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I have a 1990 CRX SI D16 A6 motor. Block has to be bored at least 10,000 that was the information the machine shop gave me already done a valve job and resurfacing the head.
First question how much should I bore it was pretty set on Vitara pistons and rods. Notch or no Notch not sure. Any help would be appreciated
My goal is 250 to 300hp, daily driver. Highly likely on turboing. Thanks for any help. Motor out and sanded down Parts laid out
Unless you are doing custom pistons, you'll likely need to bore to the next 0.5mm (probably 75.5mm if it's never been bored). "Vitara" pistons drop the compression, require the specific longer rods, and will suck unless you are turbocharged. There are definitely better pistons out there if you have a little more money. If you go with a forged piston, you can run regular length rods and your piston options open way up. Notching isn't very difficult if you have a dremel and some carbide bits - just take your time.
What pistons would you suggest for the d16a6 motor? The machine shop that's doing the boring said to just bring him the new pistons and the block. The shop that has done the head work said it needed at least .10, am not familiar with the sizes. Or the stock size. I thought that I would try and see what other guys have done being an not to familiar with the Honda Motors. Thanks for any suggestions.
I would only have the block bored to what it needs (75.0 mm is stock, and it goes up in 0.5 mm increments) Take the block to a machine shop and have them check the bores, the deck, and the crank. Buy pistons based on whether or not you are boring up to the next size, and after the pistons arrive at the machine shop, they will size the cylinders to fit. They should resurface the deck so that it is flat and true, and measure the crank so you know what size bearings to buy.
The cylinder head shop is probably talking about taking 0.010" off the head surface so that it is flat and true.
Regarding which pistons, that depends on your goals and budget. Folks drive around NA on the Vitara-spec pistons, but it probably will suffer power-wise until you are turbo due to the drop in compression ratio. I would not recommend using a cast piston for a turbo build if you want it to last, but that's my opinion. If you're unsure if you are going to go turbo but want to spend some money on good pistons now, I would recommend finding something forged that is close to the stock compression ratio.
Ok I called and checked with the shop and they stated that the block did need to be at least bore .10 at least that's his professional opinion because the engine blow a head gasket 15 years ago. After checking them this was his conclusion. But they dont do boring there. Still searching for a good bottom end setup
when you rebuild an engine, you need to rebore the cylinders. this means taking a little bit of material out to remove all the worn out areas and make it a "true" cylinder again. its like resurfacing brake rotors. its a very little amount of material. and on a honda, its typically either .020" (twenty-thousandths) or .040" (forty-thousandths) because its a a conversion from metric, 1 mm = .040" inches. so its either half a mm or a full mm. typically if you need to rebore a cylinder more than twice or more than .040", its trashed. the walls will be too thin to be useful.
a +.010" bore is not typical. i dont think you can find rings and pistons that size. unless the machinist means taking .010" off the wall, or radially which equal .020". but its not typically spoken like that, its always measured by the size in diameter.
.010" is probably referring to the resurfacing the TOP of the engine block. and/or the bottom of the head. typically when an engine blows a head gasket, only the head needs to be resurfaced because that is smaller/weaker and will warp. actually this is almost certainly the RIGHT way to do it, but doesnt always get done due to the cost and work. if you dont do it, the gasket will blow again soon after. its less necessary to resurface the top of the block and more difficult because it means removing the engine and tranny, but if the bottom block is already out and being rebored, it will typically be resurfaced like .005" or .010" (as needed) anyway.
i'm not trying to be critical of you typing "10,000" or .10", its just wrong and confusing and hopefully saying the correct thing makes it easier for you to communicate with others when asking a question.
Right, ok, check. Like I was saying the block has to be bore ten-thousandths, that is the information that the machine shop has given me. Thanks for clarifying how it's written so people will understand what I'm trying to say. Should have just spelled it out the first time. So back to the initial question. What pistons and rings are recommended. Yes the obvious answer would be the head needs to be two be milled and yes that's already been done, also had a valve job done. With all the d-series being built I would have thought somebody would have had a recommendation on something they may have used before I just order something. Thanks for all the help.
Your initial question was "how much should it be bored". You can choose any brand of forged piston you like - there are varying opinions on all of them. I'm using CP 9.0:1.
Right. First part before that. It has to be bore at least ten thousands as I stated, as the machine shop has stated. The question about the bore size is because am already going to be there and I want to know the best bore size as guys would have already had built a d16a6.
If anyone has built a d16a6 am looking to see your list of your upgrades and lower.
I know humble performance is running viterra pistons and rods notched but they also have a built head cam retainers Springs
Sad to say someone rear ended my daily (06 honda civic) it was a hit and run. So what am saying is I unfortunately have to go a little different route to speed up the process. I hope to be up and running in two weeks. Another d16a6 I picked up with other parts for $300. Hate to do it. Now I have to clean it all up and put all new seals in it.
06-27-2019, 03:59 PM
1990 crx si build d16a6
