Thread: 1993 D1 3.9L V8 - buggered sparkplug hole

If anyone wants a good runner for a quick fix I have one in market place and am very negotiable on price....3.9ltr, 176000kms odd Bosch coil conversion, 10mm leads. Usual oil weeps. No smoke no clinks or clunks. Just don't want the scrap guy to score again.

Block fitted with new core plugs. All plugs were replaced as a matter of course.



The key reason I went to all this trouble was to have flanged liners fitted.



Sleeves ended up shorter than I expected, but gudgeons remain well within the sleeve at bottom of stroke. In the end approximately 15mm of the piston skirt dropped down below the base of the sleeve.



Detail showing base of sleeves with new cam in place. Bearings were all checked with plastigauge (all within spec after 0.010" grind on mains) and bump clearance was nicely done at the smallest end of spec. Great care was taken to ensure that the bearing crush was at the tight end of the range. All bearings required substantial work. About half a day went into checking and end-finishing the main bearings to achieve desired crush but this is vital to ensuring that the bearings have along and happy life.



Another of same. Before final clean and assembly I gently stoned the base of the sleeve to ensure there were no sharp edges that would damage the pistons.



Closeup showing base of sleeves.





Another couple of sleeve tops.



All side core plugs were replaced. This engine has always had 50/50 glycol coolant and distilled water, and I was pleased to see that the original plugs were all in good condition. However, it's one of those situations were a $1.00 part not put in at the time can really cause issues later.



Bottom end



Front of block, new cam in. The cam bearings proved to be a real nuisance and source of delays. The machinists who did the block and head work had to replace the cam bearings as a matter of course since the block has to be cleared of grit after the liners were fitted. However, they fitted the #2 from front bearing with marginal alignment with the oil gallery behind. In addition they dented the surface of that bearing and scratched all the others. I took it back and insisted they do the job properly. Cam to bearing clearances ended up around middle of the 0.002" to 0.006" acceptable range. Cam is standard 3.9L EFI - part number ERR5924. I saw no reason to experiment with different profiles since the original cam ran well in spite of its 307,000km life.

Detail shots of crank. Adequate bump clearance was achieved by machining the #3 journal on the crank while this was not expected it did mean that it could be done just right.

After finding myself questioning the care taken by the mob who did the block, crank and head work (more on that later) I decided that I wanted a second opinion on just about everything. The first mob had assured me that the crank and new pistons would be fine to put in as they'd been finished. But I had my doubts. Annoyingly they had done a very sloppy job of fitting the new pistons to my rods. Some were very tight on their gudgeons and upon close inspection they had damaged the ends either on removal or installation in the swap. Most of them needed to be adjusted in some way or another. This took nearly a full day for me to resolve and really left me feeling quite bitter towards them, but grateful that I was the one who decided when things were finished. Had I asked them to build the engine they would have just slapped everything together. After pulling them up on the issue with the cam bearings they'd also honed the second set to make them look nice. Clearly they thought I was being pedantic but I'm certain they would have taken more care on an engine they were doing for themselves. I wanted all of the cam to bearing clearances checked and documented, and all of the balance verified.

I was surprised that the balancing mob reported that the crank, harmonic balancer and flywheel were all in need of correction. Substantial adjustments were made to the front of the crank. Because of the issues with the gudgeon pins I was reluctant to have anything further done to the pistons, but thankfully the assembled masses were all very close to each other (total deviation of 3 grams only). All of this was a major source of delay but I'm very glad I took the time and spent the additional $300.

Moving on, I was finally ready to start the assembly proper. Everything was given a serious clean, and the upper bearing shells were put in. I used Clevite Bearing Guard assembly lube (red) and some other CRC Moly assembly paste (black) on all rotating parts.









New rear main seal in place, slipped on with a small amount of vaseline.







Just to be sure nothing started dry, all the journals on the crank were coated in the CRC paste.



Crank in place for the last time.







#3 bearing was coated up the sides of the bearings and crank journals.



Rear main drops into rebate in the block.



Still more lube.



Rear main cap with dry cruciform seals.



Rear cap with CRC lube applied to bearing and sealant applied to face that mates with the block around the main seal. Cruciform seals installed in grooves pre-treated with sealant. Excess wiped off to avoid overflow into block.



Side of rear main cap - excess sealant removed from the inside end of the cruciform seal. Lack of care with sealant here can leave great chunks floating around just waiting to block the oil pickup.



Rear cap in place.



Another dash of Clevite lube, then all caps were tightened in sequence and free rotation of crank checked.

