N/A Questions!!!

[pos]

Hello,

I've started using my 2.5 N/A for motorway runs between Leeds and Ipswich and it's running really well (all apart from springing a few oil leaks which I'm on with fixing now). Anyways, the head gasket has started spewing oil everywhere again so I've taken the head off. The bores still look in good condition (a bit polished) but my new pistons are still in tact with no cracks etc.

1) Why does driving at higher speeds 60-70 seem to blow my head gasket? Technically there's no extra compression being created, it's just happening at a higher rate!

2) Should there be oil down the rocker shaft bolt holes?

3) If the head oil return pipe is blocked what will happen?

I'm planning on running this engine into the ground. I'm not too bothered about running at at high revs because it does perform well, doesn't over heat and pulls up hills on the motorway surprisingly well too. I just don't understand why my head gasket keeps popping!!!

Thanks for any help / suggestions
-Pos

 

[boydy1989]

Evenin mate!

Oil will get down the rocker shaft holes, but it shouldn't be as you can sometimes cause a hydraulic lock when you put the bolt in.

Where does the gasket fail, is it always in the same place?

There is no head return passage for the oil, it runs down the push rod holes. If your upwards pipe is blocked then i think something lower down will stop working/pop from the pressure, or your valve gear will suffer.

 

[pos]

Gurrd evening!

Alright, that's fine then! I'll just run the bolts in to push the oil out before tightening them. Yeah, it's that bastarding little hole in the block which I decided to unblock. I'm going to fill it with liquid metal and then emory cloth everything down nice and smooth ready for the new gasket. There's also the fact that I hadn't torqued the stud bolts down properly last time I put the head back on, so that'll need doing first and I'm going to let the engine tickover to temperature this time as opposed to revving it ****less once the new gasket is in and the head is on.

Also, just out of interest, is it worth fitting those little crankcase breather filters to the filler cap and intake manifold breather intake to stop my engine burning its own oily blow by!? Or will my engine bay just fill with a toxic mist?

Cheers
-Pos

 

[boydy1989]

youll need to soak out some of the oil with a cotton bud - running the bolt in will only get you to the same state you are already in wrt. hydraulicing the bolt.

Make sure you fill that hole nicely and mek it REALLY smooth!

Also, i wudn' bother with the breather filters - the breathers work better with the vacuum from the manifold. Just make sure the gauze is in good nick is all.

Anyways, aint seen you about on here for a while?

Boydy

 

[landowner]

Another thing which I have always found useful is to wear new gloves when handling the new gasket from packet to head. keep everything grease free and very clean when fitting gasket and head.
Any grease even off your hands will burn the gasket when everything gets hot.
Probably think thats a bit over the top but best be sure than have to do it again in a few months.

 

[pos]

youll need to soak out some of the oil with a cotton bud - running the bolt in will only get you to the same state you are already in wrt. hydraulicing the bolt.

Make sure you fill that hole nicely and mek it REALLY smooth!

Also, i wudn' bother with the breather filters - the breathers work better with the vacuum from the manifold. Just make sure the gauze is in good nick is all.

Anyways, aint seen you about on here for a while?

Boydy

Alright cheers. I've been keeping a bit of a low profile for a while! Actually I havent had much time to do anything land rover wise so I haven't been snooping around asking for help or helping out others. Things have cropped up again now, so I've come back to give and take!

-Pos

 

[discomania]

Have you had the head checked?

 

[pos]

Haven't had it checked no! Can't afford to be doing stuff like that!

 

[Sean]

Haven't had it checked no! Can't afford to be doing stuff like that!

tis false ecconomy not getting it checked Pos, unless you like spending yer dosh on top ups

tis usually less than £50 to get it checked n skimmed if required.

 

[boydy1989]

use a straight steel rule to perform a basic home check, jus lay it along it edge on and look for gaps.

 

[discomania]

What boydy says... Also, you can use a new window (new because modern glass is square).

It doesn't really make sence to be honest, if everything has been done properly (and I know you have loads of practise at this now).

Though - it could be your tyres are too small your gearing has been changed at some point and your effectively knocking its head in on the m-way and blowing it up. Do you have SatNav - what speed are you doing when your speedo reads 65?

When I had my offroad tyres (huge) on my 2.5NA I would cruise up and down the motorway fine, then I bought some AT's for the mainly road driving I was doing at the time and the engine screamed on the motorway.

These engines don't like to be driven at 70 I would say, they will sit all day at 60ish after that I think you get into risky territory.

What gaskets are you using? How are you cleaning the surfaces of the block/head?

If you re gasket it and keep below 65 see if you can get it to beat the others and then you know its speed related.

Get some good clear photos of the head, top of the block and the gasket posted here.