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Which way to go.....

Discussion in 'V8 Engine' started by vaultsman, May 18, 2017 at 2:59 PM.

  1. vaultsman

    vaultsman Active Member

    Forumites may have seen in this section that Occie, my 3500S, is pretty poorly at the moment and won't be coming out to play for a while.
    Long story short, the main and big end shells are badly scored and she can't get oil pressure above 20psi. But worse is the fact that the two main crank journals I've checked so far are also showing scoring. :mad:

    I did a top-end rebuild on the original 10.5:1 3.5 8 years ago, including fitting Range Rover heads/inlet manifolds, composite gaskets, 3.9EFi cam, and duplex timing set.

    Now, I could just have the crank reground and fit shells to suit but I'm considering getting a short (or even a long/strip) engine....maybe even a 3.9/4.6.
    I'd like to get away from the P6/SD1 oil pump if possible.

    Thoughts/suggestions/suppliers, anyone?
     
  2. vaultsman

    vaultsman Active Member

    I know Ron runs a 4.6.....what configuration do you have on your engine, Ron? i.e. front cover, etc.
     
  3. harveyp6

    harveyp6 Well-Known Member

    Just thinking aloud.

    The 3.9/4.6 engines have their own problems, and I think you've been very unlucky to experience the problem you had with your 3.5 oil pump. I've certainly not seen that one before, so I'd probably stick with a 3.5.

    Problem is that a crank grind is expensive, but you could find a good used crank fairly easily I would think.
     
  4. vaultsman

    vaultsman Active Member

    You're probably right re the oil pump, H...but having had it happen, it can knock your faith a bit. :)

    Hasn't the top-hat liner approach cured a lot of the potential ills with the larger capacity lumps?

    Am I right in thinking cranks for autos and manuals are different?
     
  5. harveyp6

    harveyp6 Well-Known Member

    I can understand that.


    Pretty much, but it's an expensive fix.


    No, they're the same.
     
  6. cobraboy

    cobraboy Active Member

    This I don't think is bad value, depends on finances.
    Rover V8 "Top Hat" Cross Bolted 4.0/4.6 Cylinder Block. - V8 Tuner
    These engines consume vast amounts of money, I am building up a 4.6 for my car with a top hat linered block and the bills just keep coming.
    I would grind the crank and stay as you are if you need a quick economical fix, otherwise the long haul to more cubes is way more expensive.
     
  7. vaultsman

    vaultsman Active Member

    Thanks, Harvey.
     
  8. vaultsman

    vaultsman Active Member

    Yeah, I've looked at his offerings, plus the other usual suspects.

    I've had Occie a long time and I can't see me ever wanting to let her go so not necessarily looking for a quick fix, just sorting out a route...and interested to hear other people's experiences.

    Before I do decide, I'll need to have a look at the bores of course - which I've never touched.
     
  9. harveyp6

    harveyp6 Well-Known Member

    I have got a delivery mileage SD1 crank here somewhere (in the loft I think) which was perfect, but it's been lying around for so long that you probably wouldn't get away with a polish, it would probably need a grind, which is a shame, as it would have helped you out a bit, but if it does need a grind it's no better than the one you've got.
     
  10. colnerov

    colnerov Well-Known Member

    Hi, Good steel in a crank tends to not rust pit so deep so readily, so an electrolysis tank first might be a wise move because it will take the rust and not the metal like a polish with emery would.

    Colin
     
  11. mrtask

    mrtask Well-Known Member

    Sorry to hear about your trouble. Time to inspect the bores! With luck you can re-hone them and re-use the pistons and rods, right? Just out of interest, what does it actually cost in 2017 to have a 3.5 litre crank re-ground, and to get the right set of shells? What about swapping to a remote oil filter, and/or using an electric oil pump instead? If I understood correctly the Buick V6 has a timing cover that fits, but a better oil pump. I stand to be corrected here!
     
  12. ghce

    ghce Well-Known Member

    Have you measured your crank? Is it out of round or scored?
    Damaged shells is one thing but that doesn't necessarily mean a new or reground crank.
     
  13. SydneyRoverP6B

    SydneyRoverP6B Well-Known Member Staff Member

    Hi Stan,

    I was thinking about you and your Rover as I drove to university yesterday. From my point of view, given the engine needs to come out regardless of what you decide to do, I would opt for a 4.6 replacement. My 4.6 was installed circa June 2007, and in the years that have followed, has covered some 153,000 miles (246,000km) of trouble free Rovering. The engine has been faultless, idle oil pressure at running temp is 30psi, just like it was when fitted. Apart from the normal consumables, the engine has not cost me a cent in that time. Sure it was expensive at the time, but so would rebuilding my original engine have been.

    Configuration wise, I am running an SD1 timing cover with genuine oil pump gears, a P6B oil pump base. The distributor was at the time a NOS 35D8, with a wobbly drive replacing the original. It was re-graphed as the bigger engine needs less advance compared to the 3.5 to deliver maximum torque. I run it at 12.5 degrees BTDC @ 600rpm. The block is a Thor, top hat liners fitted, 8.37 : 1 CR. Dyno testing show that for automatics, the low compression engines are the better choice, as they deliver a greater percentage of torque at lower revs, making them superior to the HC engines up to 3000 rpm or so. My camshaft is a custom ground high torque - highway configuration, made in Australia.

    Are there any negatives that the 4.6 has compared to the 3.5? No, in my view, the 4.6 is a vastly superior engine, the bearing caps don't come loose, the inside of the engine doesn't fill with dry dirt, the engine does not purge coolant in the way that the 3.5 always did. The 4.6 is a smoother engine in power delivery than the 3.5, the crank, rods and pistons have all been factory balanced to a far higher standard that that used for the 3.5. I love my 4.6, it has transformed my Rover, making it infinitely more enjoyable to own and drive. A couple of P6B owners have had a drive, and they say the feeling and sensation that you receive behind the wheel is fabulous.

    If you decide on a 4.6 replacement Stan, I will offer all the assistance to you that I can. I know that you will not be disappointed. If you choose to go for rebuilding your 3.5, then again, anything that I can do to assist, I shall. Speaking from the position of having made this decision, I knew of no one who had done this to a P6B before, at that time. The Range Rover business that did the swap had not done one before either, my Rover being their first P6B engine upgrade. I read widely, sought different opinions, and then decided. I spoke to the gent who owns the Old Auto Rubber company in Melbourne. He had a P76 Leyland 4.4 litre V8 in his P6B, which he said was an incredibly satisfying transformation. He said the difference though was that his 4.4 would deliver more power, but my Range Rover 4.6 would deliver more torque. So the decision was mine to make. Now in hindsight, was it the right decision? Most certainly! Would I do the same again if I had the choice? Absolutely!!

    All the best Stan,
    Ron.
     
    Last edited: May 19, 2017 at 8:25 AM
    Baron von Marlon and rockdemon like this.

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