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Exploring the Early 1958 430 MEL Engine

Posted: Fri 3. Jun 2011, 08:04
by 58-Pagoda
Decided to start a new topic for exploring and tracking changes on the early 430 engine. I happen to be restoring a vehicle with just such an engine and am learning that the design underwent many changes between the summer of 1957 and early 1958.
Lincoln engine final A.JPG
I will attempt to discuss and document these changes as best possible, but it dawned on me recently that these changes resulted in 3 engine variants:

1-big valve, high compression engine (from around 9/1957 to 1/8/1958)
2-small valve, high compression engine (from 1/9/1958 to 2/16/1958)
3-small valve, lower compression engine (from 2/17/1958 onward)

The changes primarily came about from issues regarding fuel detonation and rough idle. The factory service bulletins discuss the issues and stressed the importance of using a high octane fuel and keeping the timing and idle adjusted correctly. There was also an early issue with defective gas tanks causing clogged fuel lines or filters. Some older restorers have also told me their belief that Lincolns were only affordable to the older, wealthier crowd who typically did not drive them hard enough to clean out the engine deposits and other buildup. Bad gas tanks, bad gas, elderly drivers...
fuel filter2.JPG
#4 11-22-57
#14 1-24-58
fuel req.JPG
#18 2-21-58
low octane final.JPG
#16 2-7-58
Prior to the above releases, the distributor had been re-worked to correct for light spark knock that was noticed under light load drive-away conditions:
dist rework final.JPG
#1 11-1-57
dist 3 final.JPG
#16 2-7-58

Re: Exploring the early 1958 430

Posted: Fri 3. Jun 2011, 09:14
by 58-Pagoda
Here's an article that sheds light on the detonation issue- Ford designed the engine with 98 octane in mind, but the petroleum industry was slow to release that. The article also has theory behind the axle ratios found in the 1958 Merc/Linc.
On the topic of fuel pumps and fuel filters...
It would appear, according to the service bulletin below, that Mercury, Lincoln, and Continental built before 1958 were not equipped with a fuel filter between the fuel pump and carburetor. I'm still trying to confirm this and would appreciate input from others on this topic.
fuel filter 1 bull 31.JPG
#31 5-16-58
The Sept 1957 advance service manual for Lincoln discusses overhaul of the fuel pump and removal of the fuel filter but oddly shows no pictures of either one except for on a rendition of the assembled engine. Below is a copy of the AMA specs for the 1958 Lincoln (dated 10/14/1957) which references use of a fuel filter, so perhaps it was being placed into production in late Fall of 1957.
ama fuel2.JPG
The diagram below is taken from the 1958 service manual. According to Mike Casella at Then and Now, the fuel pump is an AC #4441. He offers rebuild kits for the pump for around $38 (kit #FPA-241) and says they are straightforward to rebuild. I inquired on replacing the valve springs but he said it's usually only required if they are bent out of shape or broken, otherwise should be fine. He also offers a rebuilding service.
fuel pump filterb.JPG
As best I can tell, the fuel filter is an AC and likely #854392 which pre-dated the later #854444. The exterior visual difference is mainly attachment of thumb nut on the bail attachment clip. They appear on Ebay in the $20 range. The inside of the top cover is also supposedly date coded although I have not seen an original 1958 to confirm this. Any additional info on the correct fuel filter would be appreciated.

Finally, here's another bulletin documenting changes to the fuel pump push rod. Production changed from a bronze bushing to an oil-lite bushing. The eccentric was also changed.
fuel push rod.JPG
#17 2-14-58

Re: Exploring the early 1958 430

Posted: Tue 7. Jun 2011, 11:13
by 58-Pagoda
Camshaft & Valvetrain...

One of the earliest internal changes to the 430, other than the distributor which was re-curved around or just prior to 11-1-57, appears to be the camshaft. The 1958 service manual references the EDJ-6250-A cam as being used from 9-10-57 through 11-10-57.

I have no reference for what, if anything, was used prior to 9-10-57. Based on the old ads at the following link, the cars (Lincoln) were formally introduced to the public on 11-1-1957 so it would seem that engine production might have only started in September 1957.
1958 Service Manual- early cam
Early valve springs are brown or maroon colored.

Here are the early 1958 cam specs. First, from the Mercury Advance Service Manual for 1958:
merc advanceb.JPG
10-58 Merc Advance Service Manual
The red highlights indicate possible typos or revisions based on subsequent publications (refer to 1958 RM specs guide posted later).

