Have I cracked the Block?

[Guesty]

During our last outing we had an overheating problem with the 3.9L which developed into a blown head gasket(bare minimum).
I have removed and disasembled the engine, while cleaning the block I noticed the 6 marks on the tops of webs in the casting, they dont seem to go down the side of the webs at all.
I'm fairly sure this is not the first time this motor has been in bits

Any Ideas

Regards
David

[Taz]

The normal 'cracked block' failure mode of these (and all 94mm bore blocks) is cracking behind the liners, not the webs. Those marks dont appear to be cracks, but its hard to tell from the picture. If you have overheated the engine, have a close look at liners. If any have dropped below the block deck then it's most likely you have a crack behind the liner which releases it's grip on the liner and allows it to move.

[mike 90 RR]

I'll run with Taz .... I would expect cracks would be more "Hair line" rather than broad & shiny



Mike

[p38arover]

They look more like scratches.

This is what a slipped liner looks like:

https://www.aulro.com/afvb/

[87County]

They look more like scratches.

This is what a slipped liner looks like:

https://www.aulro.com/afvb/


for a sec I just couldn't work this out and then I saw the engine was upside down.... like in a tiger moth... I hadn't realised they were that way in P38s...:D

....I don't know if that's a dead mosquito,... or something worse.... in the bore...:)

seriously, an instructive pic - thanks Ron

regards - Laurie

[Blknight.aus]

might be worth getting a dye penetration test done just for peace of mind...

you can buy the 4 spray can packs that comprise the test kit if you want to DIY for about $30 but most reputable machining shops should have a kit and may do the test for you for a small fee, it takes about an hour to do but is a case of spraying each can on in turn and waiting the prescribed time between the different sprays.

[p38arover]

for a sec I just couldn't work this out and then I saw the engine was upside down.... like in a tiger moth... I hadn't realised they were that way in P38s...:D

....I don't know if that's a dead mosquito,... or something worse.... in the bore...:)

seriously, an instructive pic - thanks Ron

regards - Laurie

The engine was in a scrap metal bin (not mine) when I photographed it. It is a 3.9, not a P38A 4.0/4.6 :) - I'll invert the image. You may need to refresh the page to see the upright image.

[Guesty]

thanks for all the info, the block will be off to an engineer on Monday.

Can anyone recommend (if thats allowed) a good workshop in the Nth Canberra area?

Ron,

How do you put the photo in the text?


while pulling the engine down I found that the Flex Plate was only just hanging on - see pic

Cheers
David

[p38arover]

Ron,

How do you put the photo in the text?

Like this:

http://www.aulro.com/afvb/attachments/technical-chatter/11129d1223709267-have-i-cracked-block-flexplate.jpg


When you are creating a message, see the image symbol on the second row (5th from the RHS)? Click on it and a dialogue box will open. Put the URL of the pic in there and click OK.

That was lucky, finding that broken flex plate. Two of mine broke around the centre.

[Range Blitzer]

Birko in Mitchell is as good as anywere to get engine machining and testing done. Know of a few people that have had stuff done there and are happy. I guess they could handle rover V8s.
Robert.

[PLR]

I have removed and disasembled the engine, while cleaning the block I noticed the 6 marks on the tops of webs in the casting, they dont seem to go down the side of the webs at all.
I'm fairly sure this is not the first time this motor has been in bits

Any Ideas

Regards
David

G`day David ,

i`d say your right and it`s not the first dismantle for your engine .

When you find an engineer ask them about the scars .

It`s not a fault in the block or any type of problem .

Cheers
Peter

[Guesty]

had 6 thou shaved off the block by Berco Engineering, they had no explanation for the marks.
they had to shave 6 thou to level the block with the sleeves, they said the tops of the sleeves being lower than block wouldnt have helped the gasket to seal properly.

while seperating the motor from the gearbox I found the drive plate was broken

now I'm about to put things back together , but first I need to remove the old rear main seal, to do this I have to get the adaptor off the back end of the crank shaft ( Its held on by 6 slightly butchered hex key bolts, any Ideas )

Cheers

[Guesty]

on the subject of the flex plate, can someone tell me if the one between a 3.5 L and chrysler box is the same as the one between a 3.9L and a ZF ??

