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  1. #1
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    Default Another 393 cam selection question

    Long story short, wiped a lobe and time for new cam/lifters etc but I'm not sure which way to go.
    393, steel crank, forgies, CHI 3v's 208, bowls tickled + manifold. Lil 750 quickfuel streeter, 11.5 comp, 5 speed, 4.11's in a XD. Current cam is crane solid roller 262/272 @.050 and .727 lift. On a quick mixture check it made 420rwhp at 7000rpm and was still going with a torque curve that sat flat all the way from 4k
    Now as i'm never going to be taking it to 8k, something a bit more sedate is in order, but i'm hooked on the power and pull. Solid has it's plus's but so does hydraulic. It will mainly be seeing weekend miles with a bit of fun. Surely there has to be something that will let allow it to top out around the 7k mark and not need me to rip the manifold off every oil change (ok exaggerating) whilst still allowing the occasional wayyyyy up to the mountains picnic and similar (or even dreaming more) grinning power !

    Very interested in people's ideas and experience on what works
    Last edited by torana74; 19-04-2018 at 10:45 PM.

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    Quote Originally Posted by torana74 View Post
    Long story short, wiped a lobe and time for new cam/lifters etc but I'm not sure which way to go.
    393, steel crank, forgies, CHI 3v's 208, bowls tickled + manifold. Lil 750 quickfuel streeter, 11.5 comp, 5 speed, 4.11's in a XD. Current cam is crane solid roller 262/272 @.050 and .727 lift. On a quick mixture check it made 420rwhp at 7000rpm and was still going with a torque curve that sat flat all the way from 4k
    Now as i'm never going to be taking it to 8k, something a bit more sedate is in order, but i'm hooked on the power and pull. Solid has it's plus's but so does hydraulic. It will mainly be seeing weekend miles with a bit of fun. Surely there has to be something that will let allow it to top out around the 7k mark and not need me to rip the manifold off every oil change (ok exaggerating) whilst still allowing the occasional wayyyyy up to the mountains picnic and similar (or even dreaming more) grinning power !

    Very interested in people's ideas and experience on what works
    Que the cam master. Pauly

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    Quote Originally Posted by 427 View Post
    Que the cam master. Pauly
    **** that shit, If you must, just put a smaller hydraulic roller in it and be done. Take 20 degrees off the intake, 15 off the exhaust so 242/257 109LSA. Less lift, down to .650 or so. It'll make power 6500 but you need to keep the exhaust duration higher to keep it revving up above peak power.

    The cam as a solid roller is too much, as you said it needs to go 8000+RPM on every gear change if you race it maybe more gear than 4.11, could be 4.56

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    Wiped a lobe on a roller cam?
    Too much idle time, low rpm cruising on a high spring pressure allowing the lifter wheel bearings to run dry and seize?

    Look for something with around 250 @.050 duration and the lsa/lift Paul suggested and choose your springs carefully.

    Better still, talk to your favourite cam suppliers for recommendations.

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    Quote Originally Posted by EH179 View Post
    Wiped a lobe on a roller cam?
    Too much idle time, low rpm cruising on a high spring pressure allowing the lifter wheel bearings to run dry and seize?

    Look for something with around 250 @.050 duration and the lsa/lift Paul suggested and choose your springs carefully.

    Better still, talk to your favourite cam suppliers for recommendations.
    Seen this on a mates 355 can lobe was pitted and it picked the material up on the roller wheel nothing wrong with the roller the joys of shit quality parts

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    Out of curiosity, what valve springs are on it now?

    They'll probably have to change .650" HR the spring pressure is a lot higher and it'll be too far from the correct spring height at open.

    If you are buying get a comp cams one on the -9 billet core, dont stuff around with the ductile iron -8 stuff...

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    thanks all. paulzig , if you must?
    Funny you mention those specs.. Camtech threw up a 248 255 on 109, 625 645. As for the springs on it, just took two of this arvo to get checked tomorrow. I'd dare say you will be correct. We bought this car as a bit of an unknown and now discovering. I have to say i like the solid, but just scared with how much cruising this car will end up doing.

    EH179, all of the above and add in excessive clearance.

    tuf72, looking at some of the other lifters in this thing, i have feeling the bouncing from the excess lash brings the pitting quite quickly with it on this one.

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    Quote Originally Posted by torana74 View Post
    thanks all. paulzig , if you must?
    Funny you mention those specs.. Camtech threw up a 248 255 on 109, 625 645. As for the springs on it, just took two of this arvo to get checked tomorrow. I'd dare say you will be correct. We bought this car as a bit of an unknown and now discovering. I have to say i like the solid, but just scared with how much cruising this car will end up doing.

    EH179, all of the above and add in excessive clearance.

    tuf72, looking at some of the other lifters in this thing, i have feeling the bouncing from the excess lash brings the pitting quite quickly with it on this one.
    The cam tech one is close to my guess... Its not the excess lash that makes the valve bounce, all that does is hammer the valve tips. I'd say its been idled around a lot, and then had the crap revved out of it,valve bouncing it... For 6500RPM peak you'll need something like a PAC dual 160psi seat 400psi Open spring.

