Fixing My 4×4: The Battle Of The Bent Valves

If you know me at all, you know I’m a car guy. I’m pretty green as far as hardcore wrenching skills go, but I like to tackle problems with my vehicles myself – I like to learn by doing. What follows is the story of how I learned a few hard lessons when my faithful ride died slowly and painfully in my arms over the final months of 2016.

For context, my beast of a machine was a 1992 Daihatsu Feroza. It's a 4WD with a 1.6 litre fuel injected four-cylinder engine. It had served me faithfully for over a year and was reading around 295,000 kilometers on the odometer. But I was moving house and needed to pull a trailer with all my possessions on an 800 km journey. I didn't want to put the stress on the car but I didn't have a whole lot of choice if I wanted to keep my bed and my prized Ricoh photocopier. I did my best to prepare the car, topping up the oil which had gotten perilously low and fitting new tyres. I’d had a hell of a time over the winter aquaplaning all over the place and wasn't in the mood for a big ugly crash on the highway.

In the end, the journey was tough on the car but we made it. Foot to the floor in fourth gear, screaming along in the vicinity of 3500 rpm, pulling 600 kg of trailer uphill at 70 km/h was never going to be a cakewalk. I dropped off the trailer and drove home, and everything seemed alright. But the next day, my poor old Ferozi was suffering.

Initially, I wasn't worried. The car was bogging down under acceleration – it felt just like running on an almost-empty tank of petrol. "Probably just a clogged fuel filter!" I thought. There's plenty of dodgy petrol between Victoria and South Australia, after all. I put off a repair for a couple of weeks as I’d just started a new job and the car was still getting me to and from work. This was a mistake.

Two weeks passed, and the next time I went to start the car, it was very much dead. The starter was engaging the motor, everything was spinning up – but it simply wouldn't start. But if you’ve ever tried to start a sick automobile, you’ll know you’ve only got three or four good shots before the battery dies. For some reason, I was able to crank away endlessly without problem. Why? Well, it's a little thing called compression.

The reason you can only crank over your engine for a short period before your battery dies is because of compression. In a properly functioning internal combustion engine, the pistons moving up and down inside the cylinders go through a compression stroke, which increases the pressure of the incoming air-fuel mixture. Compressing this mixture takes a great deal of energy, which has to come from somewhere – during starting, this comes from your car's battery. There's only enough in the average car battery for four or five starting attempts – we’ve all heard that sad, groaning sound as the starter motor gets slower as the battery runs out of juice.

Why then, was my battery soldiering on? I had very little to no compression, thus, my starter motor simply needed to spin around a few kilograms of rotating masses. This takes very little power in comparison and places a much smaller load on the battery. This was very bad – compression is vital in an internal combustion engine to generate power. We had to figure out where it had gone.

There's a few ways you can lose compression in an engine. One of the most common on an old engine is a failed head gasket. But there's other symptoms of this – oil in the coolant, coolant in the oil, overheating – my car was suffering from none of these. I ruled it out and instead suspected the timing belt. The timing belt is responsible for synchronizing the valvegear with the pistons. If they’re not properly synced up, your piston will be moving up on the compression stroke while the valves are open, pushing the air back out the intake instead of compressing it in the cylinder. The previous owner had assured me they’d swapped the timing belt recently but who can you really trust these days? I decided to check it out and started disassembling the engine.

Taking off the timing belt cover, I was disappointed. The timing belt was still there! That meant it hadn't broken, so that wasn't the problem. There was a chance it had slipped a tooth though, leading to a loss of proper synchronisation. After much arguing with my friendly mechanically minded assistant, and referring to the service manual which outlined the proper timing belt install process, we determined that while the timing belt was installed properly, things still weren't right. As we tried to crank over the engine by hand, we could hear and feel the valves impacting the pistons. This was getting worse by the hour.

The next step was to remove the head. This would allow us a better look at what was going on with the valves and also tell us if our head gasket was junk. It sounds easy but it was a four-hour job of swearing, cuts and bruises. One of the problems of being a DIYer is that you’re often lacking in tools. A stuck bolt that would be easy to reach with a $500 socket wrench set is only just barely possible with a mashup of every extension you and your friends can lay your hands on. Rust and cross-threaded fasteners are also far too common when you’re working on a car over 20 years old.

For us, it was a single nut seized onto an exhaust manifold stud that caused us two hours of pain. Just one nut! Besides that, it was then a process of figuring out how best to remove everything else to lift the head. The key here, especially in a car with electronic fuel injection, is to take a lot of photos. Take more than you think you’ll need! This will help you massively when it comes time to reassemble – an EFI engine will not easily run if you misplace the wrong vacuum line or forget to plug in a certain sensor. Having a few photos that show where everything went will help you out no end.

With the head off, my worst fears were confirmed. Clearly visible were marks where the valves had hit the pistons – this is never supposed to happen. This led to the valves bending, and thus they no longer sealed with the head. This is why we had no compression! How did it happen? I still suspected something to do with the timing belt. Perhaps it skipped a tooth, and then skipped back. It didn't seem to be as tight as it should, anyway. The plan then became to get the head reconditioned with 16 new valves, refit it, and go from there.

No dice. The workshop rang me back a little too soon after I’d dropped it off – the head was toast. The camshaft had seized in the head, almost certainly due to low oil pressure. This is what caused the valves to hit the pistons and bend. This was not what I wanted to hear, but I put it down to the fact I’d driven the car very hard with the trailer attached, and that it had low oil in the week before the trip.

