Bosch gets all the credit.
Bosch Gets the credit, It said so on the box. lol
Well, for starters Land Rover didn’t design the engine, Buick did.
Land Rover bought a engine design and dies from Buick years ago. Buick Engineers, From who I have talked to, retired now, said the Buick engineering was disappointed in the design falling short of their goals, and that the engine was very difficult in passing emission test. Too numerous modifications were necessary to alleviate longevity issues and the emission problems, so selling the design and dies seemed attractive to Buick, since some of the key issues have to do with the original design and how long ago that really was.
External engine design issues:
# 1 Crankcase ventilation. Or positive crankcase ventilation { pcv } system. First of all there are no check valves in this system. Should the engine backfire, it will pressurize the crankcase. So I placed check valves in the system.
2nd The pcv system is all pretty much at the same level as the pressure differential source…. Aka…vaccum, and all land rovers I’ve seen have an oily residue in the hoses, leading to the intake. Oil going down the intake is not a good idea. Oil when compressed quickly can ignite far before the plugs fire to light the mixture in the combustion chambers before their predetermined time. This is somewhat how a diesel engine runs, not gasoline. Oil, yes oil can cause the timing of your ignition system to change and become more advanced. This not only kills horsepower, but causes detonation. This kills valves, seats and pistons & rings, and is one of the Achilles heals of the land rover longevity designs. I heavily modified this system, after seeing all land rover rear tailpipes oily black inside…………… I found a good cure was to drill and thread a hole in the oil pan for a ¼” npt ****** with a male 3/8” hose barb on the other end. A 3/8” hose goes from the oil pan to the bottom of a filtered reservoir, which both valve cover hoses tee into. On the top part of the box above the filter, is the line that goes to the intake plenum.
This helps a lot, and aids in cleaning up tail pipe issues. The filter system does need to be replaced periodically, it gets oil soaked.
Exhaust gas flow: pure and simple, the more bends and the more restrictions, the less flow. In back pressure, pipe size, and volumetric efficiency
aid in cylinder scavenging properties. In modifying this unit, you have to know your physics, or leave it to the aftermarket people who design these systems. Porting in the wrong place will cost you horsepower. I’ll have to admit, after opening the manifolds, and a few modifications here and there, I prefer the stock system, It’s well thought out, and a little porting, and a baffle, and it really flows well without that tinty sound of headers. I not only ported the manifolds, but I flowed both sides with the heads on so they match. The baffle placed between all head exhaust ports and exhaust manifold ports aids in cylinder scavenging properties.
The plenum………….. I tried and tried to get the runners to match, got close but there is room for improvement on design here. I don’t know of a fix here without throwing the original one away and starting over.
On the flow meter, I got a few really close, but a couple are off. I’d like to see each port balanced, but not with this design. There’s some turbulence issues in the plenum, they’re not horrendous, but not balanced. And balancing it is tricky!
Exhaust valves: I’m not running Land rover valves. I’m using stellite seats and sodium filled valves. Exhausts have rotators on them.
Intake seat pressure is 90 lbs same with exhaust . At .450” lift the intake is at around 200 lbs and the exhaust is at around 240 lbs for the extra weight of the rotators. The rocker assembly was modified to contact the valves properly.
Push rods, I’m using fully adjustable pushrods, all seated @ + .040” deep into hydraulic lifter. I replaced all lifters.
Cylinder liners: I replaced them all. When I rebuilt my wife’s engine I replaced the liners……….. About $80.00 per bore to eliminate the old liner and $90.00 per liner plus another $60.00 per liner to trim the bottom to fit and install. It costs around $1,900.00 just to change the liners. I feel it was worth every dime. No problems and we are getting around 16 m.p.g. we fitted the new steel liners and kept the bore to use the old pistons that only had 29,000 miles on them. I know it’s expensive, but it is the ultimate cure for dissimilar materials in this environment.
Surface tension of oil:
When I bought the land rover repair manual, I shook my head and said why ?
Main crankshaft clearances = +/- .0004” - .0009” . These bearings spend their whole life trying to spin in the journals. I’d be afraid to put anything thicker than 5-20 wt oil in it. It’s a little too tight for good sense, and costs horsepower. Surface tension of oil becomes a serious issue when all you have is .0002” clearance on each side. I opened all bearings, mains and rods to .0018” or .0009” on each side……….. It spun sooooooo sweet when I finished.
Head gaskets procedure:
I took a good look
how the head gasket is designed and it comes with a sticky adhesive on the
composite part of the gasket. This will work beautiful if both surfaces are left
perfectly dry, and free of oil, i.e. lacquer thinner. Use NO OIL PERIOD on the head bolts, You’ll regret it if you do. You see the oil you put on the threads, like the book tells us to, will push off the threads as you thread it into the threads of the block and it
gets between the block and head pushing into the gasket areas ruining the effects of
the adhesive on the gasket, Oil and adhesive isn't usually a good combination......
What I did and this works well, I put only 2 layers of Teflon Tape on the threads of the new head bolts and a small amount of grease just under The bolt head. What this does is not let the bolt head gall into the heads and lubes The threads into the block without any oil. I believe this is an area where a lot of people have got themselves into trouble, and they followed the book. This would probably cause gasket failure in a few thousand Miles or so, and would probably be blamed on the mechanic or machinist, when it is A procedure problem. Use the Teflon tape on the bolts, it runs in nicely and life Is good.
Remember, Torque in the sequence the book tells you to follow at 15 ft lbs, then turn 90 degrees more repeating the same sequence, then an additional 90 degrees more repeating the same sequence completes this task.
This is a few of the modifications I did. Oh I almost forgot, I used the new Bosch Iridium plugs. It said on the box, guaranteed better performance and mileage………. So I guess they get the credit. Lol
So far 3900 on the engine......... still the same mileage.
either that or the man at the shell station needs to re-calibrate his pumps.
Chongo
