1939 LZ V12 Identification Question

[Guest friscozephyr]

While tightening the head bolts on my heads the other day I noticed a part number stamped on the heads that started with 26H. This makes my think that the heads are not original to this car since 26H is for a 1942 model which has a larger cylinder bore than a 1939/96H model. My questions are as follows: 1) How can I identify what year the block is? (I can't find any ID number on the block) 2) Is a 1942 26H head compatible with a 96H block which is what my '39 is supposed to have.

I am hoping that at least the block is original to the car so that I can find some 96H heads to make it "original".

Any insight to this would be helpful.

Thanks,

[Guest imported_V12Bill]

26H heads were frequently used on engines with aluminium heads that had been damaged in removal or other reasons. The 26H heads will work fine until the correct heads can be found. If your block is original there will be two tapped bosses on the left side rear above the bell housing. One will be for the oil feed to the filter and the other will have a plug in it. If it is a later block there will be 3 tapped bosses at that location. One for the oil feed, one for the oil return from the oil filter and the third will be plugged. It is quite possible that you have a later model engine. the bore for 36 to 39 will be 2 3/4". the bore for 40, 41, 46 to 48 will be 2 7/8" 1942 and very early 46 engines have a 2 15/16 bore.

[Guest friscozephyr]

V12 BIll,

I took a look at the bosses on the left side of the bell housing. I found the top boss had a line going to the oil filter container. The bottom boss looks like it is for the return line from the oil filter and in between those two bosses was what looks like a plug. So it looks like the block is a post '39.

Although it is disappointing that this is not the original engine ( I am not sure what this does to the value of the car) the good news is that I get another extra 10 HP from the larger bore engine.

I was planning on performing a compression test so it looks like I should use the compression ratio for a 2-15/16 bore.

Thanks for the tip.

[Guest friscozephyr]

Bill,

I looked at the engine block again just for fun. The oil filter supply comes from a tube or stem that appears to be part of the bell housing and sits above the two tapped bosses (which are tapped right into the bell housing). The oil feeder tube also contains the oil pressure sender which has a wire that goes to the dashboard. The oil sender tube coming from the bell housing rises several inches and then has a tapped boss which connects to the tube that feeds the oil filter. This situation seems consistent with the diagram in my 1939 owner's manual shows the oil filter being feed by this. The manual also shows a return oil tube going into the area of the bell housing.

The other two tapped bosses which are right next to each other and below (by several inches) the oil feeder tube are clearly for the oil return and the other has a plug.

I am not sure if I am supposed to count the oil feeder tube as a "tapped boss" since the tapped boss is not actually on the bell housing.

I'll attach a few photos if it help ID the engine block year since I am still baffled.

[Guest imported_V12Bill]

Another item to help ID the block is to check the sides of the block. In the center of each side will be a swelling running from the pan up to the V section where cylinders are. At the bottom of this swelling area in the rail that contacts the pan will be a frost plug. I am certain that this IDs blocks from 42 to 48. Older blocks may not have this swelling or have the swelling pronounced. I think that the 2 threaded boss blocks have the oil filter return line going to the pan and not the block. Either way just having a V 12 is a plus for any Lincoln 1936 to 1948. Not too much emphsis is put on correct year and should not take from the value of your car.

[Guest friscozephyr]

Bill,

I just checked the block I found a swelling or hump in the center of the block between the pan and V of the cylinder. I also found another swell about five inches away close to the bell housing area. To me the swells do not seem very pronounced (they swell about 3/8" or less from the engine block. I could not locate a frost plug in the rail.

I am not sure if this helps further ID the block.

Personally I am not to worried if it is not a '39 engine. I want to make sure I know if it is a post-39 engine or not so I can run a compression test and use the correct compression ratio.

[Guest friscozephyr]

One another point. If the frost plug is on the oil pan rail then I would have to remove the oil pan to see it ? Or is the frost plug under the swell and located outside of the oil pan.

I looked at some photos of a Peecher's block which shows a frost plug located under a swell but would be covered by the oil pan. I am not sure what year Peecher's block is.

This is turning into quite a detective story trying the figure out what model engine this is.

[Guest imported_V12Bill]

You found the swell! If you look close you can see the frost plug at the edge of the pan. There are 7 frost plugs in the later model engines along that rail which are covered by the pan lip. A compresion test should disclose an even amount on all 12 cylinders + or - 5 to 10 #. It would be unlikely that an older engine would come up to the maximum level.

[Guest friscozephyr]

So it looks like this engine is a post '39 engine since I found the swells unless someone has some other way to ID the engine.

I'll run my compression test based on the larger bores which I think have a compression ratio of 7.0. I am right by San Francisco Bay so I will assume my elevation is sea level.

I'll let you know how the compression tests turn out.