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[stealthiskey]

so I just changed the clutch/fixed the ac/changed the breaks etc, and naturally the first thing my car does is go and blow up.


Was driving off in first, the wastegate failed. Not sure how much boost it saw, but I have it set so when it goes over 11.3, it runs way rich and way retarded.  As such I got a nice big backfire, and then started hearing a clicking or a ticking noise.

Sounds like its coming from the head, it's definitely related to engine speed, not wheel speed.  And the sound doesn't change (pitch, intensity) with load, only with rpm.

What have I got?  Bent valve somehow? spun bearing? (it sounds like this i think, but i thought that would change with load).  Can a backfire fuck up valves?

[BoostedSchemes]

what rpm did you rape it at? hard to believe that one pull of less than 1 bar to less than redline damaged a head

[stealthiskey]

Not real high rpm, prolly only hit 5k when it over boosted.  Car sti.ll runs and idles smooth.   I'll check compression later today

[Teg2boo]

Don't you have a boost cut? It's like the second thing you want to set when you tune a car after idle.

[stealthiskey]

I was just thinking that would be a good idea

[snm95ls]

Super rich and way retarded ignition timing sure sounds a lot like anti lag...

[Joseph Davis]

Probably bound a piston in the bore and now have some slap, if a D-series then your probability of this doubles.  Not saying it couldn't be in the valvetrain, but I'd pull an injector clip or plug wire and see if it goes away or not.

[Phate]

Super rich and way retarded ignition timing sure sounds a lot like anti lag...

Simple solution for overboost:  MOAR BOOST!!!

[theidealone]

Super rich and way retarded ignition timing sure sounds a lot like anti lag...

Simple solution for overboost:  MOAR BOOST!!!

This. LOL. If I hit more boost than Im tuned for, I max out the MAP sensor, and it shuts off anyways.

[random-strike]

doubtful anything happened as honda pistons are very strong stock, stronger than SBC pistons by far

[stealthiskey]

Probably bound a piston in the bore and now have some slap, if a D-series then your probability of this doubles.  Not saying it couldn't be in the valvetrain, but I'd pull an injector clip or plug wire and see if it goes away or not.

It's a d series.  What does this mean exactly, it bent the skirt or something?  If its just piston slap then its safe to drive right?  Am I right to assume that since sound doesn't change with load it is NOT a spun bearing?

Does kinda sound like piston slap...

[random-strike]

keep woting it until it lets go then you'll be able to see what went wrong

[Joseph Davis]

Probably bound a piston in the bore and now have some slap, if a D-series then your probability of this doubles.  Not saying it couldn't be in the valvetrain, but I'd pull an injector clip or plug wire and see if it goes away or not.

It's a d series.  What does this mean exactly, it bent the skirt or something?  If its just piston slap then its safe to drive right?  Am I right to assume that since sound doesn't change with load it is NOT a spun bearing?

Does kinda sound like piston slap...

Pull VTEC solenoid, check for bearing material.

If piston binding, it'll either try to bind again or the skirt will collapse from all the slap.  What piston-wall was it set to?

[stealthiskey]

Did a compression test, 190, 190, 190, 150.   Also The ticking is definitely at the same frequency as the cam shaft.

Turns out the cause of the boost spike was the shitty wastegate line collapsed and blocked the wastegate from seeing any boost.

I think the huge backfire held open an exhaust valve slightly and the piston kissed it at like 5k.  Still seals well enough for 150 psi compression, but has a small leak and ticks when it seats.  I suppose I'll just drive it until I decide to replace it.  A slightly bent valve (150 psi compression) isn't gonna fuck anything else up is it?  Really didn't want to have pull the head ever.

JD, it's OEM D16z6, I haven't pulled the vtec solenoid, but I did pull the valve cover and didn't see any bearing flecks in the oil there.

[Joseph Davis]

JD, it's OEM D16z6, I haven't pulled the vtec solenoid, but I did pull the valve cover and didn't see any bearing flecks in the oil there.

Did you check the valvecover screen?

[stealthiskey]

Sooooo I was going to put the new head on yesterday, and I crank it over to TDC on piston 1, but what do I see?   I got those custom S beam rods!  piston number 4 is 3/16"  lower than piston 1 at TDC!  That explains the 150 psi compression, (vs 195 in all others) because if it was a leaky valve, shit would be more like 100 psi or less.  And the old valves looked just fine.  Yep


SO do i replace with a used OEM rod/piston for like 12$?   Orrrr 400 hp vitara build?

Who wants to selll me a good oem piston/rod?

