Freshly Rebuilt 59AB Help Needed, Near end of my Rope

[richard crow]

plastic gauge the mains a must.if to much clerance remember what i said about the boses. it,s rare but i have seen it

[anothercarguy]

Originally Posted by richard crow

plastic gauge the mains a must.if to much clerance remember what i said about the boses. it,s rare but i have seen it

So far, the engine is out of the car, and the valve train is removed (crank and rods still in place). Tomorrow, I'll mount the block on a stand and remove the crank and rods and put the micrometer to them.

Originally Posted by Walt Dupont--Me.

That flat spot belongs there, it's a little rough but that's not the problem, you can install a couple of small flat washers in the cap to raise pressure on the spring, are you sure the plug is installed in the front of the main oil line behind the cam gear? I put oil in the pressure tank and force it in to the engine, if that plug is out oil will running out by the front main. Walt

I had checked for the gallery plug behind the timing gear before I first pulled the oil pan...it is in place.

I've measured the front cam bearing...in the front half (forward of the cut around the circumference) there is .0039" clearance, and the rear half of the bearing has .0042" clearance. I can't measure the mid bearing until the crank is out (no bore gauge...have the telescopic gauges so need room to be able to get in there).

Also good to know the flat spot on the pressure relief valve is supposed to be there.

The quest in the shop will continue tomorrow. Again, Thanks to all for your help, suggestions and knowledge. Tim

[flatjack9]

Cam bearing clearance spec is .002.

[chuck stevens]

Tim, When you take out the cam I would be interested in what it mic's out to. You can hold the valves open with a small pieces of wood, turn the engine upside down
so the liftters drop down. Check the size of the inside of the bearings with the outside of the cam. It's alot to go though but now is the time to find out. Chuck S.

[jimTN]

Have you checked the pressure relief spring and bobbit that is located in the front of the valve and tapped valley? That could have the spring missing, bobbit missing or stuck. You do not have to remove the valves to pull a cam. Raise the valves with a valve lifter, pull the tapped up and stick a nail in one of the side holes. (provided you have traditional tappets or adjustables with the side slots). Unless the rear cam bearing is worn bad, there should not be enough oil lost thru the pushrod hole to make much difference.

[JSeery]

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Might want to take a look at previous post, in #37 Tim showed a photo of the pressure relief spring removed and checked. In #42 he discusses the current state of progress:

"So far, the engine is out of the car, and the valve train is removed (crank and rods still in place). Tomorrow, I'll mount the block on a stand and remove the crank and rods and put the micrometer to them."

[anothercarguy]

Today started with a couple hour project of building a sidemount flathead adaptor for my engine stand...then on with the teardown. This is what I measured. Not sure I've had the aha moment that said this is it!

Originally Posted by chuck stevens

Tim, When you take out the cam I would be interested in what it mic's out to. You can hold the valves open with a small pieces of wood, turn the engine upside down
so the liftters drop down. Check the size of the inside of the bearings with the outside of the cam. It's alot to go though but now is the time to find out. Chuck S.

I measured the cam journals at both the front and rear of the groove cut into each journal. The cam journals mic'd at:
1.7994" (front side of front journal), 1.7991" (rear side of front journal)
1.7997" (front side of mid journal), 1.7993" (rear side of mid journal), 1.7996" (front side of rear journal), 1.7992" (rear side of rear journal)

Cam bearing clearances measured at:
.0038" (front side of front journal), .0042" (rear side of front journal)
.0047" (front side of mid journal), .0045" (rear side of mid journal), .0039" (front side of rear journal), .0035" (rear side of rear journal)

(higher than the .002" limit)

Main bearing clearances measured at:
.0021" front cap
.0015" mid cap
.0019" rear cap

(within spec of .000-.003")

Con rod clearance measured at:
#1 .0013"
#2 .0001"
#3 .0017"
#4 .0034"
#5 .0015"
#6 .0011"
#7 .0015"
#8 .0018

#'s 1,2, 5, 6, & 7 (especially #2!) have clearances tighter than the acceptable range of .0017"-.0036"

With the engine out and the flywheel removed, I can confirm that the rear oil gallery plug is also in place. It seems to me that low oil pressure is still quite drastic relative to the oversize of .002"-.003" of the cam bearings...and the too tight con rods which would cause heat but not necessarily oil pressure loss (or am I missing something?).

