7.250 pushrods wih PRC LS6 2.5,G5X3 cam and morel lifter?
06-14-2011, 02:08 PM
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7.250 pushrods wih PRC LS6 2.5,G5X3 cam and morel lifter? I ve just finished my head/lifter swap and the install of a new o-ring pick up tube...
Specs:
53 000miles LS6 stock block(untouched);
PRC LS6 2.5 heads with PRC .675 dual springs
LG G5X3 camshaft
Harlan sharp pedestal 1.7 rocker
Stock multi layer head gasket
Morel 4708 lifters
I know that the morel have a higher cup (around .025-.030 isshh) and i also do know that they require less preload(between .030 and .050).
I did all my measurement with my comp cam pushrods checker:
-While my ex valve began to open i knew that the intake was on the base circle.
-While my int valve began to close i knew that my ex lifter was on the base circle.
I did get the same result on each side:At 8 1/4 turn (7.2125) the rocker was really tight and at 8 turn it was slightly loose(but really just a little).
Pushrods checker 6.80 +.4125(8 1\4 tunr) = 7.2125
with some 7.250 pushrods i would get .0375 preload wich seems good to me...
Does it seems ok or i should not have such a short pushrods lenght with my setup???
Thanks
Specs:
53 000miles LS6 stock block(untouched);
PRC LS6 2.5 heads with PRC .675 dual springs
LG G5X3 camshaft
Harlan sharp pedestal 1.7 rocker
Stock multi layer head gasket
Morel 4708 lifters
I know that the morel have a higher cup (around .025-.030 isshh) and i also do know that they require less preload(between .030 and .050).
I did all my measurement with my comp cam pushrods checker:
-While my ex valve began to open i knew that the intake was on the base circle.
-While my int valve began to close i knew that my ex lifter was on the base circle.
I did get the same result on each side:At 8 1/4 turn (7.2125) the rocker was really tight and at 8 turn it was slightly loose(but really just a little).
Pushrods checker 6.80 +.4125(8 1\4 tunr) = 7.2125
with some 7.250 pushrods i would get .0375 preload wich seems good to me...
Does it seems ok or i should not have such a short pushrods lenght with my setup???
Thanks
Last edited by always faster; 06-14-2011 at 02:25 PM.
06-14-2011, 03:36 PM
#2
Where did you get .4125 per turn? Should be 0.050" per turn although your numbers seem to come out OK. Typo?
Your final length seems OK to me.
I have AFR heads, and if I didn't shim the rockers to ensure proper wipe, my pushrods would have been approximately the same length.
Did you ensure the rockers are correctly set up, you need to do this first then measure as any shimming of the rockers will change the required pushrod length.
Your final length seems OK to me.
I have AFR heads, and if I didn't shim the rockers to ensure proper wipe, my pushrods would have been approximately the same length.
Did you ensure the rockers are correctly set up, you need to do this first then measure as any shimming of the rockers will change the required pushrod length.
06-14-2011, 10:03 PM
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Where did you get .4125 per turn? Should be 0.050" per turn although your numbers seem to come out OK. Typo?
Your final length seems OK to me.
I have AFR heads, and if I didn't shim the rockers to ensure proper wipe, my pushrods would have been approximately the same length.
Did you ensure the rockers are correctly set up, you need to do this first then measure as any shimming of the rockers will change the required pushrod length.
Your final length seems OK to me.
I have AFR heads, and if I didn't shim the rockers to ensure proper wipe, my pushrods would have been approximately the same length.
Did you ensure the rockers are correctly set up, you need to do this first then measure as any shimming of the rockers will change the required pushrod length.
Yup i did everything like you explain to me on th corvette board
I ve used a black sharpie on the top on the int and ex valve.I then put some puhsrods in with the rocker and make the engine spin a couple of turn.My wipe pattern is ok.The comp cam checker come with only one mark on it.So you have to guess where is the 1/2 turn or 1/4 turn.My machinist friend precisely engrave/carve the 1/4-1/2-3/4 mark on the checker.This way its more precise.
1/4 turn = .0125
1/2 turn = .025
3/4 turn = .0375
1 turn = .050
I get 8 1/4 turn so:
8 turn = .400 + 1/4 turn = .0125 = .4125
Stock lentgh checker = 6.80 + .4125 = 7.215
Adding some 7.250 pushrods and i would get .0375 preload.
