Engine break in

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theothergarth

theothergarth

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Going to have a newly built motor soon (hopefully). I have seen many versions and opinions on other sites of "proper" engine break in techniques. It will have new cam and lifters, fresh hone (not sure if I will have it bored from the .03 it's at to .04) possibly new pistons and a milled block. I also plan on new TTI (yeah I know...$$) headers with the ceramic coating. TTI says not to break in a new cam with the headers because it will ruin the coating.
The question I have is...can you break in the motor without any type of exhaust system on it without hurting anything?
 
Old school trick.Fire it,run until you smell paint.Shut down,let cool off.3 or 4 times should be good.Make sure it lights quickly,flat tappets are fussy nowadays.Make sure you have a ZDDP additive in your oil.Or buy Valvoline Racing,or Joe Gibbs.With TTI, I would be more worried about cam break in.
 
I wouldn't break it in with no type of manifolds on it cause they run real hot while breaking in and it might warp the exhaust valves. Can you find a set of cheap stock manifolds to slap on it for break in? If you were close I'd loan you my set but we're several states apart.
 
Abodybomber said:
Old school trick.Fire it,run until you smell paint.Shut down,let cool off.3 or 4 times should be good.Make sure it lights quickly,flat tappets are fussy nowadays.Make sure you have a ZDDP additive in your oil.Or buy Valvoline Racing,or Joe Gibbs.With TTI, I would be more worried about cam break in.
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Yup, it works, keep it above idle way above idle about 2 k if you are running a flat tappet.

DO NOT START YOUR ENGINE WITH NO MAIFOLDS.
IF YOU DO BURNT VAVES ARE IN YOUR FUTURE.

You are not really going to try to stat your motor?
Really?
 
fishy68 said:
I wouldn't break it in with no type of manifolds on it cause they run real hot while breaking in and it might warp the exhaust valves. Can you find a set of cheap stock manifolds to slap on it for break in? If you were close I'd loan you my set but we're several states apart.
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This is what I have read was leading me to believe, While others say go ahead with the break in with nothing bolted to the exhaust may be true, I would rather err on the side of caution. That being said, does anyone close to or in the Space Coast part of FL have a set of manifolds I can borrow for a week? It will be a month or so before I am ready for them.
 
How will the valves get warped running with no manifolds ??

I do know that your engine compartment paint (as well as wiring) will take
a beating.
 
yellowdartdave said:
How will the valves get warped running with no manifolds ??

I do know that your engine compartment paint (as well as wiring) will take
a beating.
Click to expand...

To be honest I don't know if it is because the manifolds can act as a sort of heat sink to draw heat away or if it's because of no back pressure at all it causes them to run lean but I've seen it happen.
 
Make sure it has plenty of total timing when breaking in. If it doesn't have enough timing, the exhaust temps go WAY up...

Get about 36* total timing in it while breaking in. If the balancer doesn't have a mark on it make a hillbilly timing tape.

Set the balancer zero line line at the 10* BTDC mark and scribe another line at 15* away (5* ATDC), then roll the new 15* mark to the 10BTDC indicator mark on the cover and scribe another mark 15* (5* ATDC) from that one. Now you have a balancer with the capability of timing it up to at least 40* BTDC. I'll use a file and put a small groove, then fill it with black paint.

340build001.jpg


Low buck timing tape with a little math... :)
 
There is cam break in, and ring seating. Your main concern should be the cam break in. Which definately should involve it firing instantly and being pre-lubed properly and fuel system primed and cooling system functional. It most certainly should NOT involve turning the engine onver and over trying to get it to fire, or turning it off for any reason, or letting the rpms drop below 1800 for the first 20 minutes. If the cam is a modern fast rate type that requires a dual valve spring, the smaller inner spring needs to be left out for the cam break in. Oil choice and additives for cam break in are also important. If the cam is larger, I also use the VR1 that is not for street use to break in the cam.
The ring seating is pretty much all dependant on the machine shop making sure the bores were clean when it was assembled, and that it was properly honed and finished for the rings. Once the cam's broken in, the rings will be well on thier way to being seated.
 
Without manifolds the valves tend to cool too fast, and some what unevenly. Then they warp.

Oh yea. If the cylinders are prepped properly the rings will be almost completely sealed in about five seconds. This is why proper assembly is critical.
 
magnumdart said:
Without manifolds the valves tend to cool too fast, and some what unevenly. Then they warp.
Click to expand...

