Featured Technical Rebuilt 302 has no get up! Help.

Stock HO cams-

'85-'88 E5ZE-6250-AA
'89-'95 E8ZE-6250-CA or F1ZE-6250-AA

You'll need lifters, spider and dogbones for these, and shorter pushrods.

 

I agree, something is fundamentally wrong, bad spark or off time, low compression or not enough fuel. Check all the basics cranking compression. Check the ignition, valve and piston position of each cylinder, if you or a friend has a wide band o2 sensor you could see what your AFR is at various rpm’s and loads, you could also swap carbs if you have another one.
Dan

 

Ok, found the problem!!!!
#1 cylinder- 0 PSI
#6 - 95 PSI
2,3,4,5,7,8 - 150 + PSI

 

Ya. I’d say you found a problem

 

Stuck or bent valve? Broken valve spring?

 

I’m pulling the valve covers now to look at # 1 springs and valves.

 

So it doesn’t appear to be a bent valve or broken spring on #1. But, #4,6 ,7 Tappets are totally collapsed…

 

If you take the rockers off, leave a PR on the lifter, does it rise and fall? Or just kinda sit there.
And I’d look at #1 first with zero compression.

 

PR?

 

My money is on the valves going "Kissy Kissy" with the pistons.

The problem is quite common on long duration cams on 5.0 engines. But the larger diameter valves will also come into contact with the edges off the valve pockets in the pistons.

An easy[ish] repair for a DIYer , but the heads need to come off.
Lay the heads upside -down and level on the bench ,then fill the chambers with gasoline [gasoline always finds the leak]

Dont throw the old head gaskets yet [you'll need to install them on and of again 16x]
You need some soft substitute valve springs
Rotate the engine through it's range of motion each side of TDC [with the valves "rocking"] and use a dial test to check valve clearance, by pressing on the valves and compressing the springs. Test this approx 30° each side of TDC

The valve pockets are easy to cut with the correct tool and a cordless drill [I've made my own tool by welding cutting tips to an old intake AND an old exhaust valve.
edit: the pockets need 0.050" clearance around the valve, so 2" intakes need a 2.1" diameter cutter
https://www.lindytools.com/ihpc [for the cutting tools]

You set some collars on the valve stems to limit the cutting depth cut the first piston [several cuts may be required and checked]
You then "lift" the valve and measure under the collar with a feeler gauge.
Then all the other pistons can be replicated in reasonable time

A lot of masking tape is needed to protect the engine from debris.

 

Bingo!

 

I checked piston to valve clearance with play doh when I assembled the motor. But, I’ll know as soon as I pull the head! Either way, the motor is coming out! And I will be changing the cam with a full roller!

 

If you didn't use a solid (non hydraulic) lifter when you checked clearance, the hydraulic lifter will be full of air and only open the valve partially, making you think it's all fine. Start engine, lifters fill up and valve meets piston.

 

Is the ford “B303” cam equivalent to the “HO” cam? The B cam is $607 as a kit, minus the pushrods.

- I took apart the tappet and made it solid when checking for clearance.

 

Don't go shopping until you have located/sorted / repaired the problem.

Your original cam had 0.512" lift and 228° @0.050" duration and 112° lobe separation.
The B303 cam has 0.480" lift and 224° @0.050" duration and 112° lobe separation. which is slightly better.

Duration and lobe separation is the problem [not lift]

This would be a better cam for dragging a heavy ol' barge around
https://www.compcams.com/magnum-215-215-hydraulic-roller-cam-for-ford-221-302.html
It has Higher lift, less Duration and Tighter lobe separation [0.533" lift and 215° @0.050" duration and 110° lobe separation.]

While your heads are off ....... Check the valve spring stiffness over the nose and at installed height.
They were generic springs that came with the heads already installed.

 

Winner winner Chicken dinner!, wow, glad you found the problem hopefully no pistons are damaged. Did it make a lot of noise when you fired it up the first time ?
Dan

 

PR = push rod, also check to make sure all your push rods are straight.
Dan

 

The B cam isn't same as stock HO. Kerry has good info...good plan to follow what he says. Stock HO short block pistons were not designed for long duration cams and 2.02 valves and may have interference at the valve relief edges, slightly bending the valve heads.

