This is for all you experts on the ZZ502. I am wanting to do a cam change on this motor. I am looking at a Lunati solid roller. It has 722 lift and I need to know can I put that much lift and still have enough piston to lifter clearance?
ZZ502/502HP
bskaggshd
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This is for all you experts on the ZZ502. I am wanting to do a cam change on this motor. I am looking at a Lunati solid roller. It has 722 lift and I need to know can I put that much lift and still have enough piston to lifter clearance?
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Total lift has very little to do with p/v clearance except for the fact that higher lift cams are usually more aggresive.
Duration & lobe separation are much more important.
And as Todd said a cam that big is normally going to have some serious duration which will need more compression
As for will it clear, probably not,,
Duration & lobe separation are much more important.
And as Todd said a cam that big is normally going to have some serious duration which will need more compression
As for will it clear, probably not,,
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I had my heads flat milled .060, cut the spring pockets for larger springs and home ported/gasket matched it. The cam is a comp 260/268 .715/.715 l12 solid roller and it just plain woke up my car. I did the clay test with zero lash and had plenty of clearence. I have taken the motor to 6800 and it's still pulling hard. I figure the milling gave me around 11:1
I had a pretty decent hydraulic roller before this one and the solid roller cleary performs better, it idled better and had a little more vacuum!
Lee
I had a pretty decent hydraulic roller before this one and the solid roller cleary performs better, it idled better and had a little more vacuum!
Lee
This is the cam that Lunati recommended for my application. This is in a 1600# RED.
ROLLER, Super Gas or Super Comp with big engine or with light chassis. Power range 4400-8000, 316°/320° adv dur, 280°/284° duration @.050", .722"/.722" lift, .424"/.424" lobe lift, 110° Sep/108° Int C/L, timing events: 32°BTC 68°ABC / 74°BBC 30°ATC, 50225LUN, .028"/.030" lash, grind RRB 280-2
What would any of you recommend. Can be hyd or solid roller.
ROLLER, Super Gas or Super Comp with big engine or with light chassis. Power range 4400-8000, 316°/320° adv dur, 280°/284° duration @.050", .722"/.722" lift, .424"/.424" lobe lift, 110° Sep/108° Int C/L, timing events: 32°BTC 68°ABC / 74°BBC 30°ATC, 50225LUN, .028"/.030" lash, grind RRB 280-2
What would any of you recommend. Can be hyd or solid roller.
You need new pistons to run that cam. You need at least 13 to 1 compression to run that cam...no way a hydraulic roller will work as your rpm range is gonna be very high for a 502 ci motor.
BTW, when they state big engine, there not taking about a 468 or 502...there mainly talking about 540's, 555's, 565's, and bigger.
Why such a big cam?
It does say big engine or Light chassis. A RED is a light chassis. My goal is that I just want to step this motor up the best it can be , with out going into the bottom end. And that is what I told Lunati and they came back with the above. I currently run 5.60/5.70's in the 1/8. I would like to get into the low 5" as much as possible. I want to get the RPM range up from it's 5400 limit now. I would perfer to stay with a hdy, but don't have too. I have to change the springs to aid in getting up RPM Red line. New piston maybe in the furture, but for next season, just the cam , springs, and lifters if I need them.
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Did you happen to tell Lunati your compression?
As Todd stated that cam is designed for a compression engine.
I highly doubt it is going to clear your pistons but having never put something that big in a stock 502 I cannot say it won't.
My inclination is it will not clear with that much duration especially on a 110 seperation.
There is no way you are going to be spinning a hyd roller to 7000+ in a rat.
That is a solid & will need solid lifters.
If you go to solid lifters then the limits imposed by the stock retainer parts no longer apply as you will be using retrofit type lifters.
In my opinion you are not going to have enough p/v clearance with that duration.
Don't take this the wrong way but it would be nice if you stated your purpose in the first post so you didn't get 20 answers assuming you are just sticking a big cam in a street deal
It is very hard for anyone here to answer questions without a couple of clues as to the application.
As Todd stated that cam is designed for a compression engine.
I highly doubt it is going to clear your pistons but having never put something that big in a stock 502 I cannot say it won't.
My inclination is it will not clear with that much duration especially on a 110 seperation.
There is no way you are going to be spinning a hyd roller to 7000+ in a rat.