[PLR]

had 6 thou shaved off the block by Berco Engineering, they had no explanation for the marks.
they had to shave 6 thou to level the block with the sleeves, they said the tops of the sleeves being lower than block wouldnt have helped the gasket to seal properly.

while seperating the motor from the gearbox I found the drive plate was broken

now I'm about to put things back together , but first I need to remove the old rear main seal, to do this I have to get the adaptor off the back end of the crank shaft ( Its held on by 6 slightly butchered hex key bolts, any Ideas )

Cheers

device that secures the block = marks

[PLR]

on the subject of the flex plate, can someone tell me if the one between a 3.5 L and chrysler box is the same as the one between a 3.9L and a ZF ??


No , they aren`t

[PhilipA]

The head gasket does not seal onto the liners, but onto the block outside the liners.
So the engine place is very inexperienced with Rovers.
That of course is the problem with a slipped liner, the water from a crack in the block behind the liners moves up and into the combustion chamber, to cause a mysterious loss of water and/or pressure .
The stepped liners' main claim to fame is that the gasket seals onto the liner, and holds it in place.
I would be concerned at reassembling your motor without replacing the liners .
I wouldn't do it with mine as the risk of having to do it all again is to me is a greater hassle than the cost of having new stepped liners put in ( by someone who knows their stuff)
Regards Philip A

[LOVEMYRANGIE]

The head gasket does not seal onto the liners, but onto the block outside the liners.
So the engine place is very inexperienced with Rovers.
That of course is the problem with a slipped liner, the water from a crack in the block behind the liners moves up and into the combustion chamber, to cause a mysterious loss of water and/or pressure .
The stepped liners' main claim to fame is that the gasket seals onto the liner, and holds it in place.
I would be concerned at reassembling your motor without replacing the liners .
I wouldn't do it with mine as the risk of having to do it all again is to me is a greater hassle than the cost of having new stepped liners put in ( by someone who knows their stuff)
Regards Philip A

What, no "quotation" on that one Phil???? lmao :Rolling:

[Guesty]

well the guy at Berco Engineering seemed to know what he was talking about, he should as he does all the machining for Canberra Motor Works (LR Specialists) according to Ray at CMW.
so I got one of the new gaskets out of the kit and sat it on the block, and guess what, the inside ring of the gasket sits very neatly on top of the sleeve so hopefully there wont be any problems with it sealing.

[PhilipA]

well the guy at Berco Engineering seemed to know what he was talking about, he should as he does all the machining for Canberra Motor Works (LR Specialists) according to Ray at CMW.
so I got one of the new gaskets out of the kit and sat it on the block, and guess what, the inside ring of the gasket sits very neatly on top of the sleeve so hopefully there wont be any problems with it sealing.

OK Mate I bow to your superior knowledge.
All those books and the experience of forumites and experts with the most common serious fault of a Rover V8 must be wrong.
Regards ( a bemused) Philip A

[Guesty]

sorry Phillip,

Definitely not superior knowledge, I can only trust what I see to be true and hope the advice I get is correct

Cheers

[101RRS]

I am not able to comment on the issues raised here however I can assure all concerned that Berco are a quality organisation - maybe there is a misunderstanding.

I have had many dealings with Berco with a number of different makes of vehicles - they have all the gear and are a large specialist engine rebuilding organisation. Shame we no longer have an equivalent landrover serviceing establishment in Canberra since Morwoods closed.

Garry

[LOVEMYRANGIE]

had 6 thou shaved off the block by Berco Engineering, they had no explanation for the marks.
they had to shave 6 thou to level the block with the sleeves, they said the tops of the sleeves being lower than block wouldnt have helped the gasket to seal properly.Cheers

If they knew what they were doing, they would have known the liners have slipped.
And being an engineering shop, I presume they dont just do engines either??

[Guesty]

I could well be wrong but I find it hard to believe that all 8 sleeves slipped and only by 5 to 6 thou, still, strange things can happen, has anyone come across this before?

