Hey guys

I have a 99 LXI from middle east area, the engine is d15z4, i bought d15b vtec head from a 95 Civic, and i got p29 pistons.

i used the rods of a d16 cuz the d15 rods didnt give me piston clearance.

i finished now and i hooked the vtec to a vtec controller, the is car knocking like hell, and very very slow, it doesnt knock untill i retard the ignition all the way.

what is my problem here? too lean on fuel? i wanna try using the d15b vtec injectors tomorrow to see if it can be better.

any hints?!

 

Your problem is a compression ratio of around 15.34:1. Now i'm not an engine builder, but i'd say thats just flat out unrealistic to run. If you were going to try to keep this setup you would at the very least need to run race gas and have a really good tune.

 

how come?! 15.34:1 CR?!!! i didnt have piston to valve clearance at all with the d15 rods, the d16 were shorter and done the job, it runs ok when i retard the car iginition, but no power at all

 

I am confuse! All D-16, D-17 and the D-15BVitec ( only Japan ) use the same rod with 137mm long, bigger piston pin and bigger end bore. All the rest of the D-15 engines in U.S.A used a 134mm rods. Some D14 engines in Europe use a 138mm rod.

How long is your rod to calculated your compresion ratio?

 

If your are using 137 mm rods you have a 15.34.1 C.R. . This guy 94GE8 is correct. If you change for a 134mm rod from most D-15 your compresion ratio would be 10.50 with the D-16z6 head gasket, or 10.80 with the D-19Y8 head gasket ( 2 layer metal )

 

ok but when i was using the d15 rods i didnt have piston to deck clearance at all

the piston will hit the head

 

Should i get a d16 crank to fix this?

 

using the compression calculator online this wont fix the problem, but the d16 rods are longer than the d15 rods, i think i got some rods that i dont know what they are, they are shorter than d15

 

please help

 

hey i just got pics from the setup i used

i had p2c pistons on my original engine d15z4

i got PM3 pistons and rods, i only used the rods

maybe this will help

 

If they're PM3 D15B7 rods thats even worse, 15.65:1 compression. Yiu're going to have to get rid of those P29 pistons, get some flat topped PM3s and drop the compression down.

 

i have the pm3 pistons now, but that will make the compression around 14:1 which still not good.

 

why i couldnt get clearance on the p29 pistons using the rods from p2c? on the compression calculator it seemed ok :S

what have i done wrong here?

 

??

 

anyone?!

 

Guys i'm desperate here? i'm going to open the engine tomorrow, any solution?!

 

ive got a d15z4 engine and it has no pluk. Got a cai and sidedraughts and free flow. The enginne is too weak to handle the power you want and will cost alot. Just buy a new b series vtec engine.

 

what sort of power are you looking for with this setup. do you plan to boost it. ??

 

I think somehow you have either the wrong rods or a weird crank. Because the d15 crank should have a shorter stroke and shouldnt have the issue that your having. The D16 rods are even longer than the D15 rods so I dont understand how changing from D15 to D16 rods can make you have deck clearance. As the D15 rods are literally 3mm shorter. It almost seems like somehow you ahve a D16 crank in your D15 block? You need to measure the rod lengths. Because the pistons that you put in must either have alot higher deck height, or you got the rods mixed up. Either way according to the calculator it seems that you have a negative piston to deck height. Your stock pistons must have had a low compression height, but I am unsure about this because they are not listed on the comp calculator website. Why dont you try putting your stock pistons back in? And if you used the rods from the PM3, then those are D15 rods which are 134mm. So keep those rods and put your stock pistons on them and you *SHOULD* be ok.