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Engine Rebuild: 4.6 components in a 4.0

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Old 05-04-2019, 06:49 PM
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Default Engine Rebuild: 4.6 components in a 4.0




Hello fellow Rovers, I just pulled my engine out of my ‘99 Disco 2 and had my heads/intake manifold sent out to a local shop to get them cleaned up. Currently down to the block and will be replacing the waterpump, power steering pump, Timing Chain, oil pump and installing a 4.6L camshaft, 4.6 crankshaft as well as the 4.6 connecting rods. I have a few questions that I’d like to be resolved prior to going any further:

1: can I run my stock 4.0 pistons with the 4.6 Crank and rods? Are there pros and cons to keeping the 4.0 pistons, or do I have to get the 4.6 pistons? For piston rings, I heard Hastings is the only way to go. Is that accurate?

2: I’ve heard you’re supposed to lubricate the oil pump since it’s going to be dry upon first engine start up, and that Vaseline isn’t good to use. What lubricant should I use instead?

3: is there any other things I should be thinking about replacing now that I’m this far into my rebuild? Any recommended parts?

4: I found some minimal rust in the metal inlet tube that flows coolant into the engine, (mounted on the front, not sure of part number), should I replace, or try to get it cleaned up?

I also am having trouble pulling the injectors out, any advise on how to accomplish this?

Thanks for everyone’s input!
 
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Old 05-06-2019, 10:08 PM
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Subscribed. I have the same set up. 4.0 Coscast block w new top hat sleeves and can bearings, 4.6 con rods, 4.0 pistons, and some re-worked heads. Waiting on a good 4.6 crank to start the build. All my internals have about 30K. Debating whether to buy a new cam and lifters or use the existing Crower. I’ll most likely get new fuel injectors, coil packs, cam, crank, and knock sensors (all original w 237K).
 
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Old 05-06-2019, 10:46 PM
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Will you need the ECM from a 4.6? I would think so to make a setup perform optimally, but I am not certain. I'm confident someone else here will know for sure.
 
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Old 05-06-2019, 11:09 PM
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Every set of hastings rings ive encountered was at the max gap spec out of the box. Id go with any other brand. I think the ones in my 4.6/4.0 combo may even be brit part.

Ive always packed oil pumps with vaseline when assembling.
 
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Old 05-07-2019, 12:53 AM
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Originally Posted by robertf
Every set of hastings rings ive encountered was at the max gap spec out of the box. Id go with any other brand. I think the ones in my 4.6/4.0 combo may even be brit part.
Ive always packed oil pumps with vaseline when assembling.
I was told by a Land Rover specialist that Hastings is the ONLY brand he goes with because it’s the original brand. I haven’t seen any posts about that being true or false.

In regards to vaseline, how does it ever dissolve in Engine oil? I feel like it will always be circulated in the system...

I’m genuinely curious on all of this, especially the 4.0 pistons and what’s different about them from a 4.6 piston. According to Hasting’s ring specs they have the same diameter? Every post on ALL Rover forums don’t really have a “this is WHY” it always seems to be just speculation.
 
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Old 05-07-2019, 08:25 AM
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Originally Posted by mln01
Will you need the ECM from a 4.6? I would think so to make a setup perform optimally, but I am not certain. I'm confident someone else here will know for sure.
My existing is 4.6 (‘04).
 
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Old 05-09-2019, 01:08 AM
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Alright, so I dropped my heads off at Cylinder Head in San Diego. Turns out Greg (the owner) agrees with the Rover specialist I’ve spoken to before that Hastings rings are the way to go in LR engines. Specifically Bosch engines. He cleaned and resurfaced my heads for a good price if anyone is in SoCal and needs head gaskets done.

Anyways, something he wasn’tsire of was the size difference between the 4.0 and 4.6 pistons. Is there a difference? Can you stick with the 4.0 pistons with 4.6 crank and connecting rods?
 
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Old 05-09-2019, 11:55 PM
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I ended up talking to a local shop who works on Bosch engines. Apparently Hastings piston rings are what he orders.
Im still trying to figure out if there is a size difference in pistons between the 4.0 and 4.6. Any guidance would be great!

i also ended up ordering a new Elbow for the coolant just because of the rust. I figure getting rust particles in the coolant isn’t the best thing for the engine
 
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Old 05-10-2019, 05:25 AM
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Seconded on the Vaseline. That's what I always use as well.

4.0 pistons will work. They'll actually give you about another 1/3 of a point of compression. I wanted to do that for a long time before I decided I'm not fooling with the factory engine any more.
 
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Old 05-10-2019, 08:45 AM
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Originally Posted by Stephen Perez
I ended up talking to a local shop who works on Bosch engines. Apparently Hastings piston rings are what he orders.
Im still trying to figure out if there is a size difference in pistons between the 4.0 and 4.6. Any guidance would be great!

i also ended up ordering a new Elbow for the coolant just because of the rust. I figure getting rust particles in the coolant isn’t the best thing for the engine
Use only a genuine. I had a Britpart that cracked in less than two weeks. The Britpart is noticeably thinner.
 


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