Sign in to follow this  
zman

V-12 Engine Disassembly and re build

Recommended Posts

I noticed on the tear down of a V-12 that the previous re builder

had installed the none rotatable valve assemblies, Using the later F/H

Ford assemblies These assemblies should not be used on the Lincoln

with hydraulic valve lifters as they do not allow for requied clearances.

The valve retainers at the bottom of the stem sit to close to the top

of the push rod bore and creates interference for removale of the keepers,

in adition to checks required for checking clearances of the stem and the

colapsed push rod on assebmbly.

Now I'm wondering if the Rotatables are still available, I noticed that

the 49 to 51 F/H fords did have rotatables.

Bill :shocked:

Share this post


Link to post
Share on other sites

Bill, sounds like a couple of things could have happened here. Someone may have used an aftermarket valve that was "close" but positioned the spring retainer lower on the stem. The straight stem valves used on the '49 to '53 Fords position the spring/retainers exactly in the same location as on the regular mushroom style stem used on the Zephyrs and pre '49 Fords. The mushroom style stem valves are still available if you choose to use them. Another possibility is that the valve seats and/or the valve heads were faced/ground way too much positioning the stem further down and approaching the boss of the tappet bore. The spring retainers were fairly close to begin with making clearance checks difficult. To my knowledge there were no "rotators" with either design of valve stem for Fords? If the valves themselves are the problem ( not Ford) you may be able to use either the straight or mushroom style Ford valves when you rebuild. If the valve seats in the block have been ground too deep you may have to have new seats installed. Let us know what you find.

Share this post


Link to post
Share on other sites

Hey peecher, the valve seats look good and they do not appear to have been

re-surfaced.

I have attached a jpg on valve assemblies with the mushroom types I picked

out of my parts bin.It seems that I can get the later ford rotating

assemblies from job Lot.

Made a few measurements on the bores and it was a 2.875 + .030, the readings

are to high and may have to go to the 15/16th's bore size.

The crank rod Journals are 2.125 and .020 undersize,but that may create a

problem unless I change the crank with a 2.250 journal's.

Possibly it would be best to sleeve it and stay with the 292 Cu.In.

The cam shaft is scored badly on some lobes, so it has to be re placed

post-38756-143137916291_thumb.jpg

Share this post


Link to post
Share on other sites

Bill, sleeving one of these engines is fairly expensive and you still have to buy new pistons. Unless there is a lot of taper or deep pitting in the bores they should clean up at .060" over or less. The block could even be safely bored another .0025" to make it a standard 2-15/16". Oversize pistons along with all other new parts for rebuild are available. The post-war crank would be the one to use not so much for the size of the journals but because there are no sludge traps to clog up. If your oil passages are all clear in your crank you may be ok? New bearings in standard and undersizes are available for these cranks also. I recently finished rebuilding a 292" '47 engine and used the Ford change-over valve kit to redo the valves and guides. The only advantage doing this is in future disassembly ease and perhaps the seals on the intake guides. Your camshaft may be grindable, mine had some pretty good size nicks in some of the lobes and they were able to regrind it. I'd have it checked before condeming it. Lobe(s) can be built up if necessary but this can too become expensive so you have to weight the costs. I would regrind or micro polish the cam in any event along with resurfacing the lifter bodies.

There's probably enough meat in the cylinder walls that you could even go .010" to .020" over on the 2-15/16" bore. I'm presently doing a "big " 12, boring a '42 block to 3-1/16" and using standard early Ford pistons. I'm holding my breath on this!

Share this post


Link to post
Share on other sites

Thanks Peecher,sounds like a winner,looks like I can go with the 2-15/16

bore, which will also take care of some of the taper I noticed.

I'll see what I can do with the cam and about the crank,

We have a Winter Swap Meet comiimg up in Feb, at Lancaster Pa.I'm sure I can pick

up the later crank and possibly a better cam

I agree on the valves,I see where the later Flat heads have the correct

sizes of the rotatable valve assemblies, all the dimensions are the

same as the Z mushroomed Valves,including the shoulder just below the

valve head,which I assume is a stop for the valve guides.

