Whats the difference between a d15 and d16 block?

[doug294]

Well I am looking for a d series block to rebuild for my turbo kit. I found a d15 block for $65. Whats the difference in a D15 and a D16 block?

[girlsrace2]

I think the stroke is the only differance...the 1.5 has a shorter stroke than the 1.6

[alexdog69]

I assume that you are talking about a DX motor (D15B2)... The D15B1 (STD) is the same AFAIK.. However, the D15B6 (HF) motor is a bit different (8V head but 9.6:1 CR) ...

Besides the 100cc's displacement difference... The D15B2 has a shorter stroke of 84.5mm (and a better rod-to-stroke ratio .. i.e. less side loading of the piston) versus the 90mm stroke of the D16A6... also, the D15B2 has a 9.2:1 CR while the D16A6 has a 9.1:1 CR...

The 1.5L crank also has smaller journals.... so the 1.6L crank is technically more durable... but in practice I don't think it matters much either way unless you are planning on upgrading the valvetrain to support >8000 RPM operation...

for $65... I wouldn't be scared to use the 1.5L...... especially if you are upgrading the rods and pistons.. having the rotating assembly balanced.. etc

general rule of thumb...
shorter stroke = happier with higher RPM

[doug294]

Well heres what I plan on doing just to make sure it's to my benefit. I pieced together a D series Turbo kit. Everything I need I have. Well my motor has 193K on it so a turbo would kill it in no time probably. So I decided to rebuild my motor. Well this is my only car so I don't need it in the shop awhile. I then decided to buy another D series block to build up. I am going with 8.5:1 comp forged pistons, Eagle H beam rods, crane stage 3 turbo cam, titanium valves, and adjustable cam gear. (Any other suggestions to what I might need?) After I get my block built I am going to redue my head so and put it on for little down time. My question is should I go with another D16 block or will the D15 block work just as well? I am going to be running low boost daily, but when I take it to the track probably 20 psi. I wan't the best block possible. Also are our blocks sleeved from the factory?

[alexdog69]

Come to think about it.. the D15B6 _bottom end_ is probably the same... and just has higher CR due to a smaller combustion chamber in the head....

[doug294]

Also will the pistons and rods for a D16 work in the D15? They are the same right?

[alexdog69]

you would be best off sending the block to these guys http://www.rsmachines.com/ for Darton MID (Modular Integrated Deck) sleeving

They do Bisi (as in Bisimoto) Ezeriohoa's sleeving :-)

if u dont know about him he is a brainiac engineer/drag racer who runs 10.23 @ 132mph on a NA SOHC

Also... posting the block is good.. a mod performed by Endyn... here is a DIY HowTo
http://www.homemadeturbo.com/tech_pr...ing/index.html

When you have the block resleeved.. you can increase the bore.. to >75mm.. so you can use the 1.5L crank and the bigger bore to get the best of both worlds.. (shorter stroke, but more displacement than stock D16A6)... and build something like a 1614cc with a short stroke... instead of the 1590cc stock "1.6L" config....

if u get your block sleeved and posted.. and use nice pistons and rods ... you will be able to run a lot of boost without destroying the block ...

also you might want to look at having your pistons ceramic coated http://www.swaintech.com

titanium valves are very sexy.....

1.5l crank + sleeved block + titanium valves + cams.. u could have a real screamin high rpm / high hp sohc turbo..

[alexdog69]

the d15 has a 5.276 stock rod length... the d16 has a 5.394 stock rod length... the compression heights are 1.213 and 1.161...
nobody says you have to keep those the same...

the stroke changes the CR when the piston is kept the same.. i think that the pin diameter is the same (19mm) ... so they will fit on the rod .. but if the CR was calculated for a 1.6 it wont be the same on a 1.5 crank...

d16 rods have a 1.89" big end bore for the crank and d15 rods have a 1.772" .... so.. they wont fit ..

have you already bought the parts?

you should call endyn (www.theoldone.com) for your rods/pistons.... they should be able to help you .. i think they even have some custom sized rods .. to get you closer to oh so desirable ~1.75:1 rod:stroke ratio.... of which Larry Widmer (Endyn owner) knows quite a bit as he is running a de-stroker moldex crank and extra long rods in his 11s daily driver...

[doug294]

No I haven't bought the parts. I was under the understanding all the parts for D series would fit. So does this mean I have to have a D15 piston and rod set? What about a gasket rebuild kit. Will the 1.6 D16A6 gasket set still work?

[alexdog69]

Everything else should be the same .. It's just the rotating assembly that's different ...