Rckybobby26
Newbie
Need too know asap
What length push rods will I need if I have a 525 lift cam and 1.6 rocker arms
- Thread starter Rckybobby26
- Start date
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This is not something anyone can answer for you, which is why you never got a reply.
Correct answer: Measure yourself with adjustable push rods. There are tons of articles online on 'how to measure push rods'
Correct answer: Measure yourself with adjustable push rods. There are tons of articles online on 'how to measure push rods'
MrPink
Bainisteoir Páirteanna
^this 100%
Hipster
I'm Awesome
It's best not to guess on pushrod length. Roller rockers are less forgiving then stamped ones on set up and several things such as head gasket thickness and how much a block or head has been milled can affect the required length and change rocker geometry. Add small base circle cams into the mix etc. It has to be done on the actual engine being built so the cam manufactures won't be any help unless they're building a set of pushrods based on the end users measurements.
There are AT LEAST three different ways to measure a pushrod.
Make sure YOU are using the same method your PUSHROD SUPPLIER uses.
Make sure YOU are using the same method your PUSHROD SUPPLIER uses.
Frank Enstein
Best. Day. EVER!
If it's a hydraulic roller cam
https://www.summitracing.com/parts/tfs-9501 6.8" to 7.8"
If its anything else the 9501 AND the TFS-9502
https://www.summitracing.com/parts/tfs-9502 7.8" to 8.8"
The shorter length is the minimum length for the tool. Each revolution is .050".
Comp Cams, Trick Flow, and Summit pushrod lengths match these tools.
Either way I recommend checking springs
https://www.summitracing.com/parts/cca-4758-2
They don't come with instructions so;
Install the checking springs into the head for whatever cylinder you are using to test.
Paint the tip of the valve with either machinist's layout dye (Dykem) or a red, green, blue, or purple permanent magic marker.
Believe it or not black marker is harder to see.
Put the cam on the base circle (the lifter as far down in the block as it will go).
Take your best guess of pushrod length and put it in.
Install the rocker arm and remove all the lash by rattling the pushrod up and down (not spinning).
Rotate the crankshaft 4 complete turns.
Remove the rocker arm and note where the wear stripe is on the valve tip (the rocker will remove the dye/marker).
If the wear stripe is in the center of the valve tip count the rotations needed to get the test pushrod back to it's shortest length, put your tools away, and go order your pushrods.
If it's not in the center, re-paint the tip of the valve, change the test pushrod length and try again.
Sometimes this takes three tries, sometimes it takes three DAYS.
Get it wrong and the valve guides won't last long and worst case they can drop a valve into the engine.
This is why nobody can tell you the pushrod length you need.
I wish these tools weren't need and that there was a magic chart.
Happy measuring!
https://www.summitracing.com/parts/tfs-9501 6.8" to 7.8"
If its anything else the 9501 AND the TFS-9502
https://www.summitracing.com/parts/tfs-9502 7.8" to 8.8"
The shorter length is the minimum length for the tool. Each revolution is .050".
Comp Cams, Trick Flow, and Summit pushrod lengths match these tools.
Either way I recommend checking springs
https://www.summitracing.com/parts/cca-4758-2
They don't come with instructions so;
Install the checking springs into the head for whatever cylinder you are using to test.
Paint the tip of the valve with either machinist's layout dye (Dykem) or a red, green, blue, or purple permanent magic marker.
Believe it or not black marker is harder to see.
Put the cam on the base circle (the lifter as far down in the block as it will go).
Take your best guess of pushrod length and put it in.
Install the rocker arm and remove all the lash by rattling the pushrod up and down (not spinning).
Rotate the crankshaft 4 complete turns.
Remove the rocker arm and note where the wear stripe is on the valve tip (the rocker will remove the dye/marker).
If the wear stripe is in the center of the valve tip count the rotations needed to get the test pushrod back to it's shortest length, put your tools away, and go order your pushrods.
If it's not in the center, re-paint the tip of the valve, change the test pushrod length and try again.
Sometimes this takes three tries, sometimes it takes three DAYS.
Get it wrong and the valve guides won't last long and worst case they can drop a valve into the engine.
This is why nobody can tell you the pushrod length you need.
I wish these tools weren't need and that there was a magic chart.
Happy measuring!
^^^ The only thing I'd change is that I don't care if the witness mark is in the CENTER of the valve tip...I care about how wide the witness mark is, as long as it's "somewhat" centered on the valve tip.
The more-narrow the witness mark, the better, as long as it's not close to running off the edge of the valve tip. Anywhere in the "middle third" of the tip is fine by me.
The more-narrow the witness mark, the better, as long as it's not close to running off the edge of the valve tip. Anywhere in the "middle third" of the tip is fine by me.
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