Practically Classics Forum

good work ! id be interested to see pics of your security system.. as things here go missing now and again..

Today I got a big part of the way to getting the HLS running by getting the entire head cleaned up and rebuilt ready to go back in the car. I've never rebuilt a head before, but I have to say that on the whole I quite enjoyed it and I'm looking forward to doing this again for the HL when I've found a head that I can actually strip down fully properly and that doesn't have ruined bolt holes.

At the trouble end of the engine lived the worst of the valves. This crusty deposit was pretty powdery and looked a lot like it was burnt oil deposit. This would make more sense later.


With the rest of the valves out it was clear that they all needed lapping to get them looking and performing their best again. I found this bit quite therapeutic. All the valves were kept in the cardboard and numbered in the correct order so they could go back in the head without issue.


Same with the springs, plates and cotters so that I didn't lose or disorganise anything though no need for numbers in this instance since they were just put in order on the tissue paper.


With the valves out I could properly inspect the head and I found that it was actually perfectly, beautifully straight. No need for a skim or testing here, this will bolt straight back onto the car. I did spend some time cleaning up the face and lapping the valve seats but I didn't go crazy with polishing or anything like that. I just want the engine back together and working without fear of it exploding rather than attempting to win prizes.


A close up of the state of things before any cleaning or lapping was done.


After cleaning all the various bits up before they went back in it was time to remove the valve stem seals. This was actually really easy because the valve stems hadn't been fitted correctly and just fell out. They should - according to the manual - be located on the valve stem and sit under the valve spring seat and are then compressed into place. Unusually, only 4 stem seals are fitted and only to the inlet valves even though eight are provided in the gasket set. I did things according to the manual so hopefully I haven't done it wrong. Whoever had fitted the stem seals before had pushed them onto the valve stem after the spring plate and they were free to ride up and down the valve stem doing absolutely nothing to stop oil getting where it shouldn't. Probably explains in part the big cloud of oil smoke out the exhaust when we fired the car up earlier this year.

Do you like my classy workbench? Old speaker cases are pretty knackered, but they're just right for this job. I would like to find the creator of split cotters and punch them in the face, they have to be one of the most annoying and fiddly things I've yet done on a car.


Halfway.


Fresh core plugs were also fitted to the head, along with a new gasket for the end plate.




Camshaft also had new seals fitted at both ends so that should stop leaking oil everywhere. The old seal was very hard and plasticy just like the valve stem seals had gone.


We then spent some time cleaning the distributor up and fitting that with a new O-ring to hopefully stop the oil leak from there, the old O-ring was not too dissimilar in appearance to a tie wrap and not really sealing anything.


The rocker cover was given some Rhinoseal to ensure the best possible fit and once bolted down the fuel pump was likewise sealed. Hopefully all this means the head won't leak at all.


I'm very pleased with the end result, it looks very smart.


I will be bolting the head onto the block tomorrow, the timing sorted and the manifold bolted up. I've got fresh oil, antifreeze and timing belt to go on and providing I've done all this correctly the engine should run very nicely. I'll likely have to borrow the battery and spark plugs from the HL as I forgot I had to get some of those and I don't fancy shopping for them at the moment.

If I get enough time I'll do some more work getting the interior bolted down. Once the brake line arrives I can look at moving the car under its own power properly as at the moment I have no brakes due to having to cut a rear hose to get the displacer arm off.

Happy days.

Looks like you had a very productive day - it must be a satisfying feeling to do a good job without any problems.

Mike

Nice work. Annoying though they can be as they come, I'd love to see anyone fit valves with collets that weren't split!
Stretchy ones maybe? Press them down the stems while they click into their grooves? Nah, split collets are the only easy way to solve that particular riddle!

May I ask how you know it's flat with that protruding dowel still in place at the corner by the front of the face? When these do warp, which is most times they've been off after cooling system and/or weak mixture issues, they do so in barrel fashion as a rule but that doesn't guarantee that there couldn't be a twist on there and it would only take a further five minutes to pull the dowel and check the surface properly on glass, which would allow you the chance to crack test it too, the cracks tend to be between the water jacket and the bosses that the guides fit into. Steam in there at high pressure would admittedly have taken care of that carbon buildup so again, chances are it will be sound but many's the sheep that was spoiled for the want of the proverbial hap'orth of tar on its feet.

