HELP!!! just got a custom ground cam
11-05-2004, 11:55 PM
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HELP!!! just got a custom ground cam How do you know whether to install the cam straight up or whether to degree it? The specs are 236/240 .601/.608 on a 112 lsa with comp xer lobes. I have stock heads and will be running comp 921 valve springs. I was just going to install it straight up but a buddy of mine questioned whether it would clear the pistons or not. I thought it would since there are much bigger cams clearing. Any experienced cam help would be greatly apreciated!!!!! Also do I need to shim the springs for more seat pressure or with they be fine without shimming. Thanks for the help in advance!
11-06-2004, 02:15 AM
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You have to degree it and also check the piston to valve clearance. You can order a kit through summit. Get and adjustable roller timing chain. Most are designed to run straight up but retarding it 4 degrees will lower the power band in theory.
11-06-2004, 03:27 AM
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You should ALWAYS degree the cam to make sure it is installed properly.
As for running it advanced or retarded that will depend on the vehicle itself as there are no hard and fast rules. It's just another avenue for tuning.
Most cams are ground with advance in them. Usually 4 degrees. I suggest you get a look at the cam card,call comp or as a last resort have it cam doctored.
good luck.
As for running it advanced or retarded that will depend on the vehicle itself as there are no hard and fast rules. It's just another avenue for tuning.
Most cams are ground with advance in them. Usually 4 degrees. I suggest you get a look at the cam card,call comp or as a last resort have it cam doctored.
good luck.
11-06-2004, 05:27 AM
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Originally Posted by Bowtieman4life
You have to degree it and also check the piston to valve clearance. You can order a kit through summit. Get and adjustable roller timing chain. Most are designed to run straight up but retarding it 4 degrees will lower the power band in theory.
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11-06-2004, 09:35 AM
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I always shoot for a 109 ICL as long as p/v clearance allows ya to. I am doing a stoker 383 for a guy now that has a cam very simular and thats what I will put it in at.
11-06-2004, 09:47 AM
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Originally Posted by Cheatin' Chad
You should ALWAYS degree the cam to make sure it is installed properly.
As for running it advanced or retarded that will depend on the vehicle itself as there are no hard and fast rules. It's just another avenue for tuning.
Most cams are ground with advance in them. Usually 4 degrees. I suggest you get a look at the cam card,call comp or as a last resort have it cam doctored.
good luck.
As for running it advanced or retarded that will depend on the vehicle itself as there are no hard and fast rules. It's just another avenue for tuning.
Most cams are ground with advance in them. Usually 4 degrees. I suggest you get a look at the cam card,call comp or as a last resort have it cam doctored.
good luck.
INTAKE EXHAUST
Valve adjustment HYD HYD
Gros valve lift .601 .608
Duration @
.006 Tappet Lift 285 289
Valve timing Open Close
@.50 INT: 10 BTDC 46 ABDC
EXH: 56 BBDC 4 ATCD
These specs are for cam installed
@108.0 Intake Centerline
INTAKE EXHAUST
Duration @.050 236 240
Lobe Lift .3540 .3580
Lobe Separation 112.0
I take it from the cam specs it is saying that I install it straight up. I don't have a degree kit and I am fairly new to the cam world so if it as to be done then I can buy one but I was hoping to install it this weekend. Does anyone think that this cam won't clear my stock heads and pistons?
11-06-2004, 09:52 AM
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Yes, just put it in straight up. Comp cut that cam so that it would be at 108 put in that way. But its always nice to be able to double check it though when you do.
11-06-2004, 10:52 AM
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Bo White: Do you think this cam will clear stock heads with no problem? I know that it is not as big as the magic stick and it clears so I should have no problems right?
11-06-2004, 11:13 AM
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Originally Posted by Bo White
Should, but that is like tellin' ya Alabama is going to win today.
11-06-2004, 11:16 AM
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why would I have to degree it if the cam says that the specs are with the cam installed centerline? Can anybody tell me how to check PTV clearance?
11-06-2004, 02:25 PM
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Originally Posted by hc_performance
bump...
The intake is going to be your problem, not the exhaust. The TDC lift on the intake is going to be 0.0835", actually 0.142" after correcting for your 1.7 rockers. Assuming you have stock heads your valve drop will be close to 0.200". Doing the math that give you 0.058" of clearance at TDC. It's going to get even tighter than that between 15* BTDC and 15* ATDC. As a rule of thumb you shouldn't go below 0.100" of clearance at any point to be safe.
Either flycut, buy a different cam, or retard the cam with a degree kit.
Last edited by torchedZ; 11-06-2004 at 02:33 PM.
11-07-2004, 01:21 AM
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Originally Posted by torchedZ
That cam is advanced 4 degrees (112-108=+4) It's not going to fit comfortably without flycutting though.
The intake is going to be your problem, not the exhaust. The TDC lift on the intake is going to be 0.0835", actually 0.142" after correcting for your 1.7 rockers. Assuming you have stock heads your valve drop will be close to 0.200". Doing the math that give you 0.058" of clearance at TDC. It's going to get even tighter than that between 15* BTDC and 15* ATDC. As a rule of thumb you shouldn't go below 0.100" of clearance at any point to be safe.
Either flycut, buy a different cam, or retard the cam with a degree kit.
The intake is going to be your problem, not the exhaust. The TDC lift on the intake is going to be 0.0835", actually 0.142" after correcting for your 1.7 rockers. Assuming you have stock heads your valve drop will be close to 0.200". Doing the math that give you 0.058" of clearance at TDC. It's going to get even tighter than that between 15* BTDC and 15* ATDC. As a rule of thumb you shouldn't go below 0.100" of clearance at any point to be safe.
Either flycut, buy a different cam, or retard the cam with a degree kit.
