ready to check pushrod length and ptv...
03-15-2012, 05:42 PM
#1
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ready to check pushrod length and ptv... I have searched and researched this topic alot and i just want to be sure before i jump into this...
Im getting my heads back tomorrow. They are 241s,-.030, stock valves ground for clean up and im going to use stock mls hg's. Im also using ls7 lifters and with ls1 trays. My cam is the ed curtis ssht (228/232 dur .612/.600 lift 112+4 lsa)
Nep said i would have NO problems with ptv clearance using this setup but i want to make sure and check anyway for peace of mind. It seems easy enough to use the clay/playdough on top of the piston with a bit of oil so the valve doesnt stick and rotate the crank clockwise. My question with this is do i have to compress my new gasket and basicly waste it just to check this? I know the piston comes out of the block at tdc so thats why i was wondering. OR could i use my already compressed old hg? Forgive me if this is a completely stupid question but this is my first rodeo. Haha
As far as pushrods go nep also said 7.4. Again, not discrediting their knowledge. Im just looking for peace of mind. So i got the comp 6.8 to 7.8 adjustable checker to get my length. I will be using a caliper so i will need to add .17 or subtract due to the oil holes... I have it wrote down somewhere. Also figure in the lifter preload which seems up in the air on ls7 lifters and thats my pushrod length. Im wondering though how to make a solid lifter out of one of my old ones to get an accurate reading. And like asked above can i use my old compressed hg while measuring so i dont waste a new hg? Or would it be easier to get a couple checking springs and go that route? I feel like im overthinking this but with this being such an important part of the job i dont want to eff it up.
Any experience, advice or helpful hints will be appreciated!
Im getting my heads back tomorrow. They are 241s,-.030, stock valves ground for clean up and im going to use stock mls hg's. Im also using ls7 lifters and with ls1 trays. My cam is the ed curtis ssht (228/232 dur .612/.600 lift 112+4 lsa)
Nep said i would have NO problems with ptv clearance using this setup but i want to make sure and check anyway for peace of mind. It seems easy enough to use the clay/playdough on top of the piston with a bit of oil so the valve doesnt stick and rotate the crank clockwise. My question with this is do i have to compress my new gasket and basicly waste it just to check this? I know the piston comes out of the block at tdc so thats why i was wondering. OR could i use my already compressed old hg? Forgive me if this is a completely stupid question but this is my first rodeo. Haha
As far as pushrods go nep also said 7.4. Again, not discrediting their knowledge. Im just looking for peace of mind. So i got the comp 6.8 to 7.8 adjustable checker to get my length. I will be using a caliper so i will need to add .17 or subtract due to the oil holes... I have it wrote down somewhere. Also figure in the lifter preload which seems up in the air on ls7 lifters and thats my pushrod length. Im wondering though how to make a solid lifter out of one of my old ones to get an accurate reading. And like asked above can i use my old compressed hg while measuring so i dont waste a new hg? Or would it be easier to get a couple checking springs and go that route? I feel like im overthinking this but with this being such an important part of the job i dont want to eff it up.
Any experience, advice or helpful hints will be appreciated!
03-15-2012, 06:59 PM
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You can use your old head gasket and bolts, just torque the bolts down to 30lbs ft. I'm not sure what the rule is for cometic or graphite gaskets but for MLS it is ok. If you don't have one around you can always go without and just add the head gasket thickness to the measured pushrod size/ptv spec.
It is easier to use the checking springs. I took apart 2 brand new lifters and actually found a bolt and nut that fit pretty well in there. I'd put it together, and if there was still play in the lifter cup I'd take it all back apart and loosen the nut up a bit until the retaining clip was sorta hard to get back in.
Not sure what type of clay you are going to be using but I used play-doh and it was kind of a pain. I'll be re-checking everything once more with some clay I bought at a craft store that's a little harder and keeps it's shape better.
It is easier to use the checking springs. I took apart 2 brand new lifters and actually found a bolt and nut that fit pretty well in there. I'd put it together, and if there was still play in the lifter cup I'd take it all back apart and loosen the nut up a bit until the retaining clip was sorta hard to get back in.
Not sure what type of clay you are going to be using but I used play-doh and it was kind of a pain. I'll be re-checking everything once more with some clay I bought at a craft store that's a little harder and keeps it's shape better.
03-16-2012, 02:06 AM
#3
As far as pushrods go nep also said 7.4. Again, not discrediting their knowledge. Im just looking for peace of mind. So i got the comp 6.8 to 7.8 adjustable checker to get my length. I will be using a caliper so i will need to add .17 or subtract due to the oil holes... I have it wrote down somewhere.
