40K Elise: Changed My Lift Bolts / Cam Wear / Oil Thoughts..

[ronin]

We still shave cats....

[Bruce]

Stan, those are the rocker shaft retention bolts aren't they? Why do you call them lift bolts? Also, what oil have you used for most of your mileage?

[Stan]

Stan, those are the rocker shaft retention bolts aren't they? Why do you call them lift bolts? Also, what oil have you used for most of your mileage?

They are commonly known as lift bolts by the Celica guys. Toyota calls them flange bolts. Or "rocker shaft set bolts". What they do is hold the rocker shaft in position. The nickname came along because when one breaks...the rocker shaft can then rotate on it's axis a bit...which jams up the cam switchover. As in no big cam (lift, the L in VVTLi) anymore on that camshaft until rectified.



I've run mostly Mobil 1 0W40 oil, first in the API SM version, and subsequently in the latest SL version. Both API specs have reduced ZDDP compared to prior specifications. It also appears that some of the Mobil 1 weights are fully synthetic only in the legal sense. Now I'm running Mobil's (legal and actual 100% synth) Delvac 1 5W40 API SL for now along with a Mobil 1 #209 (larger than stock) oil filter Delvac 1 has much more of the proven cam protecting elements in it. This may be healthier for our high cam and slipper along with parts of the cam switchover mechanism.



Here is a TSB writeup about them...a how-to in case one snaps:

http://teamcelica.com/tech/installs/liftbolts/liftbolts.pdf

If I had to do this I'd yank both cams and reset the shims to perfection based on a hot engine clearance. It's much easier to just change out the bolts from time to time.

[Stan]

This article is an example of why moremonkey has now become my primary Elise board.

Thanks Man!

[Bruce]

When you had the cam cover off, did you measure the valve clearances to see how they compared to the factory specs after 40,000 miles?

[Stan]

When you had the cam cover off, did you measure the valve clearances to see how they compared to the factory specs after 40,000 miles?

Nope, I'll have to do so. It appears that clearances are fairly stable on this engine.

"Valve Clearances
a) It is unlikely that valve clearances will require adjustment unless components are replaced. A single
forked rocker arm is used to operate a pair of valves, which are shimmed during manufacture for equal
clearance. Routine service clearance checks should be made between the cam and roller follower. Only
if a valve or rocker arm is replaced need the clearance between individual valves and the rocker arm be
measured. Adjustment procedure is detailed in the text.
b) When using the shim adjustment special tool, before removing a shim from a valve stem, ensure that
the oil drain passages on the exhaust side of the head are blocked with paper towel. Shims are easily
dropped and may fall down the drain passages into an oil gallery in the crankcase, requiring engine removal
to retrieve."

[Stan]

When you hit 6200 RPMs, a solenoid valve (near the oil filler cap end of the head) opens. This sends high pressure oil down both rocker shafts. The high oil pressure overcomes the spring holding the Rocker Arm Pin in the low lift position. The pin is forced under the slipper follower which activates the high cam. While on the low cam, the high cam's Slipper Follower pulses up and down, following the high cam profile but producing no useful action.

There are 8 of these rockers to be switched over. Each rocker handles a pair of valves. The tip of the Rocker Pin and and bottom of the Slipper Follower experience switchover wear as previously noted and diagramed a few posts up... I'd guess they'd prefer EP oil additives...

[PsychoRallye]

What do you think of using a Group 3 (cause they are cheap) and adding something like this? http://www.hughesengines.com/partDetail.asp?partID=12697

At $7 per pint (their suggested ratio is 1 pt to 5 qt) when you buy a case, it's pretty inexpensive... basically $7 per oil change plus $20-ish for Standard M1 (close enough anyway).

Do you see a big positive to using Delvac 1 over M1 besides additives? Any negatives to using an oil with lots of additives usually geared towards diesels?

Found this kind of interesting too (From bobistheoilguy.com forums):
http://www.hotrod.com/techarticles/engine/flat_tappet_cam_tech/oil_summary.html
And, seen any places that sell it cheap (by the gal) locally ?

Thanks as always...