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Push rod measuring starting point?
Posted: October 21st, 2012, 9:58 pm
by Alexia
Example, for intake:
Stock push rod length is 9.640
0.020 is removed from the deck
Stock lift is 0.408
New lift is 0.440
9.640 - 0.020 - (0.440 - 0.408) = 9.588
A good starting point for measuring push rod length should be 9.588, correct? Of course, it could always go up or down from there.
I am getting Comp Cams push rod measuring tool soon. Supposedly they are easy to read measurements from, but would it be better advised to use a caliper to measure the push rod tool when finished?
Re: Push rod measuring starting point?
Posted: October 22nd, 2012, 4:21 am
by SilverXJ
9.620 would be a good starting point. Lift has nothing to do with the preload. The cam may have a smaller or larger base circle though. Usually, the more lift the smaller base circle, which would make for a longer pushrod. A 10 inch caliper would be pretty expensive.
Re: Push rod measuring starting point?
Posted: October 22nd, 2012, 8:53 am
by dwg86
If you only having .020 removed, your stock pushrods will probably still be OK. Don't factor in increased valve lift, that has nothing to do with preload. You can use a shim on your rocker arms. That is a less expensive alternative to longer pushrods.
Re: Push rod measuring starting point?
Posted: October 22nd, 2012, 10:00 pm
by Alexia
Alright, that makes a good bit more sense! I am fine with buying new rods if it comes to that.
However, I just bashed my head against a wall for a bit. I have the MOPAR P4529229AD camshaft, but entirely forgot about springs. I really do not have it in the time crunch so I am just going to save the MOPAR camshaft for the stroker build in my other Jeep and reuse the stock camshaft since it is in excellent condition.
Re: Push rod measuring starting point?
Posted: October 23rd, 2012, 9:20 pm
by Muad'Dib
Im guessing 229AD is the latest version of the 229AB\229AC?
Specs appear the same. and i KNOW for the 229AC, you use stock springs. Thats the cam i have in my stroker.
Re: Push rod measuring starting point?
Posted: October 24th, 2012, 4:38 am
by Alexia
Muad'Dib wrote:Im guessing 229AD is the latest version of the 229AB\229AC?
Specs appear the same. and i KNOW for the 229AC, you use stock springs. Thats the cam i have in my stroker.
I entirely meant P4529229AC!
I keep typing D for some reason. It says it has a 0.440"/0.440" lift, but I read around the forums here that the stock springs are only good up to 0.430" of lift and that the complimenting MOPAR springs are recommended. There seems to be some disagreement between all of that.
http://www.jeepstrokers.com/forum/viewt ... 726#p25719
http://www.jeepstrokers.com/forum/viewt ... 31&p=32269
Re: Push rod measuring starting point?
Posted: October 24th, 2012, 9:22 am
by Muad'Dib
Alexia wrote:Muad'Dib wrote:Im guessing 229AD is the latest version of the 229AB\229AC?
Specs appear the same. and i KNOW for the 229AC, you use stock springs. Thats the cam i have in my stroker.
I entirely meant P4529229AC!
I keep typing D for some reason. It says it has a 0.440"/0.440" lift, but I read around the forums here that the stock springs are only good up to 0.430" of lift and that the complimenting MOPAR springs are recommended. There seems to be some disagreement between all of that.
http://www.jeepstrokers.com/forum/viewt ... 726#p25719
http://www.jeepstrokers.com/forum/viewt ... 31&p=32269
Stock Springs are supposedly only good for .43 of lift, however if you look at the recommended springs for the 229AC they are stock springs.
I am using stock springs with my 229AC without issues (granted i did purchase new ones but i would doubt it would make a difference).
Re: Push rod measuring starting point?
Posted: October 24th, 2012, 11:17 am
by Alexia
Stock spring numbers are 53020556(1997, 1998) and 53010388(1999). P4529214 is from their performance line. As far as I know they part numbers are not interchangeable.
I am picking up some extra tools tonight for the head work so I will do some compression tests on the springs to see what happens.
Re: Push rod measuring starting point?
