proper cooked my 3.9 in my discovery on sat header tank had split and it boiled all its water away comon problem aparently.
anyway its loosing huge amounts of coolant so im assuming the head gaskets have gone i havent taken it apart yet but as its done 170,000 i decided its pointless tearing half the engine apart to do the head gaskets on such high milage so i thought i would do a full rebuild on it and
then i thought about increasing the displacement in the process as its used to tow a big boat and could do with abit more torque lol
so what do i need to do to make it a 4.6 i know i need pistons rods and a crank what about the rest of the engine?
could i just fit a 4.6 ecu to my loom or is it not plug and play?
sorry for all the questions just waying up what to do
i have tryed a search but me and the search functions on forums just dont go together lol
Thanks
Si
Cooked 3.9 EFI
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topcatcustom
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You can't put a 4.0/4.6 crank in a 3.9 as the journals are bigger. With regards to rebuilding your 3.9 you will almost definately need a re-bore after that many miles which will set you back a fair bit so you could either do that or invest in a later 4.0/4.6 short engine for about the same money- but that may need a re-bore too!
Rather than an increase in capacity you could just put a hot cam in and modify the cylinder heads which will see a power hike, maybe increase the compression a little too. Others will tell you more about the cams and head work if you wish!
TC
Rather than an increase in capacity you could just put a hot cam in and modify the cylinder heads which will see a power hike, maybe increase the compression a little too. Others will tell you more about the cams and head work if you wish!
TC
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CastleMGBV8
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Si,
The bad news is if you boiled the engine dry you may have damged the block and caused liner slippage because of cracking of the bores behind the liners.
You will need to at least have the heads off and check for any cylinders that look as if they have been steam cleaned, 6 & 8 seem to be the most common and also look to see if any of the liners are lower in the bores than the rest.
If any of the above are apparent then its probably cracked but you could fully strip the engine and have the block pressure tested to confirm any problems.
Your second question re increasing capacity, the 4.6 engine rotating assembly does not fit the earlier 3.9 blocks because of larger main bearing size, you can buy a 4.8 stroker kit or even larger capacities are available but are more expensive, see link to V8 Tuner at bottom of main index page.
A cheaper and simpler solution if your block is cracked would be to buy a 4.6 Coscast (Cosworth)half engine from RPI for around £1650.00 with a bit of haggling, you can still use your existing heads but have then skimmed as they could have warped due to severe overheating and your hotwire system will work but may need a re chip for the larger engine.
let us know how you get on.
Kevin.
The bad news is if you boiled the engine dry you may have damged the block and caused liner slippage because of cracking of the bores behind the liners.
You will need to at least have the heads off and check for any cylinders that look as if they have been steam cleaned, 6 & 8 seem to be the most common and also look to see if any of the liners are lower in the bores than the rest.
If any of the above are apparent then its probably cracked but you could fully strip the engine and have the block pressure tested to confirm any problems.
Your second question re increasing capacity, the 4.6 engine rotating assembly does not fit the earlier 3.9 blocks because of larger main bearing size, you can buy a 4.8 stroker kit or even larger capacities are available but are more expensive, see link to V8 Tuner at bottom of main index page.
A cheaper and simpler solution if your block is cracked would be to buy a 4.6 Coscast (Cosworth)half engine from RPI for around £1650.00 with a bit of haggling, you can still use your existing heads but have then skimmed as they could have warped due to severe overheating and your hotwire system will work but may need a re chip for the larger engine.
let us know how you get on.
Kevin.
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CastleMGBV8
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Si,
Not quite that simple i'm afraid, even if your block is ok to re-use.
An 82mm. crank whilst the 3.9 rods are ok will need a special set of pistons with the gudgeon pin height closer to the top of the piston for approx £400.00, the standard type 3.9 piston would be approx 5mm out of the top of the bore with the longer stroke crank.
Factor in the cost of a rebore £160.00 - £200.00 plus a full engine rebalance £200+ and allow for some engine machining work and you start to see why it would make sense to go for the the 4.6 bottom end from RPI with no worries about the integrity of the block, which is cast to a far higher standard than the original Rover castings.
If you used the new 4.6 Coscast block you would only need a new high torque cam a set of lifters and new valve springs and a decents all steel timing set, bolt on your heads after refacing and a standard re build with the new valve springs and the valves lapped in and you would have it all back together fairly quickly with a virtually new but higher spec engine.
You can also use your 3.9 front cover with the distributor which means that all your ancillaries will bolt straight back on, but allow for a new set of oil pump gears and check that the pump base is not badly scored.
I'm assuming the R/R is automatic so you are limited on what cam you can use but as you are looking for high torque from low RPM rather than ultimate BHP this is not really a problem, also the high torque cams are usually ok with the hotwire EFI system but check with the supplier.
Have a look at RPI auction the block also comes with a standard cam, lifters and timing gear which would probably be fine for your use.
http://cgi.ebay.co.uk/4-6-coscast-V8-Ro ... 240%3A1318
Kevin.