Pistons. The whole process of fixing shoddy work on the gudgeons, very careful checking of ring groove clearance and ring end gap (matched for pistons and respective bores) and big end bearing clearance and crush, I was finally ready to install the pistons.

All of the big end bearings were set to the tight end of crush fit, and all of the bearing to crank clearances were at the low end of spec - ideal situation.

The pistons and Grant rings had come from Rimmer Bros in the UK. I'd broken a compression ring and found another that was faulty, so tried to chase up another single set of Grants locally. No joy, and it ended up being more cost effective to order another complete set for 8 pistons including freight. All of the compression rings in the first set had insufficient end gaps. I had to file and check them all individually and went for bare minimum clearance at 0.017". However, the second set came in with a few rings that were improperly ground - one end thicker than the other - and all were 0.016" to 0.0.020" out of the box. I was lucky to find 3 out of the whole set that were well made and had 0.017" gaps. I'd not use that brand again.

All pistons were marked to allow quick set up with gaps in right places.







Before putting them all in, I had to dial in the cam. I'd decided to go with the Rollmaster CS7000 kit with duplex chain and multiple keyways. One annoying thing I found was inconclusive timing specs in the genuine Rover WSM, and even then I had only open and closing moments, no clarification of actual lift at those moments. I had to do a series of installations and measurements to make sure I knew what the old and new cams were doing:

Old cam, old gears - measured.
Old cam, new gears - measured at 0° keyway.
New cam, old gears - measured.
New cam, new gears - measured at 0°, +2°, +4° keyways.

Here was a nasty trap for young players. Even taking wear into consideration with the old chain and gears, it appeared that to obtain a true zero on factory timing, the new gears had to be set up to an indicated 4° advance! I checked this multiple times over two sittings looking at both cams at peak lift, opening and closing on both lobes for #1 cylinder. This was made even more complex because the measured durations of the old and new cams were not the same - presumably a wear issue. Instead I came at the problem from both ends starting from peak lift. I found that if I measured the open and close at 0.002" lift everything timed up perfectly With nothing else to go on I had to settle with that. And so it was. Decision made.



Some of the in progress shots.



Bump stop made up.









0.002" = 0.05mm on my metric stuff.

Pistons were all ready to go in for keeps. #1 piston was removed, everything cleaned again, then bearings lubed and fitted up.







All fitted, caps torqued and then on to gaskets and heads.

Both heads had been reconditioned with skimming, new guides, stem seals, valves cleaned up (5 replaced), seats recut and were installed using tin gaskets and ARP studs. I'd decided to go with Payen tin gaskets - purportedly OEM but who knows - but were the preferred brand for my preferred local parts supplier. As a precaution I treated all gaskets on this engine with Hylomar spray on sealant. I wanted tin to keep compression ratio up.



















Upon sniffing around the net looking at various experiences with the ARP studs in Rover 3.5/3.9 blocks, there were some tales of woe where studs had pulled from the blocks when the nuts were torqued to ARP's specified 80ft/lb, even when using their proprietary stud lube. I decided to play cautiously and run 3 equal steps to 75 ft/lb (25, 50 then 75 ft/lb, observing normal tightening order). When doing the first head, two studs felt strange in the last 20° or so. I pondered this and decided to back them all off 90º one by one and retorque to 75 ft/lb once more - if they had pulled I'd know about it. All was good, so all I can suggest was that the gasket or fasteners reorganised themselves. The second bank went without a hitch. Even though I was not all the way up to ARP's figure, I was confident that the clamping force was certainly going to be greater and more even than with the TTY bolts originally fitted. I should add that while the bottom 4 studs were added (remembering this is a 14 bolt block) they were done up finger tight + 20° so they're just sitting there to fill the holes.









It was a great relief to get the heads on!

Rocker preload took a full day to do carefully. I ended up fabricating a 1mm steel shim, and then adding 0.25mm shim to one bank and 0.125mm to the other. To my annoyance I'd omitted to check the finished valve stem heights before bolting the heads on. The left hand head had the most variation - another strike against the first lot of machinists. In the end the preloads still worked out OK but the variation was more than strictly necessary if they'd taken more care. On average the preload was around 0.030", but one pair of valves ended up 0.022" and 0.048". Rockers and shafts were all in good, serviceable condition so went in again without full strip down, just external clean and lube. The engine mainly runs on LPG so there was no sludge to worry about.





End pedestal shims had extra rebates for oil feed.









Ends folded over to keep them in place.





Once everything was installed for the last time and every preload rechecked, I did the final lube up and put on rocker covers.





