Engine Break in Procedure.

[Amskeptic]

I will re check the valves tomorrow, before any more driving.

It is too soon to record your valve adjustments for trends, but do keep an eye on any that seem unusually tight or loose (more than .002 off).
Colin

[murphyslaw]

I will re check the valves tomorrow, before any more driving.

It is too soon to record your valve adjustments for trends, but do keep an eye on any that seem unusually tight or loose (more than .002 off).
Colin

I was just going to check the valves to see if everything there is ok. Its not really for any thing other than to look under the rocker cover , and re assure my self that all is well, and to see if thee is any rogue settings developing.

Can you tell me more about " recording valve adjustments for trends". Is there a pattern over a set mileage that will give me some information of how my engine is performing, and what type of readings that I should expect to see. Thanks

murphyslaw

[Amskeptic]

I will re check the valves tomorrow, before any more driving.

It is too soon to record your valve adjustments for trends, but do keep an eye on any that seem unusually tight or loose (more than .002 off).
Colin

I was just going to check the valves to see if everything there is ok. Its not really for any thing other than to look under the rocker cover , and re assure my self that all is well, and to see if thee is any rogue settings developing.

Can you tell me more about " recording valve adjustments for trends". Is there a pattern over a set mileage that will give me some information of how my engine is performing, and what type of readings that I should expect to see. Thanks

murphyslaw

A trend is three adjustments in a row that deviate in the same direction by a noticeable amount.

Too tight: if you lost .002" clearance on #3 exhaust, jot it down. 3,000 miles later, if you have lost .002" again, you should be concerned, maybe even check it in 1,000 miles. If you have lost a total of .006" or more, you might want to consider what is going on.

Valve stretch (heat is making valve stretch like toffee)
Valve seat recession (heat is softening aluminum which lets the seat pound deeper into the head)
Valve seat failure (this happened with my Squareback where factory did not harden seat material)

Too loose: if you have gained a sloppy .002" so that a .008" feeler blade fits in between the valve and the rocker, the noise will have told you. If the valve starts getting all clacky again, and you adjust it down, and it gets all clacky again, well, you have a problem.
Lifter failure (lousy metallurgy is rife in the marketplace)
(if valve exactly across from this one also loosens, you have cam lobe failure going on as well)
Insufficient lubrication (rocker arms are galling on the shaft)
Loosening rocker shafts (retighten to 10 ft/lbs Type4 18 ft/lbs Type1)

Please note that during break-in, the usual tendency is to have the valves tighten up as the heads seat to the barrels.
Colin

[midatlanticys]

Is it my imagination or do the headstuds *stretch* in length after X number of hot/cold cycles . . . . . . enough to warrant a retorque of the heads after 50 or 100 miles? Can this variable also figure into changes found when setting valves?

[Amskeptic]

Is it my imagination or do the headstuds *stretch* in length after X number of hot/cold cycles . . . . . . enough to warrant a retorque of the heads after 50 or 100 miles? Can this variable also figure into changes found when setting valves?

No, the head studs do not stretch. The soft aluminum, however, both at the head contact surfaces and the crankcase contact surfaces, does "set" to the cylinder barrels during break-in. This makes the heads migrate closer to the centerline of the engine. Picture what happens to the rockers as their supports move in. A tenth of a millimeter in at the supports translates into two tenths of a millimeter at the valve stem due to the pushrod, whose placement never changes, because all it knows is the camshaft.

The original torque specifications supposedly take into consideration this slight break-in "contraction" of the engine's dimensions. An overheat, however, changes everything. In the old days, an overheat would rip the studs right out of the case. Current case-saver engines merely distort the spigots and head sealing ledges. Either way, the nuts lose clamping force.

If you have a serious overheat, or are doing an engine removal for other reasons, I do suggest a re-torque. . . the one-at-a-time 1/2 turn ccw followed by one smooth motion to torque specification following the Bentley sequence **mirrored on the other side of the engine**.
Colin

[murphyslaw]

Just a quick up date on my recent engine rebuild. here,s a short vid of my engine running,

http://www.youtube.com/watch?v=RoG7AMZOIYI

murphyslaw

[midatlanticys]

Nice one Murph! =D> =D> Sounds good and must be fun to drive after having it open on the bench!!. I've never seen a pull start bug before; nice touch!!

Gotta love the Harp on the Irish €2 coin!

[murphyslaw]

Nice one Murph! =D> =D> Sounds good and must be fun to drive after having it open on the bench!!. I've never seen a pull start bug before; nice touch!!

Gotta love the Harp on the Irish €2 coin!

Thanks, its going great, and a nice smooth driver. The pull start on the normal alternator pulley was used by my uncle in the early 70,s, on old 6 volt beetles.