Thanks
Eric
06-15-2011, 04:21 AM
#4
Yes, sounds like everything is good.
Make sure you clean the new pushrods and blow out the hole real well. They do make a brush for cleaning the internal hole in the pushrod. I usually soak mine in oil to prefill the pushrod with oil and then when installing hold my finger over one end to keep them from draining. Use some assembly lube on the pushrod upper end where it goes into the rocker and on the valve stem where the rocker tip is in contact. This will keep things lubricated until the oil gets up there. I like the Redline Assembly Lube for this as it dissolves very quickly in the oil and there are no solids.
Make sure you clean the new pushrods and blow out the hole real well. They do make a brush for cleaning the internal hole in the pushrod. I usually soak mine in oil to prefill the pushrod with oil and then when installing hold my finger over one end to keep them from draining. Use some assembly lube on the pushrod upper end where it goes into the rocker and on the valve stem where the rocker tip is in contact. This will keep things lubricated until the oil gets up there. I like the Redline Assembly Lube for this as it dissolves very quickly in the oil and there are no solids.
06-17-2011, 08:34 PM
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Damn there must be something that i cant do correctly.
I start the car for the first time after that i ve correctly installed all my parts.Im now happy that i get 52 psi of oil pressure in less than 5 secs with the new o-ring(compare to 36 psi after 35 issh secondes with a worn o-ring
) No leak,no strange noise.All perfect except for the valvetrain.
The lifter are noisy...Did i put too much preload and they dont like that or not enough preload on them and they are too loose.I cant seems to find the good measurement.Sometime i would get 8 1/4 then 5 mins later i would get 8 turns or even 7 3/4
I start the car for the first time after that i ve correctly installed all my parts.Im now happy that i get 52 psi of oil pressure in less than 5 secs with the new o-ring(compare to 36 psi after 35 issh secondes with a worn o-ring
) No leak,no strange noise.All perfect except for the valvetrain.The lifter are noisy...Did i put too much preload and they dont like that or not enough preload on them and they are too loose.I cant seems to find the good measurement.Sometime i would get 8 1/4 then 5 mins later i would get 8 turns or even 7 3/4
06-18-2011, 07:35 AM
#6
Two questions.
Were the lifters empty when you measured? I found if very easy to depress the lifter plunger and get an inaccurate answer.
How long did you run the motor? The first start on my Morels took about five minute before they quieted down.
Were the lifters empty when you measured? I found if very easy to depress the lifter plunger and get an inaccurate answer.
How long did you run the motor? The first start on my Morels took about five minute before they quieted down.
06-18-2011, 02:56 PM
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The lifter where brand new .I had them soaked in oil for 2 weeks.I let the engine idle for 15 mins and did a small road test(5 miles).
Everything run well but i can clearly hear my lifter.I know that those are not normal valvetrain noise.My friend got a ms3 with 5.3 stage 2.5 heads and i doesnt hear any lifter noise.
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06-19-2011, 02:32 PM
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Well i went to work today.By work i mean that i retook all my measurement on each valve on all 8 cylinder.Not once ,not even twice but 3 times to be sure.
The result are:
Intake valve are all at 8 1/4 turn.
6.8 + .4125(8 1/4 turn) = 7.2125
So my 7.250 are good since it give .0375 preload
Exhaust valve are all at just a little over 8 1/2 turn
6.8 + .425(8 1/2 turn) = 7.225
This would mean that my 7.250 are too short(.025 preload) and that i would need some 7.275 too get .050 and a little less since im just a tad over 8 1/2 turn...
Does it sound right to have different length pushrods??? I thought that PRC would have installed the oversized valve at the exact same height...but i could be wrong.
Where do i find 7.275 pushrods quick?
Thanks
The result are:
Intake valve are all at 8 1/4 turn.
6.8 + .4125(8 1/4 turn) = 7.2125
So my 7.250 are good since it give .0375 preload
Exhaust valve are all at just a little over 8 1/2 turn
6.8 + .425(8 1/2 turn) = 7.225
This would mean that my 7.250 are too short(.025 preload) and that i would need some 7.275 too get .050 and a little less since im just a tad over 8 1/2 turn...
Does it sound right to have different length pushrods??? I thought that PRC would have installed the oversized valve at the exact same height...but i could be wrong.
Where do i find 7.275 pushrods quick?
