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DB18/2 low compression

Mark Bullen
Posts: 109
Joined: Mon Feb 15, 2016 1:07 pm
Location: Wiltshire

Re: DB18/2 low compression

Post by Mark Bullen »

Rebuild continues, head is on and torqued down. Went to refit the rockers and found zero clearance on the tappet adjuster. I measured the head in situ (wish I'd done it on the bench) at 103.4mm, does anyone know how thick it should be? My concern is that having had 10 thou skimmed from it that it might have been skimmed before and thus might need packers/shim under the rocker pedestals to gain back the clearance.
The other fear is valve clearance to piston could then be an issue

Help please, I was planning to run it this weekend

Peter Grant
Posts: 324
Joined: Thu Mar 10, 2016 10:02 pm
Location: Sydney, Australia

Re: DB18/2 low compression

Post by Peter Grant »

Double up the head gasket perhaps?
Peter Grant

Mark Bullen
Posts: 109
Joined: Mon Feb 15, 2016 1:07 pm
Location: Wiltshire

Re: DB18/2 low compression

Post by Mark Bullen »

I am happy to report success. A head gasket change is probably small beer to a professional but not having worked on big jobs on cars for about 30 years there was plenty of trepidation. With the help of this forum, some great friends, neigbours, local garage, suppliers who delivered quickly and thinking through problems without the pressure of needing to use the car for work, i was able to start the engine, get it hot, retorque the head and drive. The retorquing was a bit nerve racking and amazing how much some of the bolts had relaxed. Now to get some miles added and a retorque again. If anyone needs a head skimming in Wiltshire I am happy to recommend someone. Also good delivery from David Beales and ba-bolts.co.uk.

What it has confirmed is that there is plenty to do on rocker faces, cam and folllowers, all for another day.

PS if anyone would like some silt I emptied plenty into the garden.

Db n j
Helpful Person
Helpful Person
Posts: 430
Joined: Sun Mar 13, 2016 8:55 am
Location: uk shropshire

Re: DB18/2 low compression

Post by Db n j »

Well done Mark. Sounds like a win.

How did you resolve the rocker height problem?

For the long term, start collecting now. New camshafts are available, cam followers can be found in good nick. Rockers do wear, so make sure the oil feed is working well (via the pipe on the side of the engine). Again look out for a better second hand rocker assy.

Time is your friend in this case.

Regards db

Mark Bullen
Posts: 109
Joined: Mon Feb 15, 2016 1:07 pm
Location: Wiltshire

Re: DB18/2 low compression

Post by Mark Bullen »

I realised the height of the rockers problem was my poor recollection of the last time I rebuilt them. It was all ok when I applied engineering logic. I've got oil flow to the rockers, it flows quite nicely so that is good. The wear on the pads is quite bad so I suspect oil flow hasn't always been good.

Collecting parts is a good idea although I hadn't imagined that they would be readily available. Ideally I would like to keep the original parts and have them reground/reprofiled but any sources of cam, followers and rocker arms gratefully received.

Thanks again

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