My toy, P38 Range Rover 4.6HSE Top end gasket set arrived.

[Speedtouch]

Use a multimeter to measure the resistance of the HT leads.

[Jesus325iTouring]

So lets say I have a blown head gasket, or 2 ( ) can someone tell me why it is always nessecary to have the heads skimmed? And is it really needed?

I ask because some years ago one of my R5's blew a head gasket, I pulled the head off, didn't clean anything and promptly fitted a second hand head gasket I pulled out of a spare engine I had and threw it all back together. The car ran for many thousands of miles without fault after. Is the Rover V8 a little more complex than a 1.1 4 pot? It could be argued a V8 is no more than two 4 pots bolted together afterall

I'm not suggesting just bodging it up like the R5, just curious re the skimming etc.

[Speedtouch]

Assuming only the gasket has blown and there has been no overheating leading to warping of the head (check with a straight edge, or by laying it on a flat pane of clear glass), just light cleaning up is required prior to fitting a new gasket and torqueing the head down in the right order and to the right torque.

Skimming is only required if you are in doubt as to the flatness of the head/block. Even then, it is possible to do a DIY light skim using fine emery paper and a (flat) rubbing block...

[Satan]

So lets say I have a blown head gasket, or 2 ( ) can someone tell me why it is always nessecary to have the heads skimmed? And is it really needed?

I ask because some years ago one of my R5's blew a head gasket, I pulled the head off, didn't clean anything and promptly fitted a second hand head gasket I pulled out of a spare engine I had and threw it all back together. The car ran for many thousands of miles without fault after. Is the Rover V8 a little more complex than a 1.1 4 pot? It could be argued a V8 is no more than two 4 pots bolted together afterall

I'm not suggesting just bodging it up like the R5, just curious re the skimming etc.

If you "think" you have a blown head gasket then you will have one, just "think" about the cheaper option, look up the "law of attraction"

[aimlessrock]

personally i would be both HG's as opposed to just one of them (in for a penny etc). I would take the heads to a machine shop for pressure testing, if they pass then a skim would be wise.

[Jesus325iTouring]

Thanks Maurice, good advice there. It did over heat due to a blocked breather back in the summer, but since sorting the cooling out all has been well.

Aimless, I quite agree, if one has gone I will do both, whilst all of the inlet etc is off would be lazy to not do both for piece of mind.

Stefan, I don't like too admit you're right, but you probably are!

[Speedtouch]

Carry out a compression test prior to tearing it all apart - it may turn out to be something simple...

[Jesus325iTouring]

That's my next move Maurice, just need to buy myself a compression tester, should be ordering one this week.

[Satan]

Carry out a compression test prior to tearing it all apart - it may turn out to be something simple...

Its a Range Rover,

[Jesus325iTouring]

At one time, yes the P38 had a bad name, it still does, but difference is now every problem is out there on the internet many times over with fixes and get arounds etc. Can still be a pain for example when my computers went into melt down, but with the help of the internet it was fixed, all be it it took three weeks, but it cost zero pounds. Go back 15-20 years and everything was dealer only, even then the dealers had no clue how a P38 worked so it cost a fortune for owners to have them repaired.

[Jesus325iTouring]

Results are done for compression test.

All between 115psi & 160 except cylinder 7, that was, well, 0psi

Looks like I have a blown head gasket. What are the chances of a holed piston though?

[Satan]

Can you borrow a camera to check the piston?

[Jesus325iTouring]

Don't think much point Stefan, head has to come off now whatever. I suspect it is just the gasket because I now recall hearing a "chuffing" noise a short while ago but had forgotten (chose to ignore) it.

[martauto]

Thats bad news mate is it worth changing the gaskets or replacing the engine with a second hand unit ?

Mart.

[Jesus325iTouring]

Gasket for sure Mart, a gasket set is about 80 quid, some new head bolts about 20 and then just my time to do it/f uck it up Double it if I do both banks, which I should, but probably won't, unless it is a piece of p iss to do.