Bagged valley gasket dropped in place to help keep things clean and pre-shape it for final installation while I focused on the timing cover.

Before I'd decided on the Rollmaster timing set I'd done some checking up on when the timing cover design changed to one that wouldn't allow proper clearance. I thought I had one of the early covers that would accommodate the wider chain and gears without problems. I was wrong. A dry fit up without gasket clearly showed that the chain was making contact. An hour with the Dremel on the other side of the garage was enough to resolve it.



Blu-tac works a treat to verify these sorts of things.







I went as far as I could in the distributor tunnel without breaking through. I left the bump stop where it was because it will still do its job with the shape of the cam pulley.







I didn't measure the difference in widths across the chain pins of the old vs. new Rollmaster chains, but it's substantial.



One incidental thing was a mod I had to make to the alternator bracket. I'd already modified it long ago to allow use of a Bosch alternator from a Mitsubishi V6 Magna (rather than the Lucas/MM trash) but the tab that normally locates on the front head bolt needed to be cut off and replaced because the stud is too thick and the nut too high. I later had to remove a tiny bit from the front of the new tab to fit the power steering pump. I HATE this arrangement of brackets but I do like the 4 belt design.



Hylomar treated gasket.



Cover on, water pump gasket fitted.



Water pump was still in good condition so went on after spending ages removing the old gasket. Because it had been so long since I disassembled it I had to work out where the different length bolts went by trial and error. All bolts were done with thread sealant on cleaned threads.

Then on to manifold.









Careful preparation of areas around water passages on the block, plus the valley gasket end seals.



Valley gasket prepared with Hylomar.





Manifold goes on. Very fiddly job fighting the gasket and bolts to get proper alignment. Thread sealant was used on all the bolts.



Preparations for sump.





I said goodbye to the bottom end. Hopefully never see these parts again up close.





Careful application of RTV sealant at ends of the block, then gasket dropped on.



A very thin layer of RTV was applied to the spotless sump. All the bolts were done up carefully to allow the gasket to settle in.



While I was at it with the engine upside down I stripped and cleaned the oil pump before packing it with vaseline and replacing all the seals and copper washers.



Flywheel and new clutch ready to go.







SPOTLESS bellhousing, and new thrust bearing. The old clutch was not worn out but was heading that way. All splines brushed with nickel anti-seize paste.



The final approach!



Happy helper in the form of Father in Law. Geoff had been an enormous help and valuable sounding board for ideas and discussions. It's been a long time since he's worked on engines to this extent so I think he got a kick out of it - especially because none of it was his problem! Before dropping the distributor in I primed the lubrication circuit with a drill home made pump drive. The oil light took about 15 seconds of driving to extinguish and to be sure I gave it all another 2 minutes with the drill.

Geoff was present during the first start and run in for the cam, allowing me to run around and check the water and so on. The engine was very slow to turn over on the starter and needed about 15 seconds of cranking to catch on LPG. I had a loose belt so shut it down immediately to remedy that. We also ended up with an airlock so that the LPG converter froze 5 mins into the cam run-in, stalling the engine. That was a quick fix with the kettle and we gave it another 20 minutes.

I had to back track a wiring mix up with the #1 injector and the coolant temp sender, but after that the refurbished Bosch 4.6L Mustang injectors all kicked into gear.

Now it's run for 150km I've been able to time it up for LPG and ULP. It appears that 16° advance is ideal for LPG without pinging, but 91 octane ULP will only bear 10° advance. ULP running is smoother than I ever recall with having with the old Lucas injectors, the only hitch seems to be slightly hesitant starting on ULP. I'll resolve that once everything is run in.

So far so good... It's been a monumental and expensive project. I trust that in time I will come to be happier with my decision to take this path than I am currently - I guess that will come as it beds in and I can drive it a little more like I want to. At this end of the process I can safely say I'll never undertake another rebuild on my only daily-driving car. The 4.5 months of the Disco sitting in the drive while I waited for things and services to eventuate started to take their toll on moral. I resented the poor attitude of the "first mob" and will never ever deal with them again. The ongoing delays, inflating costs and lack of communication were all tolerated until they tried to palm off poor workmanship and when confronted with it their attitudes gave them away. I'll not name them but if I see anyone ask about them specifically I'll speak up.

Thanks to all who assisted! Hope you enjoyed the pics.

Great build pics! Make sure you wriggle all the intake trumpets before refitting the plenum cover. Loose ones rattle something shocking. I have expanded a few on an anvil horn before refitting with suitable loctite.