That is a solid & will need solid lifters.
If you go to solid lifters then the limits imposed by the stock retainer parts no longer apply as you will be using retrofit type lifters.
In my opinion you are not going to have enough p/v clearance with that duration.
Don't take this the wrong way but it would be nice if you stated your purpose in the first post so you didn't get 20 answers assuming you are just sticking a big cam in a street deal
It is very hard for anyone here to answer questions without a couple of clues as to the application.
Sorry Mike didn't mean to waste anyones time, I am just questioning what I need. I told lunati what motor is was going into. Guess I assumed they knew what the compressions was at 9.6:1 on a ZZ502. Sorry I didn't give all info in the first post. I am sort of new to this posting busness. So with my objectives being to step up hp and RPM(6500), I would like some suggestions on the best Solid roller that would keep me within my parameters with out any additional engine work, Only want to change cam, lifters, and springs. Do not want to do any head work if it can be helped do to a limited budget. I know that I get value float at about 6000 now, that is why I want to change springs. I was running a 4:56 gear, and I changed it to a 4:10 because the motor was running out of stream before the 1/8 mile stripe. MPH's at 122, but only 5.80's. Now it get into the 5.60's but still could use alittle more rpms.
Bill
Bill
First thing you should plan is to disassemble the ZZ502. Plate hone the cylinders and deck the block about .020. GM advertises the motor as 9.6/1, but every comp calc I have seen, brings it in at about 9.3/1. Also, GM doesnot plate hone the shortblock.
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Bill,
No apology is necessary.
If you don't ask questions you don't learn, it's just easier if you explain a little more.
Look at the cam Lee posted above or something simular. He said it cleared & I think would work fairly well to 7000 for your deal even if you didn't raise the compression.
It would be much better if you got the compression up to 11.0 or so as it is going to help power but in a light dragster where you are wanting the power at a higher rpm I think you would want to cam the thing for the rpm you are shooting for rather than worrying as much about cylinder pressures, DCR, ECR or whatever you care to call it.
Plus that cam will give you the option of raising the compression at a later date & it will be a win-win deal
No apology is necessary.
If you don't ask questions you don't learn, it's just easier if you explain a little more.
Look at the cam Lee posted above or something simular. He said it cleared & I think would work fairly well to 7000 for your deal even if you didn't raise the compression.
It would be much better if you got the compression up to 11.0 or so as it is going to help power but in a light dragster where you are wanting the power at a higher rpm I think you would want to cam the thing for the rpm you are shooting for rather than worrying as much about cylinder pressures, DCR, ECR or whatever you care to call it.
Plus that cam will give you the option of raising the compression at a later date & it will be a win-win deal
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To get the most out of the engine and a big cam like that, I think you need to step up to a single plane intake, since low end torque isnt such an issue, and a port job would be great, mainly on the exhaust side. They only flow about 213 cfm @.700 on the exhaust, and a decent 318 or so @.700 intake. This is on a 4.25 bore fixture though. And as everyone else said many times, the compression.
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Bill, I think you would be a lot happier with a slightly smaller solid roller cam and try to stay in the mid .600 lift range. You'll find a cam in the mid 250 @ .050 range will be more responsive with your gear and tire combo and should easily go 7000 RPM if necessary. It should also be be much faster than the ZZ-502 factory cam which is a mild street cam to start with and usually dies at about 5500 RPM in that size motor. The ZZ-502 responds to more cam well. The Comp. Cams # XR292R ground on slightly wider lobe centers should work nicely.
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274 Posts
SS454- Yes it is. I dont have good data since I didnt have a roll bar with the crower cam and I never ran it out on the top end, but at the 1/8 mark the new cam gave me an avg of .25 faster times and nearly 4MPH.
FWIW, I can tell that about 6200 RPM the motor changes pitch and it seems to really start pulling and I cant see how 280/284 would be a good match for the 502, it just seems way too big! I dont think I would go any bigger if I had to do it again...
Lee
FWIW, I can tell that about 6200 RPM the motor changes pitch and it seems to really start pulling and I cant see how 280/284 would be a good match for the 502, it just seems way too big! I dont think I would go any bigger if I had to do it again...
Lee
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274 Posts
Bill- The part number is 01-000-9, grind CBVI 4017B/4024B R 112.0
Lee
Lee
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