Project Honda City Turbo II – Teardown

A few weeks ago I made a post about my visit to a friends place to check out their new Honda City Turbo II build (which you can read here). I promised I’d post their build progress here if there was enough interest, and boy was there ever! There was a resounding “YES” to my query about you guys wanting to see more, so here it is. In this post I’ll be showing you the initial condition of the car and subsequent teardown in preparation for an engine re-fresh. All words and images are straight from Ryan, one of the founding members of The-Lowdown. The car is owned by Tony, a staff member over at The Motor Report, and the two of them are sharing the build. These are two of the most stand-up guys I’ve ever met, I had a ball at the Winton track day with them, and they’ve even traveled across town to lend me a hand with my garage build, so I hope you’ll check out their respective sites and have a browse around. Without further adieu, it’s time to get our Honderp on…

Words and images: Ryan Lewis.

About six weeks ago a mate and I picked up a Honda City Turbo II project car. We weren’t (and still aren’t) sure what to do with it (rego/track/sell/other) but it was too good to pass up. I finished a motorbike build recently and had a hankering to rebuild something else. Plus we’ve always wanted to drive one of these things, and there’s a Motorcompo on the way from Japan so we had to pair them up. We got straight into the project so there’s already a fair bit of progress to show. I’ll start from the top.

All moved in to its new home for the next little while.

It was cheap because:

Not running. Came with a very dead turbo, no fuel pump and lots of holes where parts should be. Thankfully we also got a boot full of bits to be assembled including a head rebuilt kit and a turbo diesel Pajero turbo which was supposed to be an ‘easy replacement’ according to the last owner. Not likely. PS: COMBAX stands for ‘COMpact Blazing-combustion Axiom’. Yep.

Like I said, we got straight into it.

Boot o’ bits. Basically a bunch of driveshafts, turbo diesel Pajero turbo and other odds and ends.

More spares for the build. Looks like these radiators won’t work out so that’s on our list of things to source. The top hose fitting has broken off the original and the non-turbo City radiator doesn’t look like it’ll fit.

Derp.

The whole car is covered in filthy fingerprints and dirt. For the most part the body is in decent condition. A proper wash should bring it up to a reasonable state.

We have no idea what happened to the original rear bumper but the car came with a replacement from a convertible. City drop tops have the same wide body guards as the Turbo II but the bumpers are black plastic instead of body colour. We’ll paint it down the track.

This is by far the thing I hate the most about this car. It seems no amount of Rost Off will free up the grub screws holding it on. Angle grinder up next.

We wanted to yank the motor out straight away for a proper look at the exhaust manifold and to get started on the freshen up. The car came with a complete gasket and seal kit for the top end so we’ll be making the most of that.

Front bumper and grill removed for heaps of access. We don’t want any air con gear in the car so the condenser came out and went in the bin. Everything disconnected and labelled and rad support removed.

Engine crane time.

We dropped the oil out and got the engine onto a stand so we can work on it easily.

Dirty engine bay is dirty. Tony wasn’t havin’ it.

Degreaser and Karcher tiem.

Fair bit better. Both of us get pretty OCD at times, but this is definitely not going to be a concours rebuild. The car is a little rough so it doesn’t need to be perfect.

A friend brought over a set of CF-48s for us to use while we’ve got the City. May or may not end up on the car.

Loving having this funny car in the garage. So good to be working on a new project.

I’d never had an engine stand at home before but I’ll never go back now! So good to have it at bench height. The motor looks to be in pretty good order. We’re told that it had good, even compression across all cylinders but there’s a lot of caked on carbon under the valve cover. We don’t want to commit to a total nut and bolt overhaul so we’ll just have to see how it goes.

The A/C stuff we’ve binned so far. The car didn’t have a compressor in it when we got it. Removed a few kilos there.

Fairly sure this is the original clutch but it’s good to go back in. Pressure plate and flywheel look fine too. I should also mention that this is a low budget build. We’re trying not to get into it for more than the car will be worth when it’s finished.

Little five-speed ‘box all looks fine. Throwout bearing needs to be replaced but that’s it. City Turbo stuff isn’t exactly dime a dozen but we’ve found stuff pretty easily in New Zealand.

The interior served up a few laughs. These ‘Admit Two’ passes for Men’s Gallery have to be a couple of decades old. They were stuffed into the refrigerated compartment (!) on the dash.

We were happy to find this guy buried in the back! Original gearknob in good nick. I should’ve snapped a shot of the horrendous thing stuck to the shifter with Blu Tack when we got it. It was insta-binned. Also note the optional Citizen dash clock.

Unforgivable banana milk vinyl shift boot over the top of the standard one! Ugh.

… yep Also: DIGIDASH

So far all good! The front end has had a minor shunt at some stage (taco-shaped A/C condenser as a result) but the rad support and bumper reo are all straight. – - – - – Next up we had a win for the turbo situation with Project Honderp. How we were going to get this thing making boost again was worrying us from the day we got the car. The original ad on Gumtree said the car had a blown turbo but that it came with a replacement from a turbo diesel Pajero which would apparently work. I don’t have any great photos of the Pajero turbo, but suffice to say it is waaaaaaaay too big to be re-purposed into the City, and different to the standard turbo in almost every conceivable way, from the physical size of it to the manifold flange and exhaust flange to the compressor inlet and outlet. No good. Back to the factory turbo and the ad was somewhat understated. It is beyond dead, as this video will attest.

