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Further adventures of the Renault 6 - update p7 - Honin' In The Honeyard


djoptix

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1 minute ago, junkyarddog said:

You're supposed to move the honing tool up and down the bores as it turns.

You need to see a cross hatch on the cylinder walls.

https://itstillruns.com/hone-cylinder-4727370.html

I did, I just haven't taken off enough to completely get down to bare metal.

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That ring groove looks good. Also means the rings won't catch in any raised dirt when measuring the gaps and set your measurements off.

Looking at the way they stuck, I would hazard a guess the lands are still well within spec.

None of the rings were fractured, even after the persuasion they required to get out?

 

Plus, did you oil the hone? Looks like the stones overheated.

Phil

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5 minutes ago, PhilA said:

That ring groove looks good. Also means the rings won't catch in any raised dirt when measuring the gaps and set your measurements off.

Looking at the way they stuck, I would hazard a guess the lands are still well within spec.

None of the rings were fractured, even after the persuasion they required to get out?

 

Plus, did you oil the hone?

Phil

One of the rings did break on removal. The oil scraper ring on a couple of the pistons was coming apart after I removed the pistons, but they're quite fragile.

I may* have started on cylinder 4 before thinking "hmm, this probably needs some oil on it". After that, yes, I used oil :)

My drill is probably a bit fast for this. It's 2100rpm on its fast setting and 550rpm on slow, so slow is much too slow and fast is too fast. I might try a different drill when I do the other cylinders.

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1 minute ago, djoptix said:

My drill is probably a bit fast for this. It's 2100rpm on its fast setting and 550rpm on slow, so slow is much too slow and fast is too fast. I might try a different drill when I do the other cylinders.

550 is fine. It'll allow you to get the correct helix pattern up and down the bore. Honing isn't a quick operation.

As for broken rings; breaking as you pull them off is fine.. broken before you get to them not so much. That's at least s good sign.

 

Phil

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Ok, thanks. I will try slow speed next time. I've done liners #2 and #4, but only for about 20 seconds each if that. I really didn't want to overdo it.

I don't think any of the rings are broken (3 pistons still have their rings in).

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7 hours ago, djoptix said:

Yes.

I'm coming round to the idea that since I've come this far I might as well get things clean while I'm here. I might even paint the block...

A squirt of carb cleaner will shift that from the pistons, it's mostly carbon.

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4 minutes ago, rusty_vw_man said:

Honing wise you want to end up with a 45 degree cross hatching - so the drill needs to rotate at the same speed you are bringing to tool up and down. 550 rpm is still pretty quick on that basis.... 

When you put it like that, you're right. 2100rpm is way too fast!

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7 hours ago, somewhatfoolish said:

The angle of the cross hatch is much less important than keeping it consistent.

This.   Bear in mind that the main reason for honing in this case is to remove the glaze from the cylinder to help the new rings to bed in, so only do the minimum.  Don't try and remove all the dark markings from the bores - it may be possible, but at the risk of removing too much metal.   You are not reboring it!  I have stripped a lot of engines which have done significant mileages and found that the hone marks are still visible, which suggests that honing is often overdone.   

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On 9/11/2020 at 8:46 AM, Mr Pastry said:

This.   Bear in mind that the main reason for honing in this case is to remove the glaze from the cylinder to help the new rings to bed in, so only do the minimum.  Don't try and remove all the dark markings from the bores - it may be possible, but at the risk of removing too much metal.   You are not reboring it!  I have stripped a lot of engines which have done significant mileages and found that the hone marks are still visible, which suggests that honing is often overdone.   

Thanks @Mr Pastry, those were exactly my thoughts.

Not much of an update but switching to 550rpm and using wd40 as lubricant has given an improved result. I think 2100rpm was throwing the hones against the wall too hard. 

It still looks worse than it feels to the touch, and it's much less smooth than #3 (the cylinder that was mostly un-corroded) - but it's better than #4, the surface roughness has gone, and hopefully the new rings will be happy.

 

IMG_20200912_123802.jpg

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3 minutes ago, Mr Pastry said:

Personally I would use normal engine oil when honing - 10/40 or whatever you have handy -  which will probably give a better finish. WD40 isn't really a very good lubricant.    It's all starting to look good though.

I did start with engine oil. The result seems better with wd40 but I agree with you about wd40 not being any good for this sort of thing and so I can't really understand why it should be. I'll try engine oil and slower speed on piston #1 as a comparison. 

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On 9/6/2020 at 4:14 PM, TheDoctor said:

Oi! I've had the Tourer for nearly 6 months now, and the Fenlander will probably never sell. Are you just picking on me as Bramz7 is not around? ?

Probably. Sorry :lol: 

The thing is, we expect @bramz7 or @NorthernMonkey etc to be constantly buying and selling cars. Yours are much more interesting because we get the full detail of you agonising over it beforehand, then blow-by-blow of buying and collecting, many many posts about how good it is, then two days of silence, and then it's for sale. I'm mainly thinking of that 306 convertible...

