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1725 Hillman engine - fumes in rocker cover?
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Bellisin



Joined: 19 Dec 2010
Posts: 19

PostPosted: Mon May 09, 2011 2:45 pm    Post subject: 1725 Hillman engine - fumes in rocker cover? Reply with quote

I have a MK VI Singer Gazelle that was purchased recently during one of these ebay last minute ebay "what the hell" moments. 1725 Hillman engine.

From day one the car has had exhaust fumes under the bonnet which leak into the cabin. I replaced the exhaust gaskets and exhaust system which partly cured the problem. However, having spotted some fumes rising from the oil filler cap I investigated and found the following:

1. When running the engine pumps fumes out of the oil filler cap under light compression.
2. The fumes at least smell like exhaust fumes.

Thinking with my limited knowledge that this could be a head gasket problem I have removed the head and found that one of the head bolts between 1 and 2 cylander was sheered off. No obvioud signs of blowing on the head surfaces or gasket if this is expected?

I am now at the stage where I have removed the broken bolt from the head but the head is still off. The bores have a slight lip but are not scratched etc.

Question:

Is it likely that replacing the gasket and broken bolt will cure the issue or are the symptoms typical of another problem such as piston ring failure?

P.S. I have never seen so much instant gasket on one car!
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victor 101



Joined: 03 Apr 2009
Posts: 449
Location: East Yorkshire

PostPosted: Mon May 09, 2011 3:38 pm    Post subject: Reply with quote

I doubt that replacing the head bolt and gasket will cure your problem, it could be something as simple as the crankcase breather being blocked, or it could be down to worn rings allowing the compressed gases down into the crankcase and then finding their way out via the pushrod gallerys.
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47p2



Joined: 24 Nov 2007
Posts: 2002
Location: Glasgow

PostPosted: Mon May 09, 2011 3:54 pm    Post subject: Reply with quote

Have you checked for excessive wear in the valve stems?
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Bellisin



Joined: 19 Dec 2010
Posts: 19

PostPosted: Mon May 09, 2011 4:21 pm    Post subject: Reply with quote

Thanks for the quick replies.

I am a novice have a go classic car owner and I am still welding mymain restoration project so my knowwledge of engines is limited to teenage tinkering and car mags. However, I am keen to learn.

1. Is there a way to test the rings without removing the pistons? I am guessing that changing the piston rings will require the engine out? I do have an engine hoist so it could be done although I am all for an easy life!

2. When you say valve gear do you mean the stem seals? I see these are cheap to buy. The valves are in tact but of course caked in soot as are the piston heads. Is there a safe way to clean the pistons and valve surfaces? I am guessing its still ok to grind in seats with the those suction sticks and paste?

3. Is it acceptable to fit new piston rings to lightly worn chambers? I fear that if I have to consider a rebore I then have to consider economics for what is a bit of a banger.
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47Jag



Joined: 26 Jun 2008
Posts: 1470
Location: Bothwell, Scotland

PostPosted: Mon May 09, 2011 6:11 pm    Post subject: Reply with quote

The easiest way to check for worn rings is a compression test but it's too late for that. Can you move the piston sideways in the bore? That can give an indication of how much wear there is. Worn valve seals wouldn't show as smoke in the rocker cover more likely it would appear on overrun. I agree with Victor101 that you should check the crankcase ventilation system.

Art
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Phil - Nottingham



Joined: 01 Jan 2008
Posts: 1254
Location: Nottingham

PostPosted: Mon May 09, 2011 7:15 pm    Post subject: Reply with quote

This engine is noted for excess crankcase fuming when piston rings wear to the extent that fumes upset the mixture at idle and cause smoking.

The well known bodge from 1960's to now is to disconnect the breather tube and vent underneath the car and when it starts spraying out oil which it soon does poke the end in an empty lager can to catch it Shocked

The Vauxhal?Oepl cam in head engines fitted to old Cavaliers/Rekords and Carltons does the same.

Want the T shirt Wink
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bob2



Joined: 06 Dec 2007
Posts: 1722
Location: Malta

PostPosted: Tue May 10, 2011 8:12 am    Post subject: Reply with quote

Is this the arrow shape?
My hunter does something similar and it has the 1500cc engine, we did a compression test which gave 135psi on numbers 1 and 2, 150 on number 3 and 140 on number 4 so not too bad considering its over 40 years old.
However it does let out fumes from the rocker cover breather which I had connected back to the air filter housing but now am thinking of putting a pipe from it to below the car as it too sometimes does splatter a little oil.
It also lets out some greyish smoke from the exhaust so if the rings look to be okish it may be the valve seals letting out some oil onto the pistons?
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Phil - Nottingham



Joined: 01 Jan 2008
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Location: Nottingham

PostPosted: Tue May 10, 2011 7:23 pm    Post subject: Reply with quote

Same engine used from Series Minxes 1957 to Arrows to 1978 (1500cc to 1725cc) - piston rings/bore wear!
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Ray the rocker



Joined: 01 Aug 2008
Posts: 187
Location: south wales

PostPosted: Tue May 10, 2011 10:04 pm    Post subject: post subject Reply with quote

rootes group engines---especially the 1500/1725cc suffer crankcase ventilation problems very early (40,000+). normally a sign of poor compression with combustion fumes bypassing the piston rings.If you got plenty of cash --rebore--if not--you can get oil control rings to try and take up the free play on worn bores.I used to use "cords" years ago but i`m not sure if they are available nowadays.good luck with your repairs...