I dare you to run the engine for 5 minutes with no manifolds, shut it off and let it sit for a minute and then stick your finger up in the exhaust port.
 
I've always heard the cooler outside air (and yes 90 degrees is cool compared to the engine heat) compared to the engine popping out hot air is what warps the valves.I'm not sure that normal idling would do it but 2000 rpms is pretty high considering a long time idling.I think usaully it happens when ther car is driven and hot rodded with no manifolds.So I would definiately have some kind of exhaust.
 
Let's put it another way.

Bake a cake in the oven at 400 deg for 20 minutes.

Open the oven door and 3 minutes later..grab the cake pan with your hand.

Bet ya the 'cool outside air' hasn't cooled the pan very much at all.
 
yellowdartdave said:
Let's put it another way.

Bake a cake in the oven at 400 deg for 20 minutes.

Open the oven door and 3 minutes later..grab the cake pan with your hand.

Bet ya the 'cool outside air' hasn't cooled the pan very much at all.
Click to expand...

O.K. Part of the valve is in the guide and part of it is exposed to the air. It is cooling at a different rate. It will warp. Kids in the neighborhood ruin their mini-bikes all the time running them without mufflers. I always used a straight pipe and had no trouble. Even top fuel cars have pipes. By the way, the cake pan is cooling at a good clip. It is just being re-heated by the cake. I would be willing to bet that if your cakes pans are not new they are probably warped some. Guess why.
 
" Part of the valve is in the guide and part of it is exposed to the air."


Yes, but the exposed valve is surrounded by a very hot head and very hot air in the exhaust port.
 
yellowdartdave said:
" Part of the valve is in the guide and part of it is exposed to the air."


Yes, but the exposed valve is surrounded by a very hot head and very hot air in the exhaust port.
Click to expand...
That hot air in the exhaust port is forced out and with no air left a vaccum is created which rushes ambient air back into the head.:happy1:
 
yellowdartdave said:
" Part of the valve is in the guide and part of it is exposed to the air."


Yes, but the exposed valve is surrounded by a very hot head and very hot air in the exhaust port.
Click to expand...
Not after you shut it off. 410 you are exactly correct.

I will be gone a few days so let me add just a little to this. Valves can warp without any help from us. Hot spots in the heads caused by scaled up water jackets can cause all sorts of problems, including warped valves. I have seen people run with cracked exhaust manifolds and sure enough the valve where the crack is will warp. Why anyone would go thru the time and expense of putting a nice engine together and then run it with out pipes is beyond me. Sure, you could run it for a few seconds like that, then shut it down, but what will a new cam gain by that?
 
soooo....better to play it safe and throw a set of old manifolds on the engine for break-in, then putting on my pretty new headers/w full exhaust once it's ready to drive, got it!
All I have to do now is find a set to borrow.

And btw.....great discussion guys, that's what makes this site so awesome!
 
"That hot air in the exhaust port is forced out and with no air left a vaccum is created which rushes ambient air back into the head."

How is hot air forced out and what happens to 'cool air' when it is surrounded by hot metal??

And kids ridding the mini bikes and go karts around with no mufflers at full throttle are running them way lean.

That is a lot different than 1500 rpm with no load.
 
crackedback said:
Make sure it has plenty of total timing when breaking in. If it doesn't have enough timing, the exhaust temps go WAY up...

Get about 36* total timing in it while breaking in. If the balancer doesn't have a mark on it make a hillbilly timing tape.

Set the balancer zero line line at the 10* BTDC mark and scribe another line at 15* away (5* ATDC), then roll the new 15* mark to the 10BTDC indicator mark on the cover and scribe another mark 15* (5* ATDC) from that one. Now you have a balancer with the capability of timing it up to at least 40* BTDC. I'll use a file and put a small groove, then fill it with black paint.

340build001.jpg


Low buck timing tape with a little math... :)
Click to expand...

FINALLY! I read a lot of stupid information around here. THIS IS EXCELLENT ADVISE. If you follow it, you can fire up and break in the cam with NO damage to your headers. Install the complete exhaust system and you will be able to listen to you engine during the break in procedure. Red colored headers during break in is because the combustion gasses are still burning after exiting the combustion chamber. By advancing the timing as suggested, you start the combustion process earlier and will burn more of the fuel/air mixture in the chamber and less in your header. Way to go Cracked, a breath of fresh air!
 
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