I'm going in... (another 3.5 rebuild tale)

[logrover]

Hello, great forum, read loads, very helpful, started my rebuild today, so thought I'd start posting and seek some help and advice.

My intro - mostly have land rovers (including the "Log-Rover"), a Rover P4 100, an Autotune Gemini kitcar (fiat 2l), and a Range Rover (all viewable in www.log-rover.co.uk). Sit in an office all week and meddle with cars/chainsaws when i can

V8 intro - It's a 1989 3.5 efi and normally sites in my Range Rover (auto, 110k miles), gently powering me to the office and back each day (so, normal road use, auto, heavy range rover, no drag racing ). I fitted LPG injection to it (Etagas) many years ago, and also ditched the Lucas ECU and Megasquirted it (just for the petrol side of things).

40k ago I replaced the cam, followers, honed bores, rings, 1xpiston (worn lands), had the heads skimmed, tin gaskets.

10k ago I had to replace a different piston (melted around possibly worn lands again (see below ), cleaned the bore with hydrocloric acid, rehoned, and I fitted composite gaskets with stretchy bolts.




So, back to now - burning lots of oil, chuffing out the crankcase, all compressions lower at about 130 to 140'ish psi with cyl 5 down at 123, leakdown test resulted in just noise of air rushing past rings on all cylinders, oil on sides of block, seemingly from heads. and then a tapping noise at lowish revs, especially under load, goes at higher revs.

So, time to dig in yet again (each time i do this i say never again...).


Started digging in situ:


horrible oil, but still some lobes:


tappets a mix of flat and slightly concave:


out she comes:


bloody heavy those torque converter thingies:


plugs look ok, but its the otherside which matters....


been leaking i think:


10k old comp gasket



no great ridges



valves look the right colours, but signs of gaskets leaking


no lumps in the sump


cyl 1 piston replaced 10k ago has some very rough scoring on the skirt and wear in the bore:



cyl 5 piston has gummed up rings, a rather wavy top land, a new fangled 3 piece top ring


the pile of bits grows:


Soooooo, this is what I'm thinking:

- Piston 5 obviously knackered and letting lots of compression into crankcase (causing chuffing from filler, oil out of breathers, seals).

- Piston 1 knackered as I didn't clean up the bore well enough from the earlier melting so now causing it not to run true and skuffing its skirt?

- Generally lower compression readings on all cylinders (were 150'ish in the past, now 130ish) due to fitting comp gaskets without skimming the heads to compensate and what i assume to be poorly bedded in rings on all cylinders (allowing hushing air past on leakdown test) or poorly clamped heads due to stretchy bolts, well, stretching.

- Ticking noise - who knows with everything else going on.


So what to do? I want this to be reliable and reasonable cost (less than 1k) rather than powerfull and expensive, so i'm thinking:

- Get the bore taken out by 20thou, new pistons and rings.
- Get crank measured and replace all bearings.
- Replace cam with a 3.9 one and new followers
- Get heads skimmed to allow for composite ones, fitted with either ARB studs on high tensile early bolts - not sure £100 cost difference, relap valves in.
or - just buy a pair of stage1 heads but blow budget.[/list]
- use running in oil this time and load it up a bit instead of being too gentle.


Grateful for any thoughts, comments, suggestions please - on what else i should do, parts i should consider, what i've missed, etc.

Neil.

[kiwicar]

Hello and welcome.
a pit and an overhoist not jelous honest
some thoughts on your listed points.

- Ticking noise - who knows with everything else going on. it looks to me as if you have a severe pinking (detonation) problem, piston 1 failure and piston 5 on it's way. I think you need to put this as a priority to sort out


So what to do? I want this to be reliable and reasonable cost (less than 1k) rather than powerfull and expensive, so i'm thinking:

- Get the bore taken out by 20thou, new pistons and rings. Yes but I would get the block crack tested. Even if it is OK get it thoroughly cleaned, hot tanked and the oilways cleaned out. Have you considered going 3.9 or 4.2? just I think the 3.9 suites the weight of the RR much better, my 3.9 did better MPG than my 3.5 and was nicer to drive (never owned a 4.2)

- Get crank measured and replace all bearings. Buy a micromiter off ebay and do it youself, cheeper and you will then be able to again if you ever need to
- Replace cam with a 3.9 one and new followers. yup

- Get heads skimmed to allow for composite ones, fitted with either ARB studs on high tensile early bolts - not sure £100 cost difference, relap valves in.
or - just buy a pair of stage1 heads but blow budget.[/list] I would do this, it'll pay for itself and make the RR nicer to drive.
- use running in oil this time and load it up a bit instead of being too gentle.
there are various threads on oils and running in (especially cams) I would suggest e read.