Not quite that simple i'm afraid, even if your block is ok to re-use.
An 82mm. crank whilst the 3.9 rods are ok will need a special set of pistons with the gudgeon pin height closer to the top of the piston for approx £400.00, the standard type 3.9 piston would be approx 5mm out of the top of the bore with the longer stroke crank.
Factor in the cost of a rebore £160.00 - £200.00 plus a full engine rebalance £200+ and allow for some engine machining work and you start to see why it would make sense to go for the the 4.6 bottom end from RPI with no worries about the integrity of the block, which is cast to a far higher standard than the original Rover castings.
If you used the new 4.6 Coscast block you would only need a new high torque cam a set of lifters and new valve springs and a decents all steel timing set, bolt on your heads after refacing and a standard re build with the new valve springs and the valves lapped in and you would have it all back together fairly quickly with a virtually new but higher spec engine.
You can also use your 3.9 front cover with the distributor which means that all your ancillaries will bolt straight back on, but allow for a new set of oil pump gears and check that the pump base is not badly scored.
I'm assuming the R/R is automatic so you are limited on what cam you can use but as you are looking for high torque from low RPM rather than ultimate BHP this is not really a problem, also the high torque cams are usually ok with the hotwire EFI system but check with the supplier.
Have a look at RPI auction the block also comes with a standard cam, lifters and timing gear which would probably be fine for your use.
http://cgi.ebay.co.uk/4-6-coscast-V8-Ro ... 240%3A1318
Kevin.
ye i see what you mean its just abit gutting when the cars only worth 1200-1500 quid lol
i will take the old one out and have a look at it see where we go from here will get the block checked at my local engine builders
if i decide to go the 4.6 route how do i go on about fueling? can i just increase the pressure of the fuel abit and let the ecu do the rest or is it not that safisticated? lol
Si
i will take the old one out and have a look at it see where we go from here will get the block checked at my local engine builders
if i decide to go the 4.6 route how do i go on about fueling? can i just increase the pressure of the fuel abit and let the ecu do the rest or is it not that safisticated? lol
Si
The whole point of an ECU is that it measures the air going in, and matches it with the right amount of fuel. So increasing the fuel pressure will just muck up everything everywhere without necessarily helping.
What you need is a remapped ECU which can cope with the higher maximum air-flow and fuel demand a larger capacity engine will require.
I think the 3.9 you have uses the Hotwire system, hopefully somebody else will know if these can be remapped to work OK with a 4.6 engine...??
The pukka 4.6 ECU and engine management system is completely different and is a non-starter.
Chris.
What you need is a remapped ECU which can cope with the higher maximum air-flow and fuel demand a larger capacity engine will require.
I think the 3.9 you have uses the Hotwire system, hopefully somebody else will know if these can be remapped to work OK with a 4.6 engine...??
The pukka 4.6 ECU and engine management system is completely different and is a non-starter.
Chris.
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Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
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CastleMGBV8
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Si,
Take your point about the value of the R/R, is it your main means of transport or just used for lugging the boat?
I suppose if you just want to get it back on the road cheaply and if your block is ok, a budget rebuild may suffice but at 170K its going to be pretty worn and may need a rebore and the crank reground although rover V8's don't seem to suffer from excess bore wear if they have had regular oil changes.
Whats the oil pressure like at idle and 3000RPM?
The cam is very likely badly worn unless it's been replaced at some time and new lifters will be required with a new cam, new cam bearings will also be required.
The rocker gear is also likely to be pretty worn, check the cups in the lifter bodies where the pushrod fits there's an insert that can wear out and sometimes disappear completely on high mileage engines and is there any excess clearance between the rockers and shafts.
For a standard budget bottom end rebuild if you were doing it yourself could be done for probably around £500 to include main, big end and cam bearings, new cam, lifters and timing gear and new rings.
You would probably need to get the cam bearing fitted by an engine builder with the right tool and have the bores honed at the same time.
If the block is cracked then a s/h engine may be the cheaper solution.
Alan Coote at Range Rover Heaven is a man i trust and normaly has full or half engines available so if you went for a 4.6 bottom end he would be able to see if the engine has had any problems.
His tel. numbers are 01249 890511 or Mob. 07711 369785
Re the fuelling, thats a fairly complex matter and all depends on what you decide to do engine wise, if you go to 4.6 capacity then clearly the 14CUX ecu from the 3.9 will need a re-chip to supply the correct fuelling for the larger engine, chips are available but cost around £400 the i don't think the ecu for the 4.6 will work with the 3.9 Hotwire system.
Anyway find out what the state of your current engine is and then you can make a decision.
Kevin.
Take your point about the value of the R/R, is it your main means of transport or just used for lugging the boat?
I suppose if you just want to get it back on the road cheaply and if your block is ok, a budget rebuild may suffice but at 170K its going to be pretty worn and may need a rebore and the crank reground although rover V8's don't seem to suffer from excess bore wear if they have had regular oil changes.
Whats the oil pressure like at idle and 3000RPM?
