P38 4.6 Engine repair - what to do next?

[MikeAK]

Well 2 months on and garage floor is sorted and nicely painted so back on with with engine rebuild.

Started to take the engine (4.6 GEMS) out today and all going well until it came to removing the torque converter bolts. Access plate at bottom of housing removed for access to bolts but can't get a 1/2" drive ratchet in wherever I position the bolt due to ratchet fouling on sump. My offset ring spanner does not have enough offset to clear the crank sensor toothed ring. I can get a 1/4 drive ratchet on but can't get enough leverage to undo. Surprised they are so tight as they are only 10mm bolts, maybe loctited?

I presume access is better with the sump removed? so I will try that tomorrow.

Also does the starter motor bolt through to the housing or is it just into the engine?

Thanks

Mike

 

[Bowie69]

10mm head bolts? Are you sure you are undoing the right ones?

[Bowie69]

There should be just 4 bolts, I believe, through the access holes:

 

[MikeAK]

Thanks for the pictures Bowie69, they confirm I'm on the correct bolts. When I said 10mm I was referring to the thread, that's what Microcat says they are, the head is 13mm.

Will be having another go this afternoon. I'm going to get hold of a 3/8 drive single hex socket and have a go with that.

Thanks

Mike

[Bowie69]

Cool, good luck, they are tight!

[MikeAK]

Torque converter bolts are now out, they were tight! Had to take the sump off for better access and get an impact gun on them.

Started on the housing bolts and got the bottom ones OK but struggling with the middle and upper ones due to the limited access. Decided to take heads and exhaust manifolds off in the car to give better access. Left hand head taken off complete with exhaust manifold no problem. Struggling with right hand head as the manifold flanges seem to be overlapping some of recesses where the head bolts seat, including the one with poor access under the ABS block. This is stopping the socket going on the bolt square and is going to round off if I apply any force. I don't want to end up like this again!

Especially with the even more limited access at this side. So decided to take the manifold of the head first to give clear access to the head bolts. Then found all the heat shield bolts have corroded to the point where so can't get the shields off! Been pratting around with them for half the afternoon with no progress. Might take air chisel to them tomorrow, but don't really want to destroy them they are expensive for what they are.

This engine seems to be fighting back at every turn! Maybe this is why I didn't have a Land Rover for a few years 😉.

Back on it tomorrow weather permitting (RR doesn't fit in garage so engine has to come out on the drive). If anyone has suggestions for a cunning way to remove the heat shields it would be very helpful.

Thanks

Mike

 

 

[JohnnoK]

20 hours ago, MikeAK said:

Thanks for the pictures Bowie69, they confirm I'm on the correct bolts. When I said 10mm I was referring to the thread, that's what Microcat says they are, the head is 13mm.

Will be having another go this afternoon. I'm going to get hold of a 3/8 drive single hex socket and have a go with that.

Thanks

Mike

I welded a shortened 6 point socket to a piece of flat bar and used that. Also bent up a "hook" tool that lies on the flat of the bellhousing at the bottom and the hook part engages the ring gear to loosen, and when flipped to the other side, tighten the bolts. Use Locktite when refitting.

[Escape]

The easiest way to get to the upper bellhousing bolts is by removing the engine mounts. Lift the engine a bit, wiggle them out and then lower the engine again. That should give you just enough clearance to get to all the bolts from the top.

Once the engine is out, you'll have much easier time getting the heatshield etc off. One solution is to grind off the bolt heads and replace with standard bolts and washers afterwards.

Filip

[MikeAK]

JohnnoK, good idea, I will make something similar for when it goes back in.

Escape, I will try that when I get back on it.

Drizzly weather today and I am otherwise occupied for the next couple of days, so will probably be wednesday before I get another go.

Thanks

Mike

[MikeAK]

When I lower the the engine as recommended by Escape to gain access to the bell housing bolts. How far can I lower it without straining anything. This is the first P38 I've owned so am not familiar with it, I don't want to break anything!

