Pop goes the 86

[smudge]

So, since my last update on 22nd November when the car was at Brands Hatch for a show & shine competition, you may have noticed I've been a bit quiet...
Today, I am back to break my silence! Many of you have been asking questions over the past few weeks and it seems that there have been a few rumours flying around as well. I told a select few over Christmas what I knew then, but today I got to see the real extent of the damage.

Unfortunately, during the last dyno run of the day at Abbey Motorsport at the end of November for the final stage of tuning, Mark phoned me to break the bad news that the engine had gone pop (more of a BANG according to him!) and that we need to strip the engine down after just 2,100 miles of running after being rebuilt with the HKS stroker kit.

After finishing the call with Mark, my head was all over the place. We were both very confused as to how this could happen after we've ensured that every single component necessary to be upgraded to take the new charger was looked at. This project has been months in the making and to hear that it had let go after such a short amount of running time, I was absolutely gutted. I told Mark that there was no rush to get it looked at as I had no plans for the car until Spring 2016 - I wanted to make sure that we didn't rush into anything and see what has happened before we made any further plans.

However, over the Christmas break, my mind started jumping to all sorts of conclusions. I started doing some research on other 86's that had gone bang and came across various threads on the FT86 forum stating that the rocker pins for the cams are prone to failure on boosted engines due to poor manufacturing quality control in the factory. Below are a couple of pictures showing what can happen and a comparison of 2 OEM rockers which you can see are quite different





Praying that this was the issue, I started to look at stronger heads which there are a few companies in the States that offer such services and products. But unfortunately, Mark confirmed that it was a rod that had let go so my hopes were smashed and I once again felt absolutely gutted that a main component that we had upgraded was at fault.

Over the weeks I even started to look at completely changing my plans for the car. 2JZ and LS swaps were investigated, but I was just getting ahead of myself before knowing all the facts and I don't really have a spare £15k for an engine conversion...I even seriously considered selling the car in recent weeks. Just jacking it all in and starting with something new. But I've somehow managed to hold onto my optimism and stick with my original plans despite the situation we're currently in.

Today I met with Mark to see the devastation for myself. It's not pretty - I'll let the pictures do the talking...





Picture showing that the big end bearing is perfectly fine and was still attached to the crank













Basically, rod #4 has decided not to play ball. Although the rods aren't actually forged like the pistons and crank are, they are still made of a "high strength material" according to HKS which are rated to 550ps (about 500bhp) so this should have happened.

All of the bearings on the crank are fine and the crank itself is perfectly serviceable. Piston #4 has the large chunk taken out of the side so it looks as if the small connecting end has suffered as a result of the rod snapping. As it was all still connected to the crank, this has then "windmilled" around inside the crank case causing the huge gouge marks in the case itself. AMAZINGLY none of the valves are bent and both heads are fine...HOW? We have no idea

Mark has had a sample of oil inspected and tested by Millers who have reported back with the oil performing as it should with no issues. So there was no oil starvation or anything that caused this. It simply looks to be a faulty part. Mark has been speaking to Maz at HKS about all this who will be inspecting the parts himself next week before sending them onto Japan for an official inspection and report.

Whilst I fully appreciate that internals come with no warranty as such, running at just over half the 500bhp rating and with only 2,100 miles on them, I would never expect to see such a major failure as this. Yes it's extremely disappointing but I have full confidence in Maz. HKS and their products - it's just one of those things unfortunately.

The next few weeks will probably be even more nerve-racking than the last few months while I wait to hear back from HKS. We'll just have to wait and see...

[Dream20b]

Miracles are often lost in the tragedy that is a blown engine.

In for results.

[smudge]

Originally Posted by Dream20b

Miracles are often lost in the tragedy that is a blown engine.

In for results.

What annoys me most is that we chucked so much money into buying on the best parts for this build. I could have saved at least £2k by using other pistons and rods but I wanted the HKS stroker kit for the extra capacity and the brand name, yet it still let me down

[Dream20b]

Originally Posted by smudge

What annoys me most is that we chucked so much money into buying on the best parts for this build. I could have saved at least £2k by using other pistons and rods but I wanted the HKS stroker kit for the extra capacity and the brand name, yet it still let me down

Just imagine if you'd gone with the Trust/GReddy one for 6k USD!

