Technical Ford 289

This happened to us at a Ford dealer I worked at. I think we did a cam swap and none of us knew about the reverse rotation thing.

 

I pulled the cam last night it’s a Erson still doesn’t explain if it’s a marine or not without cross referencing part numbers, I have a 351w cam I threw in it last night just to see if that will change anything I mean might as well since im already this far, it’s confusing because I can physically see the valve springs/ rocker arms moving appropriately and registering compression but literally no vacuum on intake the only thing the vacuum gauge will do is bounce but it doesn’t bounce high enough to read numbers just moves, I have done a wet compression test and the compression grew some but not significantly and with what compression it has without the wet test is more than sufficient to fire, I’m thinking that no fuel is making into the cylinder since there is no suction from the intake, you can pull plugs after you try to start it and dry and no smell of fuel, no bent rods and all lifters are free and move

 

If you decide to try and start it remember 351's use a different firing order than the 289-302.

 

Forgive me for asking, because I am sure you have already done this.....but have you fully inspected the manifold runners for a blockage....mouse nest, mud dauber, etc.?

As for pulling a vacuum while cranking, I confess I have never tried that, but given the volume of the intake system, I can't imagine much of a vacuum draw being created at cranking speed. I mean, I know a vacuum exists in the cylinder on it's intake stroke, but atmospheric pressure quickly negates that vacuum. On the other hand, when the engine is running, things are happening far more quickly, the throttle plates are a formidable restriction in the intake system and a vacuum is easily registered.

Anyone in the gallery have direct experience with observing a vacuum gauge on a cranking engine?

Ray

 

Be careful there are two firing orders for the small block Fords and the cam determines that.





Bones

 

Yes sir, I’m aware of the firing orders, Ray it just has straight headers on it as of now that I pulled off and put on when I first got it but I’ll double check them again, As far as the cranking speed it seems a bit sloppy and slow compared to other small block fords, all connections are good , only thing I’m concerned about would be the CCA of the battery would that drag down the cranking speed causing some of these issues?

 

What are your compression readings for each cylinder?

 

They all match around 100-120, which is low I know but I’ve seen cars start with less, but maybe this one just won’t which could mean rings are shot

 

When you strip a timing chain you get vapor blowing out the carb, not ****ing in.

 

302 HO & 351W are the same, 289 & early 302 are different. Just a matter of rearraigning the plug wires.

 

So how does vacuum make it to the intake manifold? When the piston is going down it pulls through the intake valve against the restriction of the carb creating a low pressure below the throttle plate. Hence the reason vacuum varies with throttle position


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Now thinking about this further, if an intake valve was stuck open it would push back to the intake drastically reducing vacuum. Didn’t think of that, that’s why timing can affect vacuum. Sorry was in a hurry earlier


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Not being a smart *** but the last time I saw this the distributor was wired the wrong direction. Are you going counter clockwise from number one?

 

Yes sir, distributor is correct but a good one to hang up on though

 

Would your rocker arms and spring still actuate if a valve was stuck or sticking? Because all of these are moving properly

 

How did you adjust the valves ? Also I wonder if the P.O. used the push rods that matched the heads the 289 and 302 are not the same length.

 

Somewhat...depends on where they are sticking.




Bones

 

Bones is correct. They should all travel the same distance, possible to have a limited range of motion


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He's got 100 to 120 compression I don't think he's got valves sticking. Check my post 11 to see if the damper mark has slipped.

 

I’m sorry sunbeam, I’m not sure I follow on damper mark? Meaning harmonic balancer?

 

Yes the balancer to see if the outside ring has slipped. Making the mark in the wrong place.

 

Oops I missed the compression test...definitely not valves, definitely confirm timing


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Timing is confirmed, I’ve found a crack in the intake, underneath where the plane is there is a pan riveted into the intake and it has a crack

 

Have you run the battery down so far it won't crank fast enough to run?
SPark

 

Lm14 I asked earlier if a lower CCA would cause a slow start and not fast enough to draw in and get good compression still unsure

 

Probably what has happen, is he has cranked on it so much, been out of time and what not and has washed down the cylinders and gas fouled the plugs. I have seen times when brand new plugs got gas fouled and would not fire. He’s missing something! Remember compression+fuel +spark at the right time= a running engine!






Bones

 

Plugs are spotless like they’ve never seen fuel before and no smell of gas either, and they still are firing each time I change something or try something different I run a spark test after ward, what are you meaning by washed down cylinder?

 

That would cause vacuum problems

W/O the engine firing the gas condenses on the cyl. walls, if you get enough of it, it can remove the oil that was coating the walls.

 

Roger thanks, but the fuel is never making it to the cylinder I don’t believe, carb/intake never draws in to allow any fuel into the cylinder

 

If you are getting compression, air is getting in SOMEWHERE.
A single bad intake valve will not stop airflow thru the intake or zero out your vacuum gauge.
Start with the basics.
Is your vacuum gauge any good?