New motor is circa 5-800, plus a lot more potential aggro getting my computers to accept the new engine, a P38 engine change is akin to a heart transplant, the body may accept it, but just as quickly reject it

[maxfield]

If I’m honest, I’d expect a bit more damage if it’s just the one cylinder on low compression, usually headgaskets go between cylinder leaving 2 cylinders low on compression.

Whip the head off and find out what the crack is, could potentially be head/valve related.

[Jesus325iTouring]

What else could cause total loss of compression on just one cylinder Jamie? I am lead to believe there is an area on the Rover V8 that the head gasket blows out the side, not close to a water jacket, hence the non over heating etc.

[maxfield]

Am I right in thinking it’s a push rod engine?

I wouldn’t suspect a holed piston as you’re exhaust would be smoking more than you do a˜‰

In my experience if you’ve lost compression on 1 cylinder, I’d suspect valve/spring/rocker.

[Jesus325iTouring]

Thanks for that info, having done a bit of research on your suggestion (yes it is a push rod engine), the compression AND oil pressure light on does indeed point to a rocker issue, that would be fine and dandy if thats the case, seems a pretty esay fix if thats the case. (Assuming nothing else has been damaged!)

[BenHar]

Aren't these prone to dropping liners?

Ben

[Jesus325iTouring]

They are, but my symptoms don't reflect that failure.

[maxfield]

Have you stripped the donk down yet?

[Jesus325iTouring]

Starting tomorrow morning mate, be interesting!

[Satan]

Starting tomorrow morning mate, be expensive!

Fixed for you Rog ;o)))

[Jesus325iTouring]

I am hoping not, I would be pleased if Jamies prognosis was on the mark!

[Satan]

Fingers crossed, as then you can visit London in it and do my repointing.........

[Jesus325iTouring]

Not sure the Lord Mayor would allow my 'eco friendly' vehicle inside the LEZ

[Satan]

I don't live within the ULEZ ;o))))

[Satan]

Well not yet........

[martauto]

I had a 3.5 rover in the early 1980`s (car was old then) and one of the gaskets went but when I looked deeper, the rocker arms had eaten into the shafts so I had to re-grind the shafts and bush the arms, now would this be in the same area that you could be in ?

Mart.

[Jesus325iTouring]

Interesting Mart, interesting. The cylinder with no compression has push rod issues. I turned the car over with just the rocker cover removed to see what was moving. Everything (to an untrained eye) appeared to be operating correctly, ie the rocker arms moved up and down.

See attached pictures of the push rods on the defunct cylinder, they appear to have heavy weld like deposits (none of the other rods have this.



The top end, in my view looks pretty coked up, though does appear to have oil being pumped up there which is promising.

Left Bank..



Right bank with defunct cylinder..



General overview, note all the masking tape notes, so many bloody connections I would never remember how to put it all back together!




Another thing, though unrelated, so many bolts were not tight

[Satan]

*sneaks in to garage and removes masking tape............

[Speedtouch]

Maybe just leaking valve stem seals. Perhaps try cleaning off the crud, particularly the 'weld' with gunk/paraffin/petrol and see how it responds...

[martauto]

Am I correct in saying these are hydraulic tappets?
Hell I have just looked closer at the pics and in my humble opinion , some one before you had this car had not looked after the oil.
They used to say 6000 miles or 6 months for a change but that was not enough for this engine and if it was not done it would hang on to "crap" like you see in the push rod pics.
People say "its only done 2000 in three years so it should be OK ? "
Wrong.
If you had to flush the engine now , who knows what shit it may disturb but it seems like there could be an oil blockage which may be affecting the lifters?

I change the oil in both of mine twice a year for what it costs, the Baur being @£15 inc filter. The sport costs a bit more but it is worth it.

Mart.

[Jesus325iTouring]

This is what I am thinking before pulling the head off, a bloody good clean up which it clearly needs and see what happens. I am wondering whether the lumps on the rods are affecting something. Not sure how it would affect compression though.

Are they hydraulic, tell you the truth I don't know, this is all a learning curve for me, I have only changed a head gasket on a Renault 5, and that was a doddle! All the rods seem to do is be pushed up and down by the cam in the bottom of the valley, I would assume by that, they are not hydraulic.