The cam is very likely badly worn unless it's been replaced at some time and new lifters will be required with a new cam, new cam bearings will also be required.
The rocker gear is also likely to be pretty worn, check the cups in the lifter bodies where the pushrod fits there's an insert that can wear out and sometimes disappear completely on high mileage engines and is there any excess clearance between the rockers and shafts.
For a standard budget bottom end rebuild if you were doing it yourself could be done for probably around £500 to include main, big end and cam bearings, new cam, lifters and timing gear and new rings.
You would probably need to get the cam bearing fitted by an engine builder with the right tool and have the bores honed at the same time.
If the block is cracked then a s/h engine may be the cheaper solution.
Alan Coote at Range Rover Heaven is a man i trust and normaly has full or half engines available so if you went for a 4.6 bottom end he would be able to see if the engine has had any problems.
His tel. numbers are 01249 890511 or Mob. 07711 369785
Re the fuelling, thats a fairly complex matter and all depends on what you decide to do engine wise, if you go to 4.6 capacity then clearly the 14CUX ecu from the 3.9 will need a re-chip to supply the correct fuelling for the larger engine, chips are available but cost around £400 the i don't think the ecu for the 4.6 will work with the 3.9 Hotwire system.
Anyway find out what the state of your current engine is and then you can make a decision.
Kevin.
got it out yesterday morning what a pain in the arse lol
its all wires and pipes it has lpg also so even more wires and pipes to play with lol
i think some one has been playing with the engine who had no idea or it was a reposesion and the previous owner had as when it came to taking the heads off all the bolts that wernt under the rocker covers were fingure tight
none of the liners have moved and there was no water in the oil at all so i think 80% of the coolant was just been blown straight out the header tank
i checked the bores with a mercer gauge and there not oval at all and the pistons are a realy nice fit you cant rock them at all so i think i have been lucky
you can still see light honing marks on the bores and there standard pistons so they seam good i havent looked at the condition of the bearings yet will do that in the week
Thanks
Si
its all wires and pipes it has lpg also so even more wires and pipes to play with lol
i think some one has been playing with the engine who had no idea or it was a reposesion and the previous owner had as when it came to taking the heads off all the bolts that wernt under the rocker covers were fingure tight
none of the liners have moved and there was no water in the oil at all so i think 80% of the coolant was just been blown straight out the header tank
i checked the bores with a mercer gauge and there not oval at all and the pistons are a realy nice fit you cant rock them at all so i think i have been lucky
you can still see light honing marks on the bores and there standard pistons so they seam good i havent looked at the condition of the bearings yet will do that in the week
Thanks
Si
CastleMGBV8 wrote:Si,
Your second question re increasing capacity, the 4.6 engine rotating assembly does not fit the earlier 3.9 blocks because of larger main bearing size, you can buy a 4.8 stroker kit or even larger capacities are available but are more expensive, see link to V8 Tuner at bottom of main index page.
.
Kevin.
mine is a 95 block it would seem is it possible to convert that to a 4.6 since its a later version
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CastleMGBV8
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Si,
The outer rows of head bolts are usually left untorqued as it causes problems with cylinder sealing, they were deleted on the 4.0 anhd 4.6 engines.
Now you have the heads off check for the steam cleaning effect of any cylinders and heads and liner slippage, ie if any of the liners seem lower in the bores than the others, which would indicate potential cracking of the block behind the liners which causes the the block to lose tension on the liners, allowing them to move and potentially pressurise the cooling system.
Si, if you can see honing marks in the bores it's likely the engines had a rebuild at some stage, any ridges evident at the top of the bores? you'll find out for sure once youv'e got it stripped down and checked the bottom end.
Good luck,
Kevin.
The outer rows of head bolts are usually left untorqued as it causes problems with cylinder sealing, they were deleted on the 4.0 anhd 4.6 engines.
Now you have the heads off check for the steam cleaning effect of any cylinders and heads and liner slippage, ie if any of the liners seem lower in the bores than the others, which would indicate potential cracking of the block behind the liners which causes the the block to lose tension on the liners, allowing them to move and potentially pressurise the cooling system.
Si, if you can see honing marks in the bores it's likely the engines had a rebuild at some stage, any ridges evident at the top of the bores? you'll find out for sure once youv'e got it stripped down and checked the bottom end.
Good luck,
Kevin.
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CastleMGBV8
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It will still have the smaller main bearing size so it's the same amount of work and cost to convert to 4.6.POAH wrote:CastleMGBV8 wrote:Si,
Your second question re increasing capacity, the 4.6 engine rotating assembly does not fit the earlier 3.9 blocks because of larger main bearing size, you can buy a 4.8 stroker kit or even larger capacities are available but are more expensive, see link to V8 Tuner at bottom of main index page.
.
Kevin.
mine is a 95 block it would seem is it possible to convert that to a 4.6 since its a later version
You might pick up the crank rods and piston from a 4.6 with a cracked block and have the crank main bearings machined down to the 3.9 size which may be economic.
Kevin
