3.5 EFI rebuild advice?

[Taz]

Hoping you can help... I dont want to get sucked in to the 'while I've got the heads off I might as well replace XXX" routine... I dont really need more power either - reliability and economic towing are my goals.

Some background;

89RR auto, 270,000km. Oil consumption not noticible. Smoked a bit when cold upon startup. Didnt want to rev much above 3500rpm. New cam fitted 2 owners ago (around 50,000-80,000 km ago). Recent compression had around 145psi in all but one cyclinder (it's 9.35cr engine - so should be around 170)

It's SWMBO's daily driver and doubles as the family tow beast for a 1.8t caravan. Planning on keeping her for another 3-4 years (about 40,000km). I'm trying to minimise time off the road for repairs.

Pulled the heads and found a split exhaust valve (see pic). I've never stripped a v8 before and it took me about 5hrs just to do that! Apart from the split valve, the inlet valves are fairly badly recessed. I droped them off to M&D engineering who will sort them out for me.

First question - there's a fair amount of blow-by gunk on and around the inlet trumpets (see pic). Is this excessive? Would the rings last another 40-50k ? Or would it be more cost effective to replace them?

Second question - The cam is not discolored but is showing slight signs of wear on the peaks of the lobes (see pic). I understand to replace the cam I should replace the lifters, chain and probably the rocker shafts and rockers - about $1.2k all up. Again - would this be cost effective to replace? i.e. would the assumed better fuel comsumption/power be worth it?

If the answer to the above two questions is yes - then it may be worth buying a new 3.9 short motor from triumph-rover spares or british motor imports - around 3.5k for block, pistons, cam and chain?

[mudmouse]

First off, I'm not a qualified mechanic but I've got years of experience at tipping good money after bad into cars:D

If you're only plannng on keeping it another 40 or 50k and the rebuild is looking at be 5 grand (3.9 short motor plus heads...plus miscellaneous) then thats about 1 grand for every 10k - which is expensive. Is everything else south of the flywheel in order? Is the cooling system okay too. What are you hoping to get in return when you sell it? Is LPG an option to assist in resale or economy?

I get waaaaay too emotionally attached to mechanical stuff and as a consequence try to save everything from extinction. So, she's in bits and you want to keep it for a while longer - you could have a look around for a 'better' exchange motor perhaps ???

Thats my two cents. Good luck with it.

Matt

[djam1]

Rover V8 if it seems ok apart from low compression due to the state of the Valves and you only need 50 000ks I would get the heads done put them back on and drive it.
Just spoke to TRS and they wanted $2100 for a used 3.9.

Out of curiosity what oil were you running in that engine??

Horrendous amounts of black gunk can be as a result of leaking head gaskets blowing into the valley the resultant soot and grime can take the cam out prematurely

[PhilipA]

It looks really tired to me.
The amount of black gunk in the plenum is a LOT and this would primarily be blow by coming in through the oil breather.
I think if you do the heads, the rings will not be long for the world due to the extra compression, particularly towing.
I reckon go for a second hand engine.
Regards Philip A

[Taz]

I always thought this motor, being the last of the 3.5's, was 9.35 compression ratio. I discovered I was wrong whilst cleaning the block surface this arvo - 8.13 is stamped into the block :o

This means my initial compression test results were pretty good. It also means I can shave some metal from the heads to increase the CR, but first I'd really like to know why LR reduced it? Was it a fuel quality thing or something to do with the EFI? Or any other reason why I should not increase the CR?

Any suggestions on how much to shave off the block before needing to use PULP? about 9.75:1?

BTW
I've been using Caltex GTX2 oil.
I dont think I would risk buying a second hand 3.9 (or any 94mm bore) block.

[PLR]

Hoping you can help... I dont want to get sucked in to the 'while I've got the heads off I might as well replace XXX" routine... I dont really need more power either - reliability and economic towing are my goals.

Some background;

89RR auto, 270,000km. Oil consumption not noticible. Smoked a bit when cold upon startup. Didnt want to rev much above 3500rpm. New cam fitted 2 owners ago (around 50,000-80,000 km ago). Recent compression had around 145psi in all but one cyclinder (it's 9.35cr engine - so should be around 170)

It's SWMBO's daily driver and doubles as the family tow beast for a 1.8t caravan. Planning on keeping her for another 3-4 years (about 40,000km). I'm trying to minimise time off the road for repairs.

