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Originally Posted by rqsall
OK, not wanting to hi-jack the "95 SWB smells like coolant thread" ( 95 SWB smells like coolant and blows air bubbles)
I have a couple of questions on replacing my head gaskets. Already posted this on rangerovers.net forum, but haven't got any actual answers there. Seening as the predominant topic here is head gaskets, I figure I'll try my luck here 
Seems like the gasket blew at cylinder 1, between the coolant channel and the combustion chamber. Now I have the choice between going the original route of metal gaskets, or composite ones.
I am aware composite ones cost you a bit of compression, but I'm not worried about that. What I wonder though, is if I need to change anything else if I switch to composite gaskets:
1. Do the pushrods need to be replaced for longer ones, because the composite gasket is thicker, the distance from the camshaft to the rockers is larger? Or does the self adjusting nature of the hydraulic tappets take care of this?
2. Because of the reduced compression is the engine characteristic changed in such a way that the ECU needs to undergo re-chipping?
For completemess, it is a 1991 Vogue (non-US, same as Hunter in the US I believe) with the 3.9 efi engine. (14 head bolts, as opposed to the newer 10 bolt heads), compression ratio is the higher 9.35.
Another thing that puzzles me, is how the coolant flows out of the cylinder head into the intake manifold. According the the shop manual that is how it flows, but I can't see how when I look at the heads.
Thank you very much for any input. |
The difference in compression between the two gaskets is very minor, but if you are concerned, you can have your heads planed. It's always a good idea to have them checked for cracks andflatness anyway, so while they are out, have them take off .012-.015".
The new gaskets are not even punched for the bottom row of holes. Use the new torsion torque head bolts, not your old ones. I don't think LR has yet made a torsion bolt to replace the special one used at the alternator mount.
The hydraulic tappets will adequately compensate for the extremely slight increase in distance. Some purists insist that the rocker arm mount pads on the heads need to be milled down.
Little can be done apart from expensive performance chips, to the 14CUX ecu. Splitting hairs, in my estimation, and little is gained for the money.
I did the 3.9 over in my 110 and did nothing, and never saw the difference. When I built the 4.2 for the truck, I took .025" off the heads (intentionally) and that engine is killer (non stock cam, but standard rockers, flat wound diesel engine valve springs, so no spring pocket milling necessary)
Even though there is a water passage port in the head at the front of the heads, there is only a vent hole in the block, not a true passageway. Water travels to the heads via the ports at the rear of cyls 7 & 8. It then goes into the intake via ports at the corners.
Heres a trivia question: The idea of 14 headbolts is a Land Rover stroke of genius. How many head bolts did the original Buick engine use?
