Honing advice

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Discussion

HRCM

Original Poster:

70 posts

88 months

Sunday 20th November 2016
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Good afternoon all,

I'm looking for opinions on how to proceed here. First a bit of background: I've stripped the engine to the block and crank and made some neat, thick industrial cardboard bungs to plug up the bottom of the cylinders and sealed them in from above with decorators caulk. I've cleaned the bores using carb cleaner, which actually makes the surface rust look worse than it is, in my opinion anyway. The car had all oil and water mixing and I suspected HGF but it seemed to run sweetly enough, not withstanding the clouds of white smoke coming out of the exhaust. I only ran it briefly for this very reason. It was also difficult to start which on further inspection I put down to having approximately 7 litres of fluid drained out of the sump (coolant and oil) and on even further inspection, the state of the bores. The piston rings were pretty tight at first but I've carefully managed to get the pistons out without much of a fight and they look ok to me at first inspection.
Taking the remainder of the engine out isn't really an option, hence the bungs/ tape etc. Im planning to use a shop vac to clear most of the escaping dust as I clean up the bores. I've bought a three legged hone but the stones are coarser than I'd hoped (180).
I'm now contemplating either 240 stones or a flex hone with 240 grade silicon carbide 'bobbles'. I've read everything I can find and found this to be good inspiration so far: http://www.pistonheads.com/gassing/topic.asp?t=813...

Advice appreciated


HRCM

Original Poster:

70 posts

88 months

Sunday 20th November 2016
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A better picture of the worst bore. This was before I took the piston out (obviously), just after a light clean with wd40 and a clean cloth.

99hjhm

426 posts

185 months

Monday 21st November 2016
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I'm guessing they have banned Puma again so I'll try and help.

Flex hone is far better in this situation follow what was said on that thread, the trick is to move the hone up and down in sync with rotation. Basically battery drill on slowest setting and move the hone in and out as fast as possible to get a 45 degree ish finish. Don't try to get all the marks out just get it clean.

I would get it as clean as possible first with scouring pads and or solvent.

Boosted LS1

21,165 posts

259 months

Monday 21st November 2016
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As above. You move the tool up and down rapidly. Try to source some honing solution or maybe even paraffin and watch out for the stones either snagging at the bottom of the bores or coming out of the tops'. Don't overdo it.

steveo3002

10,493 posts

173 months

Monday 21st November 2016
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quick wizz with a flex hone will have that looking great, make a special effort to clean it afterwards

HRCM

Original Poster:

70 posts

88 months

Monday 21st November 2016
quotequote all
Many thanks to you all. That's confirmed it for me - I was leaning towards the flex hone after some reflection.
Do any of you have any recommendations about where to buy these flex hones from?
eBay and Amazon list them but they're supplied from the states and not exactly cheap in the first place. Thinking about it, i might actually try the place I'm going to use for the head skim and pressure test.

Boosted LS1

21,165 posts

259 months

Monday 21st November 2016
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Sykes Pickavent should have one.

HRCM

Original Poster:

70 posts

88 months

Monday 21st November 2016
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Thanks again. I'll give them a try.

steveo3002

10,493 posts

173 months

Monday 21st November 2016
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had to get mine from the states

what size do you need?

HRCM

Original Poster:

70 posts

88 months

Monday 21st November 2016
quotequote all
The bores are 73.4mm diameter so I was looking for a 3" diameter tool in a 240 grade and I think I need silicon carbide for Iron liners (from what I've read).

I've contacted the uk distributor (pacehigh) for a price and asked them to clarify that I've specified the right tool. I'll post back when I get a reply.

Mignon

1,018 posts

88 months

Tuesday 22nd November 2016
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I don't know what you're hoping to achieve here in terms of how well you expect this engine to run. Just enough to sell it or actually run properly and anywhere near its normal performance. The bores are way past reclaiming with flex hones and the like. It's clear the piston rings have rusted to the bores while it was sat with water in it and those horizontal grooves will be murder on the next set of rings as they bounce over them. You'll only find out how deep that damage is with a proper hone with straight stones and see which areas clean up and which don't. A flex hone will just float over everything and conceal any damage without actually improving it much.

It's probably rebore time if you want it to run properly and if you're not bothered then save your money and just go over everything by hand with some 180 grit and try to do that at a 45 degree angle to put a bit of cross hatch in. It'll never be right though. Sure it'll run of a fashion if that's all you need but at maybe 75% of the stock cranking pressure and 80 to 85% of the expected power output. You can't magically make rusted away metal reappear.

HRCM

Original Poster:

70 posts

88 months

Tuesday 22nd November 2016
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Thank you for the detailed reply and the advice.