Thanks again

Mike

[elbekko]

Don't think you can break anything, First thing to hit will be the transfer box against the tunnel.

Didn't take any special care on mine anyway.

[Escape]

I think we put a 1" piece of wood in place of the rubber engine mounts and that gave enough clearance. Without the risk of anything else like the transfer case hitting the tunnel.

[MikeAK]

Got back on this today, The engine is out!

What a fight though, all the bell housing bolts were stuck tight had to get heat on them and buy a 9/16 single hex socket. When the came out they had some greenish looking loctite type substance on them. This seems to be a recurring theme on this car, so far the PO or whoever did work for him seems to have slathered bolts in whatever the the green stuff is and/or whacked everything up an impact gun.

Then came to getting the RH head off, this fought back in similar way to the left hand head when I first had that off a couple of months back. Couldn't shift them on the engine stand. Had to put the engine on the floor with a piece of box section bolted to the engine mount with a mate sat on it while I used a 4' breaker on the bolts and then could only just shift them! Strange thing is the instant they "cracked" could be wound out with fingers.

Anyway engine back on stand and quickly popped the pistons for a look. Oil rings are all firmly stuck flush with the piston face so they weren't doing much sealing, maybe the cause of excessive HC on MOT test? Pistons otherwise look OK. Tried a top compression ring in one of the bores and the ring gap was 0.68mm against spec of 0.5mm max, presume this indicates worn rings?

Pistons are "B grade" which RAVE lists as service replacement. So looks like someone has been in before unless "B grade" were ever fitted as factory installation?

Bores look reasonable, still have faint honing marks in places. A couple have very light vertical scratches (not the one with low compression) which may hone out. A couple have slight marks like you get when an engine has stood for a while and rings have been freed off after sticking to bore. Again may hone out.

Big end shells worn out down to copper. Very light scoring on crank journals that may polish out. Not got the mains off and the crank out yet.

Outside of engine is filthy, so next step is to get everything cleaned off and get the crank out followed by proper measuring of everything.

Sure I'll be back with more questions after that

Mike

 

[JohnnoK]

On 11/8/2020 at 7:58 PM, MikeAK said:

When I lower the the engine as recommended by Escape to gain access to the bell housing bolts. How far can I lower it without straining anything. This is the first P38 I've owned so am not familiar with it, I don't want to break anything!

Thanks again

Mike

I raised the vehicle on a ramp in front and axle stands at the back and with my suspension pumped up, I was able to sit under the vehicle with the handbrake drum removed. I lowered the rear until I could comfortably sit and see the top bolt heads to loosen them. The rear propshaft flange was visible below the chassis rails.  RAVE does say to remove the top of the fan cowl for fan touching.

I also don't use a jack, but remove the centre console and use 2 small A frames and my block and tackle to lift and lower boxes. On the P38, I remove the shifter and on my Disco I removed the whole panel that covers the tunnel. The P38 box is very front heavy and still needs a jack to hold the wieght, the R380 and LT230 hang perfectly level. I prefer this as the box can't easily fall OFF a chain from above, but having had a gearbox slip off a jack before, the extra schlepp is my safety margin for working alone. I am also not working on a hard surface, so a wheeled jack is out of the question for me.

[MikeAK]

Engine now completely dismantled. Crank definitely needs a regrind, main shells were all completely down to the copper and scoring on the crank journals. I'm amazed it wasn't noisier!

Block and crank now with local machine shop for assessment. With his initial quick look he was unsure if bores would hone enough to remove scratches and still be in standard size spec or if it needs re-bore.  He will check it properly and let me know next week.

Just need to clean up all the remaining parts now then do the valves etc while waiting for machining.

Mike

[Arjan]

You have overcome !!

Well done.

[MikeAK]

Well this hasn't progressed much, the local machine shop, small father and two sons business, where my block and crank are have been hit by Covid. Fortunately they are now recovering and expect to be back on the job next week.

