Do dart block's cylinder sleeves need to be honed/machined before you install your pistons? Or are they already cross hatched?

 

as with any new block, it should be honed for proper piston-to-cylinder clearance, even if it comes bored to, say, 84.5mm and you have 84.5mm pistons.

 

Mine was completly unfinished, needeed a bore and hone. But they have changed a few things since then. IM Moxie here on htec, he works for Dart.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tbone &raquo;</TD></TR><TR><TD CLASS="quote">Mine was completly unfinished, needeed a bore and hone. But they have changed a few things since then. IM Moxie here on htec, he works for Dart.</TD></TR></TABLE>

what he said.

 

Yup, unfinished bores as each eng. builder has their oun sizes and finishes they like to use.

 

thanks for all the good info.... Oh yeah, I'm getting an 84.5mm one, Just ordered it

 

We leave the cylinders about 0.5mm under, so your engine builder can finish hone them.

 

Hi Moxie, I should be getting mine any day as well. Other than matching bearings and honing is there any other work required? For example, opening up the oil passages or deburring?
Thanks

 

cheapest place to get a dart block.

 

 

Oil passages should be ok. After honing, you should always clean the block, and inspect all holes and threads. Be sure to tell your machinist to finish hone the cylinders with a torque plate installed on the deck.

 

allright another quick q's, with a tall dart block can you run a longer rod with a stock stroke b20 crank or is the displacement of the block based on a b16/b18 with over bore? just toasted my b20 block from hydrolock/rod failure and need a few things cleared up before the credit card gets swiped.
water sucks

 

Yes, you can run a longer rod with your B20 crank. Eagle makes a longer rod, I believe Crower does as well. There may be other rod manufacturers also.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Moxie &raquo;</TD></TR><TR><TD CLASS="quote">Oil passages should be ok. </TD></TR></TABLE>

Have you changed things since I built my Dart? Because my oil passages were far from "ok"

 

silence; hmm... .

 

i just got a b16a dart block and it was bored to 80.75mm so that my machine shop could finish bore and align hone my block to the right tolerances for the pistons i was using. I believe all dart blocks come with a .25 to .5mm or extra material to make sure you can bore your cylinders perfectly and make sure they are all in alignment.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmturbosol &raquo;</TD></TR><TR><TD CLASS="quote">i just got a b16a dart block alignment.</TD></TR></TABLE> Dart makes a b16a block now?

 

i responded to Tbone's unanswered Q about the oil passages.

 

I would definitely have it bored to match your pistons. You will need to have it tanked and run thru the washer. Remove all plugs to clean excess casting and machining slag then hondabond every plug. If there is any way to have the oil and coolant system pressurized before you assemble it then you best do it(trust me). You better take your time checking it thoroughly before you assemble it(trust me).

 

Sorry for the delay, I have been traveling for work. Please let me know what issues you had with the oil passages, and I will check with the block dept. to see how they have addressed them.

 

This might be an issue you want to discuss on pm. I will send you a pm.

 

Ok, or email me at gwold@dartheads.com. I will be on the road again from Thursday until Tuesday of next week. I will follow up as soon as I return. Thanks.

 

Would it be safe/possible to bore a dart b20 block to 87mm bore?

 

With sleeves inserted, no. You can't go past 85mm. You could remove the sleeves and have a nikasil (nickel and silicon carbide matrix coating) coating applied. This is thin enough to allow a 87mm bore. Keep in mind that this is very expensive, and probably not worth it. Even with a 95mm stroke, increasing from a 85mm to 87mm bore only increases displacement by 6.37 cubic inches, or about 0.1 liters. There are better ways to spend your money for increased power.