Max cam lobe lift

[gectek]

Anyone know how much lobe lift the stock lifter retainers will take until the lifters clearance the top out of them? meaning how much lift until they blow through the top

[WrathOfSocrus]

In order to create more lift, the cam is ground down. Making the lobes any bigger would make it impossible to fit the cam in past the bearings. The point at which the cam makes maximum lift remains roughly the same and the base circle is cut down. The difference between the base circle and top of the lobe is the lobe lift. Reducing the base circle increases the difference between the high and low spots creating more lift. That is why it is very critical to get the proper length pushrods when changing cams or having a regrind performed.

[bszopi]

So its not a matter of the lifters going through the top of the retainer, but more an issue of the lifters falling out the bottom of the retainer...

[SappySE107]

and id like to see that. I had a cam ground so the base lobe was barely larger than the shaft part of the cam and the lifters didn't fall out. I don't think there is enough travel possible to have a lifter issue but I will take some measurements once the garage is warmed up.

[bszopi]

Just from memory, I'd have to say the retainers are 0.75"-1" deep, so you'd have to have in excess of around 0.65" of lift at the cam before it would probably become an issue.

[gectek]

well i know that for lift, you can go almost all the way up to the journal size for max lift, but i didnt know if that would make the lifter go way to high on the retainer.

you can use the 4.3 cam bearings right? they are the same size?

[ForcedFirebird]

You can't create enough lift to penetrate the retainers without going to a bigger bearing journal. Decreasing the base circle make the lift. .625" is the depth of the retainer pockets.

[gectek]

yah that would be way too massive on the lift...so gaining 600ish lift with a 1.6 rocker is going to be cake then.

but on the other question....you can use the 4.3L cam bearings on the 660s right they are just wider?

[ForcedFirebird]

Yes, 4.3 and SBC bearings are the same diameter (but they fill the bearing race in the block fully, not centered like the stockers). I have a SBC cam bearing tool I can use on the 660 as well

[gectek]

does that mean the full roller cam bearings could be used in the 660?

[ForcedFirebird]

does that mean the full roller cam bearings could be used in the 660?

Should work fine. In fact there's more, the 660 crank snout is the same as a SBC, so a modified timing belt could as well

[gectek]

wayyyyyyyyy too much money. i know i sell jesels and comp cams ones. TCE single roller FTW

plus it would still be a custom gear for the roller guys...at least for now with one ginormous bolt and all

[ForcedFirebird]

wayyyyyyyyy too much money. i know i sell jesels and comp cams ones. TCE single roller FTW

plus it would still be a custom gear for the roller guys...at least for now with one ginormous bolt and all

Funny you mention that, I thought about making custom cam blanks to use the Gen1 or 2 chain set with a Gen 3 roller grind on it, but no one seems interested

[Superdave]

Should work fine. In fact there's more, the 660 crank snout is the same as a SBC, so a modified timing belt could as well

I thought the cam had to be machined a bit for those bearings to fit.. that's why I didn't use them.

[gectek]

superdave you mean the 4.3l bearings or the full rollers?