Thor Head Gasket replacement

After a long hard drive down through Germany and Holland the car developed a roughness at anything over 70mph. Had a ferry to catch so held her at 65/70 to get home. Found the problem. On the Thor engine there is an idle control valve with one of the pipes going into the plenum intake. Where it joined the plastic was broken causing a bad air leak. Compression test shows two adjacent cylinders (8 and ) down to approx 100psi (the rest are 150psi)

So its (RH if sitting in the car) head off. Its been about three years since I pulled a head of a P38 and that one was a GEMS engine. Have done several complete engine rebuilds on 3.9 Classic engines but its a while ago. A week is a while ago at my age!

Quick questions that would help me. All the top stuff inc plenum I have done recently to overhaul the injectors.
a) Will the cylinder head lift off with the exhaust manifold attached ? - would be really great if it would. Seem to remember I fitted the exhaust manifolds on Classic engines prior to dropping them in, this was a great time saver.

Intend to fit Composit gasket and OEM Bolts.

b) Anyone know a good place to buy a reconditioned head with rockers if possible.

Any tips welcome - Car is a 2000 year 4.6 Thor and my Rolls Royce engine project is still in the early stage so can't use that yet!

Hi,

PaulP38a has a wonderful step by step guide for replacing the heads on a Thor engine.
Have a look here:

Engine Refresh (top end) PaulP38A.com

Hope this helps. Thanks to Paul for his great job.

NicP38 said:

Hi,

PaulP38a has a wonderful step by step guide for replacing the heads on a Thor engine.
Have a look here:

Engine Refresh (top end) PaulP38A.com

Hope this helps. Thanks to Paul for his great job.

Click to expand...

This is a very interesting site and very informative. Many thanks.

stopover said:

After a long hard drive down through Germany and Holland the car developed a roughness at anything over 70mph. Had a ferry to catch so held her at 65/70 to get home. Found the problem. On the Thor engine there is an idle control valve with one of the pipes going into the plenum intake. Where it joined the plastic was broken causing a bad air leak. Compression test shows two adjacent cylinders (8 and ) down to approx 100psi (the rest are 150psi)

So its (RH if sitting in the car) head off. Its been about three years since I pulled a head of a P38 and that one was a GEMS engine. Have done several complete engine rebuilds on 3.9 Classic engines but its a while ago. A week is a while ago at my age!

Quick questions that would help me. All the top stuff inc plenum I have done recently to overhaul the injectors.
a) Will the cylinder head lift off with the exhaust manifold attached ? - would be really great if it would. Seem to remember I fitted the exhaust manifolds on Classic engines prior to dropping them in, this was a great time saver.

Intend to fit Composit gasket and OEM Bolts.

b) Anyone know a good place to buy a reconditioned head with rockers if possible.

Any tips welcome - Car is a 2000 year 4.6 Thor and my Rolls Royce engine project is still in the early stage so can't use that yet!

Click to expand...

You wanna buy a sync-mate for after the rebuild?

Hi, a sync-mate would be very useful for my long trips but its just for one possible fault. I normally take my TestBook T4 system (or part of it just for p38 issues) I made it into a mobile unit ages ago, it sits in the spare wheel well (just). So have full backup if needed. So far I have done something like fifteen or more long distance overseas trips, inc Scotland every year in this car and only needed the T4 once for an EAS reset (I do carry an emergency EAS set too!). The last trip across to the UK (I live in the Isle of Man) and from Hull and over to Rotterdam and up through Germany and into Denmark resulted in a missfire the T4 showed a fueling issue and I wish I had noticed the air leak that was causing it, could kick myself so I am blaming the very bad weather as I had high winds and deep driven snow and sleet and no cover didn't help. Unforunately the twelve + hour drive to the ferry in Rotterdam and then the journey across the UK and home did the Head Gasket in so have to change that asap as next trip in three weeks/ish.

ps: when home also found three injectors well below spec so probably picked up some grot fuel at some stage. The air leak was, I believe the main culprit and caused lean running at 70+ speeds necessary to catch the ferry. Was bliss to get on it. Been living with the slight missfire but must fix it now.