And from the 1958 AMA Specs pages for Lincoln
10-57 AMA (Lincoln)
10-57 AMA (Lincoln)
9-10-57 through 11-10-57
Intake duration= 276 degrees
Exhaust duration = 276 degrees
Overlap = 54 degrees

Later style cam and valve spring usage from 11-11-57 onward:
springs 2final.JPG
1958 Service Manual- later cam
Later valve springs are green or olive colored.

Bulletin on the cam and valve spring changeover
cam change.JPG
#8 12-20-57
1958 cam change service bulletin.JPG

Re: Exploring the early 1958 430

Posted: Wed 8. Jun 2011, 10:24
by 58-Pagoda
Cam specs for the later style 11-11-57 onward, which changed to:
Intake duration= 270 degrees
Exhaust duration= 270 degrees
Overlap= 49 degrees

1958 RM Service Specs
1958 RM Service Specs
Note revisions from the 1958 Merc Advance Service Manual which stated the following for the Early 430:
Intake Open BTDC = 0.002 @ 27 degrees... Changed to 0.003
Intake Open ATDC = 0.100 @ 26 degrees... Changed to 27 degrees
Intake Closes ABDC = 0.100 @ 12 degrees... Changed to 13 degrees

1958 RM Service Specs
Note revisions from the 1958 Merc Advance Service Manual which stated the following for the Early 430:
Exhaust Closes ATDC = 0.004 @ 27 degrees... Changed to 0.005
Exhaust Open BBDC = 0.100 @ 16 degrees... Changed to 15 degrees
Exhaust Closes BTDC = 0.100 @ 34 degrees... Changed to 29 degrees

1958 RM Service Specs
1958 cam changes final.JPG
1958 Lincoln Service Manual
1958 cam changes final.JPG (55.62 KiB) Viewed 12150 times

Re: Exploring the early 1958 430

Posted: Mon 27. Jun 2011, 14:53
by 58-Pagoda
Continuing with camshaft discussion a bit more:

According to the 1958-59 Continental Master Parts Catalog, the replacement camshaft is listed as
B9ME 6250-C for 1958/59 with the following note: Use with B8S-6513-A (Maroon) valve spring.

However, this is contradicted under the valve springs listing:
B8S-6513-A Valve Spring. Note: Maroon-two piece design includes valve spring and valve spring damper- use with all camshafts EXCEPT B9ME-6250-C camshaft.

PB8M-6513-B Valve Spring. Note: Brown- use with B9ME-6250-C camshaft.

It would be interesting if someoone has the specs on the B9ME-6250-C camshaft and can post to see how it compares to the earlier cams. I have seen NOS ones sell on Ebay periodically.

428 Cobra Jet profile

In researching this topic, I found that others have previously reported good results with using a 428 Cobra Jet camshaft profile, reground on the stock 430 cam. I was curious about this and contacted Oregon Cam Grinders who have done this in the past and who confirmed this could offer improvement over the original profile. For history on the 428 CJ/SCJ cams, see

I plan to go this route when the time comes. Oregon Cam Grinders provided the specs for the stock 428 CJ as:
206/220 duration @ .050" lift (274/290 advertized), .481"/.487" lift using 1.73:1 rockers, and 116 degree lobe separation. Valve overlap would be 50 degrees at 116 separation. They can reduce the lobe separation to 110 degrees and increase overlap to 62 degrees with the chance of running a little rougher idle. Their price for regrind is around $70.

Re: Exploring the early 1958 430

Posted: Mon 27. Jun 2011, 15:25
by 58-Pagoda
Head change as of 1/9/1958

Continuing with attempts to resolve valvetrain issues, a new head was introduced for 430 production on 1/9/1958 (according to the 1958 Registered Mechanic LMC Specs Handbook, the date of introduction is revised to 1/20/1958). The new head is reported as the Mercury 383 head #5750062 and basically reduced the intake valve diameter from:

intake valve head diameter: 2.140-2.150 .... to 2.080-2.090
intake valve seat diameter: 2.120 .... to 2.060 Seat angle stayed at 30 degrees

The theory I've heard on this is that the larger valves collected more deposits from low quality gas/ customers who did not drive regularly or at particularly higher speeds.

*There were no changes made to the exhaust valves- they were same for 383 and 430.
exhaust valve head diameter 1.770-1.780
Seat angle: 45 degrees and stayed at 45 degrees.

*Note: There were no changes made to the intake valve seat angle at this time, but they were changed to 45 degrees later in 1959 (see 2nd to last article).
new head bull 26.JPG
new head.JPG
1958 head change.JPG
Intake valve seat angle change for 1959.., from 30 degrees to 45 degrees.
seat angle change 1959.JPG
2-4-59 (1959 Service Bulletin)
There was also a change to the exhaust valve stem seal as of 6/16/1958 to reduce oil consumption and engine smoking.
valve stem seal final.JPG

Re: Exploring the early 1958 430

Posted: Tue 28. Jun 2011, 12:43
by 58-Pagoda
On the topic of cylinder heads and numbering...

