Head off/New Head Gasket Coming/Anything Else?

[neophyteguy]

Driving home a couple of days ago and STNDUP just wasn't really running as good as usual. It seemed "ok" at higher RPM's but when starting off from a stand still it sounded almost like a cracked manifold. Got home and tested compression and noted 2 & 3 were almost non-existent.

This morning I took off the head and found a nice big split in the original copper gasket directly between the two cylinders. I didn't notice any water in the oil and only VERY minimal bubbling in the top of the radiator.

I took the head down to a local machinist to have it looked at and he noted that all the valve guides were loose and the oil seals needed replacing. While I was there he took out the valves and cleaned them up and then said the inlet valves needed to be replaced as once they were cleaned up that they would be too thin on the edges. So, I ordered new valves and a VRS kit.

I've got a few queries and would appreciate any help you can offer as this is my first "head off" experience.

- Does the new VRS head gasket (from ALL 4x4) require any type of sealant?

-Is it best to put the manifolds together before mounting them on the head, or to put the exhaust manifold on and then the input manifold?

-I didn't really specify it, but would you reckon the head will now be "unleaded friendly"?

-As I was pulling out the head bolts, I didn't pay any attention to which bolts came from where. I'm sure I'll figure it out, but does anyone have a general quid as to where the different size bolts go? DOH!

-Is it ok to clean the top of the pistons while the heads are off or should I just leave them alone? If so, what's the best way to clean them?

-Is there a gasket between the bottom of the exhaust manifold and the top of the pipe? (Where the pipe meets the manifold-triangular fitting)

I'm really hoping this freshen up will sort out some of the issues I have with burning oil, but not really sure. Either way, I'm sure it will run better than before.....The valves were completely covered in oil, so the machinist is sure I'll have a decrease in oil use--hehe

All up (without valves), the work is costing $400 which includes all the work mentioned above and machining of the head.

Thanks for any help in advance!
Neo

[neophyteguy]

any help is greatly appreciated.

Cheers in advance!

[neophyteguy]

The engine has used excessive oil and the valves were covered in oil when I dropped them off a the engineers yesterday. He reckons new valve oil seals will fix the oil getting past the valves.......

Do you guys think I should drop the pistons while I've got the head off to have a look at the rings? My guess is that I would need to replace them.....

Cheers,
Neo

[isuzutoo-eh]

If you think rings might be the problem, you'd be wise to attend to that whilst you're in the guts of it, and before it becomes less of a problem and more of a fail to proceed.

[chazza]

I've got a few queries and would appreciate any help you can offer as this is my first "head off" experience.

- Does the new VRS head gasket (from ALL 4x4) require any type of sealant?
Not sure but all of the head gaskets I have used in the last 35 years were assembled dry. Most important of all is install the right way around.
-Is it best to put the manifolds together before mounting them on the head, or to put the exhaust manifold on and then the input manifold?
You should be able to put them on afterwards with not much hassle which will make it lighter to lift.
-I didn't really specify it, but would you reckon the head will now be "unleaded friendly"?

It was from the factory so don't worry about it.

-As I was pulling out the head bolts, I didn't pay any attention to which bolts came from where. I'm sure I'll figure it out, but does anyone have a general quid as to where the different size bolts go? DOH!

-Is it ok to clean the top of the pistons while the heads are off or should I just leave them alone? If so, what's the best way to clean them?
Use a piece of hardwood cut at 90 degrees on the end as a scraper. when it gets blunt re-cut it with a carbide saw.
-Is there a gasket between the bottom of the exhaust manifold and the top of the pipe? (Where the pipe meets the manifold-triangular fitting)
It depends on which exhaust you have but from your description it is the conical fitting which doesn't need a gasket. Use a smear of high-temp silicone on it for a guaranteed seal.
I'm really hoping this freshen up will sort out some of the issues I have with burning oil, but not really sure. Either way, I'm sure it will run better than before.....The valves were completely covered in oil, so the machinist is sure I'll have a decrease in oil use--hehe

Neo

Give the pistons a good shake with your thumbs when they are at TDC - if there is appreciable movement, it probably needs new rings. If there is a prominent ridge at the top of the bore, it probably needs re-boring. A reconditioned long-engine with new parts and gaskets etc. will cost about $2500 unassembled, depending on what work needs doing.

For the head work; examine all of the fasteners and discard any that are damaged or rust-pitted. Clean the male and female threads before assembly. Use a tension wrench on the fasteners with the head bolts lightly oiled. I usually use Loctite 243 on the manifold fasteners. Make sure that all of the manifold faces are completely flat and the corresponding head faces - quite often there are raised lumps around the female threads.

Get the rocker gear examined as well; check for worn bushes and shaft and wear on the rocker arm faces - replace or re-condition.

Treat the machine to some new coolant hoses when you glue it together again - good luck and have fun :D

Cheers Charlie

[neophyteguy]

Thanks guys, I appreciate the replies!

I'm not getting much movement from the pistons, but still wondering if perhaps the "scraper" ring isn't right in one or more pistons.

The pistons are marked as:

1B
2A
3D
4D

The engine has not been re-bored according to the piston sizes.

--DOES ANYONE KNOW HOW TO ORDER RINGS FOR A STANDARD OEM PISTON?

--There is certainly a ridge large enough to catch my fingernail on in each of the pistons. I've read that if new rings are put on, they'll break off on the ridge? If I only replaced the other "rings" and left the top one one (assuming there ok), would this get around the issue?

--Can a machine shop come up with rings or is this a land rover only item?

