D1 GEMS oil pressure, oil pan reseal, front cover

JohnnoK

Well-known member
Mar 19, 2017
180
17
Cape Town, South Africa
Have a good look at the oil pick-up tube where it bolts to the block as a possibly not correctly tightened leak source, too.
If I recall, the half moon cover on the bell housing does have some sort of a strip across the top, but a bead of mechanic's sealant will probably suffice.

Don't use a silicone that smells of vinegar, they are liable to cause corrosion issues, get a sealant like Reinzosil or similar.
For the sump, run a bead on the inboard edge of the bolt holes and let it start to set off until it is touch dry before fitting the sump. A smear of sealant on the block face immediately before installation should ensure it all stays dry.
 
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jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
Waiting for parts, looking at the details. This is the end of the pressure feed oil hose exiting the pump and heading to the radiator oil cooler. I replaced these not too long ago, the old hoses were leaking. I am pretty confident this is the correct type for my truck. I see now that I have things apart, the end of this hose is blanked off and the tiny o-ring actually blanks up an oilway. That is sure an odd and frankly stupid way to do it, rather than threading a plug in there. I wonder now if the o-ring is the proper size and if it was leaking, if it might have contributed to pressure problems. I don't have a way to measure the ID of the bore way down inside the front cover. I guess I'll try fitting a few different OD o-rings down there and see if I can confirm if I've got the right one. I never quite trust aftermarket parts anymore but in this case it was the only game in town.

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jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
Still waiting on parts for this project, I ordered an intake manifold gasket set. There is a little leak looks like from the valley gasket running under the right side cylinder head. I am also going to drop the exhaust Y pipe out to get a crack welded up. So that means it's only a little more work to pull the heads...

Has anyone ever port matched the intake, exhaust and heads? I won't be in this deep again for a while so sort of pondering getting it done. If I could pick up 15-20 horsepower I would be super happy with this old girl. From what I've read the ports on these things are very badly misaligned.
 

Flyfish

Well-known member
Oct 29, 2004
1,026
69
49
St. Louis
.
Has anyone ever port matched the intake, exhaust and heads? I won't be in this deep again for a while so sort of pondering getting it done. If I could pick up 15-20 horsepower I would be super happy with this old girl. From what I've read the ports on these things are very badly misaligned.

I would say it might not be worth the cost with the stock exhaust manifolds choking things off. And not many alternatives out there. Headers etc...
 
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jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
Well as usual this project is taking on a life of its own! I had a long wait for a new "NOS" harmonic balancer and crankshaft key from England. John Craddock checked in with photos of the balancer before shipping, it was on a shelf for a long time! But clearly never used. A bit of cleaning up followed by some black high temp paint and a quick polish up of the seal surface has it looking good. Likewise the old rusty oil pan is all cleaned up with new paint and ready to go back on.

The job of the weekend was getting the mangled crank key out of its slot. I ended up carefully slicing it down the middle using a cutoff wheel in my Dremel tool, pinched it together and punched it free without damage to the crank.

Now that I'm in this deep, I've taken off the exhaust Y pipe to have a crack at the right side manifold flange welded up. I'm glad I did, the crack is huge and explains why the V8 has always sounded like crap! That job was made a little easier thanks to the oil pan being out of the way.

Speaking of access, now that the Y pipe is on the floor, it will be easy to change the transmission mounts which are past their prime, and exchange the front transfer case output seal which is puking all over the gearbox.

I also have a new set of (aftermarket) timing sprockets and chain, the old ones I believe were renewed along with the rest of the engine, but there's a bit of play in the chain. I think that's normal but while I'm in here...

I checked in with the PO who reported not having changed the rocker assemblies. I can't believe they aren't original then, and must be far past their prime and probably costing some power and oil pressure, if not puking metal into the oil. I'll take a look since the valve covers could use resealing anyway. Looking around it appears Britpart is the only game in town besides $800+ Land Rover branded parts. Britpart does not appear to have a quality product here judging by quite a few complaints in the forums. Is there some other alternative? I see some fancy roller rockers, but those require different valve covers which is a no-go on the GEMS engine.
 

jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
With regard to the rockers, most of the complaints seem to be around the aluminum ones having issues with the pressed in steel inserts on the pushrod end either breaking up or squeaking due to lubrication issues. I wonder if the steel arms which are also available would be a better alternative along with new shafts.
 

jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
I have been chipping away at the old girl. I was happy to remove the valve covers to change seals and inspect the rockers, and find them in perfect condition with no wear evident at all. I asked the original owner and he reports always having changed the oil at short intervals, and he switched to synthetic oil "back in the day" when it became commonly available. Clearly that pays off, and I'm happy to not need to replace things with aftermarket junk, or pay up for the expensive Land Rover parts.

Things are coming together now, I've sent out the injectors for service, repainted them along with the fuel rail which was looking a little haggard, and got the intake reinstalled with proper gaskets and sealant. I also peeled back and replaced all the perished tape on the engine wire harness. Everything looks a lot tidier.

