I asked this question on the 61-79 Board and no one answered,so I'll ask here. What years and motors (M's) had a problem with lifter bore cracking? I've heard alot of different things, are there certain numbers to look for etc. One thing I've heard is that when they brought out the 351M the problem was remedied. Is this right? I want to get a motor to rebuild and don't want to get a junk block. Are there any certain models better than others? Thanks in advance for any info.
Jeff

 

[font size="1" color="#FF0000"]LAST EDITED ON 24-Oct-00 AT 10:55 AM (EST)[/font][p]The lifter bore problem is with blocks from the Michigan Casting Company. You can ID these by looking at the top of the block next to the oil pressure sending unit. Look for a M over a little c inside a big C The date you want to avoid is anything before March 2, 1977. This covers both 351M and 400s. I believe castings from the other companys were okay, it was just this one that had problems.

Stryder

 

[font size="1" color="#FF0000"]LAST EDITED ON 24-Oct-00 AT 12:44 PM (EST)[/font][p]Jeff,

Stryder is mostly right.

All 351M/400 engine components were cast at one of two casting plants, both owned by Ford (not separate companies), the Michigan Casting Center and the Cleveland Foundry. The MCC and CF marks identify the plant at which each component was cast.

The problem is actually cracking between the water jacket and the outside of the block (not inside the lifter bores) at the top of the block in the lifter bore valley area, i.e., the area between the cylinder decks. It affected only engine blocks cast before March 2, 1977 at the Michigan Casting Center (MCC casting mark).

As Stryder mentioned, you can look for the MCC casting mark on the top rear of the block, behind the intake manifold. Date codes (usually cast in the same area) are in the form: nAnn, where the first number is the last digit of the year, the letter is the month, and the last two numbers are the day of the month. The date March 2, 1977 is coded as: 7C02. Any date before that on a MCC block would be suspect.

The easiest way to avoid these blocks is to look for a date after March 2, 1977 on a MCC block, or just look for blocks cast at the Cleveland Foundry (CF mark), which never had this problem.

The 351M was introduced in the 1975 model year, well before the problem was corrected at the MCC plant, and since both 351M and 400 engines used the same block, engine size makes no difference.


BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.

 

Thank to both of you for the info!!
Jeff

 

Oh, this is just great! The machine shop has already bored my '76 351M block, and I'm not sure if it was MCC or CF origin. I do know that the bottom of the intake manifold had a great deal of flaky rust on it, which I thought was kinda unusual. Valley pan wasn't so rusty, though.

Let's say I find it is an MCC- is failure of this type a sure thing? If my machinist didn't notice any problems (block has 100k miles on it) am I good to go? He should finish with hot tanking early this week.

Or, is this the time to (gulp) put ANOTHER couple hundred into this project and get a different block core?

Bob A
'77 F-150 4x4 "the project"

 

>Let's say I find it is
>an MCC- is failure of
>this type a sure thing?
> If my machinist didn't
>notice any problems (block has
>100k miles on it) am
>I good to go?
>He should finish with hot
>tanking early this week.

If this engine has 100K on it already it's probably going to be OK. That's a lot of heat cycling. Remember this thing was happening in the late 70s and early 80s. I'd venture to guess that most of the blocks that were going to crack already have!

 

I would have your machine shop magnaflux the block for cracks to be absolutely positive. It may not be cracked in the valley, but it could be elsewhere. Your shop should have told you this before they bored it. I consider it mandatory for any rebuild. That way you dont find out the hard way...usually a few thousand dollars later. I would also have the heads, crank, and rods checked as well for added insurance.

Styder

 

I would have your machine shop magnaflux the block for cracks to be absolutely positive. It may not be cracked in the valley, but it could be elsewhere. Your shop should have told you this before they bored it. I consider it mandatory for any rebuild. That way you dont find out the hard way...usually a few thousand dollars later. I would also have the heads, crank, and rods checked as well for added insurance.

Styder

 

Thanks for all the information. I went by the shop today to look at my block, and happily its a "Cf" casting. I gave the machinist a copy of the posting of this thread so far, and he seemed pretty impressed with the detail (pinned it to his board). He said he thought the lifter area jacket cracking was mostly a 351C problem.

Anyway, all is well for now. I reserve the right to ask more questions later, though!

Bob A
'77 F-150 4x4 "the project"