When you buy pushrods make sure you find out if they are specified as gauge length ... I know Comp Cams pushrods are.
You're right ... and yes, it seems pre-load recommendations are all over the place. Seems most guys set the LS7 lifters around 0.080" to 0.100" of pre-load.
03-16-2012, 08:18 AM
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If you measure the pushrod flat-to-flat with a caliper you will have to subtract 0.017" from that measurement to get "gauge length" of the pushrod. The Comp Cams pushrod checker measures in gauge length.
When you buy pushrods make sure you find out if they are specified as gauge length ... I know Comp Cams pushrods are.
You're right ... and yes, it seems pre-load recommendations are all over the place. Seems most guys set the LS7 lifters around 0.080" to 0.100" of pre-load.
When you buy pushrods make sure you find out if they are specified as gauge length ... I know Comp Cams pushrods are.
You're right ... and yes, it seems pre-load recommendations are all over the place. Seems most guys set the LS7 lifters around 0.080" to 0.100" of pre-load.
03-16-2012, 08:21 AM
#5
See below.
My question with this is do i have to compress my new gasket and basicly waste it just to check this?
Use your old gasket for this, if the rubber on the new gasket sticks to the surface it will wreck the gasket when you remove. Note also that minimum PTV will be on the exhaust stroke. I found I got better PTV results using the dial indicator method.
And like asked above can i use my old compressed hg while measuring so i dont waste a new hg? Or would it be easier to get a couple checking springs and go that route? I feel like im overthinking this but with this being such an important part of the job i dont want to eff it up.
I would wait until the heads are on before measuring. You can do this with the new lifters. You should first check the rocker wipe pattern with a check spring and dial indicator so that any corrections in rocker height will be included in the pushrod measurement.
Use your old gasket for this, if the rubber on the new gasket sticks to the surface it will wreck the gasket when you remove. Note also that minimum PTV will be on the exhaust stroke. I found I got better PTV results using the dial indicator method.
And like asked above can i use my old compressed hg while measuring so i dont waste a new hg? Or would it be easier to get a couple checking springs and go that route? I feel like im overthinking this but with this being such an important part of the job i dont want to eff it up.
I would wait until the heads are on before measuring. You can do this with the new lifters. You should first check the rocker wipe pattern with a check spring and dial indicator so that any corrections in rocker height will be included in the pushrod measurement.
03-16-2012, 08:27 AM
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You can use your old head gasket and bolts, just torque the bolts down to 30lbs ft. I'm not sure what the rule is for cometic or graphite gaskets but for MLS it is ok. If you don't have one around you can always go without and just add the head gasket thickness to the measured pushrod size/ptv spec.
It is easier to use the checking springs. I took apart 2 brand new lifters and actually found a bolt and nut that fit pretty well in there. I'd put it together, and if there was still play in the lifter cup I'd take it all back apart and loosen the nut up a bit until the retaining clip was sorta hard to get back in.
Not sure what type of clay you are going to be using but I used play-doh and it was kind of a pain. I'll be re-checking everything once more with some clay I bought at a craft store that's a little harder and keeps it's shape better.
It is easier to use the checking springs. I took apart 2 brand new lifters and actually found a bolt and nut that fit pretty well in there. I'd put it together, and if there was still play in the lifter cup I'd take it all back apart and loosen the nut up a bit until the retaining clip was sorta hard to get back in.
Not sure what type of clay you are going to be using but I used play-doh and it was kind of a pain. I'll be re-checking everything once more with some clay I bought at a craft store that's a little harder and keeps it's shape better.
So i think ill be getting some checker springs. Just any checking spring will work? Im guessing i will need at least two. I found 8 of them by moroso for 12 bucks.
Im not sure what will work best. Im gonna try playdough since my 2 year old has a ton of it. Ive read to put a little oil on it to keep the mess down.
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03-16-2012, 01:15 PM
#8
When you use the checking springs, you simply set your adj pushrod to 0 lash on the base circle and go from there. If using clay (not sure about playdough) you will want to rotate through several cycles to make sure you get the full imprint on the clay. I agree with Vettenuts, dial indicator is best method.
On the gasket, good that you have used. However, I don't think the MLS compress more than a few thousandths.
I'll be doing this process today. Oh boy!
So with my cam 226/230 .598/.608 114+1 I got:
.095" Intake and .154" exh clearance.
The AFR heads have 2.02 intakes.
Ron
On the gasket, good that you have used. However, I don't think the MLS compress more than a few thousandths.
I'll be doing this process today. Oh boy!
So with my cam 226/230 .598/.608 114+1 I got:
.095" Intake and .154" exh clearance.
The AFR heads have 2.02 intakes.
Ron
Last edited by RonSSNova; 03-16-2012 at 03:33 PM.