Meantime the Y pipe has been out for welding a crack under the flange, and I had the shop weld it on the inside too. Then I was able to match port it to the manifolds and eliminate the awful exposed tubing section, although there's another one of those where the downpipe meets the collector, which I can't reach. I also match ported the manifolds to the gaskets, taking off 2-3mm almost all around every port and blending them in, but found that the head ports already lined up fine to the gaskets. I hope this will give a little bump to power, everything was so badly aligned that it HAS to help. Manifolds got several coats of high temp ceramic paint, we'll see if it holds up. For now they look new. I filed the Y pipe flanges flat and put in a new stud kit in the manifolds so I hopefully do not have to cuss at them anytime in the near future.

The intakes needed some cleaning up too, but I was reluctant to grind on the heads in situ and did not want to remove them. A project for a rainy day in the future, perhaps. If the exhaust porting makes a noticeable difference, I might strip off the top end next time she needs a coolant change, take the heads out for a good look over and maybe even have a shop port and flow the whole intake side for me.

New heater hoses going in along with new stainless proper Norma/Gemi clamps. The good stuff!

I stripped back the aluminized heat shielding on the fuel feed and return hoses. The original hoses are making me nervous due to age, but there does not appear to be a way to easily replace them given they are made with special fittings and factory ones are NLA. But the hoses are in great shape externally. Another rainy day future project, I'll strip these out one day and take them to a hose shop to get new ones made out of braided stainless. They really should be replaced, as should the stub hose by the pressure regulator, but honestly I have become shy about swapping even such things as hoses when the old ones look so good. Not even the best quality rubber, including fuel line, seems to hold up very well anymore. I have some aftermarket heat shield material to put back on the fuel hoses as well, and a new steering shaft heat cover is coming since the original one is really making things look bad under the hood now that all else is looking better!

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jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
Getting close to the end now, but I have a question for the group. I replaced the engine oil cooler hoses some time back. The new ones were installed the same as the old ones, oil pump output (port facing down toward the ground) connected to the lower radiator port, return hose (side of front cover) connected to the top radiator port.

I always had a long wait for oil pressure on cold startup, despite using Land Rover branded or other high quality (Mann/Mahle) oil filters. Since there is no non-return valve in the oil hoses and I do not believe the original hoses had this feature either, it makes me wonder if the oil wasn't draining back to the sump via the oil pump, since the pump output went to the bottom of the radiator instead of the top. I did find the below diagram which suggests my hoses are/were connected up properly, however. Perhaps this issue will be resolved after all the work I'm doing, but I didn't pinpoint any problem in particular that would account for it.

It does appear, though, that connecting the return pipe to the lower radiator port would serve as a non-return valve on its own, since the oil would not be able to drain back under gravity via that path.

What is the wisdom here?

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discostew

Well-known member
Sep 14, 2010
6,372
476
Northern Illinois
Really nice truck, btw!

Many people suggest to pack the pump with Vaseline or similar so you don’t have any priming issues. Just figured I would mention it.

I always do this. When it was Buicks engine thats what they recommended. You don't have to pack it, just some grease in there to seal up those two metal parts. It helps it get primed faster.

While you have the pan off maybe pull down a main cap and have a look at the bearing and the surface of the crank. A good rule of thumb is if you can feel the grooves with your finger nail when you scrape it across the surface, it needs to be fixed. Crank at least polished new bearings fitted with good tight clearances. If you crank is screwed I would get a 4.6 crank and go that route.

That's a great looking truck. Put some tires on it would you? I recommend the BF Goodrich commercial T/A traction.
 

jetpoweredmonkey

Active member
Oct 19, 2018
28
11
Sacramento, California
Thanks discostew, yeah I did pack the pump with assembly grease. And yeah, she came with a set of brand new Michelin Defenders, very nice quiet road tires that absolutely wear like iron. They are getting down to the wear bars now and she will likely get a set of BFG ATs next.

I got her all together and fired up tonight! Fired on the first try after cranking a while with the fuel pump fuse pulled to build oil pressure. Had a leak from one of the oil cooler fittings that just needed another 1/4 turn, and the throttle body heater gizmo lost one of its spigots which had to be tapped back into place with sealant. Otherwise she's dry, zero issues and sounds GREAT! Like a new motor. No rattles, no taps, no gritty noises up front...between the old clapped out belt tensioner and the exhaust leak, she was sounding pretty tired.

Yesterday I slogged through renewing all the motor mounts with OEM ones, man did that ever pay off. Much smoother off the line, no more chatter, and the whole drivetrain feels like it's cushioned by velvet now. Very nice.

Here is my idle oil pressure after a 20 minute drive, oil gauge strapped to the front bumper! I used a sandwich fitting for a take-off between the filter and front cover. She seems to max out around 30PSI which I believe is about right. I am really happy, it was a lot of effort but I think she is good to go until it's time to renew the cam in another 50-60K miles or more, and I won't dread that job one bit, now that I now how to get in and out. I also probably saved myself $5K of shop labor, but of course I do feel it in my bones!

I did end up connecting up the pressure side of the pump to the top fitting on the radiator, and so far I want to say she gets oil pressure quicker than before. Time will tell.

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