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    Quote Originally Posted by paulzig View Post
    The cam tech one is close to my guess... Its not the excess lash that makes the valve bounce, all that does is hammer the valve tips. I'd say its been idled around a lot, and then had the crap revved out of it,valve bouncing it... For 6500RPM peak you'll need something like a PAC dual 160psi seat 400psi Open spring.
    paul you don't think the lash set at 025 cold would have hammered the rollers? And definitely this thing would've sat in traffic very often.
    I might be dreaming but i'd like it hit the upper 6 mark (TKO 600CR and too many gear changes) which is why i'm iffy about the hydraulic but i'm sure i've seen some setups with a 7200 gear change recommendation. Not sure if lifters have had some major improvements in recent times

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    Quote Originally Posted by torana74 View Post
    paul you don't think the lash set at 025 cold would have hammered the rollers? And definitely this thing would've sat in traffic very often.
    I might be dreaming but i'd like it hit the upper 6 mark (TKO 600CR and too many gear changes) which is why i'm iffy about the hydraulic but i'm sure i've seen some setups with a 7200 gear change recommendation. Not sure if lifters have had some major improvements in recent times
    There is no reason you can't reduce the lash down to say .020"... and this prevents a few other problems.

    I would think 6500 on a 393 on the street is plenty, don't you?

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    Quote Originally Posted by torana74 View Post
    paul you don't think the lash set at 025 cold would have hammered the rollers? And definitely this thing would've sat in traffic very often.
    I might be dreaming but i'd like it hit the upper 6 mark (TKO 600CR and too many gear changes) which is why i'm iffy about the hydraulic but i'm sure i've seen some setups with a 7200 gear change recommendation. Not sure if lifters have had some major improvements in recent times
    Well, it'll be around .028-.029" if you set it .024" cold you should go to .016 if you want .020 of course you check it after its got some heat in it.

    If someone set it like that on purpose its to increase seat time and cylinder pressure. If the cam isnt designed for that sort of lash it will hurt it if you piddle around in traffic like that.
    I have morel hydraulic roller lifters,PAC dual springs (**** beehive springs) and a billet cam engine goes up to exactly 7200 where the limiter is. Quality lifters,valve springs and a billet cam core eliminates potential problems. Inadequate springs, both in quality and pressure/rate is why people badmouth the HR cams, they put on a 125/300 cheap spring set on there and say hydraulic roller doesnt go past 6500.

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    Quote Originally Posted by EH179 View Post
    There is no reason you can't reduce the lash down to say .020"... and this prevents a few other problems.

    I would think 6500 on a 393 on the street is plenty, don't you?
    That's my opinion too. Lash should be around .018 to.020 hot in my opinion,,, most likely nearer 30 now. That little bit more rpm suits 2nd 3rd gearing too well. If i can keep it there it would be nice.

    Quote Originally Posted by paulzig View Post
    Well, it'll be around .028-.029" if you set it .024" cold you should go to .016 if you want .020 of course you check it after its got some heat in it.

    If someone set it like that on purpose its to increase seat time and cylinder pressure. If the cam isnt designed for that sort of lash it will hurt it if you piddle around in traffic like that.
    I have morel hydraulic roller lifters,PAC dual springs (**** beehive springs) and a billet cam engine goes up to exactly 7200 where the limiter is. Quality lifters,valve springs and a billet cam core eliminates potential problems. Inadequate springs, both in quality and pressure/rate is why people badmouth the HR cams, they put on a 125/300 cheap spring set on there and say hydraulic roller doesnt go past 6500.
    Totally agree Paul and that's what i'm blaming on it getting hurt.... and my laziness on not checking as soon as i got it. But it looks like this wasn't the first time it's happened to this motor judging by the two sets of engravings on the cam. Somehow i don't think it is the cam i was told it was.
    Before you mentioned a -9 billet... would that necisitate bronze dizzy gear as current looks steel coated to me. Morels were always my plan...bushed? And i learned long time ago about cheap barely adequate valve springs
    Rang CHI yesterday and that popped up a crower cam/lifter with 540-630 hp results in similiar combos (left the numbers at work. Lift around 590) but i was amazed at the smaller size and a 5900rpm ceiling and low 6's max rpm! I'd be happy with around there on power, just being fussy on hearing it sing some more. I'm getting old and need the rest between changing gears

    EDIT; after finding the cam specs i had written down, the smaller 590 CHI numbers are infact for a smaller combo. Conversation was about variation on their stage 3 package and the actual cam specs quoted looks to be what they call the stage 2 with 185 heads. Breathing a sigh of relief double checking on here now before handing the credit card over
    Last edited by torana74; 29-04-2018 at 12:50 AM. Reason: added info

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    Quote Originally Posted by torana74 View Post
    Before you mentioned a -9 billet... would that necisitate bronze dizzy gear as current looks steel coated to me.
    Bronze or steel unless they have the pressed on gear, melonite or whatever its called.

    Dont let anyone talk you out of the billet core though, there is a reason GM went to a billet on the LS platform. Stopping warranty claims on camshaft wear, they would have saved millions going to cast core but they didnt.

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    paul, billet it will be. Also looking at the morel high rpm lifters. But the 5w/30 max oil recommendation on a clevo is a concern. But a bigger concern that i just thought of,,,what if this block has oil restrictors fitted coz it had the soild roller? Is that going to be a problem going to hydraulic or am I just overthinking ?
    Last edited by torana74; 01-05-2018 at 07:13 PM.

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    No you wouldnt want to restrict it for hydraulic roller, its the drainback that is the real issue anyway. Why would you worry about 5w/30 oil?

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