Thankfully, the workshop didn't charge me anything, and I instead went to a wrecking yard for parts. It's hard to find Feroza parts out here, so instead I had to do my research. The Daihatsu Applause is a small hatchback that uses the same engine as the Feroza, but in a front-wheel-drive layout. The head is the same between the two cars, so after just two hours wrenching we were able to liberate one and take it home for the sum of just $99.

A new set of gaskets was a further $187 and a timing belt kit was another $80. All in all I was $400 in the hole, but it would mean the difference between selling the car for parts for $500. or having a working vehicle worth closer to $2000.

It was a straightforward enough job to refit the head. There were a few snags – we’d done the traditional amateur mechanic trick of dumping all the bolts in a big tub. It was fairly difficult then to find the right fastener when we needed it. Nevertheless, we got the thing assembled, and much to my surprise – it fired. IT ACTUALLY FIRED. It was running awfully, but we realised we hadn't hooked up the vacuum lines to the MAP sensor. With this done… it still ran poorly.

It was blowing huge amounts of smoke because we’d filled the cylinders with oil to check the piston rings were okay. It was loud as hell because we didn't have the tools to properly tighten up the exhaust manifold studs. And finally, it was throwing a check engine light which a diagnostic test showed was to do with the coolant temperature sensor. But it ran!

This car had never run well in its whole life. One big cause of this was that its timing was always off. I was too cheap to buy a timing light, which my father had always supported because I would never use it again. It's funny – he's said that the last six times I’ve needed a timing light. Good bloke though. I was spent and tired of working on it at this point, so I took it to a local mechanic I’d heard good things about. They were able to easily cinch up the exhaust, having a far wider range of tools to choose from. They found out the coolant temperature sensor was simply unplugged. And for an experienced mechanic, it was a simple 5 minute job to set the timing properly too. They charged me $40, but I handed over a $50 because I was incredibly happy with the service and the fact that they were happy to have a frank and up front discussion about what I needed done with the car.

The car was now running beautifully – better than it ever had, in fact. I was ecstatic, except for one thing – while at the mechanic, the car had developed a new problem. The starter motor wasn't firing sometimes, and needed a swift tap with a blunt object to free it up and engage. Thankfully, this turned out to be my own dumb fault – I hadn't tightened up the battery terminals properly during the reassembly and it wasn't getting enough current. Finally, after a long and arduous three weeks, I had my own car back, and I loved it. I was so, so happy. I was independent again and no longer had to rely on others for rides.

I’d gotten the car back on Thursday evening, and shot the final parts of the YouTube video embedded below on the Friday night. The video went up the next day. Sunday rolled around and I was excited – I was going out to grab fried chicken with a friend across town which is easily my favourite thing in the world. It was the day before Christmas. I woke up in a great mood, had a lovely breakfast, and kissed my girlfriend goodbye at midday before hopping in the car. As I drove off I called my father, who had been my wrenching companion throughout the journey.

"You won't believe it – it's running so great! It's awesome! It hasn't run this well since I’ve had it!" He was as pleased as I was to hear the mighty Feroza was back out, tearing up the streets. I made it another kilometer down the road before it happened.

The light ahead of me turned green and I let out the clutch to start moving. The car coughed heavily and I lurched to a stop. I didn't think anything of it – just a stall, I thought. I tried to restart the car and was immediately filled with dread. The starter was freely turning the engine again. No compression. Surely not. But it wasn't an ideal time to perform complicated diagnostics. With the help of a fellow concerned motorist, I managed to reverse my way off the three-lane arterial road into a side street, coasting downhill. Australians are generally a friendly people but you won't find many willing to push a heavy four wheel drive uphill on a 40 degree day. Celsius.

I called my girlfriend to break the news. Besides, I needed a lift home. I wanted to believe it was a coincidence. Maybe the summer heat had killed the ignition module, and I’d just be out another $100 and an easy swap. By this point I was emotionally and physically drained and needed a second opinion – a mobile mechanic confirmed what I didn't want to believe. No compression. Back to square one. Game over.

It seems that I’d been all too eager to replace the head and didn't consider the root cause of the problem – low oil pressure causing the camshaft to seize. The fact that I’d been running on low oil prior to the problem first occurring made me think that was the cause, and if I simply swapped out the parts I’d be fine. But it wasn't to be. The issue grows even more complex, however – during the repair, we’d found a disconnected wire going to the oil pressure sender. This lights a warning light on the dash when your oil pressure is low. That system did not throw a warning during the time of the second failure. It's a bit of a mystery.

What I believe to have happened is that either the oil pump is old and dying (entirely believable on a car that's done almost 300,000 km) or there's some kind of blockage in the oil channels feeding the head (especially believable because plenty of carbon buildup was scraped off and entered the oil during the head swap). This led to the camshaft seizing once again, bending the valves and killing the engine. The rule here is to always fix the root cause of a problem. If you haven't identified the root cause, it's pure dumb luck if you actually solve the problem. I should have paid more attention during reassembly and inspected the oil flow. I should have also changed the oil when the repair was complete. Either way, I’m now once again lumped with a dead car that I once loved.

What next? Well, to purchase another head and swap the oil pump to a new unit is prohibitively expensive and there's still every chance that it won't fix the problem. Alternatively, I can harvest an engine from a wrecked Applause or Feroza for just $200. The major things preventing me from doing an engine swap are the lack of an engine crane, experience, and a car big enough to transport the engine home. But the cheers of my friends who want to see the beast roll again is deafening; I do miss rolling on the beach with the top off, screaming with my pals as the salt water sprays over the bonnet. It's pretty damn fun. Tell me what I should do in the comments. Or sell me a good engine for cheap. You’d be doing me a solid.