Running in new cams
 

My blink spec cams are to arrive soon.

Does anyone have any advice on breaking them in. I've swapped cams before but only used ones. The new ones are regrinds so I assume I have to break them in?

Also pipers site says to never use old lifters?! I assume all you guys that have swapped new cams in haven't swapped out all 16 HLA's for new ones?

16 new HLA's are £432.00 from Mazda. I am not paying that. No way.

Help appreciated.

Connor.

Ask the cam manufacturer.

They obviously say new lifters MUST be used.

I'm aware of the theory behind why that is. I'm just hoping people have had real world experience of them being ok on used HLAs as I do not believe anyone is paying that much to swap cams over.

Any particular reason you are a non-believer?

In the last year, i've put new cams in two motors.

One being a KL (4 cams, 32 lifters), and an F2 (1 cam, 12 lifters.)

So in the last year, i've purchased 48 lifters. (Actually 52, the F2 lifters came in a pack of 16.)

My experience with reground cams is to replace the lifters if you'd like to keep the cam lobes. I've seen more than one cam ruined using old lifters. YMMV

You can get new lifters from Kia for about $8 each I believe. Search on here and m.net for the part number.

Also, general rule for cam break in:

1. SLATHER in assembly lube.
2. On first start, try to run the engine at 2000 RPM for 30 minutes (make sure you have oil pressure obviously).
3. That's pretty much it.

Cam manufacturers recommend new lifters due to the wear patterns of the cam and lifters as they age. The lifters start square then belly in the middle. The old cams follow that pattern over time. With a new cam and old lifters you will not have even contact patch thus creating hot spots that could cause pitting on the cams. A machinist could tell you how bad or good your old lifters are.

Use a high ZDDP oil for break in. Brad Penn, Swepco or amsoil break in oil. Run motor for 2k+ for 20 mins and you're done.

If you choose to ignor the above you may get lucky and have no problems. On the other hand I have seen cams die in 20mins from not using new lifters, cheap oil and not breaking it in properly.

Use a goog zddp additive or oil with high zddp levels, run continuously @2000 rpm for 20-30 minutes. Re-check hot and cold lash. Never use old lifters, they need to break in with the cam.

Of course the people who actually make the cams have no fucking idea what you should do with them. You know so much more. Definitely run the old lifters to show those bastards who knows more.

Would this apply to solid lifters also? I would think the shims would develop wear patterns also.

That was going to be my question. I had always heard to never mix new cams / old lifters or vice versa....But when you change shims in your shim over bucket lifters you are fine? What gives there?

Because the shim is the surface the cam rides on, with SUB or hydros you need to change the whole unit because the top wearing surface is integral to the lifter.

If you are asking why you need new lifters with a new cam, and not a new cam with new lifters. I would imagine you are safer once the cam is broken in and has a solid wear surface.

Always follow manufacturer's specs.

Not really as long as they are not SUB. The shim is the wear surface. They should be checked for flatness when changing cams though.

That's correct. Part of the "break in" process work hardens the cam. After that it's much less sensitive to lifter/cam surface mismatch.

Well there in and run in. Spoke to a local engine builder ( the guys who did my head work ) and he said it'll be fine with used HLA's so I just fitted them on the old HLA's covered in engine oil. I ran them in for 25 mins at varying rpms between 2500 and 4000. I've Been thrashing it to death for a few days and took the cam cover off yesterday to check the lobes and it all looks fine. I changed the oil and filter just to be safe but there were no shavings I could see in the filter.

Cams made a decent improvement aswell so I'm happy.

:)

I just picked up a set of lightly used Sub in the mt classifieds, should i be concerned with using new cams? The seller stated only ran for hours and i see no wear pattern on them. There is some light scuffing which i could polish out if needed?

Yeesh, hope you don't go to that shop for any work in the future.

It's one thing for you to take a gamble and roll the dice with used lifters.... It's another thing for a so-called "engine builder" to tell you this is acceptable.