Posted: October 24th, 2012, 7:21 pm
by Alexia
Alexia wrote:Stock spring numbers are 53020556(1997, 1998) and 53010388(1999). P4529214 is from their performance line. As far as I know they part numbers are not interchangeable.
I am picking up some extra tools tonight for the head work so I will do some compression tests on the springs to see what happens.
I compressed the springs in a vice and measured 1.119" at coil bind. Stock valve closed height is 1.64".
Code: Select all
1.640 valve closed height
- 1.119 spring bind
- 0.060 safety margin
= 0.461 total valve lift
Looks like you are right and they will be fine!
Re: Push rod measuring starting point?
Posted: October 25th, 2012, 10:29 pm
by Muad'Dib
Alexia wrote:Stock spring numbers are 53020556(1997, 1998) and 53010388(1999). P4529214 is from their performance line. As far as I know they part numbers are not interchangeable.
I am picking up some extra tools tonight for the head work so I will do some compression tests on the springs to see what happens.
Look at the specs for the P4529214 they match OEM stock springs. They are just a cylindrical version of them P4529215 is the Conical "Production" spring. I did forget there was a difference.. but the ones i purchased for my 229AC were the Conical P4529215 (OEM Equivalent).
I guess it doesnt really matter.. you should save that Cam for a stroker anyway.. i was just merly mentioning that the 229AC works fine with OEM springs.
Re: Push rod measuring starting point?
Posted: October 26th, 2012, 1:20 pm
by Alexia
Muad'Dib wrote:I guess it doesnt really matter.. you should save that Cam for a stroker anyway.. i was just merly mentioning that the 229AC works fine with OEM springs.
See my last post! I was really skeptical about the stock springs being able to reused, but I did measure them to check it out. The camshaft is going into my 4.7L stroker. I received the machined block back yesterday so everything is ready to go back together.
Re: Push rod measuring starting point?
Posted: November 10th, 2012, 1:40 am
by Alexia
dwg86 wrote:If you only having .020 removed, your stock pushrods will probably still be OK. Don't factor in increased valve lift, that has nothing to do with preload. You can use a shim on your rocker arms. That is a less expensive alternative to longer pushrods.
I just measured 0.130" preload across several valves using a dial caliper. I started by tightening the rocker bolt until the push rod was just snug against the rocker arm. Then I tightened it down completely. Even if I was at the maximum specification of 0.060" with the stock engine I am wondering where the extra 0.040" of preload came from if only about 0.020" was removed from the deck.
Re: Push rod measuring starting point?
Posted: November 10th, 2012, 9:43 am
by Alexia
Alexia wrote:I just measured 0.130" preload across several valves using a dial caliper. I started by tightening the rocker bolt until the push rod was just snug against the rocker arm. Then I tightened it down completely. Even if I was at the maximum specification of 0.060" with the stock engine I am wondering where the extra 0.040" of preload came from if only about 0.020" was removed from the deck.
Maybe I am measuring this incorrectly, not sure. I did just take several measurements against my remanufactured cylinder head versus the stock cylinder head. 3.45" for stock and 3.43" for the remanufactured. I wonder how bad the thing was to start with that it needed 0.02" removed!
Re: Push rod measuring starting point?
Posted: November 10th, 2012, 4:10 pm
by SilverXJ
If you had a valve job done, that can effect the preload. If you are using a non stock cam that can effect the preload. If you are using different lifters that can effect the prelaod.
Where are you measuring with the dial calipers?
Re: Push rod measuring starting point?
Posted: November 10th, 2012, 4:28 pm
by Alexia
SilverXJ wrote:If you had a valve job done, that can effect the preload. If you are using a non stock cam that can effect the preload. If you are using different lifters that can effect the prelaod.
Where are you measuring with the dial calipers?
Maybe I meant dial gauge? I was up late last night! I put the magnetic base on the valve cover gasket surface and put the point of the dial gauge into the oil hole on the rocket arm.
Yeah, I am using the MOPAR P4529229AC camshaft. I was reading up on how the base circle can affect the preload. The cylinder is stock besides the 0.02" shaved.
I think could get away with Sealed Power ZRP3197 9.547" push rods for a 0.037" preload.