Possible cracked head & questions

[Kingscott]

Hi everyone.

After many years with a odd issue of getting oil in my water and changing just about everything I have come to the conclusion I may have a crack head.

Can someone kindly point me in the right direction of this "oil gallery" in the head that may be cracked? and what to look for.


Also the current head is quite a high specification.

Ported and gas flowed,
Valves seats as large as possible with standard size valves.
inlet and exhaust tubular manifold matched to head.
Uprated valve springs.

I run around 19 PSI at the moment with good fueling, realistically if I fit a standard head (if my one is shot) will I notice any differance? or will i be best to get the replacement head worked on to the same spec?

It will be a real shame to scrap it. I must also test to see if its been overskimmed!!!


last question, the pistons are Low comp pistons 7.4:1 CR, any idea what figures I should get during a compression test? what is the standard compression ratio? I belive a standard engine is around 145?


Thanks in advance.

Oh the joys of having the car running after 4 years..............:laugh:

[Trevhib]

The best bet will be to take it to an engineering place to have it pressure tested, or swap in a standard head to see if the problem goes away. You might be able to spot something with the naked eye but if you can't it doesn't mean there isn't a problem and if you can, you'll need to swap it out for a known good head anyway.

You're right, standard compression is around 145psi at 7.9:1 IIRC. Sorry I can't help you with what the readings should be on 7.4:1 low comp pistons.

Maybe some help in here:
http://www.rtoc.org/boards/showthread.php?t=17543

[Kingscott]

Ok ta.

Can they pressure test oil gallerys?

[Matty]

Pressure testing basically works by say sealing up the water jacket in your case, filling with hot water and putting low pressure on the system. If there is a leak to the oil gallery it will be visible. Sometimes you have to heat the head up to get the crack to open up aswell. Another alternative is to use crack detection dye, which is quite a simple process, but if th e crack is somewhere that you can't physically see then not much help.

If the head has got a crack or has gone porous (very common in aluminm heads,not sure about 5 ones specifically though) you can have it ceramically sealed.

[Kingscott]

Ok I'll have the head off and get it measured and a full check from the local engineering workshop if it's deffo not a DIY job to see any cracks.

I suppose then at least I will know for sure what's going on, nice to know that it's possible to hopefully repair.

[Trevhib]

Good stuff.

What have to replaced to this point trying to sort this problem out?

[Kingscott]

Head gasket twice.

Radiator inc oil cooler.

Turbo.


It's like a tiny bit of oil that slowly collects in the header tank, the oil is clean as a whistle.

I'm checking the comp ratio of the cylinders before I lift the head to check I'm not doing silly pressures as I know the head has had a few skims over over the years. It does run a bit lumpy but then again this particular engine always has.

[Trevhib]

Good idea, might be one or two skims too many! :agree:

The only other possibility is a cracked block. Let's hope it's not that.

[Matty]

If the head is cracked and you want it sealing, I'll find out where we get ours done at work.

[Kingscott]

If the head is cracked and you want it sealing, I'll find out where we get ours done at work.


Ok mate I'll keep that in mind, thanks :)

[RussellT]

I cant say Im an expert on engines but what you describe doesnt sound like enough oil in the water for a cracked head liner block etc.

Could it be contamination of the coolant circuit from a previous problem?

[Brigsy]

It sounds like the gallery is definitely cracked. Tbh a stock head would do the job fine, or get your current one repaired.

[Kingscott]

I cant say Im an expert on engines but what you describe doesnt sound like enough oil in the water for a cracked head liner block etc.

Could it be contamination of the coolant circuit from a previous problem?

Doubt it, the cooling system has a full strip and and was flushed with some fancy de greasing agent, then flushed again.

I've probably only done 150 miles since it's rebuild with the new headgasket and the problem has come straight back.

Going to have to bike the bullet and het the head off again.

I swear my car has a quick release head!!! it's been off more times than I can count, I just wish I knew at the times that they were prone to oil gallery issues.

Not to worry, onward and upward.

[RussellT]

Water and oil come close together in the turbo and also in the radiator, also worth considering.

When Doris had an engine oil / water interface problem many years ago the whole header tank was full of myo. I ended up with a replacement engine and looking back with much more knowledge of the car now, I think it was a cracked liner.

Good luck

[Sparkie]

you can get the oil gallery drilled out and a metal tube epoxied into place.

[Trevhib]

Water and oil come close together in the turbo and also in the radiator, also worth considering.


He's changed/checked both of those I think Russ :):agree:

[Trevhib]

I ended up with a replacement engine and looking back with much more knowledge of the car now, I think it was a cracked liner.

Good luck

Good point. It could also be a weepy liner seal. If it's a liner, will the compression test potentially flag that up?

[Kingscott]

Hi


How can I check the liner seals? Are they easy to replace?

[Markey Mark (BD)]

Hi


How can I check the liner seals? Are they easy to replace?

If you have no water leaking into the sump then the liner seals are holding out
Only way to replace them is pull the piston/liner out as a unit and fit the new seals

[Kingscott]

Hi all

Just a quick update.

After a water jacket pressure test, it turns out the suspect oil way is cracked in the head:cry: however the machine shop (stanwoods engineering Bawtry) have been brilliant about it. :smokin:

The guy hasn't done a tubby head fix like this before however he is sure he can drill and sleeve the passage.

I have asked them to go ahead with the fix and I await the phone call for it's collection!

Strange, after so many years being plagued with cheesy oil I've finally with the help of RTOC have found the issue.

Thanks everyone for the help so far :agree:

[Kingscott]

you can get the oil gallery drilled out and a metal tube epoxied into place.
:agree:

[Kingscott]

Hi


Final update.

The oil way was indeed cracked. The way was drilled and sleeved using injector pipe of all things. Also re tested with 80 psi up its arse.

So far so good, car is back together and with zero oil in water.


If only I knew about this cracked oil way 6 years ago.

160 quid later for the head repair finally it's sorted. :smokin:


Thanks for the info and input guys.

Adam

[Alex]

Excellent result. Seems like a pretty good price too :agree:

[Matt Cole]

Goid stuff matey. Job done

[Trevhib]

Ace result :agree:

[Kingscott]

http://www.stanwoodengineering.co.uk/


Just a link for stanwoods for anyone who lands on this thread in the future wuth the same issue.