240 head removal

Throttleton

Well-Known Forum User
Seeing as this is a forum and as such a source of info

That is why I haven't rung you up (yet!) Steve.
I was hoping by the end of this thread other novices would not feel too out of their depth to have a go at rebuilding an L series engine.
If you and others with the knowledge can share your information on here it gives the forum a 'point' don't you think??
'Trade secrets' and other info you have gathered over time at your own time and expense is another matter........
Putting you on the spot now.....
Do you think the oscillating tool you mentioned used correctly will be as good,better or worse than an engineering shop would achieve??
The cnc set up is too extreme for what I hope to achieve and probably too costly though I am only guessing. My target is a well built engine and increase the power to weight ratio through obvious means.
 

SKiddell

Well-Known Forum User
Firstly we need to differentiate between cutting the seats and lapping them

Seat cutting can be done with a vertical bore/mill using a Serdi tool etc
Final finish lapped using paste, this is often done with the tool shown
This is the most common route as "generic" engineering shops try to use multipurpose machines to do multiple tasks (cost effective)

A multi axis CNC solution is mainly used to produce complex 3D profiles but a variant of this is a CNC valve seat machine such as a Rottler or Newen these will do the entire thing from start to finish with exceptional accuracy

If you take your cylinder head to a specialist then there is every chance they will use the latter and often advise to install new seats as matter of course ranging £15-£30 per seat

Its horse for courses really, will a home valve job be as good as a CNC job....no of course not, will it be good enough for a modest street engine of course it will, after all, its all we had before all this CNC malarky.
 
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SKiddell

Well-Known Forum User
If you want to "borrow" a mechanical lapping tool, I have an old one somewhere (in Petes garage I think, unless he has sold it :p) PM me your address.....it will cost tea and biscuits when I come to collect my doors etc.
 

Throttleton

Well-Known Forum User
If you have one Steve please bring it up when you collect your parts.
I fear it is the 'practice' of doing such a job and not just having the right tools though to make a decent job:eek:

Having said that show me once........
 

Huw

Club Member
If you do most off the work yourself I reckon the bill will be hundreds rather than thousands for sure.
I'll keep you posted.....

Some good advise on this thread. I will be doing most of the work myself, except the hot tank and honing. Have the ' How to rebuild your Nissan Datsun OHC engine' and I only want to return the engine to as good as condition plus dont intend to do more than normal road use when done. So let the fun begin!
 

Throttleton

Well-Known Forum User
Yeah I got one of those, doesn't matter how much I cleaned the valve the sucker wouldn't stay stuck.
Chucked it in a paddy in the end.........
 
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