Wet Piston Tops

PostPost by: KevJ+2 » Fri Jul 31, 2015 10:31 am

I've run my engine a few times now and tried to lean it by fitting F9 idle jets but it still produces a lot of rich smoke.I have fitted a fuel pressure regulator to run my facet at 2lb. Float levels are good.
Yesterday I ran it again, but when I take out the plugs they are black and the tops of the pistons are wet. I also checked the exhaust which was black and I hate to say - slightly sticky. When I assembled the engine, I used Graphogen on all parts including the valves but I think this would have gone by now. I'm starting to dread the fact that oil is entering the cylinders (all four are the same). The engine had new rings +30 and the valves had new colisbro exhaust stems, inlets were ok (I was told).
I am waiting for a new compression tester to arrive but in the meantime is there any easy way of testing why I'm getting wet piston tops. I would hope its fuel but I'm probably kidding myself and its looking more like at least a head off :( Drat and double drat!
All thoughts welcome,
Kev.
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PostPost by: rgh0 » Fri Jul 31, 2015 12:13 pm

You say you have fitted new rings and run the engine a couple of times. What have you done to bed in the new rings ?

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PostPost by: KevJ+2 » Fri Jul 31, 2015 12:21 pm

Rohan,
I had the bores lightly honed and the rings coated with graphogen when assembled. I have only started the engine half a dozen times with no high revs. Have you any further hints? I think I'm going to need them!
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PostPost by: rgh0 » Fri Jul 31, 2015 12:49 pm

The rings will not have bedded in I suspect causing some oil to leak past.

You need to bed in the rings before you run it to long on light load, otherwise you can glaze the bore and the rings will never seal properly.

The normal running in procedure i use is as follows after honing or reboring and fitting new rings / pistons

1. Fill the engine with a special running in oil ( which is typically just a cheap mineral oil with a ZDDP additive).
2. Bed the rings by doing a series of full throttle accelerations from about 2500 rpm to around 5000 rpm in third gear slowing down and repeating. Do this for around an hour and maybe 60 km on a quiet section of road where you can safely do the acceleration and then cruise to the low revs and accelerate again.
3. The rings should now be fully bedded with the gas pressure forcing them against the bores during the acceleration runs. Change the oil and filter for the oil of your choice and you should be good to go.

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PostPost by: KevJ+2 » Fri Jul 31, 2015 12:53 pm

Thanks Rohan, unfortunately my car is completely stripped down ready now to start the bodywork so I won't be driving it until next year. Have you an alternative method?
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PostPost by: elanman999 » Fri Jul 31, 2015 5:54 pm

Kev,
The chap that does the bores on my blocks says DO NOT put graphogen on the bores, pistons and rings. All other bearing surfaces yes.
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John
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PostPost by: david.g.chapman » Fri Jul 31, 2015 6:03 pm

If it was me I would forget about the engine and finish off the rest of the car. Then when the car is back together I would run the engine in under load (as Rohan has suggested) and take it from there.

The graphogen could be inhibiting the running in process - all the more important to do acceleration runs as soon as possible after starting the engine again.

Sounds easy to say (I would be iching to take the engine apart again) but perhaps patience is the way forward here.

Dave Chapman.
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PostPost by: Chancer » Fri Jul 31, 2015 6:17 pm

https://www.google.co.uk/search?q=vim+c ... ChCDuUw%3D

Use with caution.

I've seen engines where the rings had refused to bed in and were smoking heavily be brought back from the dead to rude health on a Rolling road by the operator carefully introducing Vim into the inlet trumpets.
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PostPost by: jimj » Fri Jul 31, 2015 10:14 pm

The French word "elan" has pretty much the same meaning as the English word "vim" whereas Ajax was a mythical proper noun.
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PostPost by: rgh0 » Fri Jul 31, 2015 10:52 pm

I missed the bit about graphogen on the rings. That would concern me that the rings may be difficult to bed in due to that. I normally just spray the bores with WD40 or similar if i am storing the engine for a while before running in.

I would leave the engine as it is and spray some WD40 down the bores now. When the car is ready, then try to bed in the rings as I described. If it does not work you can then strip it and do whats needed.

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PostPost by: rjaxe » Sat Aug 01, 2015 5:46 am

Interesting that both the new BMW's I have owned had alarming oil consumption to start with and the cure was to boot it in a similar way Rohan advised for the Elan. I don't know if the BMW engines were filled with special running in oil but from memory I think the initial oil fill was changed quite quickly so that is a possibility. Anyway it cured the problem on these cars so should work for our twincams.
Richard
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PostPost by: Chancer » Sat Aug 01, 2015 6:52 am

jimj wrote:The French word "elan" has pretty much the same meaning as the English word "vim" Jim


That got me searching in my English dictionary :D

vim: robust energy and enthusiasm!

A good description of me if ever I want to change my username.............

Not sure that I ever knew that word in English but I've been losing it for the last decade.

"Vous m'avez coup? dans mon elan" :lol:
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PostPost by: KevJ+2 » Sat Aug 01, 2015 8:33 am

Thank you all for your replies.
Do you think because of the graphogen (Damnation!!) I should use a glaze busting running in oil such as -
http://www.ebay.co.uk/itm/MILLERS-LIQUI ... 3ce5d01e47
Or a regular running in oil such as -
http://www.ebay.co.uk/itm/Millers-Oils- ... 20fff7cb5a
Or even a competition one such as this -
http://www.ebay.co.uk/itm/Millers-Oils- ... 54101c082c
Thanks again,
Kev.
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PostPost by: vincereynard » Sat Aug 01, 2015 2:02 pm

I would suggest contacting Miller Oils directly, explaining your problem and asking them.

Vince
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