While waiting I have dismantled the front cover to check the oil pump. The rotors are scored and require replacing. Officially the front cover is replaced complete, quite expensive! I have found some places selling just rotors but they all come in a blue box! Don't fancy those for a critical component. Anyone know of any reputable source for these?

Also I want to flush out the oil cooler, but there is no way the pipes are coming off the cooler. So it will have to be flushed through the pipes. Wondering what's best to use for flushing. Thinking of putting Jizer or similar in though the pipes and sloshing about then flushing out with water. Repeat several times then put somewhere warm to dry out thoroughly. If anyone has a better method please let me know.

Thanks

Mike

[Bowie69]

Acetone, diesel, brake cleaner, petrol, all will work with varying degrees of flammability.... 

How bad are the pump gears? The gearotor type don't tend to wear much in normal use.

[ThreePointFive]

Turner's rotor set was not BP, came in a red box. They should have one in stock, as I have just returned mine having bought an entire new front cover (which came with the gears pre-installed) for the reasons you say.

Your engine build sounds almost as troublesome as mine, good luck with it.

[MikeAK]

Bowie69 I'll give it a go cleaning with petrol then. Rotors really are very scored where the lobes run against each other. There has been bits of metal or grit going through it, also evidenced by the crank and bearing scoring. That's why I want to make sure the oil cooler is thoroughly cleaned out.

ThreePointFive thanks the pointer to Turners, will give them a look.

Mike

[MikeAK]

Should be getting block and crank back from machining later this week, so getting everything together to start rebuild.

In the engine overhaul manual it says the con rod bolts (ERR1772) are angle tightened (similar to head bolts) but doesn't mention they are "stretch" bolts and should replaced like it does for the head bolts. Looking on Turners website it says they are stretch bolts and should be replaced.

Anyone know for sure which is correct?

Thanks

Mike

[elbekko]

V8Tuner also recommends replacing them. For what they cost, I would (and did) do it.

[MikeAK]

Ordered big end bolts and a load of other stuff from Turners today (bit of a wallet bashing!). As you say not worth risking re-using for the price.

Picked up block and crank from machining this afternoon, so should be able to get on with re-building this weekend.

Mike

 

[MikeAK]

Didn't get back onto rebuild this weekend, but back on this afternoon. Started checking crank dimensions before re-assembling and got very confused.

Are the imperial dimensions for the mains in the engine overhaul manual (attached) complete bobbins or am I having a senior moment?

The manual has metric dimensions of standard 63.487 to 63.500 mm and imperial 2.499 to 2.52 in

                                                    min regrind size 62.979 to 62.992 mm and imperial 2.509 to 2.510 in    2.509 is bigger than the minimum standard size!

       Converting from the given metric dimensions myself I get imperial standard of 2.4995 to 2.5000 in

                                                                                     and imperial min regrind size of 2.4795 to 2.4800 in which makes sense as 20 thou is min undersize.

My crank was machined to 10 thou undersize and measures 2.4897 in within 0.0002 in across all the mains which converts to 63.238mm which is in spec for a 10 thou (.254mm) undersize 2.4895 to 2.4900 in or 63.233 to 63.246mm according to my conversion.

Normally I would have worked in metric but only had an imperial micrometer available so was looking at the imperial dimensions and got confused.

Am I missing something or is the manual wrong?

Mike

4.0 & 4.6 Litre V8 Engine Overhaul Manual (LRL0004ENG - 4th Ed).pdf

[JohnnoK]

On 12/9/2020 at 2:24 PM, MikeAK said:

Should be getting block and crank back from machining later this week, so getting everything together to start rebuild.

In the engine overhaul manual it says the con rod bolts (ERR1772) are angle tightened (similar to head bolts) but doesn't mention they are "stretch" bolts and should replaced like it does for the head bolts. Looking on Turners website it says they are stretch bolts and should be replaced.

Anyone know for sure which is correct?

Thanks

Mike

I have heard different opinions on this.

One says that if the old bolts are the same length as a new one, then they are still in spec and can be reused, and another says always replace.