[Freeman]

Wow, I thought the HKS rods were forged. Good to know. Looks like I'll be sticking with 2L displacement in my future build

[smudge]

Originally Posted by Dream20b

Just imagine if you'd gone with the Trust/GReddy one for 6k USD!

With the exchange rate from £ to $, the HKS kit was probably around that!

[smudge]

Originally Posted by Freeman

Wow, I thought the HKS rods were forged. Good to know. Looks like I'll be sticking with 2L displacement in my future build

I did too. With the pistons and the crank being forged, it would make sense to have the rods forged too...I've asked my contact at HKS to see if he can find out why they're not

Don't get me wrong, I'm not saying "don't use HKS parts" as we all know how amazing the quality of their parts usually is. I genuinely think this is a single rod that has maybe slipped through the quality control net and I'm just extremely unlucky.

HKS wouldn't release a product if they weren't 110% certain that it could take the 500bhp they rate it at. I think this rod just didn't want to play anymore and it's extremely rare. The fact that the crank is still 100% usable just shows how good the quality of the stroker kit really is

[Matt@Cosworth]

Sorry to see that this has let go
looks like its failed around the lubrication hole on the small end ?

these need to be off the main rod axis as a rule so you would have two small holes at 45 degrees to the main beam?
also deburring of these holes on either side is crucial to prevent cracks initiating also is there any kind of small end bush ? as I don't see one and this also helps a great deal in reducing galling and stress

[weederr33]

I was looking into the HKS kit or waiting for Cosworth to release some forged internals. But it does puzzle me that the rods aren't forged. Also, doesn't the HKS stroker kit increase the compression ratio slightly? Do you think that would have something to do with it?

[xwd]

That's pretty much how stock rods fail. Most rods are not forged as a rod they are cut from forged billet steel, so the HKS are not unlike other rods from Brian Crower and other folks.

Manley rods afaik are forged and thus why they are considerably more expensive.

[cdrazic93]

If anything, when building an engine i think about it like this; what part has the most force being acted upon it? Sure the crank has to deal with the rotational inertia and can rightly so.

Pistons have to hold up against constant heat and combustion many times in a fraction of a second. You generally dont see pistons getting holes melted into them with this engine.

Con rods. They connect the crank to the piston (basics 101). They experience two types of loads. Combustion loads and interial loads. Both being compressive and one being tensile.

One reason why I think con rods are the most important of the three, another reason why they should be forged. Even hypereutetic con rods can only get you so far. Last time I checked, they werent made of anything exotic like 7075.

[smudge]

Originally Posted by Matt@Cosworth

Sorry to see that this has let go
looks like its failed around the lubrication hole on the small end ?

these need to be off the main rod axis as a rule so you would have two small holes at 45 degrees to the main beam?
also deburring of these holes on either side is crucial to prevent cracks initiating also is there any kind of small end bush ? as I don't see one and this also helps a great deal in reducing galling and stress

We're not seeing any signs of oil starvation for any of the components. The oil report from Millers shows that the oil performance was satisfactory

The small end looks to have let go and then caused the rod to windmill around and smash into pieces when hitting the block

All parts are being sent off to Japan to be investigated

[smudge]

Originally Posted by weederr33

I was looking into the HKS kit or waiting for Cosworth to release some forged internals. But it does puzzle me that the rods aren't forged. Also, doesn't the HKS stroker kit increase the compression ratio slightly? Do you think that would have something to do with it?

It lowers it very slightly and with the 1.0mm gasket kit it should be around 10:1

[Matt@Cosworth]

Originally Posted by smudge

We're not seeing any signs of oil starvation for any of the components. The oil report from Millers shows that the oil performance was satisfactory

The small end looks to have let go and then caused the rod to windmill around and smash into pieces when hitting the block

All parts are being sent off to Japan to be investigated

understood

I know you're committed to the HKS parts but I would highly recommend sourcing a rod with a copper beryliium bush on the little end if you can

unless the HKS part does actually have this?