Something I recently discovered. Correct me if I'm wrong here.

If you're using a solid or hydraulic lifter...DO NOT use synthetic oil on your initial start-up. I am not sure about the exact science behind it, but I just made that mistake. I recently rebuilt my Merkur drag car. 2.3L Ford flat tappet four cylinder, ball bearing turbo, with a new cam. At the initial start up I used full Synthetic oil instead of regular oil. I figured this was a good idea. But after about 10 minutes of break-in, the car started to run differently, and after only 30 minutes, it would barely run. I broke down the motor again, and my camshaft was as round as could be. Flattened every lobe after half an hour.

I called Comp Cams, and the FIRST question they asked me was what kind of oil I used. I told them Synthetic, and they told me that was my problem.

How come using synthetic oil on break-in would cause that problem? I know that synthetic lubricants do not interact with metals in the same way...but I would like to know why. Anybody know?

 

I heard it's because it lubricates TOO well, and doesn't let the lifters rotate in their bores, and wear to the lobes correctly.
A lot of posts recently have stressed this, so i'm glad I noticed it in time, (unfortunate for you though ...)

 

This is well and widely know in racing and professional engine building circles.

THe reason is, that a "flat-tappet" lifter is not flat; and the cam lobe is not "flat" either. The lifter is actually spherical and convex, with a radius of curvature of around 5-6 feet (different motors differ in this measurement); and the cam lobe is convex along the cam's axis also, with the "side" of the lobe toward the rear of the engine taller than the "side" toward the front, in a curve. There should only be one small point of contact between the lobe and the lifter; it should be near the edge of the lifter, and at or near the "rear" of the cam lobe. The lifter MUST rotate in its bore, as the cam rotates underneath it; in other words, it must act as if there's friction between the cam and the lobe.

This rotation MUST begin to occur within the first 10 engine cycles or so, of motion. Excessive cranking, excessively turning the motor over by hand, excessive very low speed operation, can ALL allow the cam and lifter to slide on each other. And of course, synthetic oil is so "slippery", that the surfaces don't "grab" each other well enough at this critical time.

If the lifter does not rotate, the cam lobe slides across the bottom of the stationary lifter. It only takes a few passes of sliding, before the curvature is worn off of the lobe. And once that happens, the tendency to rotate the lifter disappears, and it is permanently unable to work right. Destruction is CERTAIN and INEVITABLE. That's what happened to you.

 

I'm with the 'dommy'.

 

Does this principle of not using synthetic oil on startup also apply for the 305 TBI Engines?

 

its applies to all engines.

This is the problem with people only knowing what they are told by fancy advertising or word of mouth hype. Ya think ya know everything and don't bother to learn right. Syn oil is not the be all end all, of all oils. Its has a time and place for proper use.

If ya don't know, ya shouldn't be using it.

Sorry but its engine builder 101

Your learing to tie your shoes before you can stand. And ya stuck them on backwards being to eager to get up n walk.
Take your time and learn things right. Even if you think you know, bing closed minded to new info leads ya down these paths.

FYI
lots of engine builders [american iron] won't use syn even after break in. Call around and ask some engine shops what they use.

 

Seems a little harsh.

It doesnt apply to all engines though, there is nothing at all wrong with using synthetic when firing a roller cam engine for the first time. People do it all the time, with no ill results. Some people argue that the rings wont seat properly with it, its a little BS too.

 

I dont want to sound condensending, but many shops in this area are seeing the benefits of racers using synthetics in their motors. The shop we use recommends them as they look like new internally when it's time for a freshen up. One shop that caters to $20-$30K circle track spec motors used a drag racing buddy of mines engine for a test mule to test out synthetic for himself-any damage done to improper oiling would be fully taken care of. The motor was torn down at the end of every season to see how it looked internally, and for 3 yrs everything still looked like the day they built it and the motor used Mobil1 full synthetic for all yrs. Before the begining of the 4th season the shop did finally do a tear down freshen up out of guilt and have since recommended to their cusotmers installing synthetic after break in on the stock type class motors.

