nowa

Hallo @ All,

I need some advice from the LT5-Gurus here.

I got an 90th ZR1 and it burns some oil. I know there are 2 reasons for this:

1) Pistonrings,

2) Valve stem seals.

Problem is only visible when engine is hot (blue smoke at idle, only sometimes) and there is an oil smell.


Can someone explain the problem with valve stem seals on a 90th LT5 engine ?

1) Has the 90th LT5 engine valve stem seals ?

2) If it has no valve stem seals, is it possible to install them ?

3) Has the head to be modified to install such seals ?

4) Do I have to remove the heads to install seals ?

5) Any hints ?

thx

norbert

DDSLT5

No.

Yes.

No.

Yes - I believe so.

Not from me - but maybe someone else will chime in.

Zrxmax

As I understand the issue your addressing here... and it has been discussed here before... You need to have the head modified in the valve seal area so that valve seals can be installed...
It is not uncommon to go through a quart of oil in 300 miles on a 90 LT5 motor... letting off the throttle at high RPMs puts a lot of vacuum on the valves... and sucks a lot of oil... it doesn't hurt the motor... you just have to buy more oil to keep the level up where it should be...
When your playing around at high RPM... what is $5 for a quart of oil every 300+ or - miles ?
Do you think it is worth the down time and expence to fix this consumption problem ?
I don't... but to each his own... If you pull the heads for something else to be done... then make the conversion to valve seals... otherwise... keep going and buy the oil you need...
My 2 cents...

nowa

thx for your replys guys. I will think about it.

norbert

ZR1 MK

What oil are you using? Going to a thicker oil (15/50) might help.
Mike

nowa

I am using Castrol RS 10W60.

I will gather all the parts that I will need to fix the problem because:

1) I dont like blue smoke,
2) The CATs dont like it,
3) its a systematic failure, it has to be fixed,
4) my buddies Porsches dont smoke,
5) I present the american way of drive against the Porsches here at my location (Bremen/Germany), so my Z must not smoke.



norbert



[Modified by nowa, 10:40 PM 6/2/2004]

fake

I had a car start using oil and once i kept it topped off and i believe if you do not use it (the car) **** happens. Give it a month Walmart has cheap oil if you are using it like drinking water. When it stop grab some Mobil 1.

A26B

Hib Halverson

LT5s in 90s have not exhaust valve stem seals. When the engines were new or near-new, this didn't present a problem, however, as '90 LT5s age, it does become a problem. When you shut the engine down, engine oil begins seeping down the exhaust valve stems, onto the backs of the exhaust valves. The next time you start the engine, in an instant the back of the exhaust valves get hot and burn the oil off. The result is a short puff or a few puffs of oil smoke from the exhaust.

You can have stem seals installed on the heads, but generally engine removal is required because head removal with an LT5 in the car is quite difficult.

My advice would be–as long as we're talking a little bit of oil smoke on cold starts but otherwise no oil smoke–is to live with it because of the **** load of work involved and cost of pulling, tearing down and reassembling that engine.

You can mitigate the problem by going to a better oil such as Red Line 10W30.

ccmano