Please visit the Club's website https://www.dloc.org.uk/ to join. Visit https://www.dloc.org.uk/adhoc to DONATE towards the cost of the forum.
Please don't post someone's email address to avoid it being harvested by spambots and it's against GDPR regulations.
Always look at "ACTIVE TOPICS" to see all posts in date & time order as they are sometimes moved; or look at "Your Posts".
Please add Reg. nrs. when posting a photo or anything about a car as this will help searches. Don't add punctuation next to nr. as this negates search.
CHANGED YOUR EMAIL ADDRESS since registering?, click your username and check your address in User Control Panel, Profile, Account Settings.
If you want help to register, use "contact us" at page bottom for help.

DB18 Rocker Shaft Lubrication

bakergh
Posts: 109
Joined: Wed Feb 24, 2016 1:57 pm
Location: New Forest, Hampshire

Re: DB18 Rocker Shaft Lubrication

Post by bakergh »

The pedestals are held to the cylinder head by two studs per pedestal, The two nuts locked with tabs on top of each pedestal are what you would need to remove to release the rocker shaft assembly.
Graham

qantasqf1
Posts: 299
Joined: Mon Mar 07, 2016 10:13 pm

Re: DB18 Rocker Shaft Lubrication

Post by qantasqf1 »

Chris, all you need to do to remove the entire rocker and shaft assembly from the head is to undo the 2 nuts of each pedestal and simply lift it off. The bolts don’t need to be disturbed unless you’re planning to remove the rocker arms from the rocker shaft. As I said earlier, undo the nuts evenly.
Steve

clevitt
Posts: 184
Joined: Wed May 18, 2016 1:02 pm
Location: West Hertfordshire

Re: DB18 Rocker Shaft Lubrication

Post by clevitt »

Thanks Steve, this morning’s visit to the plumbers merchant was not fruitful except that they thought that similar small bore fittings were used in Agas. I don’t think you have Agas in Australia— they are old fashioned cooking ranges traditionally found in farmhouses. So while I research that avenue, I have taken off the rocker assembly and was pleased to find that the hole was clear and when I pumped oil into the cylinder head entry orifice, lots of oil appeared from that hole. I will check the rest of the assembly tomorrow. Could you recommend a torque figure for when I tighten those pedestals nuts.
Chris

clevitt
Posts: 184
Joined: Wed May 18, 2016 1:02 pm
Location: West Hertfordshire

Re: DB18 Rocker Shaft Lubrication

Post by clevitt »

I have manged to re-install the oil feed pipe by swapping over the compression nuts at each end of the pipe. This entailed first removing the olives, so they have suffered further damage and the leak from the top end elbow has worsened. I started the engine and after a minute or so, saw oil emerging from the rearmost rocker hole and from the frontmost rocker after a further minute. This vindicates Graham's suggestion of piston slap as the source of the knock, and I need to drive the car more gently until the engine is fully warmed up.
I now need to address the oil leak with a more permanent solution; this is taking me into a world of pneumatic/hydraulic fittings. I was able to find some new olives with an ID of 3/16" to match the OD of the pipe, but they are twice the length of the old olives and the compression nuts do not have enough depth to accept them. The elbow has a 5/16" BSF thread at the cylinder head end, but I can't identify the thread at the end that sits vertically. It measures 290 thou OD and about 28 tpi, the closest match is 1/16" BSP, but that seems to be a standard that is rarely used and therefore very few fittings are available.
Interested to hear if anybody has had problems with this pipe and how they achieved a solution. Was an external oil feed pipe common to other engines of the period in order to provide rocker shaft lubrication?
Chris

NickDeAth
Helpful Person
Helpful Person
Posts: 473
Joined: Mon Feb 15, 2016 8:41 pm
Location: South Essex

Re: DB18 Rocker Shaft Lubrication

Post by NickDeAth »

Hello Chris , have you tried taking the parts you need into your local hydraulic hose supplier and see what they can come up with?

Regards Nick
"Nick - do you think you will ever put that old car back together again?"

clevitt
Posts: 184
Joined: Wed May 18, 2016 1:02 pm
Location: West Hertfordshire

Re: DB18 Rocker Shaft Lubrication

Post by clevitt »

Thanks Nick, they didn't have anything that small, but suggested that such fittings might be used in fuel pipe applications. That, and a similar comment from the local plumbers merchant led to a call to the heating engineer that maintained our oil fired Aga when we lived in a house that had one fitted. He is old school and still looks after our 30 year old Potterton boiler, but couldn't find anything suitable in his box of bits and pieces. I then turned to online research, which led to Wade engineering, who make a wide range of compression fittings and have an informative online catalogue. Thence to a pneumatics supplier, from whom I obtained those 3/16" olives.
My plan now is to change both ends of the oil feeder pipe to 1/8" BSPP ( Parallel rather than Taper thread) fittings, which are readily obtainable, and then get the thread on the end of the adapters (elbow at the top, straight at the bottom) that connect to the block/head recut to 5/16" BSF.
Update to follow later this month-- I'm aiming for Drive It Day ;)
Chris

NickDeAth
Helpful Person
Helpful Person
Posts: 473
Joined: Mon Feb 15, 2016 8:41 pm
Location: South Essex

Re: DB18 Rocker Shaft Lubrication

Post by NickDeAth »

I hope it all turns out well.

Nick
"Nick - do you think you will ever put that old car back together again?"

clevitt
Posts: 184
Joined: Wed May 18, 2016 1:02 pm
Location: West Hertfordshire

Re: DB18 Rocker Shaft Lubrication

Post by clevitt »

I finally sorted out the leaking oil feed pipe yesterday; the first delay was due to poor quality fittings that would not accept a recut to a 5/16 BSF thread on the engine side of the fitting. Changing to stainless steel solved that, but after a test re-assembly it was still leaking, particlarly from the top end, where the new olives were unable to crimp down on the old pipe well enough to seal properly. I then commissioned a new pipe using 3/16 copper brake pipe, and the pipe is now leak free :)
If any forum members need more details, please feel free to email me.
Chris

Post Reply