Oil Level/Comsumption

[Paul Workman]

Originally Posted by tomtom72

I thought that the 405 hp motors got exh & Int valve stem oil seals? I'm almost positive the 375 hp motors are missing one or both, I think it's only the exh seal they left out?

Anyway, GOFAST how are your PCV valves? I change mine every year as part of my "get ready" for the season. I have noticed that they don't make that clear metallic clinking sound after a season's worth of use, for me somewhere between 6k to 8k miles. As I get towards season's end my oil use goes up or becomes accelerated if you'll allow me that phrase. I can't find the oil on the plugs. Anyway, my point is my LT5's use seems directly related to the health of the PCV valves...or at least that's JMHO thru my own observation. Oh yea, pounding on Her just seems to speed up oil loss no matter when I do it. One of the development issues LOTUS had, ccv blow by ( my words, not LOTUS ), as there is no place for the internal wind with oil in it to slow down enough for the oil to coalesce and fall out of the air stream. Or at least that's what I think they, LOTUS, was saying. I would think that if that is true, then how clean the PCV valves remain over their time in service would be very important to oil loss?

As for checking the oil level. I use my car only on weekends and that's when I check my oil as part of my pre-start up check list. I always get consistent readings from the dipstick. If you think about all the places in our heads that oil can hide I can easily see 4 or 5 hrs should pass before all the oil gets back to the pan. Okay maybe a bit less?

These are just my observations with how my engine behaves in this regard.


Tom

Hi Tom,

Your're correct, far as the 90s go. They were sans seals on the exhaust valves - per Lotus Engineering felt those valves needed extra lubrication (ref: Heart of the Beast?). I've also read where the particluar open deck architecture employed in the LT5 is prone to some oil consuption, as a result of the top of the sleeves anchored to the head via friction. Sleeve lenght uniformity is absolutely critical to oil consumption, and tollerances being tollerances, and vibrations and stress being what it is (read: sleeve instability), sleeve stability contributes to oil consumption.



Marc's caging the sleeves in his BIG inch builds seems to be addressing at least some of the oil consumption (have to ask 'im or Frank U) by stabilizing the sleeves (reducing the dependance on friction against the head for stability). I've not heard yet if AES' closed deck design is effective in reducing oil consumption, but clearly that design stabilizes the sleeves as well.



(Maybe someone with REAL expertise could chime in? )

Comments about "first quart" consumption was news to me. And too can you or anyone tell me if the hashed segment on the dip stick represents a quart or is it something less? I put in a quart when the level was just below the hash, and checked it the next day. The level now as above the hash (full) line by an equal amount....WTF? I'm wondering if the seal on the dipstick caught on the edge of the tube and maybe didn't allow a proper sounding of the oil level. Have you (or anyone else) ever noticed that??

From the way I drive (spirited ... Hey, living in the country has its advantages!), my consuption has always been a quart and a little more between 5000 mile changes. After getting hot a couple times, and having a coolant disaster once, I'm monitoring it closely for a while to see zackly what it is now. (I have seals on all valves now).

Gotta run!

P.

[scottfab]

Originally Posted by Paul Workman

...snip....

Comments about "first quart" consumption was news to me. And too can you or anyone tell me if the hashed segment on the dip stick represents a quart or is it something less? I put in a quart when the level was just below the hash, and checked it the next day. The level now as above the hash (full) line by an equal amount....WTF? I'm wondering if the seal on the dipstick caught on the edge of the tube and maybe didn't allow a proper sounding of the oil level. Have you (or anyone else) ever noticed that??
...snip..

P.

I have an opportunity to verify this right now. Mine is right at the bottom mark now. I'll add a qt and check it in 8 hrs or so.

[GOLDCYLON]

Originally Posted by Paul Workman

Hi Tom,

Your're correct, far as the 90s go. They were sans seals on the exhaust valves - per Lotus Engineering felt those valves needed extra lubrication (ref: Heart of the Beast?).
P.

Yep Concur the MY 90 had no seals for the exhaust valves. That started MY 91. However, before I replaced my motor it always burned through the first quart real fast. Another question if I may does anybody see a lot of black soot/carbonation on their rear fasica from there exhaust like I used too? GC

[scottfab]

Originally Posted by GOLDCYLON

Yep Concur the MY 90 had no seals for the exhaust valves. That started MY 91. However, before I replaced my motor it always burned through the first quart real fast. Another question if I may does anybody see a lot of black soot/carbonation on their rear fasica from there exhaust like I used too? GC

Yup, I see the soot. If I make the mistake of starting before opening the garage door I get two big black spots. Not exactly fun to clean.
Otherwise I get the two spots on the driveway just outside the door.

[GOLDCYLON]

Originally Posted by scottfab

Yup, I see the soot. If I make the mistake of starting before opening the garage door I get two big black spots. Not exactly fun to clean.
Otherwise I get the two spots on the driveway just outside the door.

Yep I can relate to that happened. Pre engine exchange that was a daily occurance

[Blue Flame Restorations]

In reference to getting a more accurate oil level reading. I like to check my oil before I fire up the car in the morning, when checking. It's trivial, but it does make sense to use this method when possible.

[scottfab]

Well I topped off my oil early this morning and just checked it.
It does go above the fill mark by about 1/8th in.

BTW I go through a lot less oil if I keep it at the add mark and not the fill mark.

[Paul Workman]

Originally Posted by scottfab

Well I topped off my oil early this morning and just checked it.
It does go above the fill mark by about 1/8th in.

BTW I go through a lot less oil if I keep it at the add mark and not the fill mark.

Well, this news may aly my concern about oil consumption - above the add mark. Next time I have a long trip in store, maybe I can get a chance to do some experimenting/documenting.

Interesting topic.

P.