CSpringer

V-12 conversion from hydrolic to solid tappets

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Just purchased a 1940 Lincoln Zephyr.  I noticed a distinct light knocking in the engine.  I contacted the machine shop that performed a 6.6K rebuild for the previous owner, only 4K miles ago.  I discovered the hydrolic lifters were converted to solid adjustable, he did not have very much additional information on the rebuild.  This weekend I pulled the Edmunds Custom intake and took a look, nothing broken, one of the solid lifter adjusters was very loose and far too easy to adjust, I plan to use green locktite to resolve, recommendation from other post.  I adjusted the lifters to intake .010-.012 and exhaust to .014-.016, according to the ford service guide, can someone confirm this is correct given the switch from hydrolic to solid?  Also, the check valve and spring still remain in the front of the block, however, the rear hydrolic push rod valve has been completely removed.  I have seen several post stating the rear is to be blocked and the front ball valve and spring should be removed, can someone confirm the correct set up.  Should I look at anything else while the intake has been removed?  Thank you for the help, new v-12 person, difficult to determine the proper valve clearance and set up given the change from hydrolic to solid.

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Check ball & spring should remain in the front and a small pipe plug , 1/8" I think it is, to replace the oil metering valve at the rear.  Those valve settings should be good.  

Edited by Ken/Alabama (see edit history)
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Hello I was just wondering what the reason was for blocking of the metering valve? What would someone experience if the valve remained in place? Thanks George.

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9 hours ago, gdcont said:

Hello I was just wondering what the reason was for blocking of the metering valve? What would someone experience if the valve remained in place? Thanks George.

Plugging it off keeps oil from feeding the lifters that's not needed with the adjustable lifters.  Leaving it in place would cause a drop in oil pressure , not sure how much but I'd rather keep that oil feeding the cam & crankshaft bearings.   

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Thank you Ken that makes perfect sense . I forgot they found that the engine had solid lifters. George.

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Somewhere in 50 years of  reading "Continental Comments "  and the same   years of "The Way of The Zephyr",  I thought

I read somewhere  that the '36 LZ - '37LZ  solid lifter cam was a different "profile grind" then the later hyd. lifter cam. The

part #s  in the parts book is different.  I think you need the correct cam for the type of lifters your going to use. Check back with 

the machine shop that did the engine over and see if they can tell you what cam was in the engine. An older speed shop  that

can regrind  flathead  cams, perhaps can regrind your cam.

 

 

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Larry,

You are correct.  A few more facts, while few miles were put on the engine after rebuild (around 5k) the rebuild occurred in 2014.  Notes indicate the cam was sent to the cam doctor, I can only assume the doctor was licensed to grind a cam.  My understanding is the cam was milled to be similar to the earlier v-12 cams.  I have noticed a bit of a visual gap, the lifter drops a bit further than anticipated after the engine stops rotation (and you can hear a bit of a pop) it was recommended I go with a .010 gap all around to reduce drop and noise.  I am going to give it a shot.  Short the slight knocking, the engine was running strong before I took the intake off and made adjustments.  

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So, I adjusted all the solid lifters and applied a significant amount of penetrating oil to assure the lifters were operating smooth.  I re-assembled the motor and the knocking was gone for about 50 miles, now I am back with the same knock on the drivers side third cylinder back (same as the original location).  I plan to remove the head this weekend to see if the head gasket is torn or if I have a broken valve.  I did notice (what appeared to be) back pressure from he intake manifold ports on that cylinder, any ideas on what could cause that issue?

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Did you check that the horseshoe clips that holds the valve guide in place is in the correct slot on the guide?  The  difference between .010 and .012 should not make a difference in the sound of the engine. If the clip is not holding a valve guide in place, the guide will travel up allowing the head of the valve to hit the head as well as increasing the clearance between the valve and the tappet.

 

The "back pressure" could be caused by the intake valve not seating. This could be due to incorrect tappet clearance, loose guide, sticky valve, burnt valve or bent valve.

 

On a fresh engine, I like to set the valve clearance to the larger clearance to accommodate the break in seating of the valve. It usually won't be as much as .001", but It makes me feel better about valve seating and I can't hear any difference in tappet sound.

 

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Welcome to the Forum, Springer! Here is a 2006 post by Dee Peecher on this topic:

 

"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."

 

 

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Wanted to give a update on the project.  Put the head back on and made the adjustment to the solid tappets.  Still had the light knocking and lower oil pressure, little to none at idle.  Decided to remove the pan and found one of the oil plugs (from the crank) laying in the bottom of the pan (inch and 7/8 plug).  Given the oil circulation path I am trying to decide if I rebuild the motor again (rebuilt by the previous owner 5 years ago) or if I inspect the connecting rod bearings (reinstall the crank plug, however that is done) and put it back together.  At least the problem has been found.

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I had that same problem with the plugs falling out after my engine had been rebuilt. I pulled the pan to install a Melling pump only to find that I already had one, and two plugs laying in the pan. My first effort to reinstall them using LockTite and some glancing blows failed. On the second try I made a tool to lever them in place, but I think I may still have lost one since the oil pressure is not where it ought to be. Somewhere I read that using a double-ended nut and a couple bolts you can apply a lot of pressure to the caps, which is what i will do if I ever get the gumption to pull that pan again. 

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