Building a d16a6 block + d16y8 head...need some suggestions

[bartek_b]

hey guys, I've been doing a good amount of research and I am going to pickup an engine to build for my friend in the next few days. What we are going to get is a d16a6 block(91 civic si) matted to a d16y8 head.

I have looked at the site below to get an idea what the compression ratio can be with this combination.
http://www.knology.net/~jediklc/D.htm

Now we are wanting to be in the cr range of around 11.2/11.5:1 to be generally on the safer side. I've looked at information in the past about 86-87 and 88-89 integra pistons and how the two years they very as one was a carborated engine and the other FI if I recall.

Are there any other pistons that we can use to hit out low/mid 11 CR mark?


also, I've looked around for valve train and cams and with such a higher CR ratio over stock, would stage 2 or stage 3 cams be more appropriate? Anybody has a recommendation on aftermarket cams to go with?


Thanks
bart

[Eyal 951]

I'd keep it to stage 2.

I am running 11.4:1 CR with PM6 pistons. Thats with about .010 off the block, .010 off the head, and middle layer removed from OEM HG (.012). Thats a total of .032 removed. .040 overbore as well, that seems to effect compression a little as well.

[bartek_b]

I'd keep it to stage 2.

I am running 11.4:1 CR with PM6 pistons. Thats with about .010 off the block, .010 off the head, and middle layer removed from OEM HG (.012). Thats a total of .032 removed. .040 overbore as well, that seems to effect compression a little as well.

How does your engine pull? what cams are you runing? running chippd p28 or hondata? have you hit the dyno to see what figures it's pulling out?

[Eyal 951]

How does your engine pull? what cams are you runing? running chippd p28 or hondata? have you hit the dyno to see what figures it's pulling out?

It pulls well. Everything it has is tuned for higher RPM performance, and it reflects it, so it has some pickup before 3K rpm, but not fast. 3-4K you start to feel it move, 4-5 is better, though my intake is too short, and causing a resonance dip, and 5-7500 is fun.

Crower stage 2, y8 head.

Hondata in a P28.

Dyno tuned, it made 144whp, 122 wtq

Parts used, fyi: http://www.d-series.org/forums/showthread.php?t=49144

[SMSP]

BArt,

Get the 88-89 Integra Pistons. THey have the biggest dome of the D series pistons I believe.

[Eyal 951]

why does he want the diggest dome?

[Toddnos]

i ran an 88 a6 block rebuilt, and a y8 head with jg 855vt35 cam...head was milled fourty thousandth....all stock...pulled 127hp and 110 tq...b4 the mini me..so id say 138 hp, and 117 tq with mini me...

[bartek_b]

Thanks for the response's guys

I just ordered an exedy stage 1 clutch with a XTD 8lb flywheel.
Still trying to figure out what CR I want to set this engine with and what camshafts

[AJxr]

Thanks for the response's guys

I just ordered an exedy stage 1 clutch with a XTD 8lb flywheel.
Still trying to figure out what CR I want to set this engine with and what camshafts


WHAT? what forum are we on again?

haha jk sounds like a good plan

[Toddnos]

WHAT? what forum are we on again?

haha jk sounds like a good plan
dont even try it noob......flaming is for the grown folks....

[bartek_b]

Well after thinking about this most of the day and trying to figure out a safe way of running this engine, I've decided to do the following.

-d16a6 block
-d16y8 head
-PM6 pistons instead of the PM3 to prevent the piston edge/desk issue
-d16y8 2-layer head gasket(.025")
-mill the head .029"

that should bring me to about 11.4:1 which is what i want for this engine.


now my question is...with the engine @ 11.4:1 CR...would a stage 2 or stage 3 camshaft be recomended for this ratio? valve springs and retainers will obviously be replaced but I can't figure out what a good stage cam would be.

thanks

[transzex]

VTEC head with non VTEC pistons, kiss kiss.......

esp with a stage 2 cam when VTEC engages.

Basically you stating on keeping the PM6 pistons (stock D16A6 bottom end) your still gonna run into valves kissing pistons. The ZEX 59300 has been proven to kiss at the edge of the valve reliefs.

IIRC the crower has more lift, more likely to smack a valve and RUIN parts. Maybe I'm anal, but my current cylinder head is worth over $1000 and it's not finished. I have another $350 to drop into it for springs/locators/retainers/seals.

[mattie_96]

Im pretty sure you already know this but there is no actual "2layer y8 headgasket". ALthough thats what you may read on the compression ratio calculators on the net, they are all sold with 3 layers and currently have the same part number for z6 and y8. CAll cometic, they should be able to find you a custom thickness you desire.

Hey Transzex, about the piston valve interference with vtec head and non vtec pistons, im just wondering if you ever had any experience with a y8 head on a z6 block with a6 pistons and stock y8 cam..I think i should be safe, what do you think?

[Toddnos]

VTEC head with non VTEC pistons, kiss kiss.......

esp with a stage 2 cam when VTEC engages.

Basically you stating on keeping the PM6 pistons (stock D16A6 bottom end) your still gonna run into valves kissing pistons. The ZEX 59300 has been proven to kiss at the edge of the valve reliefs.

IIRC the crower has more lift, more likely to smack a valve and RUIN parts. Maybe I'm anal, but my current cylinder head is worth over $1000 and it's not finished. I have another $350 to drop into it for springs/locators/retainers/seals.
i have a mini me a6 block y8 head jg 85vt35 cam..no kiss kiss.......head is milled fouty thou.

[primercrxSi91]

i think it sounds good..but to me id rather here BOV and the sound of spooling..

