PTV Cam Clearance?

[azvren]

Ive been looking at this cam but idk if it will require flycutting.

here are the specs:
Comp LSR Cam (231/239 .617/.624) 113 LSA

any thoughts on the clearence, and is it too big for stock gears and daily driving?

[SC2150]

You will need to clearance the pistons IMHO...what trans do you have?

[Jason 98 TA]

It really depends a lot on how tight p/v your confortable with & how much advance is in the camshaft. It's definitely worth checking at that large of a duration.

[danhr]

SHOULD clear

but you should check

[J-Rod6410]

I have the cam 1 step bigger in my LS3. I bought it from LMR in Houston. They told me it had plenty of clearance, installed it myself and I do rev it to 7200 (on occasion). So you should be just fine. BTW the lobes are almost as big as the journals

Good luck with your build

[azvren]

Originally Posted by SC2150

You will need to clearance the pistons IMHO...what trans do you have?

I have a manual transmission.

sorry for being a newb but how would you check for clearence? Does it require putting the cam in first to check?

Thanks for the help everyone I greatly appreciate!!

[azvren]

Originally Posted by jrrod6410

I have the cam 1 step bigger in my LS3. I bought it from LMR in Houston. They told me it had plenty of clearance, installed it myself and I do rev it to 7200 (on occasion). So you should be just fine. BTW the lobes are almost as big as the journals

Good luck with your build

If yours cleared with a 1 step bigger cam then I'm definitely getting this cam now, thanks for the info!!

[danhr]

Originally Posted by jrrod6410

I have the cam 1 step bigger in my LS3. I bought it from LMR in Houston. They told me it had plenty of clearance, installed it myself and I do rev it to 7200 (on occasion). So you should be just fine. BTW the lobes are almost as big as the journals

Good luck with your build

what exactly is "one step bigger"?

[sspaul]

you can go with a wider LSA to help with ptv clearance.

[azvren]

Originally Posted by sspaul

you can go with a wider LSA to help with ptv clearance.

wider meaning a lower number like 110-112?

[gearhead440]

Take a look at the cam specs for all those tested in this link as food for thought since they all cleared. Notice that none of them had as much duration AND as much lift as the cam you specified.

http://www.gmhightechperformance.com...son/index.html

The TSP 231/236 has become quite popular and matches the specs you mentioned closely.

http://www.texas-speed.com/shop/item...=1057&catid=44

Following the lead in from SSPaul, a wider LSA will also help your idle characteristics as well.

[getarz4u15ster]

The lobe lift on the cam you have specified is within tolerance and you there will not be any problems in that regard, I have the the same lift specs on my cam /.617/.624. The Duration is a little on the high side .... That's the only thing i would be the least bit concerned with and I'm not even talking in terms of PTV clearance, that's not the issue. The real issue is with the duration. You are going to lose vacuum there fore causing lack of Intake Idle Air, the car is going to want to stall when coming off the throttle before you tune it (don't worry it's fixable). You are DEF going to have to get it tuned BTW, it's going to run like POO when you first put it in, it's sounds like a monster with the lope though! I also have a 113LSA as well... with a duration of 231/235. I notice the power band has moved up with the cam. It's now between 2800rpm and 7000rpm. It starts leveling off at around 6800. You shouldn't have any problems after it's tuned, just find someone who has the patience, because this one is a BIOTCH.. =O)

[azvren]

I never thought choosing a cam would be so difficult!
So would this cam be a safer bet then? :

Comp LSR Cam (227/235 .614/.621) 113 LSA

[J-Rod6410]

Originally Posted by danhr

what exactly is "one step bigger"?

235/251 621/624 113LSA. Grind # 285LRR HR13.

[J-Rod6410]

Originally Posted by azvren

I never thought choosing a cam would be so difficult!
So would this cam be a safer bet then? :

Comp LSR Cam (227/235 614/.621) 113 LSA

I believe this is the one that LMR recommended me for better drivability and it's easier to tune. Makes about 460/420 to the wheels.