Cheers--Ray the Rocker....
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Bellisin



Joined: 19 Dec 2010
Posts: 19

PostPosted: Tue May 10, 2011 10:49 pm    Post subject: Reply with quote

Thank you for all the replies.
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Churchill Johnson



Joined: 11 Jan 2011
Posts: 335
Location: Rayleigh Essex

PostPosted: Tue May 10, 2011 11:02 pm    Post subject: Reply with quote

I was informed cord rings not made any-more may be some kicking around in their day they were the next best thing to sliced bread and would last for a good many thousands of miles.
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Ray the rocker



Joined: 01 Aug 2008
Posts: 187
Location: south wales

PostPosted: Wed May 11, 2011 11:45 am    Post subject: post subject Reply with quote

I second that --Monster of time taken to clean the pistons to remove carbon deposits but how important the installation of the "cord rings" being removed from each packet !! each ring segment came in two sections. cup up and cup down as i remember. If you got one wrong--ie--cups facing the same way---they would suck the oil up from the sump and all the hard work results in a heavy thick fog in your locality !!! always double check before assembly was imperative. The good old days of cheap alternatives are long gone i`m afraid--it`s all high tech now--so much money about,cheaper to change your car than spend a fortune on an engine .

Cheers--Ray the Rocker...
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PAUL BEAUMONT



Joined: 27 Nov 2007
Posts: 1278
Location: Barnsley S. Yorks

PostPosted: Wed May 11, 2011 1:01 pm    Post subject: Reply with quote

This brings back memories! About 25 years ago a mate of mine, in a similar rash moment bought a similar motor, probably through Exchange and Mart in those pre-Ebay days. It looked tidy enough and he was pleased enough with it, but to me it ran on 3 cylinders. I goaded him about this for a bit until he finally gave in and removed the cylinder head. There was no no.3 piston! just a carefully fitted wooden plug. The vendor had even cut off the con-rod and bolted the remains aroung the crank to maintain oil pressure. He was less than amused and my hystertia did not help matters.
So Bellisin, just be thankful that you have compression on all 4! Laughing

Paul
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Daniel H



Joined: 12 Apr 2011
Posts: 62
Location: Herts

PostPosted: Wed May 11, 2011 1:34 pm    Post subject: Reply with quote

PAUL BEAUMONT wrote:
This brings back memories! About 25 years ago a mate of mine, in a similar rash moment bought a similar motor, probably through Exchange and Mart in those pre-Ebay days. It looked tidy enough and he was pleased enough with it, but to me it ran on 3 cylinders. I goaded him about this for a bit until he finally gave in and removed the cylinder head. There was no no.3 piston! just a carefully fitted wooden plug. The vendor had even cut off the con-rod and bolted the remains aroung the crank to maintain oil pressure. He was less than amused and my hystertia did not help matters.
So Bellisin, just be thankful that you have compression on all 4! Laughing

Paul


Reminds me of a letter I saw published in a 1960's Motor magazine, where the reader purchased a Wolseley 6/90 from a car auction which according to the auctioneer was "mechanically sound apart from a slight misfire". After driving the car home on five cylinders he proceeded to investigate the trouble and found out there was no gap on plug no.2, so after gapping and replacing it he turned the car over on the solenoid which caused an explosion inside the engine and the dipstick to literally fly out, spraying him in oil. So after dropping the sump it turned out there was neither piston nor con-rod attached to number 2 journal (which was scored beyond recognition), the oil-way had been clogged with filler and bound together with masking tape (presumably to keep the oil pressure up), and the plug had been pinched together to in order to prevent combustion. Shocked
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JohnDale



Joined: 19 Mar 2008
Posts: 787
Location: Kelvin Valley,Scotland

PostPosted: Mon Nov 07, 2011 4:46 pm    Post subject: Reply with quote

I remember,one or two moons ago, in the days of metalled bearings as opposed to shells, a gent on holiday with his family, & a car with a run big end. No time left to have the car sorted as holiday was nearing it's end. As a swift repair I cut a piece from a large Oxo tin lid & inserted it into the relevant big end after cleaning out the oil passageway in the crank. Engine ran fine, if a wee bit dour to start, but got him home to Cornwall without incident. Happy daze & 'engineering ' at it's best,cheers,JD.
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