Engine/Transmission (1994 - 1998) Cracked Block

[radar doctor]

I'm in the process of buying a 98,,, 12 Value Engine... Ram Diesel. I heard that the 12 value units had some bad Blocks. . Can anyone tell me where to find the story behind that and also the Block serial number that is the bad blocks?? thanks Bill

 

[lpearson]

Don't think that's the case.

I've never heard of a 12 valver having a cracked block. My understanding is that the early 24v that used the 12v block (53) had some rare cases especially when they added power mods to them. Cummins has since change the block and made it thicker on the 24v trucks. Someone may chime in, but I think the 2001 --on had the new block configuration.



Lowell

 

[radar doctor]

12 value Block

Thank you Mr Pearson,, That is a load off my Mind Bill

 

[moparguy]

Actually, it's been reported several times that some 98 12V's had the 53 block.

 

[Missouri Mule]

Are you sure about that moparguy?

I thought the 24 blocks were a little different from 12 blocks.

I know if one wants to put a 24 v head on a 12 v block or use a p7100 on 24 v there is extensive modifications.

Are they running 2 cams on 24v or double the cam lobes on one cam?

 

[Bill Lins]

Originally posted by moparguy

Actually, it's been reported several times that some 98 12V's had the 53 block.

Like mine! Hasn't cracked yet, though.

 

[CumminsPower98]

The '98 12 valve block is the same as the 24 valve block. I have one but I'm lucky it's not a "53". '97 and back are the older style block and I have never heard of a problem with them cracking.

 

[kentdiesel]

53 block picture

I have a 98 12v with a 53 block. The numbers 53 are cast in the block below the injection pump right above the oil pan mating surface. The date of manufacture of my engine is 8/20/97.

Mine has not given any problems and it has 106,000 miles so far and with the #10 plate I would think I have well over 300 hp.



Kent

 

[HoleshotHolset]

MM said: "Are they running 2 cams on 24v or double the cam lobes on one cam?"



The 12/24 valve camshafts are pretty darn similar... they have the same number of lobes that operate the valvetrain. However, the 12-valve cam has an extra lobe to operate the mechanical lift pump. The 24-valve cam also has a slightly better profile (with wider lobes... ) which helps the 24-valve to breathe more efficiently.



On a 24-valve - each pushrod actuates two intake or exhaust valves... . instead of a 1:1 basis on the 12-valve. There are little 'bridges' or 'crossheads' under the ISB's valvecover that speak volumes about how it all works.



As you can see in this picture - #ad
- each rocker arm actuates two valves...



Matt

 

[DEickhoff]

I am running a stock 98 12V with a 53 block at 81,000 miles with no problems as of yet.



Dawna

 

[Jim Fulmer]

I would think I have well over 300 hp



Mine has a 53 block in it and I think I'm over 700 HP.



Jim

 

[lpearson]

Originally posted by Jim Fulmer

I would think I have well over 300 hp



Mine has a 53 block in it and I think I'm over 700 HP.



Jim

Jim,



You make a good case. With that much H. P. , if it were going to crack, it should have by now.

Lowell