Perkins 4108 heat exchanger/ header tank and demons therein

[David52]

Now as some of you already know I am stupid.

So be gentle with me - what does this mean?

I have a Perkins 4108.

It was drained of cooling fluid, awaiting a speed flush once the boat is back in the water (yes I know it's late!).

As the boat has been inactive for some time (I bought her in Jan) I thought that I should inspect/change the raw water impeller - Which is a Jabsco pump type thing.

I was intrigued, when removing the pump face plate, the the water which escaped did not smell like stale sea water - more like vinegar, a solution of which I had added to the header tank a few days ago to soften up the calcification- Which I thought I had flushed out though the cylinder block drain. So over to the sink, quick cup of water poured into the header tank and whoosh more water flowing through the pump housing.
I reapeated this - just to check that I was not mad - yes there was more water - no this is not a good mental health indicator.

Now I think this means that the stack has corroded through, thus fresh water is going straight into the raw water system.

Before I attempt to remove anything - bearing in mind that most of it is welded in situ with what appear to be rusty nails, (I'd rather strip this next season rather than lose this one) does any one have any wisdom to share.

So a quick plea to the initiated - Any suggestions however off the wall would be greatly appreciated.

Rgds,

 

[LeytonC]

Which type of heat exchanger have you got? a bowman HE accross the front of the engine (inc. an oil cooller) and a seperate water cooled manifold, or an all-in-one type?

I have the seperate 1's and i had a tube stack go, its not problem to replace, a single 3/4 bolt holds the lot 2gether, Bowman in Birmingham are still in business and made me 1 for about 260 quid (inc VAT) get the 4 seals you need as well while you are there, bang the lot back 2gether, job done.

I tried to get it repaired, but the company i sent it 2 did not seem to want to mess with it when they saw it - and for 260 quid not worth the hassle.

BUT

1st off all, check to see the 3/4 bolt holding everything together is tight!!!

2nd check that its not just a seal

 

[JonJon]

Last year Pal of mine dismantled his heat exchanger on his 4108 and the end hose connection castings had virtually disappeared necessitating a new exchanger. I think yo will have to remove it previous poster has mentioned the cost pretty sure thats the same amount I recollect.
Am starting to get worried about mine now you have already got me wound up about keel bolts on the Fizz can I suggest you stop disassembling things and get back in the water like Im trying to do.

Regards

 

[David52]

Thanks for your post - Looks like the obvious is obvious - i.e. the stack is gone.

I am not sure exaxctly what type I have. But there is only full access from the aft (gearbox) end (what that there was full access to the aft end), which also seems to be attached to the exhaust. I have read my Perkins workshop manual and this is not one of the 2 types featured in pictorial format.

I don't think it has an oil section - although that is a guess, but I did read that the later models did not.

So in description it is a tubular aluminium thing bolted above the injectors. With pipes coming of to the block and the raw water feed. and some other stuff at the aft end for which I will need my miners helmet and to lose two stone to see easily.

It seems to be a sealed water system with the over flow feeding back into the water system, meaning you have to unbolt and take off a pipe just to top up the freshwater.

I think think the bowman of which you speak was/is a double ended affair with a single bolt holding the ends on?

Perhaps I should go to church now......?

 

[David52]

JonJon,

I would if I could. The sea is calling - but if it takes much longer it'll be off the quayside with stones in my pockets.

You should hear the gas engineers report om my water heater. He used to word deadly and condemed far to much....

 

[LeytonC]

Can you get a picture of it? or the coolling setup? might help....

Or get a small child (Grin) to go have a look, there is usally a plate (!) that says the make and model number...

But i think it still might have to come off.....

Leyton.

 

[pappaecho]

I had exactly the same problem in the winter having bought the boat in November. The boat included a can of antiffreeze, so it filled the "heat exchanger" with antifreeze.
Come spring, started the engine and lo and behold antifreeze coming out of the exhaust port.
Looked at the two different pictures in the 4108 manual, neither of which match my engine.
Simple ....the engine is raw water or (keel cooled).
If you look at the pictures in the manual, there are two lumps, one of which is the water cooled exhaust manifold, and the other unit is the indirect heat exchanger "stack" and the header tank.
The header tank has a traditional radiator cap which you push and twist, and should have a pressure rating of say 12 lbs.
The exhaust manifold, also has an array of incoming and outgoing hoses , one of which injects outgoing water into the exhaust elbow. It has a brass screw cap which if you open it has large spring inside and a huge ball bearing which acts a a valve.
If therefore your Jabsco pump draws water via the raw water strainer, and then pumps it into the block at the back, and the water then comes from the front of the block and connects to the exhaust manifold, then you have a raw water cooled engine. If, on the other hand you have a second lump with a header tank, then your stack has corroded. Each end has rubber ends, and the bundle of pipes can be withdrawn for inspection, and replacement. Lancing Marine and ASAP sell spare cooling bundles.
If you view the manual on this site:-

http://users.firenet.uk.com/stewartbray/perkins4108.pdf

and you cant find a picture of your engine drop me a PM and I will send you a picture of a raw water cooled 4108

 

[David52]

Errr... Thanks for that - I will be donning my Gas lamp and hard hat and doing the comparisons.

There is indeed no "radiator" cap, But there is an unscrewable thingy with what appears to be a valve which would feed water from the header tank back into the system.

Therefore I am starting to feel silly having bought some speed flush.

Cheers

 

[Nauti Fox]

Not much help on the heat exchanger, but can I suggest "Just For Men" to restore your greying beard to a completely unatural colour. My Dad went bright orange when he did this and kept us kids amused for ages.
If there's anything else that I'm unable to help with please don't hesitate to ask.
Regards, Al.

 

[David52]

In case any one is still paying attention it is indeed raw water cooled. I did warn you I was stupid.

But I still use a GPS and operate the video (of course now you all have dvds) though not at the same time.

Once again thanks for all your comment - without which I would be, if nothing else, poorer.

Cheers

PS have decided that the best form of defence is attack and am therefore going to dye my beard completely grey.