Pulled the heads and found a split exhaust valve (see pic). I've never stripped a v8 before and it took me about 5hrs just to do that! Apart from the split valve, the inlet valves are fairly badly recessed. I droped them off to M&D engineering who will sort them out for me.

First question - there's a fair amount of blow-by gunk on and around the inlet trumpets (see pic). Is this excessive? Would the rings last another 40-50k ? Or would it be more cost effective to replace them?

Second question - The cam is not discolored but is showing slight signs of wear on the peaks of the lobes (see pic). I understand to replace the cam I should replace the lifters, chain and probably the rocker shafts and rockers - about $1.2k all up. Again - would this be cost effective to replace? i.e. would the assumed better fuel comsumption/power be worth it?

If the answer to the above two questions is yes - then it may be worth buying a new 3.9 short motor from triumph-rover spares or british motor imports - around 3.5k for block, pistons, cam and chain?


G`day Taz

Looks like an honest engine and following is my opinion/plan of attack nothing more .

The carbon about the trumpets doesn`t look great but remember how long its had to build it up , if the blowby was really excessive i`d expect to see more colour/carbon in the valley .


Before you clean it up ( if not already done ) , look around each liner on the block surface to see if all cylinders have been sealing also look on both sides of the gaskets . There should be defined marks that tell this . From you pics it looks like 4 & 6 may have been leaking between each other ( mid-way where the liners are closest ) , but hard to see clearly from that aspect .

Looking at the cam doesn`t tell alot unless you peer closely at each lobe and you have a constant ( know what they should look like ) . The circular part of the running surfaces should look similar , the peaks of the lobes should appear the same distances across ( as in the pointy part ) it may vary between inlet and exhaust but you only need to find one thats much wider and therefore lower for the cam to be not working as it should .

If you pull a couple of lifters out , one tell of their condition is how readily they can be removed . Take note of which hole the lifter comes from so`s to put it back in same .

Use a straight edge on the base of the lifter and hold to the light . The part to look for is the light between the straight edge and the lifter base .

Concave is worn out , Flat is worn but useable , Convex is good .

If the ones looked at seem ok , take them all out one by one , putting them back in hole they came from , they should come out fairly easily , if they don`t want to , first see if there`s gunk on the bottom ( part closest to the cam ) . The bottom of the lifter can mushroom .
If it did have a cam when you mention they should come out easily .

The wear on the rocker shafts can be seen/felt by taking the bolts out of the posts ( if needed ) and sliding the rockers along ( with it all still asssembled ) so`s you can get to the place that they run on , look at the top of the shafy but also pay attention to under as this is where they seem it show more wear .

Clean the carbon off around the top of the liners and look/feel for a lip ( finger nail ) . Generally one thats done terrible alot of work will show a lip , one that only done alot of work will show no lip .

Couple of years ago i bought a new crossbolt 4.0ltr for less than half of what they quoted you a 3.9ltr but i think these were being quit by Landrover , buying a new one other than the warranty doesn`t mean it won`t crack , i also have a later ( earlier than the new one ) 4.0ltr , one of the good new breed no block crackers but it has suffered . From what i read cosworth? UK are now making these engines and they are the ones to have .

If you removed the valves i guess you know the valves are recessed , looking at your pics the 2 inlet i can see don`t look it , if they are sitting a little above the combustion chamber , which they look to be , i be surprised if they are . I hope you asked for a quote once looked at and didn`t just say " fix em " because the head work may be over spend if they replace seats as well as valves and do guides and then machine them .


Also while the tops off the crankcase vent system has a spot that probably could be cleaned , it is behind a small plug near the throttle butterfly , if you know of it say because i won`t need to explain then ( not that you don`t have enough on your plate .

Cheers
Peter

[Taz]

Many thanks Peter - very helpful.

Since the engine was blowing smoke at start up I'm hoping worn valve guides/seals is the main reason for the blow-by since my compression test results were good (for an 8.13 CR) and the engine was not using much oil. Although the bores look a bit glazed so I'm sure the rings are leaking a bit.

All liners are flush with the block:) And although the engine never gets hot nore uses any coolant - there was some tarnish color as you picked out across some bores (see pic).