Two schools of thought on this job. The first suggest that everything must be cleaned to as-new condition, the head tested and skimmed regardless and much money spent on making the engine absolutely pristine. The second is to get everything tidy, working and back in one piece without heavy bodging. I've gone for the second school.

I know there will be disagreement about this decision, but after testing the head for flat on a good straight edge there's no sign of warp or distortion in any direction. I haven't used a sheet of glass, I've used a known good quality metal edge and small LED torch to provide directional light to highlight were there might be any distortion along the length and width of the head, and diagonally across the head. If there's no light leak chances are it's flat enough to bolt back together with a good quality gasket.

When the engine is bolted back together I'll watch the gauges and fluid levels like a hawk during shakedown but if the HL is anything to go by, this approach is actually a good solution. Not conventional, perhaps, but it's the way I've chosen to do it. Should the head blow again within the next 1000 miles or so at least it's easy to repair and at that point I would definitely get the head checked.

Today, the new waxstat arrived, but since it's raining sideways there's no way I can tolerate bolting an engine together outside. Anybody want to lend me a garage to huddle in?

I have changed a dozen or so head gaskets over the last 10 years and have only ever had one re-blow due to the head being warped. For the cost of a head gasket vs. the cost of getting it machined, I opt for the bung it back together and see method.
Note: don't buy a used car from me

It seems to be the thing nowdays to always skim the head, I would never skim a head unless it was absolutely necessary, It changes the compression ratio and can cause the valves to be too close to the pistons, it also limits the number of times the head can be re-used.

I think it's down to modern engine's propensity to warp more easily due to there being less metal between the cylinder bores. On the HL there's a massive wall between the cylinders bores but on something like Dad's Omega there's hardly anything. The other issue is that people are more likely to let a car overheat which increases the chance of warpage. With these things in mind it's not surprising that most people will skim a head by rote.

My brother did have a little Saxo that he bought with a blown head. He rebuilt the engine and did thousands of miles in it with no bother at all and never skimmed the head. But the old Polo I had which blew a headgasket before I got it was never right after a skim and blew a second head gasket and when that was repaired it had a terminal sporadic overheating problem that I could never find the cause of.

I think sometimes it's luck of the draw. An old flathead unit like the O series is apparently a much more durable engine than newer stuff so I reckon you can get away with a lot more when it comes to fixing them.

The warped head I had was the left bank on my RR. The heads were supposedly reconditioned when I bought them. One clearly wasn't reconditioned very well :S
It was an excuse to put on a set that had been ported out

My arms have fallen off, I am typing this with my FACE. That might not be true. Anyway, plans to just bolt the head on and maybe the ancillaries were thwarted today when I found out that the cylinders were not where I'd left them. When the head was removed everything was timed accordingly and all was well, but something has moved at some point, possibly when I had the invader in the car, possibly when I jacked up the rear end to steal the sphere.

Unfortunately, I couldn't rotate the pulleys or the crank to the correct point with the rear corner in the air in part because of resistance but also because I don't have a socket big enough for the crank pulley to turn it by hand.

That meant I had to rebuild the back corner to get the car back on it's wheels.
> Fit bust sphere (attached to trailing arm) from HL.
> Fit crosstube bracket
> Jack up and bolt crosstube to bodyshell
> Tighten pivot shaft bolts to keep the trailing arm in place
> Bolt good drum backplate onto arm
> Fit outer drum
> Tighten hub nut
> Refit wheel
> Attach hydragas pipe
> Fail to attach new brake hose that arrived today because of more stubborn fixings
> Put the car on the floor.



All that meant I could then rock the car (only the driver's side handbrake now works, fun) in gear to get the timing where it should be before bolting the head on. I had made a mistake when putting the head together too, fitting an O ring to the camshaft that shouldn't be there so I had to remove the rocker cover and fuel pump, both of which were pretty firmly sealed thanks to the Rhinoseal, so I could remove it before rebolting and sealing it all again.

Once I'd got the head ready and the timing ready we put the car in neutral and bolted the head to the block with a nice fresh head gasket. It was rapidly getting very cold and very dark so I haven't fitted any ancillaries, the timing belt or even torqued the head down.

Before


After apologies for shaky potato-cam, I was very cold.



But it's nice to see the car back on it's wheels again and the engine bay is looking far better for having the head sorted out, I hadn't realised just how much cleaner and better it now looks compared to how it arrived.

There will now follow a period of sitting and drinking of sherry so that I might properly recover.