Perkins MC42 - dumps water into expansion bottle

[Toad555]

Hi

 

After reading a few posts it seems that all the movers and shakers are on this forum, I'm new to canal cruising so this is my first post on this forum.

 

Our boat has a Perkins MC42 installed and the cooling system cap is in need of replacement, I wanted to ask people's opinion if the faulty cap that is fitted is in fact the correct one.

It seems to be a 7 PSI one, is this correct for the MC42?

Does anyone know where I can download a workshop manual for a Perkins MC42?

[gazza]

7 psi is the norm.

 

The cap is there to raise pressure in system and thus the boiling point of the coolant, once this pressure is exceeded it opens and vents excess pressure to the expansion bottle or bilge/ floor delete as appropriate...

[Toad555]

Good to know the faulty cap thats currently fitted is actually the correct one, its definitely seen better days so a replacement seems the way forward.

 

Would it be safe to fit any 7psi cap that fits?

I'm quickly learning that parts for this engine aren't so simple to obtain. I spoke to Diperk who don't supply the cap although they pointed me to Duffields of Norwich and so far I haven't found if they actually exist anymore, all I find is Dufflields animal feeds in Norwich.

 

I have learned that the engine is a Perkins 104.19 which helps further as I also need a rocker cover gasket and I'm still looking for a workshop manual to see if there is a further gasket a little lower on the engine under the rocker box, it does seem like that is a removable part too so I assume it would have a gasket.

 

Obviously I don't want to start taking things apart when I'm 100miles from home unless I have all possible parts available.

[Proper Job]

I think you'll find that it's a pretty standard radiator cap.

 

Your local motor factor will probably be able to source one for you at the correct rating.

 

I can't help you on the spares front. I had an MC42 in a previous NB of mine. I found it utterly reliable and the oil fiter etc for routine servicing was again found via a local motor factor.

[Keeping Up]

The MC42 is indeed basically a Perkins 104-19 which was marinised by Duffields, who were attached to Perkins as marinisers but who no longer exist. Most engine parts are easily obtainable from Diperk, who are generally quite helpful, and are also the cheapest source of supply for things like oil filters (they have a minimum order quantity of £20 so postage is free, I just stock up with oil and fuel filters to reach the required value); the only parts not available are the marinisation parts such as the header tank.

 

Any 7lb cap that fits will do, just go to Halfords. When you refill the header tank, leave between 1" and 2" of air space or the excess will just be dumped through the cap as it expands. Don't leave more than 3" of air space or the water circulation may suffer .

 

Yes there are gaskets between the rocker cover and the next section below, and also between that section and the lower part. The gaskets are not real gaskets, they are simply lengths of circular-section rubber; you can buy them pre-cut (and possibly shaped) from Diperk, but it is more common to replace them from a straight length which you just cut to length (preferably too long rather than too short, because they shrink with age) and then fit into the groove. It is best not to disturb the lower one unless you are certain that you need to (eg if you have a leak) although of course if you need to take the rocker cover off to reset the tappets then you will probably have to replace the gasket.

 

Beware if you do have any oil leaks, they often come from places that you don't expect them to, and the engine relies heavily on the use of washers with rubber insets (I can never remember what they are called) and tightening a leaking joint will often make it worse instead of better.

 

I do not know of a downloadable source of the manual, although I have looked hard for one over the years. I do have a PDF copy of the 100-series manual, which is almost the same, that I could email to you if you like. The engine originally came with just a 6-page mini-manual that detailed the oil-change intervals etc, I could easily copy that to you as well. There is one member here who does have the full manual - it is a hefty volume - who could probably assist if you had any specific questions that weren't covered by the 100-series manual.

Edited October 4, 2012 by Keeping Up

[jelunga]

I am another MC42 owner and I think Keeping Up is refering to me as the manual owner. I have not scsnnex to a PDF yet, but with the nights drawing in anx nothing else to do in the boat I might give the pub a miss and scan it.

It you are interested PM me with your email address and for a few beer vouchers (lol) I might get a round tuit.

[Keeping Up]

I am another MC42 owner and I think Keeping Up is refering to me as the manual owner. I have not scsnnex to a PDF yet, but with the nights drawing in anx nothing else to do in the boat I might give the pub a miss and scan it.

It you are interested PM me with your email address and for a few beer vouchers (lol) I might get a round tuit.

 

I was indeed referring to you - but obliquely in case you wanted to remain anonymous and not feel under any pressure to scan it in. But having said that, if you do get a round tuit and scan it in I would be grateful for a copy too.

[STUBAG]

I was indeed referring to you - but obliquely in case you wanted to remain anonymous and not feel under any pressure to scan it in. But having said that, if you do get a round tuit and scan it in I would be grateful for a copy too.

I would like one too, Allen, but Ashbridge has a 104-22, instead of the 104-19.Same engine but with a stroke of,I think,100mm. The washers you were thinking of are known as DOWTY WASHERS, originally made by Dowty-Meco for use in underground hydraulic mining machinery. STUBAG.Sorry, Allan, not Allen!

Edited October 4, 2012 by STUBAG

[Toad555]

I've ordered a replacement rocker cover "gasket" from DiPerk and made up the min charge with a couple of filters.

I did look into the genuine manual cost and decided against it at £40. I figured that I can fix most faults without a manual and anything that I would need a manual for is unlikely to be repairable on the canalside anyway.

 

Looks like the best route for a replacement header tank cap is to match one up from a motor factors then, is the info correct that Duffields are no longer trading?

[Toad555]

Well, I still don't have this radiator cap issue completely sorted. I did get a cap from the local car spares place and after taking all the measurements they still sent the wrong one, its 4psi rather than the correct 7psi but is certainly better than the original one.

I still seem to lose some water but have little idea where its going, its not going into the overflow bottle anymore, hope this isn't the start of a head gasket or worse.

 

There definitely isn't any oil in water or water in oil and no deposits in the oil filler cap so that's promising at least.