Classic cars forum & vehicle restoration.

[trampintransit]

So...Engine been laid up for unknown period. Been running on and off during body restoration over two years. Engine always seemed great...now it's on the road however it's become clear it's blowing-by ..big time. ...smoke pours out if the crankcase breather and rocker cover vents at speed, even more so under load.

... After about a hundred miles or so I'd have thought that if it was sticky rings, they'd have started to free off by now? I've still to try the releasant / seafoam / atf whatever down the hot bores and leave it overnight ..but I'm not holding out for that one.

So...to what extent am I rebuilding the engine to cure the problem? I've never done this before so I'm a bit clueless. .. Can I just get away with honing the bores with the engine in the car? If not ...can it be rebored in situ by clever people with clever tools? ( It is by all accounts a absolute of an engine to get out ) ...the pistons are gonna have to be dropped so...can the shells be reused? ..

This is gonna be expensive isn't it?
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'60 Armstrong Siddeley Star Sapphire
'80 Reliant Scimitar
'47 Jaguar MKIV --- in bits!!!!

[peter scott]

If the pistons need to be taken out the bottom then you need to know if you can get them past the crankshaft. If not then you really need the engine out to remove the crank.

If you can get the pistons out there is no problem honing the bores assuming that all they need is glaze busting so that the new rings bed in. Clearly you will need to clean out any hone dust from the crank and crankcase before reassembly.

There used to be firms that offered re-boring in situ but I can't say I've seen anyone offering that service recently.

The shells can certainly be reused if you had good oil pressure before you started but replace them in the same places as them came from.

Peter
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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[trampintransit]

Thnks for that..I've been tossing all manner of stuff down the bores the last few days to see if it free the rings ( If it IS stuck rings)

What surprises me is that the plugs come out clean as a whiste? Surely if the rings were knackered or the bores really worn then I'd expect the plugs to be black n sooty?
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'60 Armstrong Siddeley Star Sapphire
'80 Reliant Scimitar
'47 Jaguar MKIV --- in bits!!!!

[petelang]

Compression test first. Maybe it's just one cylinder? Maybe valve guides?
Peter

[ukdave2002]

[peter scott]

[roverdriver]

Peter, one of the older style spark plugs in which the porcelain is held in place by a threaded ring, as in earlier KLG., is your starting point. The other component is a valve from a tyre inner tube. Disassemble the plug, replace the porcelain with the tyre valve and you have a very inexpensive adapter.
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Dane- roverdriver but not a Viking.

[peter scott]

Thanks Dane, I have a small collection of detachables and might sacrifice one.

I also have this that popped out of a brand new Michelin tube.

Peter


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http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[ukdave2002]

Leak-down testers have plummeted in price, this one is less than £18 delivered:


Dave

[Peter_L]

That looks like a neat piece of Kit and for £18. What's that, a decent bottle of wine ?

There is so much stuff available today, OK some of it can be a bit naff and cheap but I guess it can depend on how often it is going to be used.

I know, for some of us, there is a certain challenge and satisfaction in making things. but perhaps it hawks back to the days when sometimes DIY was the only viable option.

I remember my Dad turning up oak pulleys and cutting side plates out of old bits of chassis to make pulley blocks for our first scaffold pole tripod used to pull the engine from his first 105E. My hydraulic engine crane cost me $180 Cdn about £100. I used it not so long ago to help pull a tree stump and once used it to hold up a deck on our house while I put in a new support pillar.