Heads Off Due To Pressurised Coolant

[Stesaw]

Just thought of something l recall reading some while back. Mounting points for PAS using DG heads? No holes?

Anyone care to comment?
Also lm cleaning where lower sleeve seal mates with main cases. Ive found a small crack. Is this an issue? About 4mm long. Perhaps that why black silicone (l mean same stuff used on heads) was laid around base of all sleeves.
Your comments please...


[/quote]

Might explain all the sealant you've been finding there :?, hopefully it's not going to cause an issue for you. 
I am sure one of the engine guru's will tell you.
  
 

[937carrera]

I can't really comment on the PAS as I have never seen it, but surely that's just something you or an engineering shop could drill and tap ?

On the crack.... I expect that it looks much worse on the photo than in real life.

If you are worried by it then give it a good clean and use some chemical metal as a filler. It may just stop a tiny bit of the water jacket finding its way into the sump, but in practice I expect that the barrel seal will take up the gap. Smooth it off while it is still flexible, then you won't need to abrade the excess away when it has gone hard

[maxstu]

Thanks to both.
Yes its look far worse in photo. Viewing by eye its almost too small to fill.
As for PAS I think l can take a peep at engine in camper at mo. And work it from there.


Regards
Stuart

[maxstu]

New question please

I have a new set of Grant pistons rings.

Comparing old rings with new, the Grant top compression rings have an inner bevel, whereas the old comparable rings are flat edged. Is this an issue? Image below of new Grant 1st compression ring
Regards
Stuart

[weimarbus]

Hi Stu, Re cylinder heads, I am fairly sure that all heads were drilled and tapped as a matter of course, re, crack there is only crankcase pressure and water pressure where you have an issue so  should not create a problem ( did you have a mayonaise problem, water in engine oil, when this engine was running?) re rings, as replacement rings they are probably designed to be fitted to pistons where the ring groove may not have been cleaned properly hence chamfer to allow for some carbon in the ring groove?

[maxstu]

Thanks again,
Hi Andrew, no oil in coolant. No mayo. Just gases in the cooling system causing the usual overflow from top up tank behind flap and pressurised blue cap tank. Big whoosh everytime l released cap. I tried three other quality caps. All quacked by the way. Still same issue.
So l am at a point where l need to lift off the old fire rings in the heads. Replace with new. Drill out broken exhaust stud. And drill three new holes and tap for the PAS bracket.
Should l wipe a smidgen of Dirko over that minute crack perhaps?

Regards
Stuart

[maxstu]

Only a small amount of DG activity today. Spent most of the day working on my brother's boat. Perkins 510 V8 twin diesel engines. A complete mess with all types of pipework and linkage rusting and leaking. Made the DG a tad lightweight. Not so however.



I snapped a drill bit when redrilling to tap an exhaust stud. Extra viewing to revealed a helicoil lurking deep down the hole. Removed coil. Its a bit of a mess. So now l will likely drill out to M10 (no deeper than 22mm) and fit a reducer stud M10 to M8. Any other options?



I unintentionally left both heads in today's lovely sunshine. By chance this allowed me to remove all four fire rings with a deft flick of a finger nail. RESULT!

Still no clues why engine was pressurising the coolant..which a tad worrying. I was hoping to see a scratch or steam marks etc and then say Aha! You bugger. But nothing that my layman eye can spot. Condition prior to proper cleaning. Can you see anything suspect? Looks like l forgot to photo left side.

Right hand bank..Or furthest from waterpump.







It was at this point l noticed an exhaust valve deeply seated. I used a blade placed across top of springs to view this valve is a different height from other three. Right side bank. Anything to worry about? Other side is fine. I do not intend dismantling valve train. Just cleaning and lubrication.



Regards
Stuart

[937carrera]

Loads of pictures, loads of questions, lets' try some answers:

Diesel engine: I would be tempted to try a timesert type thread repair rather than helicoil. You don't need thinwall. Then use standard stud

Pressurising of coolant : You can see steam cleaning on 1 & 2 in the first post. I reckon either bolt has slackened, stud stretched or RTV eventually gave way allowing the barrel to move

Valve : If that valve is deeply seated then the stem should be higher than the other three. That photo suggests that the valve is not actually fully closed. I think you are going to have to remove a couple of valves to inspect and measure

[maxstu]

Hi David,

Sorry for so many photos and questions. Im not totally out of my depth. But starting to feel a bit on tippy toey

Firstly, marine diesel engine was just a photo of what l was tinkering with earlier today. The exhaust stud issue is back on the DG.

Please show me where steam cleaning is? I dont have your keen eye.
What's a RTV?
Lastly the exhaust valve on left side of picture is seated deeper in heat. Therefore stands above other three at the spring end of valve...does that sound right??

Regards
Stuart

[937carrera]

No worries, I was just teasing

Your first pictures: 3 & 4 are black, 1 & 2 have shiny bits...... steam from coolant cleaning

RTV = Room Temperature Vulcanising (silicone) = your black mastic

Valve: I misunderstood, so the one on the left is recessed, you are going to have to dismantle that at least

If any of those dings in the head have proud bits you need to remove the proud bit, potential for hot spot / detonation.

[maxstu]

Cheers matey l alway thought the right bank ran hotter anyway. Due to being furthest from waterpump. Urban myth?
Its a temp engine for when l need to replace water jacket seal on the DJ in camper.
I clean up dings on heads next time in garage.
I have spare new valves for DJ refurb. I can use one if it is suspect.
Regards and thanks
Stuart

[937carrera]

If it's valve seat recession it'll be the head that needs work.

No idea on urban myths:)

[Oldiebut goodie]

Back to the boat engine - this is one place that I use WD40 liberally to try to keep some of the corrosion at bay. I try to spray all over after each use.

[maxstu]

Thanks to both.
Hi OBG. Hope you are well?
Both engines very neglected and not started for two years. The corrision is nasty. My brothers' liveaboard boat. A 42 feet ex dive boat with twin Perkins V8 diesels. He let things slide after relationship breakup and losing job. So our Dad and me are helping him give the neglected engines a chance of survival. Flushed out both. Changed filters and got both running. Then oil cooler burst a pipe on one and the other had no gear selection...cable rusted solid in sleeve.
My bro is less mechanically minded than me...would you believe
Worst part. The engines were put in place before upper super structure added. So major headache if either fail

[Oldiebut goodie]

A mate of mine had to cut a big hole in his wheelhouse roof to change his engine! People don't usually look that far ahead when fitting out, usually the boat has been sold on by the time an engine out is needed.