I'm taking my pile of parts to a machine shop that does a lot of flathead work tomorrow.

[Kurt in NJ]

I only see one measurement for rod bearing clearance---with floating rod bearings there are 2 clearances ---between the rod and the bearing, and between the bearing and the crankshaft, plasitgauge is not reliable as a measuring system with the floating bearings ---it would take 2 pieces--one between crank/bearing---one bearing/rod then add together
In the Ford engine reconditioning book it recommends the use of the oil pressure leak detector (pressure pot)to prevent low oil pressure complaints on rebuilt engines----before the pan is put on---as a bonus it pre oils the bearings---I have never had low oil pressure problems when I used this method, by varing the pressure the releif valves can be checked for opening pressure---and reclosing pressure too

[chuck stevens]

I agree with you, I don't think the cam bearing clearance is enough to cause the lost of pressure. It's a long shot but have you looked the block main webs over for cracks. I have hear this has happened before. Look between the cam journals and the mains, long shot, Chuck S.

[anothercarguy]

Mystery solved!!!

Kurt in NJ...you almost got it...indirectly. I was so focussed on clearances, I didn't catch this (and must admit my unfamiliarity with flatheads didn't realize there was floating and non-floating con rod bearings).

The motor has 49-53 rods with non-floating bearings. The crank however is a 59AB and is drilled for floating bearings with the single hole drilled in the centre of the journal to oil the floating bearings. With regular bearings however, the oil is directed right at the parting line between each pair of rods.

The fix will be...another crank (8BA...already sourced), re-balancing, put new cam bearings in while we're at it...re-assembly and try again.

Again, thanks to all of you that made very helpful suggestions (or just watched along with interest...as I usually do ;o).

Tim

[flatjack9]

Good to hear you found it. It's always a gamble buying a rebuild by someone else.

[petehoovie]

@anothercarguy - I like your style....

[JSeery]

Good find!

[Matt in Alameda]

Wow, Anothercarguy,... this was a great thread to follow. It seemed almost like a barn raising.....a bunch of people coming together to fix a major problem. I hope everything goes smoothly from here. The Barn is such a great site..( Thank-you Ryan)...good luck to you the rest of the way! ...Matt in Alameda

[Andy]

I would not balance it. The stock cranks are in balance. You take more of a chance with somebody screwing it up. Pull the plugs in the throws and rod all passages.

[JSeery]

Just depends on your prospective, I have never built an engine I didn't balance. When you get them on the balancer, some are fine and some are way off. To me it is not worth even the remote possibility of having to take an engine back appart.

[GOSFAST]

Just for the record here, acceptable cam brg clearances are .0008" to .0044", this according to F/M and Durabond! Tighter is much more preferred but this is not an easy area for a quick-fix.

If you plan on changing them I would use a set "Teflon" coated ones, will help some with the clearance.

(Add) JSeery hit the nail on the head above, this makes 100% to me. Also, if your shop owner is a decent guy he may run it up for you to see how far out it is? If it needs no correction, he should cut you some slack. If we run one up here and it happens to be good we charge slightly less. It's worth about $100.00 just to run the shaft up and be positive. While you're at this stage it may pay to check the flywheel/plate also.

Thanks, Gary in N.Y.

P.S. Without knowing all the specs you have I would NOT put it back together without balancing that the replacement shaft. The pistons and rods should be fine, the shop will only need one setup to obtain the required bobweight for balancing!

[OLD...BILL]

A good read, glad you found it. thanks to all and your input, we all learn from it, thanks again, ...and YES on the balance .... OLD...BILL

[George/Maine]

I didn't see any OD measurement's on the cam it self.

[flatjack9]

Read post 47.