We did a bit of hunting for another standard turbo, which was fruitless. In our search we turned up a thread about adapting one from a turbo diesel Rodeo to the City. It’s a relatively common mod (meaning 4 or 5 guys have done it, which is a lot in City circles) but it’s a bit of a hack job. Eventually we concluded that rebuilding the turbo we had would probably work out best since a second-hander is likely to be flogged and in need of reco anyway, that’s if we could find one. So I took the turbo to Advanced Turbo Performance. After a long chat with the bloke he went to his warehouse and miraculously dug out a bootleg IHI turbo with an identical core to our little RHB51. It was a real fluke. These little cores are fairly unique in that they don’t use water cooling, just oil.

Externally the dimensions were identical. The flanges for oil feed and return were the same, even the banjo bolt thread was the same, so we dismantled both on the spot.

The new one is actually an RHB52 so the turbine and comp wheels are slightly larger than standard. Our old exhaust housing will fit with some machine work – enlarging the exhaust outlet to suit the larger turbine of the RHB52 – to create a perfect, bolt on, high-flow turbo. Score.

You can kinda see the difference in size here. 3-4mm will have to be machined out of our housing for clearance. There’s just enough material between exhaust outlet and wastegate.

We’re using the new RHB52 comp housing so that we can keep the bigger impeller and don’t have to machine our old comp cover. Outside diameter of the inlet is a match for our intake piping, inside diameter is larger for the larger impeller. The only difference is the placement of the hose fitting for the wastegate actuator but a new bit of hose takes care of that. Since we have all the bits, we’re just waiting on the exhaust housing to be acid bathed and machined and the whole thing reassembled at ATP. Since playing the waiting game sucks, I went on a trek to pick up an old high school science lab bench for my garage. That gave us space to start the engine tear down. We took both manifolds off and separated the throttle body and fuel rail. At some point a real amateur has been through this before and put it back together using all of the original gaskets. They’ve compensated for that with a liberal coating of gasket goo between every mating surface. For example, head – gasket goo – gasket – gasket goo – manifold. They would’ve gone through tubes of the stuff. Plan is to replace the head gasket and valve stem seals at least. We don’t have a manual for this car in English but we’re going to forge ahead. I haven’t done a rebuild like this before so it’s a great opportunity to learn. Hopefully it works out to be the project to do it on. It’s a shame we’ve never seen the engine running to know what its oil consumption is like. Given the hefty carbon build up under the valve cover it seems to have a bit of an issue. Could well be piston rings but we’re definitely leaving as much of the bottom end alone as possible. We just want to have some quick fun in this thing but it’s so hard to let things slide! Since my garage roof leaks some water we had to cover the engine last night. You might think you’re JDM, but you ain’t this JDM.

Here’s our valve train looking sorry for itself. Lots of caked-on carbon. We’ll get this taken care of before we start the head rebuild.

This rusty coolant stain on the back of the block sort of looked like it could’ve been from a blown head gasket. More likely the source was that vertical hose fitting on the bypass pipe where there’s more staining, but we’re doing the gasket anyway so off with its head.

Crank pulley, water pump, tensioner and timing belt removed. No nasty surprises so far. Timing belt is okay but will be replaced while we’re here.

Obviously the motor has been sitting for a while judging by the gunky water level on the impeller. The water pump has been replaced at some stage and is fine to go back on after a clean.

Little bit of shaft polishing. I’d never seen an oil pump like this. The shaft Tony is holding runs from the valve train down to the sump. There’s a worm drive sprocket in the middle of the camshaft driving the oil pump via that shaft. I’ll try to get more detailed photos later.

Head bolts out ready for lift off.

Voila. The crusty old head gasket was definitely worth changing. No sign of a blowout but the water channels were collecting rusty build-up. Carbon on the pistons wasn’t too crazy for an unopened motor from 1987. I’m still amazing by how advanced this thing was for its time. As you can see the block is open deck, and the lengths they went to for weight saving are amazing – the head is 60% titanium and the valve cover is magnesium all for the sake of lightness.

All cylinder bores are in good shape. No scoring and the original crosshatch markings still visible.

Head gasket still intact but it definitely feels like we made the right choice to replace it while we have the motor out.

Base of the head. We haven’t touched this yet.

Sump off for inspection. Ew. How about the state of that oil screen?

Diabolical. All of this grit is a bit mysterious. We got some more photos of it that I’ll dig up. I originally thought it was bearing material from the turbo that had found its way down the oil drain into the sump, but it’s not metallic, almost seems to be pulverised plastic or something. We thought it could’ve been a rogue valve stem seal, but they’re all accounted for.

Plenty more grit lining the sump.

Overall the bottom end is looking fine. No other demons hidden inside. We should be good to go after a proper clean, new rear main and crank seals and a new sump gasket.

It says TURBO, so you know it’s good.

Tony at our make-shift degreasing station.

Working on the PCV baffle from inside the valve cover.

All cleaned up.

Tony’s wonder job on the oil pump. The whole unit was dismantled into its individual components and thoroughly checked. Thankfully non of that grit made it past the oil screen.

Looks brand new!

Remember that rusty water pump? Well it came up pretty good too.

Gasket on ready for the head to be mounted.

The next thing to be tackled.

Until next time…

Original: Build Threads