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Discussion Starter #1
Hey guys, having some issues. First motor blew the ringlands, not sure what's going on yet with the second one, but pretty positive it's the rings.


d16y8 FJT vitara motor with 75.5mm bore. .005 PTW
Top comp ring: .019
Bottom comp ring: .024

100 miles in, compression test is 125 across the board.

250 miles in, 130 across the board, with cyl 2 at 70psi. I poured in some oil into the cylinders and compression jumped up to 170 in cyl 2, and in cyl 3 it jumped up to 210psi.
^^hence why I think rings are bad.

td04h greddy kit 10psi, 20degrees timing, 11.5 to 12.2 AFR's

Greddy catch can vented through valve cover

BKR7E plugs gapped at 30

ALL new ignition components, NGK wires

Plugs look like it might have too much timing from the ground strap. The color change is basically at the threads.

Running all Y8 timing components, distributer is modified to turn far enough to sync with S300 P28.

Anyone have some ideas?

I'll try and upload my tune for everyone to see in smanager.
 

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20 degrees of advance at 10 psi is pretty conservative. Are you certain that the base ignition timing is correct?

What injectors are you running?
 

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what tuning program are you using? fuel set up?
 

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20 degrees in your ignition table? If so, ignition dwell is adding ontop of that making it around 30 degrees at higher rpm? Thats alot of timing for a y8 head.

Ive never had to grind a distributor to get it in sync with a Y8 on an obd1 ecu. Its close to being fully clocked but i still have some room. Is your timing light fucked? Are you reading the timing marks wrong? On a Y8 balancer its 10-12-14 far mark TDC
 

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20 degrees in your ignition table? If so, ignition dwell is adding ontop of that making it around 30 degrees at higher rpm? Thats alot of timing for a y8 head.
It doesnt work that way, the dwell is compensating for the speed so at higher RPM its less advance, not more.
20 degrees in the map is not too much, in fact its several degrees less than what would still be considered conservative on 93 octane with Vitara pistons.


OP,
What injectors are you running?
 

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It doesnt work that way, the dwell is compensating for the speed so at higher RPM its less advance, not more.
20 degrees in the map is not too much, in fact its several degrees less than what would still be considered conservative on 93 octane with Vitara pistons.


OP,
What injectors are you running?
Im not understanding, the dwell is compensating for what speed?

For reference...my car, y8 with vitaras, i have my dwell table 0'd. I have around 20 deg at 10 psi of boost. Car runs great. It went 111mph in a full weight ek at 14psi with like 15-16 deg timing. So is it fair to say my car has 9.25 deg LESS timing in it at 7300(where the dwell adds timing) than this guys car? I would think so.
 

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The dwell is just how much time its giving it to charge the coil before firing, Its compensating for the engine speed to prevent the transistors in the igniter circuit from overheating. It has nothing to do with when the actual ignition event occurs within the cylinder.

20 degrees on the map means 20 degrees in the cylinder.
 

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20 degrees on the map means 20 degrees in the cylinder.
Not always. My actual timing is different than my map timing according to Neptune.

Y8 heads hate timing. Ask me how I learned. I do see where your going with the injectors though.
 

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The dwell is just how much time its giving it to charge the coil before firing, Its compensating for the engine speed to prevent the transistors in the igniter circuit from overheating. It has nothing to do with when the actual ignition event occurs within the cylinder.

20 degrees on the map means 20 degrees in the cylinder.
I wonder why the actual ignition timing value in neptune is affected by that dwell ignition value?

Quoted from Hrtuning "It's the ECUs way of compensating and preparing the coil to fire properly at various RPMs to achieve the correct timing and proper amount of spark."

So me zeroing the table, has affected my ignition timing value? In which way... Im scared to just blindly edit the table back to stock form. Reason being, when i had a stock motor with nitrous, this was how i thought i was taking timing out of the motor (lol, never blew up though). Something must have been happening, because it directly affected MPH..
 

