suppose you could have them flat and se how it works out. It would probably take a bit of mileage to determine the effectiveness.

(peter balls) #53

Me to Ed, I claim no expertise re cam gear, my comments stem from thought and observation.
Logically one would conclude that, if the followers are angled the cam lobe apexes
require a companion linear angle. I ran this past Kent Cams and their opinion was that
the SS cam lobes have no linear angle. Perhaps someone with the required expertise
will lay it down.
Peter B.