I would recommend going to either LPG all the time or dumping the LPG and running petrol then you can build an engine and injection/ ignition that matches the fuel it uses. your melted piston (and smashes piston5) will probably have happened on petrol with too much ignition timing in so it would run on lpg.
Either way get rid of the distributor based ignition and use the meggasquirt to drive coil packs and use maped ignition, the distributor will be well knkd and the spark scatter will have been adding to the detonation problem.
Best regards
Mike

[logrover]

thanks for all of those mike.

pit & hoist - yep, the pit was there when we bought the house, and was the deciding factor for me , the hoist i put in last year picking up the trolley and chain block of ebay - work really well - although shoving the rangie back and fore underneath was a bit of a struggle by myself yesterday.

the ticking hasn't been there for years, then came on suddenly a few weeks ago. cold or hot it was there, especially under load, not on over-run, but only to 2000rpm (going up a hill, loud ticking, drop down a gear so 2500 rpm and silent), also crusing at 70mph no ticking. Seemed to be coming from the back of the right hand bank, so finding cylinder 5 like that it may have been the ring?

As for timing, i have one of those RIP dual timing thingies that i fitted years ago - cant remember what settings. Sounds like I'll have to investigate settings once its rebuilt - thanks for the pointer.

Block - I'll add propoer cleaning and crack testing to the list of jobs for when i start ringing around this week (anyone know of someone good in the Aberdeen area who can do this work?). I did consider 3.9, but thought additional cost of liners (anything else?) would all add up - i'll do some more checking.

megasquirt and coil packs - would be the next logical step - it's just time to fit everything in

think i'll have to get this engine back together and in, check and reset the timing to something safe, then look at improving the ignition side of things.

Could anything else have caused the melted piston and latest problems - and if it were timing related would we not expect to see signs on the other pistons?

thanks for answers, apologies for more questions. about to head out to the garage to resume the stripdown...

[CastleMGBV8]

Neil,

I would agree with Mike that the damage has been cause by timing issues and possibly a combination of that and a weak mixture.

To salvage that engine with a rebore and new pistons say £350-£400 on top of all the other rebuild parts, all new bearings including camshaft bearings a possible crank regrind, cam and followers and decent timing set is all going to add up and the sourcing of either a 3.9 half or full stripped engine would probably be a much more economic solution with the bonus of more torque and BHP.

I bought a very good 3.9 half engine from Alan Coote at Range Rover Heaven in Wiltshire and would recommend him as someone who will accurately describe the condition the the engine. He will ship for around £60.00

You can get Alan on 07711 369785 or 01249 890511

If you get one, then a light rebuild with the bores honed new rings and a full bearing set, including cam bearings, steel timing gear set a cam and lifters and you should be good to go, and can probably be done for the £1000 budget if you do the assembly work yourself.

There is a Land/Range rover specialist up in your area who occasionally posts on the forum, I'll try dig out his contact details for you.

As you have a megasquirt ECU it would be worthwhile considering using it to run the ignition as well, you would just need a trigger wheel, sensor and coil pack from a later R/R which I'm sure Alan Coote could supply as well.

Must stress it is essential that you address the timing issues and get the ECU set up to supply the correct fuelling.

Kevin.

[kiwicar]

Just had another look at the photos you have posted, looking at the piston crowns in all the burnt oil gink is alot of ally sparkle, a sure sign of pinking (detonation) also the exhaust valves are tan/ beige which is associated with them getting very hot, this adds to the suspision pinking, I suspect the engine has got very tired, the oil has started mixing with the LPG making it even slower to burn heating the exhaust valves as it goes out the exhaust still burning, The oil will have substantially lowered the octane rating on the LPG, with hot exhaust valves you now have a recipie for detonation and holed pistons and smashed ring lands. As kevin says a you will probably find it cheeper in the long run to start with a good 3.9, if you can find a short block under 80K miles you may just need a hone and new bearings with new rings, rovers are quite easy on the bores.
Best regards
Mike

[logrover]

kevin and mike, thanks for those comments and advice - time for me to have a good think about what to do next as it doesnt make good reading....

