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Hi all, I am in the process of a tear down and rebuild of an early model A4 out of a tartan 27 I had bought last season. Turns out the engine had a broken crank. All cylinders had scoring and they were already bored .20 over, I went the route of getting new sleeves to be installed. The block is at the machine shop ATM and they called the other day to let me know he would have to deck the block mating surface down 10 thou. He asked me if this would cause any issues.I told him I would get back to him. So if anyone can enlighten me as to if this is a problem and if this is standard procedure, I would like to start ordering parts but i would like to know everything will work out installing sleeves first. Thanks!
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Your decision to re-sleeve is a good one; .020" over is max and if raw water cooled highly questionable. I hope you are planning FWC. I have never had a block taken down .010" to re-surface but if there is some distortion it is probably a good idea. Of course you are going to get a bit more compression but it should be ok. Be sure to use 2 head gaskets as recommended. I hope you are dealing with a good machine shop; this is serious stuff. Keep us posted and we do love pictures. -
You will need to probably have to touch up the valve seats.
As the seat margin is right at the top of block and as you cut the block down you will be cutting into the seats.Tyring to keep the Bay's Wooden Boat's history from dying off completely.
DanielComment
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That is an excellent point; the valve seats are indeed close to the deck but I do think you can get away with .010". Still, it would be a good idea to ask Don Moyer about this before proceeding because if this has been done to any extent he would know about it.Originally posted by Ball Racing View PostComment
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The boat has always been in fresh water as far as I know, first on lake Michigan and now lake Winnipeg. good point about valve seats I hadn't thought of this, sorry to anyone who replied in the other thread, as I double posted by accident and deleted the other thread, oops!Comment
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A double plus
northernlight, sleeving and decking are good if they do not take to much material. The raise in compression is minimal as you are only gaining the displacement of the piston travel for the material removed. The plus is the compression goes up and the breathing room in the head is not changed for the improvement. If you are a direct drive the single gasket after the deck trim may be a bit of a plus for performance.
The shop may want to install hardened seats instead of just recutting the seats. Either is fine as the seats in these A-4's are fine without the leaded fuel. I'd go with the cheaper of the two and not look back.
Dave Neptune
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The machine shop had never recommended or even talked about grinding valve seats, I will have to chat with them about this, I was planing on using 2 head gaskets. Before the block went to the shop I had lapped the valves and did a leak test with kerosene in the exhaust and intake ports, which held the fluid overnight with a little bit of leakage but not too bad.Comment
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Engine is back from the machine shop, here's a few pics. he left a bit of a shelf for the sleeves to sit on when boring, pressed in sleeves and machined the mating surface down .007. The sleeves are not honed yet as he didn't have the right size hone, he left .005 to account for honing. Next step ordering parts.Attached FilesComment
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oops don't know why the pics are gigantic.Comment
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Looks good.
Looks good! I held the control button on the keyboard and tapped the - button a few times to see the pics. Good for you and good luck with the rest of it.
Mo
"Odyssey"
1976 C&C 30 MKI
The pessimist complains about the wind.
The optimist expects it to change.
The realist adjusts the sails.
...Sir William Arthur Ward.Comment
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Fresh Water Cooled (FWC)
I'm learning a lot about the sleeving aspect from all of you, but maybe how the engine is to be cooled, as Hanley asked, is still not clear. Northern Lights mentioned the boat has always been in fresh water (as opposed to salt water). But was the engine "raw water cooled" even in fresh water and is the intent to convert to a closed water-cooled method for the engine with a heat exchanger that will be cooled using the water from the pond the boat sails in? The intent being essentially stopping further degradation of the exterior of the cylinder walls where they make contact with the water used to cool them. Just curious.Comment
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I assume (and hope) you are going to have a pro hone these bores to fit the new pistons. Is that correct?
The Machinist sent it home with you. Was he thinking you will hone to fit?
.005" will take a bit of time and muscle if you are experienced, but much frustration if you have never done it. This is not just breaking glaze on a road-commision rebuild, it is the final step in machining new cylinder bores.
Is there a second machinist to do the rest of the work?
Russsigpic Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1
"Since when is napping doing nothing?"Comment
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+1 on that. Most unusual...by all means take the block and pistons to a shop to be fitted.Originally posted by lat 64 View PostComment
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cracks
Northernlight,
Ask the old machinist why he did not address the cracks in the headbolt holes at the side of block(top of photo).
Ask the new machinist to give a complete assessment of all the work needed to do a proper job of rebuilding.
Some shops will only do what you ask, and if you don't ask, they don't tell. Was he grumpy?Last edited by lat 64; 04-17-2014, 11:54 AM.sigpic Whiskeyjack a '68 Columbia 36 rebuilt A-4 with 2:1
"Since when is napping doing nothing?"Comment
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dude! good eye. Pretty obvious now you mention it.Originally posted by lat 64 View Post"Halcyon" 36' custom sloop. 8 tons. Glass over strip plank mahoghany. Spruce mast and booms, launched 1969. Original A4.Comment
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