DirtAssassin

Any one know if the clearance of a lifter bucket could cause a oil burning issue or would it most likely be valve seals?

03 350z de

Has a tick and everyone tells me it smokes and smells terrible. I burn almost a qt of oil every 500 miles. Did a compression test and tested good cold and warm. Pretty much 170+ psi on all cylinders. Tore it down and measured all the clearances of the cams and lifter buckets.
FSM calls for intake .010-.013 and exhaust .011-.015

Cylinder 1 intake valves were .008 and .021

Cylinder 5 has one intake valve at .008

Cylinder 4 has one intake valve at .018

Cylinder 6 has one intake valve at .016

All the rest of valves are within spec per FSM
So i assume my valve seals are bad because of smell and oil burning issue but rather not try to change them if it’s just because the buckets being shimmer improperly. Looks a lot easier to change buckets then valve seals.

This car has a rebuilt motor with less than 10k miles on it.

Any ideas?

bealljk

iTrader: (13)

I would think that both the buckets and the seals work in conjunction to seal the top of the heads from the cylinder/combustion area. If your compression is solid than it's safe to say your dropping oil from the top side. If the seals are shot than no bucket is going to seal out area and if a bucket is compromised than no seal is going to keep oil out.

where did you rebuild occur?

Reality on reality's terms - get the heads off and replace the seals and the out of spec buckets.

DirtAssassin

It was a rebuild engine from Engines-usa on ebay. i bought the car with 102,xxx but previous owner said motor was replaced at 101,xxx. It now has 109,xxx miles.
Im just hoping since like you said they work in conjunction to one another that its just burning the oil because the buckets are so far off on some cylinders. But will a bad sized bucket ruin a seal?
Reason i don't want to take the heads off is i rather not have to replace the gaskets (since its suppose to be a fairly recent rebuild) or buy a JWT tool.

bealljk

iTrader: (13)

I hear ya ... if you are going to get this deep into the heads I'd say (for how inexpensive seals are) replace everything. Sucks to crack the head gaskets but it is what it is.

maybe see if there are other thoughts on this before you do dig-in

DirtAssassin

I think your right might as well do them while im at it. Thinking though to use that JWT spring tool instead of taking the heads off.

tcode

iTrader: (7)

Compression doesn't necessarily have to be related with oil consumption. Compression can be perfectly fine, but piston oil control rings can be toasted at the same time and you have an oil burner engine. As a matter of a fact, VQ35DE are prone to this scenario, seen it so many times.

DirtAssassin

Dammnnn i didn't know that. that would make more sense to why they would just replace the engine under warranty then. Well I think Im going to just do the seals and fix my bucket size issue. Im going to get that JWT spring tool so i don't have to take the heads off. This motor has a super annoying tap so hoping these buckets fix that atleast.

bealljk

iTrader: (13)

Yea - I see what you're saying. I didn't think it was as prevalent on these engines thought

secretly one of the smartest members here...

maybe post up a video of this and maybe get a second opinion on the tap...could be something different.

THIRZTY

The "Engine Builder" probably didn't recheck or even check the lifter bucket clearances. Probably just slapped them back in place after lapping the valves. Did you do leak down test too or just compression? Those lifter buckets are $20 ea... so **** can get out of control really fast if you need to change them. You may be able to swap some around in the heads to balance out clearances so that you only have to buy 1 or two. It would be much easier if the heads were off and at that point I might just let a machine shop check the heads out. They can just cut the stems instead of changing the lifter buckets.

DirtAssassin

Im trying to get one uploaded think i need to make a Flickr account.

Thats what i'm thinking they didn't check clearances. I'll have it apart this weekend and see if i can just move them around.