Just verified the right one:227/243 614/624 113LSA. Grind #277LrR HR13. So just a tad bigger on the exhaust side. The one you mentioned would prabably idle a little better.

Hope this helps, jrrod.

[SK360]

It's worth the time to check... easy to do with the heads on with checker springs and a dial indicator.

[SC2150]

Originally Posted by azvren

I have a manual transmission.

sorry for being a newb but how would you check for clearence? Does it require putting the cam in first to check?

Thanks for the help everyone I greatly appreciate!!

To check for proper PTV clearance I use a checker spring on both the intake & exhaust and do this when measuring for the proper pushrod length. On an engine build, pushrod length & PTV can onlu be estimated until the heads & valve train are assembled.

I use a used head gasket of the same thickness as the one going to be used on the engine, and torque the one head to spec, install pushrod checker and rockers on 1 cylinder and with a low tension checker spring and a solid lifter (you can make one from an old hydraulic lifter by dissasembling and fitting a stiff spring inside to keep it in the same state as a pumped up hyd would when running) I measure the clearance with the valve at the maximum open. I also run it before & past max lift open just for saftey. I target .0080 but never go less than .0060.

During this stage you can also determine the proper pushrod length for proper preload & rocker arm geometry.

I don't like to "guess" or "assume" as I have to often had parts arrive where a salesman had not figured the heads milled and sent pushrods at a length his guide tells him & if assembled would have resulted in bent valves at the least on startup, and catastrophic failure more likely. I also don't trust the cam was ground properly for "dot-to-dot" assembly and degree every cam install. Can't tell you how many (no matter what company it was from) that the grind was off.

Thats why every major cam manufacturer on their site strongly reccomends all the steps I state above. Ussually your fine, but the potential damaage is far to great not to spend the extra time to verify it all.

[getarz4u15ster]

Originally Posted by jrrod6410

I believe this is the one that LMR recommended me for better drivability and it's easier to tune. Makes about 460/420 to the wheels.

Just verified the right one:227/243 614/624 113LSA. Grind #277LrR HR13. So just a tad bigger on the exhaust side. The one you mentioned would prabably idle a little better.

Hope this helps, jrrod.

I just got my cam card out i couldn't remember the specs.. This is the exact cam i put in.. 227 / 243 .614/.624 113. it definitely wakes the motor up.. and i've had no problems after it was tuned. This is a good cam if you ever plan on throwing boost in the motor. =o).

[danhr]

Originally Posted by jrrod6410

235/251 621/624 113LSA. Grind # 285LRR HR13.

12* more duration is "one step"?

[SK360]

Dan these guys need stages and steps to understand cams, go easy on em. lol

[J-Rod6410]

Originally Posted by danhr

12* more duration is "one step"?

If you take the time to go to the comp cam website, look up the LSR cams for rectangular port heads for LS engines, my cam is listed next to the one the OP mentioned and their listed small to large. So yeah. "one step bigger" is an easy way to help a newb out so they can understand a little better. Sure, you can come up with 100's of cams in between the 2 by going custom, but why add to the confusion

[danhr]

must be two steps in their selection guide. lol.

I am doing a stage 5 build on my camaro. lol

[J-Rod6410]

Let me know how it goes, I was thinking of a stage 6.5 myself for next year. I wanna make sure mines bigger than yours

[sspaul]

Originally Posted by azvren

wider meaning a lower number like 110-112?

no wider meaning higher number like 113-116

[Scourage]

Originally Posted by getarz4u15ster

I just got my cam card out i couldn't remember the specs.. This is the exact cam i put in.. 227 / 243 .614/.624 113. it definitely wakes the motor up.. and i've had no problems after it was tuned. This is a good cam if you ever plan on throwing boost in the motor. =o).

277LrR HR13

No issues with PTV clearance here either.