[PhilipA]

Guesty,
I apologise for my intemperate reply, as it is your risk and I guess your business.
In my experience, it is so rare for engineering shops to work on Rover V8s that they do not become familiar with them unless they specialise in Rovers such as Bruce Davis in Sydney.
For example I was at Tweed heads and my diff died in my M3. The shop also did rebores etc. They had a P76 block there which had a slipped liner. We got to talking and I asked if he was going to use a stepped sleeve "what are they?". I asked whether they would heat the block."Nah we just press them in". "Are you going to replace them all?". "Nah just the one."
This is IMHO a recipe for disaster
The sunken sleeves in your block do not necessarily mean you will have a problem. They are an artifact of the way that Rover inserted the sleeves. They heated the blocks to 100c then inserted cool sleeves onto a step. As the block cooled , the sleeves were often pulled down, as yours have been.

However this gap meant that as soon as the engine was overheated, the sleeves were free to move up and down and wear looser and looser. This is because the coefficient of expansion of the steel sleeves vs the alloy block are different and once over 100C, the sleeves are relatively loose. If a crack develops behind a sleeve of course the tension is lost and they are looser again and water finds its way into the combustion chamber.

I guess my point is who knows whether yours are tight or loose?

Why did you rebuild the engine? Was there water loss? Have you EVER overheated the engine?
If any answers are yes. Good Luck.
Regards Philip A

[Guesty]

PhilipA,
I'm rebuilding the engine because it blew a head gasket.

yes it has been overheated.

I'm feeling reasonably confident about the sleeves now as they seem to be sitting on machined ridges in the casting of the block and I found no signs of any pistons having grabbed at all, pistons rings and bores are all in good condition and well within tollerances.
I replaced the big ends and mains because they were at their upper limits but they also had no signs of binding, slipping or running dry.

an interesting thing though the old centre main only had thrust faces on the top half whereas the new ones have thust faces on both halves (looks more correct to me), more evidence that the dodgy bros did the last rebuild.

Cheers

[PhilipA]

Several bearing kits only have the half thrust washer.
I had to regrind the crank of my 81 In Saudi specifically because of thrust washer face wear as the thrust washer is part of the bearing. To get a 20thou oversize thrust you have to have a 20thou oversize bearing set.
I was not impressed when the new bearing set came with only half, so I insisted the supplier send me another centre bearing.
It would be OK on an auto but you press on the thrust every time you use the clutch on a manual.
But it says that the engine has been rebuilt once before at least as OEM is two thrusts AFAIK.
Regards Philip A

[Blknight.aus]

Guesty,
I apologise for my intemperate reply, as it is your risk and I guess your business.
In my experience, it is so rare for engineering shops to work on Rover V8s that they do not become familiar with them unless they specialise in Rovers such as Bruce Davis in Sydney.
For example I was at Tweed heads and my diff died in my M3. The shop also did rebores etc. They had a P76 block there which had a slipped liner. We got to talking and I asked if he was going to use a stepped sleeve "what are they?". I asked whether they would heat the block."Nah we just press them in". "Are you going to replace them all?". "Nah just the one."
This is IMHO a recipe for disaster
The sunken sleeves in your block do not necessarily mean you will have a problem. They are an artifact of the way that Rover inserted the sleeves. They heated the blocks to 100c then inserted cool sleeves onto a step. As the block cooled , the sleeves were often pulled down, as yours have been.

However this gap meant that as soon as the engine was overheated, the sleeves were free to move up and down and wear looser and looser. This is because the coefficient of expansion of the steel sleeves vs the alloy block are different and once over 100C, the sleeves are relatively loose. If a crack develops behind a sleeve of course the tension is lost and they are looser again and water finds its way into the combustion chamber.

I guess my point is who knows whether yours are tight or loose?

Why did you rebuild the engine? Was there water loss? Have you EVER overheated the engine?
If any answers are yes. Good Luck.
Regards Philip A



Im backing that lot.....

if the liners were all in the original positions (ie all exactly the same to the nearest thou) then in theory they are all still sitting on the locating lip and machining the block down to meet the top of the liner causes the head gasket to hold them in place... its sort of the poor mans solution to doing a top hat liner install.

Without knowing the full story nor having spoken to the bloke who did the machining anyone who just machines up a rover anything v8 without extensively checking liners and reseating the liners generally shouldnt be regarded as professional landrover engine rebuilders.. Of course there are extenuating circumstances, the check may have been done prior for it going for machining, or the customer may have just said "deck skim that for me".