351C help with valve adjustment

J

johnrem46

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Sep 20, 2004

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Jun 10, 2019

#1

• Jun 10, 2019

• #1

Just purchased a 71 mach 1 with a 351 Clevland engine. When the engine heats up I get a valve tap that is pretty loud. Looked on the internet about adjusting the Lifters and they talk about 0 lash and ECT. I pulled the covers and there is no adjustment! the nuts are as tight as they will go on all lifters. Some of the push rode can spin while others are tight. does anyone know anything about this engine??? A friend told me there is no adjustment on the clevland lifters yet all over the internet they say they can be adjusted.

 

2Blue2

will be trying this sex one when I can find it

Mod Dude

Mar 5, 2019

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Jun 10, 2019

#2

• Jun 10, 2019

• #2

On a Cleveland with a Bolt-fulcrum rockers, there is no valvelash adjustment. Bolt Fulcrum Rockers bolt down tight to head.
However, bolt-fulcrum rocker arms sometimes require pushrods of varying lengths to get into proper adjustment.
But first look for wear on the rocker and fulcrum pivot points and lifters that have collapsed or bleed down to quick. If lifters are ok and valve tip / rocker ends are ok then they sell pushrods of various lengths to set the adjustment. Many people will switch to roller rockers to get away from this bolt down set up.

good luck

 

J

johnrem46

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Sep 20, 2004

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Jun 10, 2019

#3

• Jun 10, 2019

• #3

Thank you for the information. Now that I know this how do I find out what size the push rod need to be??? What is a better fix new push rods or roller rockers?

 

2Blue2

will be trying this sex one when I can find it

Mod Dude

Mar 5, 2019

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Jun 10, 2019

#4

• Jun 10, 2019

• #4

Adjustable push rod checker to test for sizes. Once again if stuff is excessivly worn its a waste of time.
roller rocker have less friction and make more horse power but cost LOTS more than a couple of .060 over push rods (typical).
Your sure lifters are ok?

To do it right You'll need a conversion kit (Crane), guide plates, new pushrods, and probable head machining to make work correctly, yes taking head off and to the machine shop. This is the old school recipe, might be other ways today.
Not gonna work on the cheap.

 

J

johnrem46

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Sep 20, 2004

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Jun 10, 2019

#5

• Jun 10, 2019

• #5

Should have said something sooner the lifters and cam are new. Hydraulic flat tappet . Not to concern about the cost. just looking to do what is necessary. if I go for roller rockers why do you think I would need to have the heads machined?

 

J

johnrem46

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Sep 20, 2004

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Jun 10, 2019

#6

• Jun 10, 2019

• #6

would it be smart to use adjustable push rods??

 

2Blue2

will be trying this sex one when I can find it

Mod Dude

Mar 5, 2019

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Jun 10, 2019

#7

• Jun 10, 2019

• #7

John~Not providing all reverent info voids all guesses

johnrem46 said:

the lifters and cam are new. Hydraulic flat tappet .

Click to expand...

Sounding more like oil pressure than short push rods

The lifters, just because there new don't mean there right for you application.
might not be push rods at all then, maybe lifters bleed down too quick or not enough oil to em. 351C Lifters or pushrods should have the small .040 oil hole for oil restriction.
Real Oil Restrictors are for solid cams only.

johnrem46 said:

When the engine heats up I get a valve tap that is pretty loud.

Click to expand...

No noise when cold?
Whats the oil pressure like hot?, cold?
What weight oil in her? Might be as simple as switching to 20w50
Did ya put a high volume oil pump in it too?
Any checking of the pump and high-pressure relief spring ( one in pump)?
In 6 mis of warm up maybe all oil has been pushed to top of motor causing your noise and starving your mains, rods, and lifters!

What else are you not telling!?!

johnrem46 said:

would it be smart to use adjustable push rods??

Click to expand...

I know nothing about adjustable push rods except they use em on harleys sometimes.

 

J

johnrem46

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Sep 20, 2004

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Jun 11, 2019

#8

• Jun 11, 2019

• #8

I know little to nothing about the valve and lifters. From the paper work I have form the previous owner a comp cam and lifter kit CL32-219-3 was installed along with a2121 timing chain and gear. I am guessing the cam and lifters are a match set and correct. There is 10w 40w hot rod and classic oil in the car now. the oil pressure is good both hot and cold. when I had the cover off I can spin some of the push rod and not others.. I do not know and doubt that there is a high pressure oil pump. All the work was done by C&C Specialties in Fox boro mass. the car is now in New Jersey. all the work was done about a year ago. I am going to change the oil and filter and will use 15 w 50 w hot rod oil. I also like the idea of changing to roller rockers.

 

Ray65-71-73

New Member

Dec 11, 2001

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Apple Valley, CA

Jun 15, 2019

#9

• Jun 15, 2019

• #9

Scorpion Racing Products has adjustable, pedestal (bolt down) rockers for 351C.

With any roller tip rocker the roller must roll in the center of the valve tip.

There are shims for pedestal rockers that allows starting with a set of push rods that are all the same length and a little too long and then raising them with shims to adjust.