On the subject of timing, whilst stripping down further today I set the crank at TDC (by pointer) and then checked the rotor arm was in roughly the correct spot for cyl 1 firing, then i removed the front cover. I then found this:


Which as well as a stretched chain/worn sprocket is the cam timing 180 degrees out, meaning that the distributor was 180 degrees out i assume? I really can't recall how we set up the ignition timing many years ago with the RPI dual amp for lpg/petrol etc, but if the distributor was wrong at that time it could have affected things.

rest of the pics may now be a bit accedemic, but here's the cam after 40k:


crank bearing:


mains (some fretting marks on block around bolts holes?):


some of the core plugs (water jacket very clean inside - no corrosion at all):


and the oil pump:


I do actually have another old 3.5 V8 lying around that I had kind of dismissed as it is had black cornflakes when i peeked through the rockers a while back and looks totally neglected - it was fitted brand new to a landrover lightweight i broke for spares a few years ago and has only 60k (guy gave me all the reciepts when i uplifted it) - but that was over a 25 year period and looks like it has been severely neglected - so i had discounted it for dropping straight in when i was wondering what to do a while ago. However, it may now be worth opening up and seeing what could be used from the two.



I'll also investigate the 3.9 though, as I can see that there is unlikely to be "low cost" rebuild route here from these two 3.5's

cheers,

neil. (now with a static rangie in the garage and bits of engine everywhere ).

[logrover]

another question i forgot to add was regarding sealing of heads to blocks in general. I had fitted new composite gaskets and new stretch bolts and torqued up as per the manual (the 90degree) method - but it appears they didn't seal very well - see pic below:



I was looking at the block, head, and gasket today, and whilst it looks like the narrow band of metal in the gasket around the bore made a good seal (no sorching marks visible), there does appear to be corrosion just outside of this band around the oil and water passageways and i assume this is why i had oil appearing to come from the head gaskets down the block. Is this because the bolts don't clamp enough in these areas (i only fitted 10 bolts by the way, not 14). I assume this is why it is recommended to use ARP studs - will they clamp down around the oil and water passageways more effectively?

also, I read elsewhere on here that earlier standard high tensile bolts would also work well with composite gaskets - and at £100 cheaper, are they a recommended alternative (for a basic road going setup)?

thanks.

[kiwicar]

Hi
With regard the cam timing marks, turn the engine over 1 whole turn, the marks will be next (or pretty near) each other, the cam runs half engine speed and you are 360 deg out not 180.
I would have a look at the 60k 3.5, your biggest worry is rust in the bores, but if it has been inside it may be minimal or none and a quick hone and set of rings on the existing pistons would freshen it. The mains and big ends will probably just need new shells but measure up the bearings, they may well be in spec), new cam tappets and timing chain will be needed, and I would freshen the heads (or better still replace with stage 1s) if you are not going to tune it up much then stay with new standard head bolts, ARPs are really for 200+ bhp engines and this won't be.
I would make a decision on the LPG front in that to run well LPG needs alot of compression (11 to 1 is on the low side of ideal and 12.5 to 1 is more like it) but this makes it pink on petrol. Personally I hate LPG and dual fuel engines even more, I had it on a vogue SE and aswell as killing the engine in under 30k miles I spent a fortune on replacing parts to try and get to run properly which it never did. The conversion never paid for itself, I sold the car.
Mike

[logrover]

mike,

thanks again.

I realised the cam runs at half engine speed but does the dizzy as well (so rotating the one extra turn would have brought my crank and cam marks into line, but also the dizzy one complete turn so the rotor arm back at cylinder 1 position)?

As for the "under the bench" 1983 3.5, I decided to investigate this evening:

Pulled a rocker cover off in situ to see whether worth even trying to dig the engine out - looked grim inside:


Decided to remove the manifold though and look further - onset of black conflakes stage, worn cam, dished followers (all bar one came out easily though):


So may as well remove a head whilst at this stage - pleasant surprise, the bores "look" ok at this early stage - visible honing marks, no visible scoring:


Head was well carboned up and tin gaskets blowing in usual places:


Close up of one of the bores - which would possibly be ok with a hone:


Now need to extract that engine and strip further - the bottom end may have suffered some corrosion yet.

Still checking out the 3.9 option as well.

As for lpg and dual fuel, I'll probably stick with it (have three landrovers on gas), but I'll be investigating the timing with priority (it'll be running on petrol only during run-in anyway, as i did last time (500 miles).

Thanks for the advice on the ARP studs, I'll probably stick with a new set of HT bolts then.

[ChrisJC]

For my 2p worth, I would get it rebored and fit new pistons.

But as already said, I'd verify the ignition timing is OK (i.e. not pinking), and more importantly check that it's not running lean.

Chris.

[kiwicar]

Hi
erm are you sure that is a 60k mile engine? looking at that I would go along with Chris if you decide to use it.
Mike

[logrover]

yep i'm sure - have every mot from when the guy first put it in in the mid eighties - just shows its the way you maintain them (or not) rather than the miles

I'll strip it further and then mic everything up on both blocks and then decide what to do next.