From my limited observation, MEL cylinder head part numbering changed every year from 58-60. I've been trying to make sense of this for some time, especially as it relates to the early MELs and inconsistent numbers.

Early 1958
Literature refers to the early head as part number 5750064, however I have not seen this number on a head. The literature is likely off and meaning to reference 5750065 based on the real life examples I've seen below.

5750065 78D (August 4, 1957)
EDJ-6090-B 78P (August 15, 1957)
EDG-6090-C 78V (August 21, 1957)

The early head casting numbers, including the 5750065, have not been externally visible as they are cast on the top of the head under the rocker shaft assemblies. I believe the EDJ-6090 numbers were the earliest identifiers used, followed by introduction of the 575- numbering convention. 575 part numbers show up on replacement parts in the Service Bulletins throughout 1958.

Literature refers to 5750062 as the replacement head (Merc 383) used on the 430 from 1/9/1958 onward. It had slightly smaller intake valves than the early 1958 heads. Again, I have never seen this number on a head. Every Lincoln I have seen that was built in 1958, including 3 that I own, have a 5750063 casting number that is external and located by the spark plugs on the left hand side of the head.

The Service Bulletin #29 (5-9-58) that describes the Super Marauder option for 1958 has several pictures of the Mercury 430 engine, and in one of them I can read the 5750063 head number. I'll post it if I can get a good scan of it. This head is consistent with what a Mercury Super Marauder engine would have installed because the 3x2 option was reportedly released for production in April 1958 and the head was already in production at that time. What could be found on a Lincoln Super Marauder is another story and I will cover later on as I get to it.
Bulletin #29 (5-9-58) Super Marauder option. Click to enlarge.
1959 saw the introduction of the B9ME- numbering convention. According to friend's interchange book, B9ME-6049-C and B9SZ-6049-A were used in 1958 to early 60, before 11/24/59 (likely as replacements if used on 1958).

C0ME-6049-B and C0SZ-6049-A used in 1960 after 11/23/59.

Re: Exploring the early 1958 430

Posted: Tue 28. Jun 2011, 13:21
by 58-Pagoda
Block deck height...

One of the final significant differences between an early 1958 and later 1958 is the compression ratio which was lowered from 10.5 to 10.0 starting on and including 2-17-58. This was accomplished by increasing block height 0.020" as a final effort to prevent detonation issues. Notice the alternative fix for early 430s was to use 2 head gaskets to reduce the compression ratio. The higher compression makes the earlier blocks and engines somewhat more desireable.
block height change.JPG
So to recap, all of these changes result in 3 variations of the 430:

1-High 10.5:1 compression, large 2.140" intake valves- from mid-1957 to 1/8/1958
2-High 10.5:1 compression, smaller 2.080" intake valves- from 1/9/1958 to 2/16/1958
3-Lower 10.0:1 compression, smaller 2.080" intake valves- from 2/17/1958 onward.

As noted earlier, the Super Marauder option was introduced around April 1958 and would have been equipped on engine variation #3 which was rated at 400HP and approx. 500 ft-lbs. It would be interesting what it would do behind door #1.

Re: Exploring the Early 1958 430 MEL Engine

Posted: Tue 12. Jul 2011, 21:33
by 58-Pagoda
Some miscellaneous other changes...

Starting 2-7-58, production implemented a reinforced rocker arm to prevent failure. Early and late styles are interchangeable.
rocker changex.JPG
Early vs. later rockers
An interesting test procedure for identifying defective rocker arm stud bores, possibly contributing to spark plug fouling and exhaust smoking.
rocker arm studsx.JPG
Push rod change to cure noisy lifters
push rod change.JPG
Push Rod change
Discontinue use of PAL nuts on connecting rods
rod nutsx.JPG
Oil pump shaft change
oil pump shaft change.JPG
New valve cover and oil breather cap to reduce oil vapor pullover onto underside of car
new oil capx.JPG
This is a treat to behold- pics of factory installation for the 3x2 Super Marauder, but I direct your attention to the valve covers which are well-illustrated here. Thanks to Mr. Kraft for pointing out the difference between 1958 valve covers from 1959 and onward... 1958 has the "fingers" affixed to the cover to hold the spark plug wires, and note the small grommets on the spark plug wires too. 1959 and on uses a removable clip to secure the wires to the valve cover.
1958 valve coversX.JPG
1958 Valve Covers