Thanks
06-20-2011, 05:30 AM
#12
I got the same 8-1/4 turn measurements on mine last month, ordered a set of Trend 7.275" pushrods and the engine is happy.
Make certain that you soak new pushrods in mineral spirits, clean the centers with compressed air and/or pipe cleaners, and wipe down the exterior prior to installation.
The only anomaly I'm finding with these Lunati/Morel big buck lifters is that they do not seem to like thick engine oil. I use Mobil-1 10W-40 High Mileage for road course days, and the lifters ticked audibly during warmup. Went away after the engine and oil were warmed up so no big deal. No tick cold with 5W-30.
Make certain that you soak new pushrods in mineral spirits, clean the centers with compressed air and/or pipe cleaners, and wipe down the exterior prior to installation.
The only anomaly I'm finding with these Lunati/Morel big buck lifters is that they do not seem to like thick engine oil. I use Mobil-1 10W-40 High Mileage for road course days, and the lifters ticked audibly during warmup. Went away after the engine and oil were warmed up so no big deal. No tick cold with 5W-30.
06-20-2011, 07:23 AM
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I got the same 8-1/4 turn measurements on mine last month, ordered a set of Trend 7.275" pushrods and the engine is happy.
Make certain that you soak new pushrods in mineral spirits, clean the centers with compressed air and/or pipe cleaners, and wipe down the exterior prior to installation.
The only anomaly I'm finding with these Lunati/Morel big buck lifters is that they do not seem to like thick engine oil. I use Mobil-1 10W-40 High Mileage for road course days, and the lifters ticked audibly during warmup. Went away after the engine and oil were warmed up so no big deal. No tick cold with 5W-30.
Make certain that you soak new pushrods in mineral spirits, clean the centers with compressed air and/or pipe cleaners, and wipe down the exterior prior to installation.
The only anomaly I'm finding with these Lunati/Morel big buck lifters is that they do not seem to like thick engine oil. I use Mobil-1 10W-40 High Mileage for road course days, and the lifters ticked audibly during warmup. Went away after the engine and oil were warmed up so no big deal. No tick cold with 5W-30.
And i do get some kinda loud ticking for a couple seconde during the warm up too.
Last edited by always faster; 06-20-2011 at 02:52 PM.
06-20-2011, 05:14 PM
#14
I got just a hair over 3/4 turn on the rocker bolts from zero lash to 22 lb/ft w/ 7.275" pushrods which was right where at least one post I found wanted them:
I use .010"-.020" exhaust and .010"-.030" intake. John Callie (the developer of that lifter) doesn't like to use actual measurments he suggested I use the following rules of thumb:
Iron block and heads 1/2 turn on the adjuster
Iron block/aluminum heads 1/2-3/4 turn
Aluminum block and heads 3/4-1 turn
Iron block and heads 1/2 turn on the adjuster
Iron block/aluminum heads 1/2-3/4 turn
Aluminum block and heads 3/4-1 turn
Understand that w/ aluminum block and heads the preload lessens as the block/heads expand during heating. That 0.0625" preload is only happening when the engine is cold.
06-20-2011, 05:47 PM
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You could go with 7.250" pushrods if you're concerned about the extra preload.
I got just a hair over 3/4 turn on the rocker bolts from zero lash to 22 lb/ft w/ 7.275" pushrods which was right where at least one post I found wanted them:
My valves aren't being held open according to my LTFT data, nice and balanced across both banks and in the -8% to -2% range running stock Z06 VE table with zero misfires recorded on any cylinders from cold start all the way through cruising and WOT.
Understand that w/ aluminum block and heads the preload lessens as the block/heads expand during heating. That 0.0625" preload is only happening when the engine is cold.
I got just a hair over 3/4 turn on the rocker bolts from zero lash to 22 lb/ft w/ 7.275" pushrods which was right where at least one post I found wanted them:
My valves aren't being held open according to my LTFT data, nice and balanced across both banks and in the -8% to -2% range running stock Z06 VE table with zero misfires recorded on any cylinders from cold start all the way through cruising and WOT.
Understand that w/ aluminum block and heads the preload lessens as the block/heads expand during heating. That 0.0625" preload is only happening when the engine is cold.
) and ill install them on the exhaust side and i will have around .050" of preload.If everything goes well i ll leave it like that but if i ever felt that it could be better,i ll try the 7.275 on the intake side and see.
Thanks
