Honda-SOHC
Other Stuff => Misc / Open => Topic started by: SteveW on October 17, 2023, 03:30:38 PM
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Before I paint my engine with the Simoniz VHT stuff I was just wondering a few things.
Do I need any kind of etch primer first?
Is the Simoniz paint resistant to petrol, if not can you lacquer over it?
Thanks.
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No etch primer needed with Simoniz VHT and once cured correctly, we find it very petrol resistant to normal everyday spills.
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I've just done all of my cases except the barrels, Simoniz vht goes on very nicely and covers well. Remember to warm up your cases a bit and put the spray can in warm water for a while before spraying and you'll get a really even finish, keep at room temp or a bit higher for 24hrs before baking.
It stinks to high heavens when baking so open all windows and keep pets out!
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Thanks Julie and Dom :)
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I just did mine with Simoniz and it worked pretty well. One thing I would do differently is to go over the cases and valve cover in the high visibility areas clean up the small dings and spatter on the case surfaces with wet and dry. They seem much more noticeable when the case is resprayed.
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Yes, second that. Also, apply a mist coat and wait 20mins before applying the finish coat or two.
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I just did mine with Simoniz and it worked pretty well. One thing I would do differently is to go over the cases and valve cover in the high visibility areas clean up the small dings and spatter on the case surfaces with wet and dry. They seem much more noticeable when the case is resprayed.
I'd agree with that. When you see the bare alloy of a crankcase you suddenly realise just how bad they are, a few hours spent just touching up small areas pays dividends in the end result.
I would add to make sure the cases are really clean as even the best paint job is spoiled if it doesn't stick.
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I just did mine with Simoniz and it worked pretty well. One thing I would do differently is to go over the cases and valve cover in the high visibility areas clean up the small dings and spatter on the case surfaces with wet and dry. They seem much more noticeable when the case is resprayed.
Agreed, I wish I had done a bit of casting clean up so mine is an 'as Honda intended' respray.
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Any thoughts on preparing the surfaces first? Vapour blasting perhaps or a jolly good scrub with Brillo pad or something similar.
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I did not remove any casting marks but where the alloy had gone almost black when the paint was removed I used a Wet & Dry 180 to 400 Grit to remove the black surface so when painting the cases were pretty much bare alloy looking.
Areas that were near bolts or flanges I treated with either a small brass wire brush or a small brush wheel in my drill. I used a Thinners rag then brushed clean thinners onto the casing before painting the casings that I warmed with an electric fan heater - this seemed to help with avoiding runs. As others have said a light dusting first before applying a second & final coat - again applying it to a warn engine casing.
It is very tempting to try to cover with the first coat, I found a light dusting helped with avoiding runs. Only in exceptional areas like the engine mounting lug areas did I need to apply a light third layer.
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Any thoughts on preparing the surfaces first? Vapour blasting perhaps or a jolly good scrub with Brillo pad or something similar.
Personally I vapour blasted and etch primed. Though simonizvht31d doesn’t require a primer. Great care is needed to avoid any ingress of contaminants. Alternatively go for soda blasting, but again clean, dry, clean dry and clean again. I blocked all holes and protected all bearing surfaces, but still cleaned every gallery and oil way scrupulously. Beware of the camshaft oil gallery as the alloy bungs need removing and replacing.
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How easy are the bungs to remove?
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You don't need to remove the bungs, that's just being over cautious. The end tunnel is a straight line, if there was anything inside it you'd be able to see it, a thin bristle brush down the internal one until you see it come out into the straight gallery is more than sufficient. I've just blown all mine out with an airline after bead blasting the head and never had an ounce of trouble. Just make sure it's free of oil/grease beforehand and it should be fine, bung the holes up if your paranoid.
I'd advise a small forward facing wire brush in a Dremel and really get into the corners of the crankcase, that's where the oil/grease/crap is hiding, painting over that means it will just blow off later when the engines hot and after that it will just start the rest flaking.
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“The end tunnel is a straight line, if there was anything inside it you'd be able to see it, a thin bristle brush down the internal one until you see it come out into the straight gallery is more than sufficient”.
Can you show us that please,Ken. I thought the only access to the cylinder head horizontal cam bearing feed gallery was via the cam shaft bearing oil feed or end bungs. I’m not sure how blast material could be seen. I’m not saying you are wrong, it’s just that I don’t understand. TBH, when I removed mine I found the gallery to be spotless.
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Can I show you? Not without a spare cylinder head and even then it would be difficult as the camera would need to focus real close.
However imagine the head and how it's been drilled for the oil gallery. The end gallery meets the barrels and is closed shut by the oring, that is a straight line drilling, if you hold the head up to the light I'd say you can look right down the gallery, if there was anything there blocking that gallery you'd be able to see it. A small bristle brush pushed up the gallery should clear anything inside it. The connecting gallery which runs to the inner cam journal was drilled before the bung was fitted, this crosses the vertical gallery and carries on until it's under the inner journal, Honda then drilled down from the inner journal to meet the horizontal drilling. Nothing special about that, just simple engineering. So a bristle brush pushed down that gallery from the cam journal so long as it's flexible enough will just bend around the join where the 2 drillings meet ( I'd imagine Honda smoothed out that join with a flexile reamer) it will then pass along the gallery until it meets the vertical drilling, it will then stop as it will hit the back of the bung. If you're looking up the vertical drilling you should see the end of the bristle brush. Any debris in the gallery should have been pushed into the vertical drilling by now, if so that an be pushed out easily.
That make sense?
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Thanks Ken. Makes perfect sense. TBH I didn’t study the cylinder head oil pathways before reassembling as I went for the bung removal method after I’d cleaned up. As you say, I was probably being over cautious as the gallery proved to be squeaky clean.
Ta again.
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To me Phil, removing them just means they have the potential to fail afterwards, I can't see the point of risking them blowing out under pressure and ruining the engine. The risk of that IMO exceeds the risk of damage caused by anything in those galleries. Especially if you clean them as I describe, like taking a lump hammer to a hazelnut.
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I'm risk averse so not a fan of invasive cleaning like removing plugs.
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So am am I, Ted. ‘Twas the reason I checked the gallery for debris. Done properly there is as much chance of the plunges blowing out as there was when the engine was originally built. Personally I wouldn’t do it again as it was a right faff with no real benefit as it turns out.
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Whilst a faff as you call it others may ruin the plug trying to get it out or it might leak afterwards for instance. No real gain IMO for what is a right pain to do correctly. If you were an engineer for instance you could always make a new plug if you ruined the old one but why bother.
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Aye. I had new ones made by a mate. Just seen a Milyard vid where he does the same to a 900 Kwacker.
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Were they just flat sided plugs Phil or were they tapered so the further they went in the tighter they become. I'd imagine Honda pressed them in hydraulically, not the same if you're knocking them in with a hammer I'd imagine.
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Just a slight taper to get them started. Cold plugs pressed into a warm head,but you could knock them in just as easily.