What do honda nogs use for rods these days?  (eagle + vitaras = what compression, non interference?  What about FJT custom length rods, they look sweet, add a little more compression)

[Joseph Davis]

If you do anything other than another OEM piston/rod, go 7.5:1 CR.  Everybody blew up big power turbo D's for years until 7.5:1 CR setups came along and then everyone made 400.  Think about it.  D-heads don't flow great, the pistons are small as fuck, that sort of power loads the engine up so it wants to detonate unless you drop the bottom out of the CR.

When people who run Vitara motors NA for a minute say they are no slower than stock... sort of lets you know what's going on.

[turbob16hatch]

If you do anything other than another OEM piston/rod, go 7.5:1 CR.  Everybody blew up big power turbo D's for years until 7.5:1 CR setups came along and then everyone made 400.  Think about it.  D-heads don't flow great, the pistons are small as fuck, that sort of power loads the engine up so it wants to detonate unless you drop the bottom out of the CR.

When people who run Vitara motors NA for a minute say they are no slower than stock... sort of lets you know what's going on.

But with that low of compression the car won't be able to move under it's own power.  I read it on honda-tech. 

[ratcityrex]

If you do anything other than another OEM piston/rod, go 7.5:1 CR.  Everybody blew up big power turbo D's for years until 7.5:1 CR setups came along and then everyone made 400.  Think about it.  D-heads don't flow great, the pistons are small as fuck, that sort of power loads the engine up so it wants to detonate unless you drop the bottom out of the CR.

When people who run Vitara motors NA for a minute say they are no slower than stock... sort of lets you know what's going on.

But with that low of compression the car won't be able to move under it's own power.  I read it on honda-tech. 

Lol, I love my Low compression b18. Fucker pulls good even with turbo cams and no turbo.

[snarf]

If you do anything other than another OEM piston/rod, go 7.5:1 CR.  Everybody blew up big power turbo D's for years until 7.5:1 CR setups came along and then everyone made 400.  Think about it.  D-heads don't flow great, the pistons are small as fuck, that sort of power loads the engine up so it wants to detonate unless you drop the bottom out of the CR.

When people who run Vitara motors NA for a minute say they are no slower than stock... sort of lets you know what's going on.

spend time with black people muuuch?

[stealthiskey]

I believe you.  But 8.5 to 1 is still pretty low too no?  main advantage with vitaras would be the non interference i think.

[turbob16hatch]

If you do anything other than another OEM piston/rod, go 7.5:1 CR.  Everybody blew up big power turbo D's for years until 7.5:1 CR setups came along and then everyone made 400.  Think about it.  D-heads don't flow great, the pistons are small as fuck, that sort of power loads the engine up so it wants to detonate unless you drop the bottom out of the CR.

When people who run Vitara motors NA for a minute say they are no slower than stock... sort of lets you know what's going on.

But with that low of compression the car won't be able to move under it's own power.  I read it on honda-tech. 

Lol, I love my Low compression b18. Fucker pulls good even with turbo cams and no turbo.

And that is why i'm not to worried about my 7.1:1 a6 with 272 cam, even though i'm more on the drastic side.

[HiProfile]

I got those custom S beam rods!  piston number 4 is 3/16"  lower than piston 1 at TDC!

That would explain the ticking being half crank speed. The rod is just nicking the sleeve on one side. You are lucky it didnt' break, as it's a whole lot easier to toss in pistons/rods then a whole new built shortblock. Plus you've already started on the notching process...

My wiseco shit is low 8's compression, and it's not bad now I added a lot of low rpm/low load timing. First time I added a couple degrees, I went from consistent 26-28mpg for two dozen tanks to consistent 32-34mpg for half a dozen tanks. If you use a ZC gearset, just downshift and punch it. If I did it again, I'd use vitaras and custom rods to up compression a bit, but I'm not looking for huge power in this motor. So far this thing has taken a beating with lots of boost and a so-so street tune I alter when I feel like it. Being an otherwise stock D16Z6, it was cheap as well.

[ratcityrex]

I'm telling you this, and if you don't want to listen to me your fucking dumb, but driving a low comp Honda is like driving a normal comp Honda. Really its such a slight difference, you wouldn't be able to tell.

[ratcityrex]

Lol, man I can't read..

[turbob16hatch]

I'm telling you this, and if you don't want to listen to me your fucking dumb, but driving a low comp Honda is like driving a normal comp Honda. Really its such a slight difference, you wouldn't be able to tell.

Lol, man I can't read..

HAHA

[crxvtec91]

My vitara motor sounds mean as fuck with the pb tuning combo+ 59500

[ratcityrex]

I love how my cams beat the ground at idle!