Running in a new engine with new cams

[Matt]

Hey Everyone,

I'm in 2 minds as to the best way to run in a new engine with a new set of cams...

Should I install stock cams first and get the rings bedded or should I just throw the new set in straight up. From google (yep everything google says must be correct) it says the best way to run in cams is to hold the engine at a costant RPM which contradicts the generic engine run in of not holding it at a set RPM.

Is this being pedantic or is it worth the effort to throw in and old set of cams, then remove them once the rings have bedded in. Or is it something done in the 80's that isn't required for the modern engine.

Appreciate your advice

Matt

[lolwat]

i have been told, idle for 5-10 mins for cam to "bed" in, then drive, not thrashing but dont take it too easy at the same time,

[t-nol]

Have you upgraded the springs too? Do you know what pressure they are set up at?
The rings will take longer to bed in, and as you said the camshaft is merely running them in at say 2500-3000rpm for 10-15 mins. It'll take km's for the rings to bed in properly, with varying loads best.
Do you guys take the inners out of the springs though? Thats the general practice to bed the new cams in nicer (run less spring pressure), then install them again after the 15mins initial run in. But maybe running a shim and bucket setup we don't need to?

[slide86]

new cams shouldnt be left to idle......20 mins at 2500-3000rpm and they should be set.

there is a VERY good web page about running in an engine, ill have to try and dig it up

[FoldKing86]

Im lead to believe stay stock cams till rings are bed then attack the head. Long and expensive way of doing it but its been known to work. Other ways im not sure on, i know cams dont take long but its what the cam does (duration and lift) that can effect other things.

[_sawyer_]

My old man has built engines for years and they way we do it is like the above, run a mineral based oil for the first start up and 1000k's, hold the engine at 1,500 rpm for 7 mins, 2,000 for 7 mins and 2,500 for 7 mins while parked and constantly checking for oil leaks. obviously make sure you have good oil pressure to begin with and dont let the engine warm up so start this process withing a minute of initial start up.

Tricky process because you wanna make sure your cooling system is good, ignition timing is set correctly etc but its a tried and proven process,

Free reving the engine without load really has no risk associated with spining bearings or anything like that to a new engine,

The rings will take a whole 5 minutes to bed in doing 'torque' runs up slightly step hills, which means really straining the engine from low revs in a high gear up hills and small inclines. the main and rod bearings are the ones to have concern about as they usually take 1000k's to bed in correctly

[t-nol]

Yep, happy with that ^^

[Gunner]

I concur.

[Matt]

Cheers guys, my main concern was holding at the constant revs. Hopefully in a couple of weeks I'll report back in how it all went

I was planning on using stock valve springs but happy to get your advice.. Cams are kelfords and I'll be retaining vvt

[slide86]

Nissan 7.5w30 mineral oil is a very good running in oil.