Alright fellas...I'm getting read to order the cam kit for the Bronco, but about broke out in a cold sweat worrying I'm going in over my head. I guess my main issue at this point is keeping the valves in place and seated. As I've watched others before, I seem to remember some sort of adapter to hook up an air compressor to the plug hole to maintain pressure on the valve while dealing with the springs, retainers, etc. But then I was also thinking wouldn't the valve seal hold it in place?



So if someone could give me a walk through or link when it comes to dealing with everything pertaining to the head, I'd appreciate it.

UTfball68 said:

Alright fellas...I'm getting read to order the cam kit for the Bronco, but about broke out in a cold sweat worrying I'm going in over my head. I guess my main issue at this point is keeping the valves in place and seated. As I've watched others before, I seem to remember some sort of adapter to hook up an air compressor to the plug hole to maintain pressure on the valve while dealing with the springs, retainers, etc. But then I was also thinking wouldn't the valve seal hold it in place?



So if someone could give me a walk through or link when it comes to dealing with everything pertaining to the head, I'd appreciate it.

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oh come on Ben!! im rebuilding an engine!!!!! chill!!

but on a serious note, trust me after you do it, you'll feel like you can do anything.

as far as the valves im fairly certain they should stay in the head. but if your in this deep, if i was you id pull the heads and replace the head gaskets also, just so you know you wont ever have to worry bout them again.

and when you do that that should make it super easy to replace the valve springs.


all you need to do to replace the cam is:

1. loosen the rocker arms, turn them to the side.
2. remove pushrods, keeping them in order.
3. remove lifters, keeping them in order.
4. get it down to bare timing chain.
5. remove timing chain and sprockets.
6. unbolt the cam retainer.
7. get a good arse grip on the cam and pull BUT BE CAREFUL!! dont want to damage the cam bearings.
8. reverse of the removal to install using lots of LUBE.... assembly lube come on guys!!

Head gaskets were replaced a few months ago. I'm not worried about swapping the cam, I'm worried about the springs with the heads still on. I'm not looking to drop a valve down a cylinder and trying to take every precaution possible. I'm going with a Comp Cams K Kit...so new springs, new lifters, new push rods. I'm comfortable with everything except for spring replacement.

Id do the compressor trick or just pull em if thats too much trouble theyll fall out if ya dont have air to it.

1985 Ford F-150 said:

Id do the compressor trick or just pull em if thats too much trouble theyll fall out if ya dont have air to it.

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Alright...any clue what the adapter is called or what it looks like? And that means I'd only be able to do one cylinder at a time.

To remove the springs simply have that specific cylinder at tdc, that way valves wont go the whole way down...

hollenjoe said:

To remove the springs simply have that specific cylinder at tdc, that way valves wont go the whole way down...

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But they will drop slightly then. So do I then need to worry about re-seating the valves? Or will they pull back in to place?

Yeah dont worry, just make sure you do it in a days work, rust is a bi"%&h, and that can ruin your seats..

Alright...and part 2 to that question, to know whether or not I'm at TDC at each cylinder I'll either have to have the oil pan off and keep checking under the rig, or have the old cam in so I can see rocker movement, correct?




Sorry for the dumb questions, but the Bronco has been down too long and I really don't feel like screwing something up and wasting $400.

i would do the valve springs first... that way you can see where TDC is....

this will probably end up being 1 day valve springs, the other day Cam...

Na, its not that tough of a job you can do both things in a day, its cool to have a pal over to help you rotate the engine or whatever else. If you're changing the cam that means you will have access to the timing chain, Tdc of number 1 cylinder is dot over dot, I also use a screwdriver in a spark hole and rotate slowly till you fill the piston coming up, anyways it doesn't have to be perfect, valves are long enough.

Thanks Joe...as always a huge help and broke it down to where even someone like me could understand and feel like I'm capable of handling the job. That being said, if you get a phone call with a guy sobbing asking what to do, you'll know who it is...hahahaha.

Seems like you're worrying too much - and going to too much bother on the valves. Pull the heads and be done with it. For the cost of new gaskets you won't need 6 hands keeping everything in place.

Also seems to be some confusion about valve seating if they move - you do realize a valve turns while the engine is operating don't you? Maybe not so much in a heavy spring engine, but they still move. That's why you lap them in in a circular motion : )

Thanks for the info Tim

No worries ben, Dont mean to go against Tim, but I wouldnt pull the heads...

you can also feed a length of rope into the spark plug hole to hold the valve up. just leave some sticking out so you can retrieve the rope

I have done that a few times.

hollenjoe said:

No worries ben, Dont mean to go against Tim, but I wouldnt pull the heads...

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Yeah, I was hoping to keep the heads on.

emeraldcoupe said:

you can also feed a length of rope into the spark plug hole to hold the valve up. just leave some sticking out so you can retrieve the rope

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Thanks for the suggestion.

surewhynot said:

I have done that a few times.

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You'll have to be more specific...You've done a lot of things once, mostly things that shouldn't be named. For all I know you're talking about the time you ran around the house naked screaming 'woo woo'. HAHAHAHA


Anyway, thanks for the help guys...gonna order the kit tomorrow. And I'll remember to be at TDC with each piston and use some rope as a precaution.

Before spending a nickel on 1975/79 351M/400 heads, have them MAGNAFLUXED first.

These heads were very prone to cracking...which usually occured after the vehicles were out of Warranty (2 years/24,000 miles back then).

The cost to the customers to replace both heads, gaskets and etc and the labor added up to $700.00, which was a lotta money back then.

Too bad you weren't closer Ben, I have all those specialty tools and experience changing valve seals with heads on.