03-16-2012, 05:25 PM
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Staging Lane
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I havent looked into the dial indicator method method as far as checking ptv goes. I got my heads back today so i will see if i can get a pushrod length tonight after work. I think im gonna try the solid lifter approach. The guy who did my heads installed the springs and couldnt believe how strong they were. (Prc .650 duals) i dont have a compressor i would feel safe using.
03-16-2012, 05:54 PM
#10
I bought a spring compressor just for this car. I kind of hate not having the correct tool. My pld C type just didn't have clearance to get over the valve cover rail.
I think clay works fine if you are clearly in the safe zone. But the dial indicator method is for sure more accurate.
I think clay works fine if you are clearly in the safe zone. But the dial indicator method is for sure more accurate.
03-16-2012, 08:10 PM
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Do yourself a favor and get the Comp or Crane tool, whichever you find suits your style. I bought the Comp tool for $100 from Speed Inc, and I would buy 3 more if I needed to. Definately a very safe tool to use vs the traditional ones, especially with the .650 PRC duals (I have them as well and worked like a champ removing them)
For the pushrods, it really doesn't matter if it exactly the correct length you need, as long as you can get the rocker down to 0 lash.
DO NOT TORQUE THE ROCKERS DOWN! Just tighten them until there is no up and down on the rockers on the base circle of the cam. You won't even need a ratchet, just the socket will get you this measurement. Trust me, I found out how to do this procedure the hard way when the checker spring let the valve touch the piston.
The last piece of advice I have is just to take your time and keep everything clean and organized. It took me 3 days to get the right measurement on the driver side, and about 15 minutes to do the passenger side all because I was rushing and being messy and using just whatever I had laying around and not researching this topic nearly enough as I should have.
For the pushrods, it really doesn't matter if it exactly the correct length you need, as long as you can get the rocker down to 0 lash.
DO NOT TORQUE THE ROCKERS DOWN! Just tighten them until there is no up and down on the rockers on the base circle of the cam. You won't even need a ratchet, just the socket will get you this measurement. Trust me, I found out how to do this procedure the hard way when the checker spring let the valve touch the piston.
The last piece of advice I have is just to take your time and keep everything clean and organized. It took me 3 days to get the right measurement on the driver side, and about 15 minutes to do the passenger side all because I was rushing and being messy and using just whatever I had laying around and not researching this topic nearly enough as I should have.
03-17-2012, 07:32 AM
#12
Before measuring for pushrod length you need to verify the rocker wipe pattern. Any corrections to the rocker height to center the pattern will change the pushrod length. First check rocker wipe and correct as necessary. Then check PTV then measure for pushrods (last step).
03-18-2012, 02:42 AM
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I understand checking the wipe pattern and all but I think regardless you need the right pushrods to equal the target preload regardless of the wipe pattern unless you have adjustable rockers. Too much preload and the valves stay open and not enough you most likely will have a noisy valvetrain. The only way you can change the wipe pattern is to have adjustable rockers and get whatever pushrods you need to achieve proper wipe.
Feel free to correct me if im wrong but im sure this is correct.
Feel free to correct me if im wrong but im sure this is correct.
03-18-2012, 08:12 AM
#15
I understand checking the wipe pattern and all but I think regardless you need the right pushrods to equal the target preload regardless of the wipe pattern unless you have adjustable rockers. Too much preload and the valves stay open and not enough you most likely will have a noisy valvetrain. The only way you can change the wipe pattern is to have adjustable rockers and get whatever pushrods you need to achieve proper wipe.
Feel free to correct me if im wrong but im sure this is correct.
Feel free to correct me if im wrong but im sure this is correct.
There are some stud mounted rockers available for the LS1 such as Crane though.
03-18-2012, 09:47 AM
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No, the pushrod length will change the wipe pattern on a stud mounted rocker but not with an LS1 rocker as it is a fixed fulcrum rocker. The only way to change the wipe pattern is with a change in rocker mounting height, i.e., you change the height of the pivot point. With a smaller base circle of an aftermarket cam, you move the starting point of the rocker wipe pattern. With more lift, the movement across the valve stem increases. Therefore the wipe should be checked to verify it is OK prior to continuing on with other valve train setup.
There are some stud mounted rockers available for the LS1 such as Crane though.
There are some stud mounted rockers available for the LS1 such as Crane though.
Thats exactly what I said.
03-18-2012, 08:49 PM
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Ok i put the adjustable in and torqued the rocker to 22lbs took 10 and around an eighth turns to take the up and down (clicking sound) out of the rocker. Measured the adjustable with a 12" caliper and got 7.3225. -.017 +.100 = 7.4055....