Oil Starvation to cams
 

Was driving up the M6 on sun night in my Version 6 Sti Wagon, accelerating nicely when at 4000rpm I heard a loud bang from the engine, then the sound of metal hitting the motorway and the engine juddered and died. My first thought was a rod going through the block as there was a horrible smell of burning oil when i pulled in.

On initial inspection by WMS Tuning who have recently rebuilt my bottom end, it seems that the cams had suffered a lack of oil, only on one side though, causing them to seize.

The engine is getting stripped this week for a full diagnosis (hopefully there's not damage to my HKS stroker kit) but has anyone heard of a similar oil starvation problem like this before?

The car is fitted with standard cams and upgraded oil pump/cooler.

Thanks peeps

How many miles since you checked the oil level?

Checked the oil just before setting off...oil level was fine

Good. HKS stroker kit uses cosworth pistons which are prone to oil usage depending on the bore clearances used in the engine build.

Was it the turbo side? The turbo is fed oil from the cylinder head, catastrophic failure of the oil line may have lead to loss of pressure on that side.

Or the cam caps may have not been put in the correct places, as they are all matched to a specific location. They could also have been done up too tight, decreasing the clearances to a level that prevented the oil flow.

Or crap in the oil way from the build process.

Or some failure elsewhere in the oil system causing low pressure and starvation to the head (ie bearing failure).

Oil cooler leak (notices uprated oil cooler fitted)

Crap in a second hand oil cooler.

How many miles done since the rebuild?

Paul

It's unlikely that "only" the cams would suffer from lack of oil.

I would check that the correct cam caps were fitted in the correct order. Check the other head too.

One possibility is that some dirt has blocked an oil feed. Excess 3 Bond, or similar (sealant used to join the block halves) is notorious for this type of thing, especially if too much is put too close to the main bearings.

Mark.

When you say cams siezed Dave did it break the belt ?

Agree with Mark regards the sealer, especially on a recent build. I would never buy an Axis racing engine for this reason, the pic on their website shows the split block with 3bond and it appears to have been applied by shovel :eek:

Hope the bottom end survived ok.

Andy

Andy,

If the engine in that picture survived, it must have been through divine intervention !!!

Daveo,

I hope it's not too bad.

Mark.

Just buy the block ;-}

What oil were you using and when was it last changed?

Cheers
Simon

HKS kit doesn't actually use Cossie pistons I don't think, but they are forged nonetheless.

Oilman,

I do hope you're not going to suggest that a less than optimum oil will cause total starvation to parts of the engine when run at just 4000rpm?

Paul

No, certainly not, I wondered whether viscosity was a contributory factor that's all.

Cheers
Simon

Pavlo,

The car has done about 2k since the rebuild, had the oil changed after 500 miles to mobil 1.

I'll be getting the full damage report in the next day or so and I'll ask John at WMS Tuning about the cam caps and the turbo side of the engine.

The oil cooler was a brand spanker mocal unit so unlikely that was the prob but I'll ask all the same. Don't think it was the bearings either - I've had one of those already (hence the rebuild) and it had all new bearings etc put in.

John's worked on a few scoobies and he's never seen anything like it but at least I can tell him it doesn't seem to be a common fault with scoobs.

cheers guys

daveo

I'll find out if the belt broke but it certainly felt as if something gave up...there was defo something landed on the M6 when it happend.

I'll be absolutely gutted if the bottom end has been damaged..my whole engine rebuild centred around the HKS stroker kit and it cost an arm and a leg.

R19KET - thanks mate hopefully it won't be too bad.


Daveo

If you can, find out how many of the cam journals were toasted. That will let you know right away if there was a restriction, and where.

I have received more than 1 set of heads that had mismatched camcaps.
Also, even slight overtorqueing of caps will result in seizure, but usually all of these things will happen in much shorter time. The fact that it did 2k before failure is a good sign.

When the engine was rebuilt, did you reuse your cam tensioner pulleys?

Ron

Ron,

Many thanks for this mate - I will pose your questions to John at WMSTuning who rebuilt the engine and is looking at the problem for me now.

He showed me the offending cam last weekend...jammed solid and shredded the teeth of a pulley. All other cams fine though, bizarre. Like I say, he's never seen anything like it before.

It had a new timing belt tensioner fitted...is that the same as a cambelt tensioner??

Dave