[bartek_b]

i think it sounds good..but to me id rather here BOV and the sound of spooling..

that's good but that's not what this section of the forum is for...

[DOHCDX]

mini-me's have been done for years. there's no kisskiss transzex with a VTEC head on a non-vtec bottom end. the problems start when you swap internals between bottom ends.

[Eyal 951]

Im pretty sure you already know this but there is no actual "2layer y8 headgasket". ALthough thats what you may read on the compression ratio calculators on the net, they are all sold with 3 layers and currently have the same part number for z6 and y8. CAll cometic, they should be able to find you a custom thickness you desire.

Hey Transzex, about the piston valve interference with vtec head and non vtec pistons, im just wondering if you ever had any experience with a y8 head on a z6 block with a6 pistons and stock y8 cam..I think i should be safe, what do you think?

PM6 in a vtec block is definetly safe. they sit .020 IN the hole. Exactly what I'm running, except with a crower stage 2 cam, and .032 off. No kissypoo, its somewhat of a common setup.
Now stock pistons in the a6, i dunno. I only built my vtec block/head, but its been done. Just clay the motor and find out.

[big_g_jando]

i want to hear about this b/c i am wanting to run pm6's to and use a crower3 cam ?

[bartek_b]

PM6 in a vtec block is definetly safe. they sit .020 IN the hole. Exactly what I'm running, except with a crower stage 2 cam, and .032 off. No kissypoo, its somewhat of a common setup.
Now stock pistons in the a6, i dunno. I only built my vtec block/head, but its been done. Just clay the motor and find out.


Well after re-thinking about this...since I'm building this engine for a friend I'm going to do something a bit different.

-D16a6 block
-D16y8 head
-P2P d16y8 pistons
-mill the head .037"
-**and if possible, contact Cometic to have a head gasket made in the size of .010" if they are able to make it so thin.


That should bring the CR ratio of 11.4:1

Hopefully I can get it done to that ratio so we can make some decent power with a lumpy cam :TU:

[transzex]

mini-me's have been done for years. there's no kisskiss transzex with a VTEC head on a non-vtec bottom end. the problems start when you swap internals between bottom ends.

really? did you not read about Stage 2 cams kissing valves?????

I believe this pics are from a member on here.........

http://i107.photobucket.com/albums/m307/bonespec/Honda/Tech/ouchie.jpg

http://i107.photobucket.com/albums/m307/bonespec/Honda/Tech/ouch.jpg

[Toddnos]

y8 pistons in an a6 block are not going to increase compression at all.

[bartek_b]

y8 pistons in an a6 block are not going to increase compression at all.

Yea...so? it will lower the CR but then I can run the vtec head with more safety.By milling the head and getting a thinner head gasket it will bring me to my estimated CR and not have as many worries about the pistons slapping the valves by running the y8 pistons.

[Toddnos]

Yea...so? it will lower the CR but then I can run the vtec head with more safety.By milling the head and getting a thinner head gasket it will bring me to my estimated CR and not have as many worries about the pistons slapping the valves by running the y8 pistons.
you said it would bring you to an 11:4:1 comp ratio not me. Oh and milling and head gasket wont get you there either..........

[little white crx]

it is posible to dig the valve reliefs out a little bigger to make the pm6's work zero decked with a vtec head and a high lift cam.

my old motor had this done it only cost me $40 at a machine shop, the machinist said its not hard and anyone with a die grinder could do it but i paid the money to be 100% sure it was done right.

was it needed? hell i dont know but the measurments showed it would be close enough to worry about with the camshaft i was originally planning to use.

[DOHCDX]

really? did you not read about Stage 2 cams kissing valves?????

I believe this pics are from a member on here.........


any more info on it? thread link? it almost looks like only one cylinder is damaged

[bartek_b]

it is posible to dig the valve reliefs out a little bigger to make the pm6's work zero decked with a vtec head and a high lift cam.

my old motor had this done it only cost me $40 at a machine shop, the machinist said its not hard and anyone with a die grinder could do it but i paid the money to be 100% sure it was done right.

was it needed? hell i dont know but the measurments showed it would be close enough to worry about with the camshaft i was originally planning to use.


See that I was thinking of doing. Take them to a engine shop locally and have them grind down the pockets a bit but was looking for maybe another method that would prevent that.

thanks for the post, I'll look into that option a bit more later tonite:TU:

[builthatch]

you guys can't be serious with this banter....

[djsgtrip]

There is no "kiss" with P29's and a Y8 head. Clearance is fine. Builthatch, myself , and many others have proven this. The compression with a Y8 head and stock head gasket is pretty high - i think somewhere in the region of 12.8-13.0:1. That might be a little too much for pump gas. You might wanna get a thicker head gasket (cometic) if you want it to run on pump. My setup is a Z6 head with Crower 3 camshaft and P29's. It's been driven almost everyday for 2 years now, and still running good.:D

[Eyal 951]

There is no "kiss" with P29's and a Y8 head. Clearance is fine. Builthatch, myself , and many others have proven this. The compression with a Y8 head and stock head gasket is pretty high - i think somewhere in the region of 12.8-13.0:1. That might be a little too much for pump gas. You might wanna get a thicker head gasket (cometic) if you want it to run on pump. My setup is a Z6 head with Crower 3 camshaft and P29's. It's been driven almost everyday for 2 years now, and still running good.:D
dyno #'s?

[builthatch]

i ran p29's and a stage 2 Crower cam with stock headgasket, i didn't have clearance issues. i, however, never ran a stock HG with a stage THREE and p29's; only with the 1.5mm HG which of course gave alot more clearance.