I just broke in my new engine. Everything went well.

I set the timing by moving the engine to 12 degrees btdc then aligning the rotor to a mark I made at cylinder 1 post in the rotor. Started up on first turn and got to 2500 rpm no problem.

I did notice later that my timing was very high, 35ish at a 1300rpm idle. Starting it was hard until I adjusted it much further counter clockwise from it was when I set it initially. The rotor didn't shift, it was tight and in the same place I put it. Could this be because the engine is hot or just mechanical advance because the rpm is high?

 

Congrats on the "new" engine and the initial start-up!!!!!!!!!

There are soo many factors that have and change during the engine break-in......and what you are experiencing is not unusual. As things break-in, the timing chain stretches just a tad, bearing begin to loosen up, piston rings seat, everything constantly changes..... less as time goes on, but still requires attention especially during the 1st few hours of operation....timing get to be re-set/adjusted, fuel mixture, etc. You are doing good and just keep up the TLC!!!!!

 

Just to be clear, and for people following along - was the vacuum advance connected? RPM 1300 will start to bring in a little mechanical advance but vacuum advance will bring in more. There's no load on an engine at idle and a high steady RPM means a high steady engine vacuum. In this instance 35° might be about where it should be. This is why base and total timing measurement is always performed with vacuum advance port disconnected and plugged so as to not interfere with the true mechanical timing indication on the damper.

 

Did it go any higher than 35* ? That's a pretty quick curve. What do you know about the dist. ? Is it a new aftermarket one ?

 

Not sure how high it went. I was concerned with other things at the time. I was running relativly smooth and I didn't hear knocking or pinging, so I hope it wasnt. I took a drive and the engine runs strong without any odd noises so I think it's no worse for ware. There is more lifter noise than the last engine but with .55 inches of lift and only the outter springs installed that's expected.

The distributor is off the old engine and was reliable. I think there might be an issue with the advance, I will have to check it after my oil change.

 

After some investigation it looks like something moved because with the rotor over plug 1 it was at 30 deg initial advance. Like I said, I timed it with a light to 12 and drove it without any issue.

What kind of damage could be in there with breaking it in at an estimated 45-50 degrees of advance at ~2500 rpm for 15-20 minutes? Like I said, I didn't hear any knocking or pinging but I was in the cab.

 

You never answered the question.

Was the vacuum advance connected?

 

You'd hear it pinging even in the cab. Check your spark plugs and see if they look like they got beat up; they will tell the tale if you were detonating or pre-igniting. The question about the vacuum advance is still relevant, because you might be running with less advance than is optimal if you re-timed it with the vacuum advance connected. 45-50 degrees with vacuum advance is not unheard of.

 

It was connected to ported vacuum on holley. It's holding steady now at 12 btdc.

 

You have to unplug the vacuum advance and plug it off too. once you have the hose on it the timing will move.
I would assume it is a hydro cam ? You can not run dual springs with a hydro cam. The valve spring psi will overcome the lifters oil psi. You need a single spring with a damper. Call the cam co. that made it and get the matched springs and put them in at the mfgrs. height spec.
You also need to check the lifter preload.

 

Right, and it probably did exactly what it's supposed to do. High vacuum - lots of vacuum advance. It works as advertised sounds like.

It should probably do whatever it was doing before... What are you doing different? Be sure to set initial and TOTAL timing first, always with vacuum advance port disconnected and plugged. Drive it around until you are satisfied. This is a good time to seat the rings hard so they don't glaze over the cylinders. Once camshaft break-in is complete don't futz around at idle with setting the carb and fiddling with the timing. Get the engine under load right away with some "spirited" driving. When you are satisfied with the mechanical timing curve, then re-connect vacuum advance and finish up the curve. Keep in mind at this point you're done with the mechanical part of the advance curve. Any timing adjustments at this point are done with the vacuum advance can only - using an Allen wrench - for part throttle acceleration, and steady cruise speeds, don't back off on the mechanical advance at this point, if it starts to ping, see where I'm goin' with that? The key is to first see what the mechanical tops out at around 3000 RPM or so, make sure it's done advancing as far as it's going to, with the vac advance disconnected. Should be around 36° or so, depending on CR, altitude, fuel quality etc. Get that straight first, without the vac advance confusing things.

 

Spring pressure has no effect on hydro lifters,

"In a modern hydraulic lifter, a hardened steel push rod cup sits on top of a plunger mounted inside the hollow lifter body. A lock ring in the top of the lifter holds the assembly together. Under the plunger is a spring that holds the plunger up so oil can fill the cavity between the plunger and lifter body. A one-way check valve in the bottom of the plunger allows oil to enter the plunger cavity but traps the oil inside when the lifter moves up. This prevents the lifter from collapsing, which would not allow it to open the valve fully.
The clearance between the plunger and lifter body is extremely tight, typically 0.0002? or less. This is done to limit oil loss from inside the lifter (called the “bleed down” rate) when the valve opens and closes. A small amount of leakage (bleed down) must be allowed with each valve cycle so the lifter can readjust itself to maintain zero valve lash."

"With flat tappet cams, too much initial spring pressure can have an adverse effect on the cam lobes and lifters until the cam is broken in. For the initial break-in, one cam supplier said open seat valve spring pressure should be limited to no more than 280 lbs. If the engine has double springs, temporarily remove the inner spring for break-in, and use a lower rocker arm ratio to reduce the load on the cam. Some racers go even lower, using no more than 225 lbs. of open spring pressure for break-in. "


You can read about lifters here, http://www.enginebuildermag.com/2012...d-lifters-101/

 

with 99% chance of "None"...there was no load on the engine... so there was likely no "pinging"..

 

I did all the math and checking, it all should be spot on. Used the adjustable comp cam pushrod to get all my lengths I broke it in and did initial drive with just the outer comp cam springs. Maybe I was using the wrong term, what I'm calling the inner spring might be a damper. I did notice that it provided maybe 20 lbs of pressure, not all that strong. It's only a few coils, the metal is around 10mm tall and 1 mm wide.

After my seconds drive everything seems good. only 30 miles total so far so I don't expect everything to be perfect. I do notice a slight "diesel" sound under light load while the engine is coming to temperature but goes away after full warm up. I will see if it goes away in the long term. I doubt that I'm getting knock now. I have 91 octane in the engine and the timing is very conservative at the moment, 12* btdc with vac connected at 800rpm. XE262H cam for what it's worth, 40 over KB Cleveland pistons and v2 heads, getting compression right around where TM would. Running 15w40 Rotella with a half bottle of comp cams break in zinc.

 

Subscribed.

I've got a new engine on the way and will likely have some very similar questions when it's in the truck for the first time!

Great information from everyone. Hope it turns out well for the O.P.