I think I'm going to try my new three-legged hone with the 180 stones after all. My hands are a bit big to attempt it with sandpaper in any case.

Most of what you can see in the pictures is actually a varnish as far as I can tell. The pictures aren't great at this resolution and the brake cleaner I used prior to taking top picture gives the impression that they're actually quite rusty.

DVandrews

1,315 posts

282 months

Wednesday 23rd November 2016
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I'd give It a flex hone first and then inspect the bores. I have a number of flex hones here at various sizes, so depending on where in the country you are it might be convenient to pop in and give the bores a going over, it will save the cost of a new one.

Dave

Mignon

1,018 posts

88 months

Wednesday 23rd November 2016
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HRCM said:
Thank you for the detailed reply and the advice.

I think I'm going to try my new three-legged hone with the 180 stones after all. My hands are a bit big to attempt it with sandpaper in any case.

Most of what you can see in the pictures is actually a varnish as far as I can tell. The pictures aren't great at this resolution and the brake cleaner I used prior to taking top picture gives the impression that they're actually quite rusty.
If you're sure the pictures make things look worse than they are, which is perfectly possible, then by all means try the three legged hone first. Your problem with most drills is getting a low enough spin speed. A few hundred rpm is plenty. Honing is a very unusual procedure and actually nothing at all like high speed grinding with a bench grinder for example. Honing is more like really violent low speed scratching where the stone breaks down as fast as the bore it's removing material from. The resulting slurry of abrasive grit is what removes the material from the bore.

Those little toy hones with spring loaded legs won't do much more than tickle the surface anyway. You are unlikely to hurt anything unless you go mad with the speed or stay in one part of the bore too long. You want to see just how much effort it takes to remove even a couple of tenths of a thou from a bore with a proper Delapena or Sunnen hone and a 1 hp drill driving it. You wind the screw adjuster out until the stones have hundreds of pounds force pushing them into the bore walls and the drill is nearly stalling before anything much happens. It's bloody hard work I can tell you.

If the bores are too small to get your hands into there's a simple alternative. Get a length of broom handle or similar and saw a slot into one end. Fit 180 grit emery cloth into the slot and wind it round a few times. You can get it in 1" wide rolls 25 metres long. You can work away in the bores like that trying to go at an angle rather than just up and down and that will clean all the muck out without damaging anything. Then maybe post some more pics.

Mignon

1,018 posts

88 months

Wednesday 23rd November 2016
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99hjhm said:
I'm guessing they have banned Puma again so I'll try and help.
Persistent buggers aren't they? You might almost think it was personal.

227bhp

10,203 posts

127 months

Wednesday 23rd November 2016
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DVandrews said:
I'd give It a flex hone first and then inspect the bores. I have a number of flex hones here at various sizes, so depending on where in the country you are it might be convenient to pop in and give the bores a going over, it will save the cost of a new one.

Dave
In reality I think it may be difficult given it's still attached to the car.

SandyTrump

4 posts

88 months

Wednesday 23rd November 2016
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227bhp said:
In reality I think it may be difficult given it's still attached to the car.
smash

DVandrews

1,315 posts

282 months

Wednesday 23rd November 2016
quotequote all
227bhp said:
DVandrews said:
I'd give It a flex hone first and then inspect the bores. I have a number of flex hones here at various sizes, so depending on where in the country you are it might be convenient to pop in and give the bores a going over, it will save the cost of a new one.

Dave
In reality I think it may be difficult given it's still attached to the car.
I wouldn't recommend honing in situ as those pesky little carbide particles can get everywhere.

However I could make a short term loan of a suitable flex honer provided it came back in one piece.

Dzce

geeks

9,121 posts

138 months

Wednesday 23rd November 2016
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DVandrews said:
I'd give It a flex hone first and then inspect the bores. I have a number of flex hones here at various sizes, so depending on where in the country you are it might be convenient to pop in and give the bores a going over, it will save the cost of a new one.

Dave
Clicked in here as I may have to do a similar job. DV I notice you are in MK, where abouts? Would you be able to come and have a peek at an engine for a fellow PHer in MK? I make good coffee smile

DVandrews

1,315 posts

282 months

Thursday 24th November 2016
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geeks said:
DVandrews said:
I'd give It a flex hone first and then inspect the bores. I have a number of flex hones here at various sizes, so depending on where in the country you are it might be convenient to pop in and give the bores a going over, it will save the cost of a new one.

Dave
Clicked in here as I may have to do a similar job. DV I notice you are in MK, where abouts? Would you be able to come and have a peek at an engine for a fellow PHer in MK? I make good coffee smile
I might be able to, it will depend on timings. I am in Bancroft BTW.

Dave