As you know some of the old 6 volts were hard to start, unless they were in tip top order. After a couple of cranks of the starter , his battery was useless, so out came the belt. He was never let down , when he had that as a backup.

The coin would be nicer if it was a silver eagle............worth more than a cupro nickel alloy

murphyslaw

[jackstar]

Colin et. al,

I am in the process of rebuilding a 2.0l 79 FI CA Westy back to as stock as I can. I have read alot of posts as to break-in procedures both here and on the Samba. Do they differ by engine size or degree of rebuild?

As to the 20 minute at 2000 rpm initial start up, am I to assume that the bus doesnt actually go anywhere? That you simply set the rpms or hold the throttle at 2K for 20 minutes? If so, after you change the oil and filter, do you then jump in and go off for the break-in procedure of gears, throttle ups, throttle downs etc never staying at the same rpm for long but above 2000 rpms. This is done for 100 miles correct? And then onto the other mile posts?

Sorry to be so thick, but after awhile of reading a bunch of threads you start to question your own ability to remember and apply the technique. If you can guide me to the Nirvana of start-up break-in procedures I would be most grateful. Thanks.

Jack

[steve74baywin]

Colin et. al,

I am in the process of rebuilding a 2.0l 79 FI CA Westy back to as stock as I can. I have read alot of posts as to break-in procedures both here and on the Samba. Do they differ by engine size or degree of rebuild?

As to the 20 minute at 2000 rpm initial start up, am I to assume that the bus doesnt actually go anywhere? That you simply set the rpms or hold the throttle at 2K for 20 minutes? If so, after you change the oil and filter, do you then jump in and go off for the break-in procedure of gears, throttle ups, throttle downs etc never staying at the same rpm for long but above 2000 rpms. This is done for 100 miles correct? And then onto the other mile posts?

Sorry to be so thick, but after awhile of reading a bunch of threads you start to question your own ability to remember and apply the technique. If you can guide me to the Nirvana of start-up break-in procedures I would be most grateful. Thanks.

Jack

Sound about right. the 2000 rpm's for 20 is good for the cam. Murphy didn't need to do that because he just did a top end rebuild. I'd probably change the oil after the drive for the rings.

[Westy78]

Colin et. al,

I am in the process of rebuilding a 2.0l 79 FI CA Westy back to as stock as I can. I have read alot of posts as to break-in procedures both here and on the Samba. Do they differ by engine size or degree of rebuild?

As to the 20 minute at 2000 rpm initial start up, am I to assume that the bus doesnt actually go anywhere? That you simply set the rpms or hold the throttle at 2K for 20 minutes? If so, after you change the oil and filter, do you then jump in and go off for the break-in procedure of gears, throttle ups, throttle downs etc never staying at the same rpm for long but above 2000 rpms. This is done for 100 miles correct? And then onto the other mile posts?

Sorry to be so thick, but after awhile of reading a bunch of threads you start to question your own ability to remember and apply the technique. If you can guide me to the Nirvana of start-up break-in procedures I would be most grateful. Thanks.

Jack

The initial 20 minute break in is for the cam lobes and lifters. You are correct that this is a run in the driveway period, no driving. You want to get the rpm right up to 2000 after it fires. No idling at all. No higher than 2500rpm. You don't have to vary the revs just find a spot between 2000-2500rpm. If you have some oil leaks don't shut it down unless it's a gusher and you're going to lose more than half a pint or so. If you do have to shut it down before 20 minutes there is a procedure for the next attempt. After the cam break in let it sit over night or until you know the engine is stone cold and do a valve adjustment. This is where you will begin your log of valve adjustments, particularly if you are using solid lifters. Take notes of valves that need adjusting every time. It could be a sign of bad things.

Then it's time for the piston ring break in which you will take it out on the road. Find a stretch of road where you can do some runs from 15mph to ~35mph in second gear and then back down to 15mph about three times. You want to let the engine brake itself when coming back down to get an even break in on the rings. In other words don't slow the bus down using the brakes let the engine slow the bus down. Then do the same thing in third gear from ~35 to ~50mph. That's it. Break in done. You should feel the power come on from the rings sealing around the third time up and down the rpm. Drive it for about 100 miles with varying speeds not just a long sustained highway drive and do the first oil change. What oil will you be using for break in?

[jackstar]

Thanks for the lead in. As far as the 20 minute cam break in I assume to use 30 wt. non-detergent. As far as after that, I am open to suggestions as to the best wt. to use on new rebuilds in NW Florida. Average temp for 9+ months of the year is just shy of Hell in June. Oh, and then there is the humidity. Like wearing a wool sock out of the hot tub. Oil suggestions??