Y Block Help Needed

[Hot Rod Reverend]

Don't know if this has been covered yet but a quick way to check out that cam would be to remove both valve covers, start the engine and watch both banks as the valves operate. It should not take too long to notice anything out of whack (like an intake valve not moving up and down, etc). The only thing that would be hard to check here would be the actual timing of the intake/exhaust event as it relates to the rest of the cylinders...

Anyone have an old Sun Machine he could borrow?

[wellcraft17]

I agree with your process of elimination as that's exactly what I went through and for someone to tell me I had a new camshaft that was bad was inconceivable and unheard of. I'm not saying this is definately your problem but there is not much left. After thinking about this for awhile I'm assuming you do not know the history of this engine and I'm wondering if the engine ran hot and cooked the rings but you indicated there's not any blow by. What else can be left? Solve your compression problem and it will eliminate a lot of other areas of concern you may have. One check of the rings you could try, and I have not seen this pop up on this discussion, is squirt some oil in each cyl. and recheck the compression. If there is a large increase in compression you probably have ring issues. If the engine had sat up for a very long period the rings could have frozen to the pistons, you could try something like sea foam to free them up but that would probably be a long shot.

[swedishsteel]

We bought a '55 bird a couple summers ago and it has/had a similar problem--cruising at road speed it had a very slight but distinguishable miss/flutter. It acted like a vacuum/spark advance leak to me but couldn't find the source. With the used parts we received along with the car is was obvious the previous owners had been trying to diagnos the problem. This winter we decided to pull the engine to replace the badly leaking rear seal and restore/clean the engine bay. When I disassembled the motor I noticed the gasket between the intake manifold and the thermo choke assembly was gone. The engine has been rebuilt and apparently that gasket was overlooked on reassembly. I don't have it back in the car yet, but I suspect that missing gasket could have been leaking vacuum and caused the uneven firing. Hope you find something simple like that. Good luck. Rod

[Oldmics]

Have not seen anyone mention a leak down test.
Are you in a position to preform that proceedure?
That would certainly address the compression/sealing questions.
Oldmics

[countrysquire]

I was helping my son with his car last night, so no updates other than I did check the timing chain and the play was 5/16".

I do plan on doing a leak-down test as part of my testing to decide how far to go while I have the motor out. That said, I'm on the slippery slope of "while the motor is out, why not do X". The time and expense of pulling it all the way down while it's on the engine stand is not great. If the cylinders are within spec, a simple hone and new set of rings is simple enough. Testing should tell me if I need to go that far, but my preference would be not to pull the heads and pistons if I don't need to. I will be installing a new timing set, and probably a new cam and lifters. We'll see what more testing tells me.

[Ole Don]

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On a Y block, the lifters go in from the bottom. The easiest way to replace the cam is with the engine on a stand, upside down, with the oil pan off. A grappling tool is used to pick the lifters out of their holes. Do NOT toss the lifters out. They have no moving parts, they can be reground and used again.

[Bruce Compton, Canada]

Bobby : I can't believe that you're thinking about removing and tearing down the engine before doing the most obvious check first. I've read and re-read all four pages of this post and lots of very informative input has been forwarded and may still have to be applied if necessary, but lately everyone seems to be focused on a camshaft problem. Your very first post stated that the engine was rebuilt, and the work done by a shop not familiar with Y blocks so I'd guess that there is probably an 80 percent chance that they used the later, and much more common intake gaskets. Right from your first post, all the symptoms including the vacuum gauge test point to an intake or carb vacuum leak. Both early and late intake sets LOOK very similar but are NOT interchangeable. The port size on the early Y block heads and intakes are about 3/16ths smaller in both directions, but either set of gaskets will appear to fit. You also stated that the heads were milled, which would also contribute to any misalignment issue. If the wrong gaskets are there you could have eight small vacuum leaks that would be difficult to discover with a propane test, especially the four bottom ports. You have already gone to a lot of work (removing the timing cover and adjusting the valves) in chasing this problem, so do yourself a favor and pull the intake. It's going to have to come off anyway even if the correct gaskets are there. Good luck (again) : Bruce

[countrysquire]

Thanks Bruce. I will definitely be pulling the intake and resealing it, and appreciate the advice about the proper gaskets.

[countrysquire]

Well, hmmm. OK. Had a little time this evening to look at the motor a little more. The dots on the cam & crank gears were at 3:00 with twelve pins between them, just as in the picture from a couple days ago. Used a piston stop and found exact TDC, then installed the degree wheel. Popped of the valve cover and noticed that the valves on #1 weren't loose, so the engine was on the exhaust stroke. Turned it 360 degrees and the cam gear dot was at 9:00, as you would expect. When I popped the distributor cap, I see that it was 180 degrees from #1. Turned it again to get the rotor pointed at #1 and that leaves the cam gear dot back at 9:00.

Can you install the cam in a Y block 180 out, or is it only possible to install the distributor that way, like on other motors? Either way, how could it run this good with something 180 out?

[countrysquire]

Am I correct in thinking that the rotor should be pointed at #1 when #1 is at TDC on the compression stroke (both valves closed)?

[Y-Blockhead]

Check your plug wires. Sounds to me that they just moved the plug wires on the cap to 'compensate' for their 'mistake'.

Now would be a good time to make it right but I don't believe that would change the way it runs…

[40cpe]

Originally Posted by countrysquire

Am I correct in thinking that the rotor should be pointed at #1 when #1 is at TDC on the compression stroke (both valves closed)?

Yes, the dist rotor should point to the plug wire that fires #1 cylinder when the #1 cylinder is at TDC. It doesn't matter where on the cap the wire is located as long as the firing order is correct.

[countrysquire]

Thanks. When standing at the passenger fender looking down at the distributor, should number 1 be at approximately 7:00?

[Bruce Compton, Canada]

Is this a trick question?

[countrysquire]

No trick question. That is how the cap fits, just trying to confirm everything and work on as few assumptions as possible.

[40cpe]

I have a Motors Manual, that is the position shown in the diagram. The clip for the cap is between #1 and the #5 wire, which is at the 6 o'clock position.

[Tinker]

https://www.fordbarn.com/forum/showthread.php?t=87855

http://www.vanpeltsales.com/FH_web/f...eup54-59V8.htm

[countrysquire]

Thanks. I've looked at the flathead info on Van Pelt's site a hundred times, but never noticed any Y block stuff.

[Tinker]

Really its about the tdc of 1 cyclinder and the rotor pointing at the 1 post. If a desired postion of the dizzy is needed or wanted. Pull it out and move it till it lines up. Can be a bear to line up the oilpump rod to the dizzy but you should be fine. On 57 and later y blocks the shaft is a hex, not sure what the earlier shafts are, maybe slotted.

[darrell]

you do know number 1 is on pass,side