Camshafts change ?

samsonhusky · Dec 3, 2019

im planning on putting comp cams stage 1 cam in pi motor. Hoping to use the stock pi valve springs. I have the Anderson tool that is supposed to help hold the cam gear in place so you don’t need to remove the timing cover.

In the directions I see they say I need to bleed the lashers after I place new cams in. Is this a must with a cam change ?

Silver95bird · Dec 3, 2019

i put mine in a pan, on top of the kerosene heater for a while. then (carefully!!!) take them one at a time and wrap them in a rag and compress them in a vise.

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96blak54 · Dec 4, 2019

No bleeding is not absolutely necessary, but why pass the opportunity? Years of oil gunk gets trapped in them. They easily are removed and replaced. Just keep them clean.

Burninriverdiver · Dec 12, 2019

Good advice about heating them up!

I agree with these guys, it isn't difficult to do and it's much easier to re-install the cam followers if the lash adjusters are bled down and soft.

samsonhusky · Dec 13, 2019

thanks for the input guys. ive decided to just leave the stock pi cams in. i was going back in forth weather to change them out. not changing the springs would worry me down the road and i dont want to spend the extra for springs. plus i may try supercharging later on.

Patientzero · Dec 13, 2019

Hydraulic lifters bleed down when the engine is not running and oil pressure pumps them back up. They get "bled" everytime you start the car.

Silver95bird · Dec 13, 2019

i bet blak will get a laugh reading that. try bleeding one cold and tell me they bleed down naturally!

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Patientzero · Dec 13, 2019

https://www.enginebuildermag.com/2012/01/hydraulic-camshafts-and-lifters-101/

They obviously don't completely bleed out but where do you think that lifter tick comes from on a cold start? That's extra valve lash until oil pressure comes up and pumps the lifters back up.

When you shut the engine down some valve will be open, some will be closed. The lifters that are sitting on an open valve are going to bleed down.

Silver95bird · Dec 13, 2019

very true, but thats not the same thing as " they bleed down while not running".

any valve that was compressed while running and the engine stops is not the same thing as bled down sitting still with the engine off. they dont.

come back to a 4.6 a year after it was shut off and ill bet over half of the lash adjusters are still full of oil.

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96blak54 · Dec 14, 2019

Patientzero said:
https://www.enginebuildermag.com/2012/01/hydraulic-camshafts-and-lifters-101/

They obviously don't completely bleed out but where do you think that lifter tick comes from on a cold start? That's extra valve lash until oil pressure comes up and pumps the lifters back up.

When you shut the engine down some valve will be open, some will be closed. The lifters that are sitting on an open valve are going to bleed down.

Thats great research patientzero! Yes the lashers are supposed to bleed down when oil psi isnt present and the oil change intervals were on spot at 3k miles with top shelf synthetic ford motor oil at its 150k miles now. Problem is old oil gets trapped in them. Changes how they bleed.

Patientzero · Dec 16, 2019

96blak54 said:
Thats great research patientzero! Yes the lashers are supposed to bleed down when oil psi isnt present and the oil change intervals were on spot at 3k miles with top shelf synthetic ford motor oil at its 150k miles now. Problem is old oil gets trapped in them. Changes how they bleed.

OP never mentioned anything about cleaning the lifters, only a "need" to bleed them which is untrue. I simply posted the link for other people to educate themselves on how hydraulic lifters work. I did my "research" as you put it when I got my degree in cylinder head and block machining and spent 3 years building engines for a shop building 1/4 million dollar cars.