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Discussion Starter #12 (Edited)
Timing/Fuel octane
20 degrees total timing as datalogged

Fuel octane is pump 91, which is the best we can get here other than E85, which was what I was planning on switching to after this tank of gas.

Injectors are Bosch EV14 750cc saturated injectors. I had Dustin at performance porting flow test them-- they all came out even across the board in all the tests. They are basically brand new with only about 5k miles on them, most of those miles were put on by the first vitara motor that blew.


If the timing that is on my maps isn't what the engine is seeing, then how am I supposed to get the motor to see what I want it to?

hrmm.. I thought it was common knowledge that with the OBD2 cam gear you had to notch the dizzy holes to make it sync up. I've heard that's what bisi had to do on his wagovan. Timing was sync'd using the s300 lock feature with a timing advance light. If it's off, it isn't more than 1 degree.
 

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Discussion Starter #13
what tuning program are you using? fuel set up?
Hondata S300, with the latest Smanager update. AEM wideband, walbro 255, injectors as stated above. Stock fuel pressure regulator, stock fuel rail, newish fuel filter.
 

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Discussion Starter #14
20 degrees in your ignition table? If so, ignition dwell is adding ontop of that making it around 30 degrees at higher rpm? Thats alot of timing for a y8 head.

Ive never had to grind a distributor to get it in sync with a Y8 on an obd1 ecu. Its close to being fully clocked but i still have some room. Is your timing light fucked? Are you reading the timing marks wrong? On a Y8 balancer its 10-12-14 far mark TDC
Weird, I didn't have to grind mine much, but I did a little bit. Mechanical timing is spot on, ignition timing i'm pretty sure is correct. I used the advance on the light to sync it with the white TDC mark, then double checked it on the three marks (mine are just stupid hard to see, hence why I went off the TDC mark)
 

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Discussion Starter #15
Another thing to add, is that the cylinder that's dead isn't consistent with the last engine. Cylinder 4 was the weak cylinder (low compression) in that engine, and this one is cylinder 2.

However, on the last motor when taken apart, pistons 2 and 3 had the ringlands cracked.
 

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I was 98% sure you were going to say "used ___ injectors", and I was going to say "AH HA"

Im not 100% on the dwell settings now (You guys have got me thinking), but Im still sure that the timing is not too aggressive, especially considering the dwell settings are probably unchanged. Unless the base timing is off.

Also, Is this the same block as the last setup? Head?

EDIT:
Oh, and what are you reving it to?
 

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Discussion Starter #18
I would get a new tuner
I am the tuner. My stock engine lasted 45k boosted miles, running high 13's all day long before it started to get a slight rod knock on cold mornings, but that motor had 185k miles and was used to deliver pizza in lol.

Now on the same turbo kit, less boost, my built engine's are dying. Keep in mind that it's a different shell than the last one. I went through and redid the grounds on this shell just to be safe-- but still something isn't right.
 

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I am the tuner. My stock engine lasted 45k boosted miles, running high 13's all day long before it started to get a slight rod knock on cold mornings, but that motor had 185k miles and was used to deliver pizza in lol.

Now on the same turbo kit, less boost, my built engine's are dying. Keep in mind that it's a different shell than the last one. I went through and redid the grounds on this shell just to be safe-- but still something isn't right.
How did you break the motor in?
 

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Discussion Starter #20
I was 98% sure you were going to say "used ___ injectors", and I was going to say "AH HA"

Im not 100% on the dwell settings now (You guys have got me thinking), but Im still sure that the timing is not too aggressive, especially considering the dwell settings are probably unchanged. Unless the base timing is off.

Also, Is this the same block as the last setup? Head?

EDIT:
Oh, and what are you reving it to?
This is the same block as before, but I had it rehoned, decked, and the head milled/checked for leaks.

The current build has never seen over 7000rpm.
 
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