Don't go changing though :) we love you juuuust the waaaaay you aaaaaare...

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8 minutes ago, djoptix said:

how good it is,

 

8 minutes ago, djoptix said:

306 convertible

You should have seen the list of faults I was sent before he even got home.  And the tourer has gone!

 

Great work on the rebuild, it's very scary looking and asking questions and getting help is inspiring and more encouraging than a "I did this" thread where all the work is more than I can even imagine doing.

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More hot Dremel action, cleaning up the head.

image.thumb.png.10dee695a9e99286701c33a6f19b22f2.png

 

Surely this can't be the optimum shape for the head chamber. The valves are shrouded way back in the head, and look at all that protruding metal. The bottom edge would be like a shelf in the combustion chamber.

If I shaped the chambers (grind back to where it meets the top of the liner) could I get a genuine performance upgrade? Maybe take it past the 30bhp barrier?!

Maybe not. It's always going to be a low powered engine built for longevity and not speed...

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That D-shaped combustion chamber has been used in quite a few cylinder head designs and I have read is primarily for emission control.  Quite how, I'm not entirely sure, but I believe it has something to do with making the diameter of the combustion chamber smaller than the diameter of the cylinder bore at the point of (or close to) ignition.

I wouldn't mess with it.  It's cleaning up really well though.  How do the valve seats look?

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29 minutes ago, Mr Pastry said:

How are the valves and seats looking? 

 

Just now, Talbot said:

How do the valve seats look?

 

I don't know yet. I haven't got as far as compressing the springs to take a look (I haven't got a proper valve spring compressor but I think I can improvise with a G clamp).

Just cleaning all the corrosion off that one chamber has killed the brass wire brush on my dremel, so I've ordered a multipack before attempting any more :-) and also a window scraper (which takes Stanley blades) to scrape off the old HG.

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1 minute ago, Talbot said:

As the head is cast iron, you'll likely be fine using a steel wire wheel.  Certainly for removing the majority of the grot, then use a brass one to polish with.

Do you need the lend of a valve spring compressor?

The head is alloy so I am terrified of fucking it up :lol: 

I already tried a poly abrasive disc on the surface of the head and immediately decided it would be a Very Bad Idea.

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To get appreciably more power you are looking at Gordini spec - a lot of modification, and not advisable as the bottom end is a bit long in the tooth.

Don't waste time polishing the chambers and ports, it won't make any difference.  They just need to be reasonably clean.  They will soon carbon up again...  The valves and seats are the important things.

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Just now, djoptix said:

The head is alloy so I am terrified of fucking it up :lol: 

Definitely stick with the brass one then.  Looking at the photo above I would have guessed it was CI, but given you've got it in front of you...

I wouldn't bother too much trying to scrape the remains of the HG off then.  If it's aluminium, it'll need a skim, which will take all that HG remains off in one go anyway.

However, word of warning, there are a lot more places that claim to be able to skim a head these days.  In fact, what they've done is buy a cheapo knackered milling machine off the bay of snot and shoved a fly-cutter in it.  They've no idea how to level the head prior to skimming, and no clue how to dial out the slop that is guaranteed to be in the machine.  The result is a wonky skim with a valley down the centre of the head.  Seen it several times now.  The head will probably re-fit and work, but not for long, and will never be able to be skimmed again as they often take off shit-tonnes more than they need to.

Ask what machinery they use to do the skim.  If it's a dedicated skim machine, you've half a chance of getting a decent skim.  If it's a mill, the potential for a fuck-up is much higher.

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12 minutes ago, djoptix said:

The head is alloy so I am terrified of fucking it up :lol: 

I already tried a poly abrasive disc on the surface of the head and immediately decided it would be a Very Bad Idea.

Don't like to contradict you but judging by the amount of rust I saw on the old head I would have thought they were cast iron. Aluminium is a bit exotic and definitely not necessary for low-spec engines like these. Easy test: does a magnet stick to it? If so it's not aluminium. Happy to be proved wrong.
 

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On 9/12/2020 at 1:07 PM, djoptix said:

I did start with engine oil. The result seems better with wd40 but I agree with you about wd40 not being any good for this sort of thing and so I can't really understand why it should be. I'll try engine oil and slower speed on piston #1 as a comparison. 

3in1 oil is the tool for the job. Nice and runny

56 minutes ago, djoptix said:

The head is alloy so I am terrified of fucking it up :lol: 

That’s a healthy fear.

Excellent work. I think you’re in Bristol? If you need help with kit for stripping and checking the head I can assist if you can get it to swindon.

Agree with the head skim comments, there are plenty of cowboys out there.

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3 hours ago, djoptix said:

The head is alloy so I am terrified of fucking it up :lol: 

I already tried a poly abrasive disc on the surface of the head and immediately decided it would be a Very Bad Idea.

Remove gasket grot with either an aluminium or brass scraper plus carb cleaner or paint stripper for stubborn bits.

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