I also noticed on this engine the teeth on the fly wheel is not correct,'

also the weight is 40.5 pounds and should be 34.5

Probably a truck Flat head fly wheel!

One other question,I see where Earle Brown has adjustable lifters, and

wondered if you have used those on any V12's and would the clearances

be the same as a later flat head?

I know the clerarances for the 36 Z's,but with the larger journals

changing the stroke.I'm assuming they should be the same as the

later flat heads"

Bill

Share this post


Link to post
Share on other sites
Guest imported_V12Bill

You don't state what year V 12 you are working with.Peechers advise on the crankshaft is good. The post war crankshaft offers more meat on the journals, but you aren't going to race this engine are you? I would be cautious about going too large on the bore. Egge will make up pistons any size you need. You shouldn't bore in excess of what you need to clean up the bore. Some day it may need to be bored again and you don't want to strike water when you bore.

Solid lifters, adjustable or solid, should only be used with a cam that is ground for solid lifters. I have seen a couple of V 12s that the lobes were badly worn when solid lifters were used. Cams for hydralic lifters are ground to slap the base of the lifter sharply in order to close the check valve. Solid lifter ground cams have a slopping step on the lobe to ease the valve up and down.

Bill

Share this post


Link to post
Share on other sites

Ok V/12 I'll be U-teeing the block anyway, so I can decide then,however

the way it's checking out and with the taper in some of the bores

15/16 would take care of it.

This V-12 block is a 40, since the bores were originally 2.875 and bored

to .30 over, I believe it was run low on oil, other wise the bore

measurements would not be so out of round.

I'll check those cams out, including the 36 Z CAM which lincoln

used solid lifters in.

Thanks for the input.

Zman

Share this post


Link to post
Share on other sites

Bill, clearance ramps for adjustable tappets can be easily added when the cam is reground. If you use the adjustable tappets the clearances would be the same as the '36 and '37 12's. Many guys have gone this route and there are some advantages. You can eliminate the secondary oil line that feeds the lifters but you must provide a pressure relief passage at the front relief valve in order to assure lubrication to the timing gear. With the proper cam grind the engine will run as quiet as a flathead Ford. The hydraulic tappets of course will run a tad quieter as long as as long as they are in good shape and oil pressure is decent.

Share this post


Link to post
Share on other sites

Peecher I did find where they do grind the cam for either

hydraulic or solid lifters, so I got to make sure when I find

a new cam it's ground properly.I also see that Lincoln had

hydraulic lifters in a one piece design, with the valve assembly

as part of the push rod body and the 2 piece consisting of a

separate,hydraulic push in the push rod body, The only ones

I have worked with is the later.

It appears that I can go easily with the 15/16th's bore

I made some measurements using clay, packed in various places

and subtracted the differences, and came up with .0190 to .0196

for the remaining cylinder wall, plenty of room for boring to 15/16

I'll still do the UT though

Bill

Share this post


Link to post
Share on other sites

I think you meant .190" to .196" for the cylinder wall thickness? I've never seen a Zephyr engine with those one piece hydraulic pushrods. I'm guessing, but that may have been the design of the very first ones used in '38? Old Henry was loathe to pay anyone any royalites but probably decided to use the Eaton design for all the later engines? Just speculation. The one piece design seems similar in concept to "modern" hydraulic lifters but there might have been some good reason to discontinue their use and someone out there might have a better answer?

Share this post


Link to post
Share on other sites

To Zman,

I have a good cam (marked 06H) i just took out of a bad block.

I

hope to be at the Lancaster swap meet. I'll bring it, plus a whole bunch of

other stuff. Larry Butcher

Share this post


Link to post
Share on other sites

Thank's Larry I'll see you there, I;ve just taken the Block

to the Machine shop, so the timing is just right.I'll be

interested in other stuff too.

Bill

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this