Thanks again!
Neo

[garrywlh]

Sounds like it might really be worth your while to get yourself a Series Land Rover Repair Operation Manual (or at the very least a Haynes). And there are a number of vendors on this forum who can supply any and all OEM or NOS parts. For me, it has been a very big help getting to know my local Land Rover parts and service outlet, too.

[neophyteguy]

Thanks Gary!

I've got the green bible, the original LR manuals and a few others. I guess my question really is more around whether or not I can simply buy new rings and put them on but:

-Will the lip break the new ring

-Can I simply replace the lower rings so the top one doesn't break off (if the lip is an issue)

I've got to take the sump off to replace the seal any ways, so I'm going to be most of the way there as the head is already off. What I don't have time/$ to do at the moment is to take the entire engine out and then have it bored.

If it's simply a matter of pulling the pistons and putting in new rings while I've got the head off then I'll be pulling things apart today.........

Thanks again everyone
Neo

[chazza]

Neo,
If you can catch your nail under the ridge, then the cylinder bore needs measuring with an internal micrometer to see if it has worn past its upper tolerance. If it is too worn it is re-bore time - fitting rings to an oversize, out-of-round bore, doesn't work for long.

If the bore is still within tolerance new rings can be fitted; however; the bores will need honing and the rings should have a stepped-ring in the top piston groove. Repco used to make them and probably still do. Ideally the ridge should be removed. Before you decide what to do, clean the bores with a clean rag and look for scoring on the cylinder walls; excessive glazing (shininess) or any other nasty defects. If any exist the engine has to come apart.

My advice is to strip the complete engine; get someone to measure the bores if you don't have a micrometer; measure the crankshaft and inspect it for scoring where the seal runs; inspect the camshaft and rollers (keeping everything in order) and get a quote to have everything re-conditioned.

Remember, that there is little point in fixing only one part of an engine, as it works at its best when everything is in perfect condition and adjustment, so check everything.

Cheap engine parts can be bought from the UK, but I can't vouch for the quality. ACL are good quality parts, which your engine re-conditioner will be familiar with,

Cheers Charlie

[gromit]

As mentioned by Charlie you can get piston rings where the top ring is stepped to miss the wear ridge.
You can also get a tool for removing the wear ridge, an engine reconditioners may hire them out. Lisle 36500 2 11 16" to 5 5 16" Cylinder Ridge Reamer | eBay (http://www.ebay.com/itm/Lisle-36500-2-11-16-to-5-5-16-Cylinder-Ridge-Reamer-/400153266807)
Third option is to scrape the wear ridge away using hand scrapers. Hard to do and you need to know what you are doing.

I hand scraped the ridges from a 6-cylinder motor (details in this thread http://www.aulro.com/afvb/leaf-sprung-military-land-rovers/118730-ffr-refurb.html ).
New rings were fitted and she runs fine now and doesn't smoke but to be fair it hasn't seen any road work yet.....

Rings should be available from the usual Australian LR parts suppliers, an engine reconditioners should be able to get them (mind you they are a dying breed) or as mentioned source from the UK.


Colin

[neophyteguy]

So, I got the head back from the machine shop. They put in new guides, seals and valves and I put a new head gasket on, torqued things up and fired it up. It runs really well, climbs hills in 3rd I used to have to slow down into 2nd gear and I'm quite happy with the result.

While I had the sump off, I replaced the bearing shells as I could see minor wear on a couple of them. There was certainly no ridges or pitting on the shells or the cam.

SO, now I have an oil pressure problem. I've always had an oil pressure gauge (electrical type) and it's always had pretty low oil pressure. As it ran fine, I just monitored things to make sure there weren't any fluctuations.

I just put on a Smiths dual gauge while I had the vehicle off the road and the oil pressure is dismal. I would be ok with looking for variations, but the green light is coming on as well which confirms the oil gauge(s) I've used are telling the truth.

At cold idle and running temp, the pressure is around 20 psi. However, when I run it for a few kilometres and then stop, the oil pressure drops to near 0 and the green light comes on. As long as I have the RPM's up then the light doesn't seem to come on....but the pressure is still lower than it should be.

When I had the sump off I didn't fiddle with the oil pump other than moving the screen around to facilitate putting the pistons and bearing shells on.

I'm not getting any bearing knocking, but then I'm also not driving it much at the moment.

Should I get a new pump and put it on, rebuild the existing one?

I'm not in the market for a new rebuild and can't imagine this is what's required as it doesn't have any knocking and runs great.

When I put the sump back on recently, I filled it with 6L of HPR 30 (Penrite - Penrite Oil - A Better Class Of Oil (http://www.penriteoil.com.au/engineoils-products.php?id_categ=1&id_products=4))

Any thoughts?

Cheers,
Neo

[chazza]

[QUOTE=neophyteguy;2050848]


G'day Neo,
Congratulations on getting the engine to run so well!

The oil you have used is suitable, so it seems that there is either excessive bearing clearance somewhere; which seems unlikely given that the engine doesn't rattle or knock; or it is something else.

My manual doesn't show the location of the oil pressure relief-valve very well, but it appears to be on the pump. It is worth checking, because if the ball or seat are damaged or dirty, the oil pressure will be lower than it should be. If you have to take the pump out to get to the valve, measure the pump and then decide if you need a new one.

Other places where oil might be leaking excessively and causing lower pressure could be the rocker gear and the camshaft bearings.

Anyway, check the relief valve first; the manual has very good instructions on how to recondition it and how to measure the pump,

Cheers Charlie