Smoking engine

[Chris KC]

Depends what you plan to use the car for - I would suggest not to go too flat as the followers are liable to wear rapidly.

[GK5268]

here are mine, plus a piece of the tappet block guide that I cut off

[attachment=3176]

[attachment=3177]

[attachment=3178]

[Andy Bennett]

Thanks Chris
The middle set it is then. Just to trim the guides an equivalent amount and another bit of the jigsaw done.
Andy

[Ian Williams]

This Hepolite doccument may be of interest to some of you.
   

[Adrian Payne]

Hello All
A quick update on progress.
On pulling the head off the guides were not that bad. That said it seemed stupid not to change them. The old ones drove out fairly easily with a turned mandrel. The guides were frozen and pressed in with a large G-clamp.
Unfortunately on our 200 mile trip to Pre War Prescott the smoking is no better.
By the way, this event is really worth going to.
What would be everyones advice on the choice of new pistons. Should I go for the sports pistons.
Are there higher quality rings I could try with a de-glaze.
Many thanks.
Adrian.

[Ruairidh Dunford]

Good morning Adrian,

Sorry to hear you have not yet solved your issue.

I use the same pistons and rings as you and have on a very frequent basis and I have not had any issues as you describe. My latest set were fitted in in May to the engine I am currently using to tour France in (it has run 2500 miles since being installed and is at the point where I consider it run in) - exhaust is clear and oil consumption has settled to very little with continued improvement, we are using it daily and this I find a very good way to bed everything in.

In your position I would be looking at glaze busting the bores - this should be done by a professional who you know and trust, if not sure, ask A7 engine builders local to you for a recommendation. I have established an excellent relationship with my local machine shop, who bore blocks the way ‘I’ want them done, others will have done the same near to you. Take all four pistons, numbered to the bores, with you. They can measure and comment on anything they find, which may be very useful and affect the way forward.

Once this work is complete post some photos here of the bores for comment, get another set of rings from the same source, gap and fit them.

I shared elsewhere my run-in routine, this is tried and tested and I can link to it, if necessary.

I am confident this will resolve your issue or highlight the cause more clearly.

[Adrian Payne]

Hello Ruairidh
Many thanks for your advice. I have seen your recommended running in procedure. I'm sure there are many types of cheep oil but what brand do you usually use. Maybe the oil I used had too many additives to allow bedding in.
I will speak to local A7 experts and find an engine shop they recommend, as you suggest.
Adrian.

[Roland Alcock]

My tourer was pumping out smoke worthy of a WWI naval exercise. This on an engine which had not completed too many miles (I believe) after an engine rebuild seven years ago. I believe it was not run in correctly.

I deglazed the very shiny bores and replaced the rings on the slipper pistons. 

I have used Comma oil and frequent oil changes. 

1500 miles now, no smoke, maybe 1/4 pint oil consumption every 200 miles. That I suspect is from some crankcase compression blowing a little oil out the filler tube. I expect that to improve. 

Interestingly, before the strip down, cylinder compressions were good, approx 110 psi.

I have not yet measured the compressions since, but immediately after the rebuild the engine felt immeasurably better ascending the unavoidable hill from my house. 

Yes Pre War Prescott was good!

Roly

[Adrian Payne]

Latest Update
Finally pulled the engine out and stripped it down.
Although not easy to photograph I hope this shows the wear marks on the oil rings.
   
They all show a missed area exactly opposite the ring gap. Some also show a missed section further round.
Does this just show the rings just not bedded in or were the rings not a good shape to start with?
Adrian

[Bob Culver]

Although not oil rings, I have noticed on other cars at least some brands of ci rings (not advertised as SGI) seem to be stressed beyond the elastic limit when just expanded to the absolute minimum.  The free  gap idecreases after insertion in a bore. Some ci seems to have a degree of ducticlity. Maybe the rings were opened too wide. Now useless so it would be interesting to see if these ductile and how far can be opened before snap.
Few (even Seven owners) get to see a lot of new rings at low mileage but wear I have seen always quite regular.

Very good of you to publish outcme. Too many posts fizzle which discourages much effort in responses.