New camshaft wear in question?!?!

[DirtyTh3rty]

Was told today that when putting in a new cam that to wear it in on the 1st start you should bring the rpms up (around 2500 or something) and hold it there for a while to help seat it in.

Well I was not aware of this even when i did a little searching I should of done more obviously. So i finished last week and have been slowly driving her around town and on the freeway a couple times (haven't gone over 4k shifting around 3 usually) im at 115 miles so far on the new HG, Studs, & cam.

So am I screwed here now have I pitted the rockers or cam? How crucial is it that this is done? It seems to run fine right now but I feel like an idiot for overlooking something like this..

[digger]

if there are no scores, grooves or anything youre fine

[jeffnhiscars]

My recollection of the 2500rpm thing is mainly to bed in new rings.

[TobyB]

Nope, it's for oil flow to the cam. Rings like the hard runs to redline, then lift- off.

D3, as long as you don't let it idle, it'll be OK. Insurance is a high- ZDDP oil.
It's really only critical for that first warm- up, and if it looks ok now, you're
statistically OK. Just drive it.

t

[digger]

if you have a stock cam and stock springs youre unlikely to have issues unless using wrong oil or crappy parts, still best not to idle it at 750rpm and make sure everything is lubed before starting especially with the moly grease on the lobes and rocker.

alot of this stuff comes from pushrod land where they use stiff springs and aggressive cams (often needing to use light springs for run in) plus ive heard the rpm is to help splash lube the cam which is in a different location on the m20 anyway.

[DirtyTh3rty]

if you have a stock cam and stock springs youre unlikely to have issues unless using wrong oil or crappy parts, still best not to idle it at 750rpm and make sure everything is lubed before starting especially with the moly grease on the lobes and rocker.

alot of this stuff comes from pushrod land where they use stiff springs and aggressive cams (often needing to use light springs for run in) plus ive heard the rpm is to help splash lube the cam which is in a different location on the m20 anyway.

Its not stock its a 280/274 regrind from bimmerheads but stock springs. Which makes me feel like even more of a dumbass not like I payed a whole lot but I hate to ruin something nice. I oiled everything of course before startup I mean theres not much I can do now If I should have done this rpm thing to start with right? or should i keep doing this rpm thing and avoid letting it idle for a while??

I guess I will see how it looks when I go back in in a few hundred miles to re check valve adj. or should i pop it back open now? can i reuse my valve cover gasket if its just been put on?

[digger]

Its not stock its a 280/274 regrind from bimmerheads but stock springs. Which makes me feel like even more of a dumbass not like I payed a whole lot but I hate to ruin something nice. I oiled everything of course before startup I mean theres not much I can do now If I should have done this rpm thing to start with right? or should i keep doing this rpm thing and avoid letting it idle for a while??

I guess I will see how it looks when I go back in in a few hundred miles to re check valve adj. or should i pop it back open now? can i reuse my valve cover gasket if its just been put on?

if you have done a new VJ on the seats id check valve clearances now.

personally i think 1500-2000 varying it a bit for 15min is fine. i did that with 290 odd cam, and stiff valve springs and lobes look mint after 8years

[jeffnhiscars]

Since I have a fresh head to install I read up a bit on this and it does seem a break in is recommended. Assembly oil for sure (too late I know), high zddp oil (such as M1 15-50) and pre oiling all seem to help. I did read that moly is not such a good idea. While it does help with break in it can also cause wear elsewhere.

[SkiFree]

if you have done a new VJ on the seats id check valve clearances now.

This, check valve clearances sooner than later especially if you've had a valve job done.

I've had a guy with a valve job and cam check clearances, bolt head on, and then proceed to destroy is rockers/cam over four days of rally racing.

Steps;
1) Fully torque head
2) THEN check valve clearances (not the other way round).
3) Initial Break in time
4) valve clearance check
5) Continue with break in

[digger]

Since I have a fresh head to install I read up a bit on this and it does seem a break in is recommended. Assembly oil for sure (too late I know), high zddp oil (such as M1 15-50) and pre oiling all seem to help. I did read that moly is not such a good idea. While it does help with break in it can also cause wear elsewhere.

when i say moly i mean an engine assembly lube with high pressure additive which is often moly but could be something else. you arent using enough to cause problems. its the same as too much ZDDP causes problems to

[TobyB]

Yeah, drive it. Re- lash the valves now and make sure nothing looks terrible,
but don't worry too much. And yes, the valve cover gasket will be fine.
You may want to use a tiny bit more rtv on the cam plug seal area.

You can always use a synthetic, high zddp oil for the cam. The only place
it MAY cause problems is if you use it first with new rings- sometimes they
don't seal to the cylinder walls...

I have only had real cam problems with very aggressive profiles, before I attended
the holy Church of the Zinc dialkyldithiophosphates and saw the light. And the metal
shavings...

t

[jeffnhiscars]

This, check valve clearances sooner than later especially if you've had a valve job done.

I've had a guy with a valve job and cam check clearances, bolt head on, and then proceed to destroy is rockers/cam over four days of rally racing.

Steps;
1) Fully torque head
2) THEN check valve clearances (not the other way round).
3) Initial Break in time
4) valve clearance check
5) Continue with break in

It would not have occurred to me to recheck the valve clearances after the initial break in but of course it makes total sense. Good point.

[DirtyTh3rty]

Good stuff.

Another thing that was interesting with this rebuild was when I was putting the head back together on one of the exhaust rockers when i was adjusting it the eccentric was all the way at its tallest point and my rocker was still too loose (not by much). So i pulled the eccentric out and switched it with another exhaust eccentric and it worked out..

Is this a sign of worn rocker or just due to fact that its a new cam and the rockers are worn a bit differently?? just curious.

[Bearmw]

The infamous Paul Burke provided me with a crazy startup sequence which I followed. Here it is:

Start with a colder plug if modified until tune is right on. Spin it without plugs to build oil and fuel pressure. Once running use medium intensity driving. Basically roll it up to cruise for about 3-4 miles then roll up using about 3/4 throttle up to about 3-4,000 RPM and cruise about 3-4 miles and go between mild cruise and moderate 3/4 throttle. Between babying it and beating on it.

After one hour of total run time change the filter.
At about 3-400 miles change oil and filter.
Both again at about 1000 mi.
Both again at 1,500-1,800 mi. (Check head bolt torque and valve adjustment)

Normally after that.

I ran Delvac 15/40 conventional oil and think I used Comp Cams break in lube.

[TobyB]

That works.

Current ring thinking is that you should REALLY get on it right at first to get the
rings to seat well- and that's worked for me on the last 3 or 4 I've done.

t