The cam lobe wear does seem a little irregular (the difference in the width of the shiny/wear sections on each lobe was around +/- 1.5mm).

The base of the followers (which all came out easily) look flat to the naked eye however against a straight edge they are slightly concave.

The rocker shafts are worn on the low side as expected, and the rocker arms have worn bores also. There is some lateral movement (I can wiggle them side to side slightly) However the push ros cups in the rocker arms look servicable.

There is no lip at the top of the bores and can still see some honing marks on some of them.

The head reconditioners are going to pull them down (I didnt have a spring remover) and ring me on monday. Worse case they said $800-$900. I'd like to say just repair the split valve and give them a shave, however the inlet valves are below the combustion chamber (see pic). Is it worth replacing the inlet valves with waisted 3.9 ones?

Thanks for your advice on new blocks too - sounds like they are a risky option also if you cannot verify their origin. I guess the ones from BMI, being imported from the UK, are more likely to be the good ones.



Also while the tops off the crankcase vent system has a spot that probably could be cleaned , it is behind a small plug near the throttle butterfly , if you know of it say because i won`t need to explain then ( not that you don`t have enough on your plate .


Sorry not sure about this. Do you mean the air by pass?

Once again - thanks for your help. This engine is clearly worn but perhaps serviceable for a few more years? No doubt it will be in pretty poor shape by then and I might regret not renewing the cam/lifers/chain/rockers now. However I'd be inclined to pull the engine to do that, and then I might as well fit new bearings and rings, but this is all more time off the road.

Cheers,
Taz.

[PLR]

Many thanks Peter - very helpful.

Since the engine was blowing smoke at start up I'm hoping worn valve guides/seals is the main reason for the blow-by since my compression test results were good (for an 8.13 CR) and the engine was not using much oil. Although the bores look a bit glazed so I'm sure the rings are leaking a bit.

All liners are flush with the block:) And although the engine never gets hot nore uses any coolant - there was some tarnish color as you picked out across some bores (see pic).

The cam lobe wear does seem a little irregular (the difference in the width of the shiny/wear sections on each lobe was around +/- 1.5mm).

The base of the followers (which all came out easily) look flat to the naked eye however against a straight edge they are slightly concave.

The rocker shafts are worn on the low side as expected, and the rocker arms have worn bores also. There is some lateral movement (I can wiggle them side to side slightly) However the push ros cups in the rocker arms look servicable.

There is no lip at the top of the bores and can still see some honing marks on some of them.

The head reconditioners are going to pull them down (I didnt have a spring remover) and ring me on monday. Worse case they said $800-$900. I'd like to say just repair the split valve and give them a shave, however the inlet valves are below the combustion chamber (see pic). Is it worth replacing the inlet valves with waisted 3.9 ones?

Thanks for your advice on new blocks too - sounds like they are a risky option also if you cannot verify their origin. I guess the ones from BMI, being imported from the UK, are more likely to be the good ones.



Sorry not sure about this. Do you mean the air by pass?

Once again - thanks for your help. This engine is clearly worn but perhaps serviceable for a few more years? No doubt it will be in pretty poor shape by then and I might regret not renewing the cam/lifers/chain/rockers now. However I'd be inclined to pull the engine to do that, and then I might as well fit new bearings and rings, but this is all more time off the road.

Cheers,
Taz.


G`day Taz

Sounds like you`re on the right track ( what i consider to be ) and nothing sound to me to be greatly over what would be expected .

It`s possible to get an idea of the chain strech , as it streches it retards the cam timing which means it will not work as well lower down but it also depends how it was timed when the cam was fitted ( something to know but not much can be done unless it was fitter with vernier type gears etc )

If you can rotate the crank a little back and forth and note when the cam has pressure on it . Go from 1 pressure to the other , the chain slack being inbetween . Measure the amount of rotation at the crank , if you get less than 3 or 4 mm it`s probably ok , much more and it has a fair bit of strech . The lower the figure the better .