I had a touch over 1800 passes on mine alont with 5-6K street miles and the main/rod/cam bearings looked like they were just installed. Synthics work-period. Just like VERY few engine builders are building loose motors requiring the used to be normal 20-50W oils, they found the hp needed to churn up that molasses ate more power than it did to build the engine a tad bit tighter allowing the use of standard type 10-30W's or 10-40W. Guys that made thw switch using the same motor specs but tighter tolerances and lighter oils were actually gaining hp...cant argue with that

 

I totally agree, and so does my engine after 15 years and 145,000 miles and less than .001" cylindertaper and less than .005" out of round, I have used Mobil 1 10w30 since the car was brand new. I drive rather agressively and take my car to the track frequently. Last year I decided to pull the heads and replace them with aluminum. After pullin the intake there was no varnish on the pushrod (something that is unheard of from conventional oils), I pulled the heads and found absolutely no cylinder ridge and after seeing that I pulled a rod and piston, bearing wear was consistant with break in with minimal wear and the rings were close to perfect.....So your right there is a place for synthetic oils.........in my engine...see ya at 500,000 miles when I might have to rebuild it..

$.02
J

 

They are talking about the first 20 min. of break in. Not when you got your car new after someone in Detroit already ran the engine for the break in period!
If synthetic is so good, how come they don't make syn. assembly lube?
I don't think your grasping the topic here.

 

so, can you clarify something for me?...if i install an LT1 cam with new springs, new pushrods and lifters, do i need to run regular oil for a while (break in period) before i go back to pure synthetic, which is what i usually run?

 

I'm sure there is synthetic assembly lube. might want to try checking that out. I know redline has some.
http://www.sportcompactonly.com/prod...167&l=2&p=2529

royal purple has some
http://www.northernautoparts.com/Pro...ctModelId=4884

techniplate makes some
http://www.motorshack.com/acatalog/Assembly.html

so guess if they do make synthetic assembly lube it really must be that good right?


or was this just acase of open mouth before checking the information?

 

If it's a roller cam you can just use synthetic.

 

Your right about that! I sure did! But I know one thing, I've never run the lobes flat on a cam during initial start-up.
I believe synthetic oil is good but should be introduced to the motor after breakin. I've built several engines since 1968 (long before you popped out of your daddy's gonads) and haven't had any problems like the original post stated useing dino oil.

 

Bingo Bango


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n yea I was a bit hash about it but ya gotta know the basics and weed out the hype before you build anything. Syn oils have a time and place for use and its best to be safe then sorry and not use them at all on a fresh build start up. Plenty of good dino oil around. Though you must discount them jap motors with tolerances so tight dino can't flow right n so on..... But to many folks think all you need is a summit catalog n a credit card to build a motor.

I really don't care if someone blows a wad and ruines a motor being over eager. I feel bad for the motor and why Im harsh about it. Poor thing never had a chance.

 

If its flat tappet yes, but if its a roller cam engine, there is no reason not to use synthetic from the very first startup.

 

If you have new piston rings, synthetic is NOT recommended for break in.

A good rule of thumb is to use conventional oil if you're breaking in *any* parts, unless synthetic is specifically recommended.

-Dave

 

Besides that, you can save alot of money! Proper break-in procedure requires you to change the oil and filter after the initial start up and break-in period. Synthetic oil is kind of expensive to throw away after such a short period of time.

 

Yeah so after reading all of this, I now feel like a complete idiot. I just hadn't ever thought about it before, call it ignorance if you want, but because all of the motors I have previously built, (I.E. my Camaro, or Z71) have all been hydralic rollers, and I've always used synthetic with no problems whatsoever. This was my first experience with a solid lifter motor, and I had never heard anybody tell me otherwise, so I went ahead and did it. Lesson Learned.

But thanks for the explination Sonix and Sofakingdom.

Sorry gumby...guess I slept too much in that class.
It's not about being closed minded to new info because I did not have the info until now. Why do you assume I was over eager? A mistake is a mistake.
I can't expect to go in and do something new and expect to get it perfect the first time. That would make life to damned boring. Some things are best learned by mistakes. But point taken.