 

I didn’t hear anything, but would it happen to other pistons also if the valves kissed the #1 piston???

 

All it takes is inconsistencies between stamped rockers and "questionable clearances"

 

How did you set the valve clearances? Are the heads studded with adjustable rockers, or bolt down?

 

When I installed them the first time I did a full turn with the tappets not pumped up. But that was too tight. So I tightened the rocker until I couldn’t spin the pushrod then tightened 3/4 turn.
So who knows, I’ll know when I pull the head tomorrow.

 

That sounds about right as long as you spun it through the firing order. I thought maybe the rockers were too tight because I’ve done that before when I switched from the bolt down rockers to heads that were adjustable.

 

Really sounds like the cam timing is wrong. Like one tooth Off!- .Out! what ever you'd like tom call it.

 

All you need is a bit of assembly lube or oil on the pushrod ends and you can spin the pushrods even when the valve is wide open.
So I don't trust that method at all .[or my fingertips]

The recommended preload for most hydraulic lifters is 20 to 40 thou so settle on 30 thou.

I made up a 30 thou "feeler" gauge from a piece of brazing wire that had a tiny bend at the end [I hammered it flat until it "miked" at 30 thou]
The feeler gauge is slipped down beside the pushrod and between the circlip and plunger. [then adjusted by feel]

Every engine I've built has been dead quiet on first start up [which really helps when you want to break-in the cam for 20 minutes]


Brandon , Don't pull the heads yet !!!!!
Why don't you try backing off and adjusting your lifters with the engine idling [ the infamous "clack clack" method ] then compression test the engine again

And hopefully it is a lifter preload issue and not a valve/piston issue
YOU MIGHT GET LUCKY [it won't cause any more damage than what is potentially already done]

Try this before you dismantle everything
If this works are you were lucky ........ then pull all the pushrods out and check for straightness [because of possible coil bind when the lifters had too much preload]

 

I only paid $149.00 for my B-303 cam brand new and used the factory roller lifters that came in my car when I first bought it new....

 

What you could do, back the rockers off all the way on the cylinders that have low compression.
Get an adapter that you can attach your air hose to. Put air in the spark plug hole.
Listen and if you hear air pissing out of the intake or exhaust, then may have definitely dinged a valve up.
When you back the rockers all the way off, the springs will extend and “should” fully close both valves on that cylinder.
I should add, since you have an auto transmission, the piston my move to BDC, no worries, when it hits a sweet spot if all is good with the valves, it will hold a lot of air.

 

Good idea ,the click clack method I’ve adjusted valves a few times this way it works however I make a hell of mess ,I even tried those rinky dinky deflectors still make a mess. If this was my engine I would back off all lifters about 1/2 turn before starting again, might get lucky.
Dan

 

Brandon what part of the planet are you from? If I am close enough I can come and help you tear it down and put it back together and it will run like a scalded baboon! I don’t know much, but I know the SBF’s like the back of my hand especially the late model 5.0’s. I can tell you from experience that the B303 is a good nitrous cam for the street, and the E303 is usually my go to for a mild street motor. All my other small motors I ran Yates blocks, Cleveland heads, stroked out Mexican blocks you name it. From my experience SBF’s don’t start making serious horsepower until they are sent to the outer limits, 7000+ rpm and they love timing. Hence why I love a solid roller motor and spraying the house down while I’m doing it (edit) Oh yeah and if you’re going to do that make damn sure you have girdles on your block because you will split one in a New York second. Even with them I’ve destroyed a couple…..

Honestly it sounds like you have a mixture of hodgepodge parts that are not matching up worth a damn. And you might have missed something when putting it together IDK but something is definitely wrong here but it can be fixed.

 

I made up a 30 thou "feeler" gauge from a piece of brazing wire that had a tiny bend at the end [I hammered it flat until it "miked" at 30 thou]
The feeler gauge is slipped down beside the pushrod and between the circlip and plunger. [then adjusted by feel]

Every engine I've built has been dead quiet on first start up [which really helps when you want to break-in the cam for 20 minutes]
I used this method on the last cam change I did and it works great! I didn't have to touch the rockers since. The lifters have such a light spring in them that you can't feel the zero lash point.

Gary