Rover valves are quite expensive , for instance an exhaust valve ( wasted , newer style ) is around $34 and these valves have a recess or concave in the face of the valve . Aftermarket stainless valves can be bought for around a third , which are flat across the face same as the exhaust valves in yours and are wasted in a similar manner to the factory one . ( aftermarket i got were from a local engineer don`t know where to obtain them other than a similar source )

Inlet factory are not as expensive as exhaust but there would be i`d expect a similar one aftermarket also , the wasted part of the factory inlet i don`t know would be much of an advantage because the guides they go will are shorter than the ones in yours and there are shorter aftermarket guides than the factory ones . Cost would be the factor that would be the decider for me .
The people that have your heads would know all of this and be able to advise you and if they are resonable won`t mind answering any questions as to your options and the outcome in $s .

Yes the air bypass , if you trace where the passage goes and comes out infront of the butterfly . From inside , infront of the butterfly place a small allen key in the hole (5/32 or smaller ). It should flop around in the hole , a 1/4 inch allen key should easily fit in . If the small doesn`t fit or can`t be entered the lenghth of its right angle it may need cleaning .
Knock the plug out ( small welch type ) using a cut of bolt or similar from inside the throttle body ( protect butterfly ) then run a drill bit through it from the outside , small till the right size but be aware that the end of or entrance that comes out infront of the butterfly is a smaller dia than the lenght of the hole/passage so the drill bit doesn`t go all the way through to the butterfly passsage .
When knocking the plug out put a rag or catcher etc over it because it can be hard to finf if it flies .

When you put it all back together , it is good practice to set the lifter preload , most of the rattle lifters we read of here would not occur if the preload had be set . You`ll need to bleed a couple of lifters down to do this but you don`t need to bleed them all if you use a bit of imigination .

Cheers
Peter

[peachey80]

Hey Taz,
If you're interested, I have a complete good 3.9. It's been in my way i the shed for abour 6 months. Planned to put it in my 84 rangie, but decided to go all out and put a 302 EFI windsor in.
The 3.9 has done 220,000, out of a 94' vogue (last of the classic) Great motor, nothing wrong with it what so ever.
$450 + postage, need it gone!!! Too many projects on the go.
PM me if you're interested.

Cheers,
Shayne

[Taz]

Yes the air bypass , if you trace where the passage goes and comes out infront of the butterfly . From inside , infront of the butterfly place a small allen key in the hole (5/32 or smaller ). It should flop around in the hole , a 1/4 inch allen key should easily fit in . If the small doesn`t fit or can`t be entered the lenghth of its right angle it may need cleaning .
Knock the plug out ( small welch type ) using a cut of bolt or similar from inside the throttle body ( protect butterfly ) then run a drill bit through it from the outside , small till the right size but be aware that the end of or entrance that comes out infront of the butterfly is a smaller dia than the lenght of the hole/passage so the drill bit doesn`t go all the way through to the butterfly passsage .
When knocking the plug out put a rag or catcher etc over it because it can be hard to finf if it flies .


You'll have to forgive me as I still dont quite follow - something to do with my tasmanian heritage perhaps? Anyway I've attached some piccies of the area I think your referring too. There is hole on the left and right of the butterfly, but the only core plug is the small one on the right. Is this the one your referring too? If so, I cannot access it from behind to knock it out?

[PLR]

G`day Taz

I`m not surprised you don`t understand and it`s all down to me and my poor and misleading explaination . I should have taken more time and put more thought into it , sorry .

What i`m taking about is to do with the crankcase vent system not the bypass .

If you look under the TPS ( throttle position sensor ) there is a small plug .

This lines up with the hole/passage , down low and left of the butterfly .

The pipe/nipple that sticks out the front beside the throttle body also lower left connects to the passage in question .

The plugs needs to be forced out from inside the throttle because the plugs is almost as deep as it is wide and turning like a normal one is done will probably render it useless but knocking out from inside does it no harm .

The cut off bolt is long enough to get the plug out and also short enough that it can be tapped on .

It`s tapped on by using a screwdriver or something flat , whatever works .

It`s not difficult but use your hand/finger to take the force where you hit the lever so it can be relayed further in to where the cutoff bolt is , i know that`s not explained well .

Because you can`t hit the bolt you have to relay the tap from outside to inside your hand/finger is a piviot for the lever , gentle light taps is all it takes and the squarer the plug can be kept the easier it comes .

I`ve made it sound difficult , it`s not , it my poor explaination .

The rest is as in the earlier post .

Sorry to waste your time , i know your on a schedule .

Cheers