Looks like you have an early 3406B 7FB engine. Based on your oil filter base, that was a rare setup not used but on around 4,000 engines. Could be out of a Volvo or something like that. The flywheel indicates this is a low HP engine. Between the rear head bolt holes, you can see an pipe plug threaded into the cylinder head. This engine has had a head gasket failure under a service recall letter. One of the up dates was to drill a hole in the back of the cylinder head. The coolant passage was not complete, so the field repair was to opened this coolant path up. A pipe plug was then used to seal it off. Your Jacobs Brake is a 346B Brake three point stand. Later Jacobs came out with an update to get more Braking HP. It went to a four point stand. They added another bolt, it was a 7/16, with a tube and foot stand. So you had to drill a larger hole in the Jacobs Brake housing for the larger fastener. Also with this update Jacobs required you to shim the Brake in order to get it level. Early 7FB's also required you to shim the Brake. The timing advance on these can slip internally and it will run retarded at the higher speeds.
Yes it is a 7fb. It was out of an 80s gmc general. Wayno from Ol2stroker channel did a few videos on it before I bought it from him. Wow you sound very knowledgeable about these engines! I am a cat 3406 fanatic and am always up to learning something new on these. Thank you very much for the advice. I'd like to stay in touch with you because there are not many guys to ask questions nowadays! Feel free to email me kgtrucking351@gmail.com and we can keep in touch. Thanks!
@@kurtisgleba3121 43 + years working on these and still going for about 1.2 years more. When I hired in 3406 92U engines was still being made. Worked on every type of Cat truck engines, except 1676, 3306 gas, 3406 gas, 3408 B, 3406 C 5KJ, I have never seen any of these, just pictures. Even worked on a few Cat 7155 truck transmissions. So I have been around the block a few times. What I liked to do, now a thing of the past. Was to rerate an mechanical engine. 7FB's was made from 1983 to 1987, then they was replaced by the 4MG. The first 4MG's to 03599 was still more like a 7FB. At serial number 4MG03600 was a major fuel system change. The 4MG's had numerous problems, VTU and Cat removed asbestos at the end of the 7FB's and all the 4MG's. Oil leaks and head gasket problems.
@@johngoldsmith6629 wow You've been working on them 10 years longer than ive been alive. The A model I put in the 69 international on my channel is a 92U. I figured something was a little different with this B model. I noticed it had no block stiffener plate and the timing advance cover wasn't a cone shape like I've seen in the passed. I figured it must be a lower HP or something. So it sounds like I got a good one then before a lot of the problems came out. Thanks
The only one i can think of is in an m915a1 at Rubicon recycling in Rome NY. A few parts were taken off but has like 6k miles on it. No clue the current condition on it. I bought the sister truck to that one a year ago and then they both ran great
I want either a 3406B or a C15
Looks like you have an early 3406B 7FB engine. Based on your oil filter base, that was a rare setup not used but on around 4,000 engines. Could be out of a Volvo or something like that. The flywheel indicates this is a low HP engine. Between the rear head bolt holes, you can see an pipe plug threaded into the cylinder head. This engine has had a head gasket failure under a service recall letter. One of the up dates was to drill a hole in the back of the cylinder head. The coolant passage was not complete, so the field repair was to opened this coolant path up. A pipe plug was then used to seal it off. Your Jacobs Brake is a 346B Brake three point stand. Later Jacobs came out with an update to get more Braking HP. It went to a four point stand. They added another bolt, it was a 7/16, with a tube and foot stand. So you had to drill a larger hole in the Jacobs Brake housing for the larger fastener. Also with this update Jacobs required you to shim the Brake in order to get it level. Early 7FB's also required you to shim the Brake.
The timing advance on these can slip internally and it will run retarded at the higher speeds.
Yes it is a 7fb. It was out of an 80s gmc general. Wayno from Ol2stroker channel did a few videos on it before I bought it from him. Wow you sound very knowledgeable about these engines! I am a cat 3406 fanatic and am always up to learning something new on these. Thank you very much for the advice. I'd like to stay in touch with you because there are not many guys to ask questions nowadays! Feel free to email me kgtrucking351@gmail.com and we can keep in touch. Thanks!
@@kurtisgleba3121 43 + years working on these and still going for about 1.2 years more. When I hired in 3406 92U engines was still being made. Worked on every type of Cat truck engines, except 1676, 3306 gas, 3406 gas, 3408 B, 3406 C 5KJ, I have never seen any of these, just pictures. Even worked on a few Cat 7155 truck transmissions. So I have been around the block a few times. What I liked to do, now a thing of the past. Was to rerate an mechanical engine.
7FB's was made from 1983 to 1987, then they was replaced by the 4MG. The first 4MG's to 03599 was still more like a 7FB. At serial number 4MG03600 was a major fuel system change. The 4MG's had numerous problems, VTU and Cat removed asbestos at the end of the 7FB's and all the 4MG's. Oil leaks and head gasket problems.
@@johngoldsmith6629 wow You've been working on them 10 years longer than ive been alive. The A model I put in the 69 international on my channel is a 92U. I figured something was a little different with this B model. I noticed it had no block stiffener plate and the timing advance cover wasn't a cone shape like I've seen in the passed. I figured it must be a lower HP or something. So it sounds like I got a good one then before a lot of the problems came out. Thanks
@@kurtisgleba3121 What is the engine serial number?
@@johngoldsmith6629 I don't know for sure. The tag on the valve cover is gone. Is there another place to find it?
Kurtis do you know of anyone with a good running 400 Cummins ? Maybe in an old farm implament or something
The only one i can think of is in an m915a1 at Rubicon recycling in Rome NY. A few parts were taken off but has like 6k miles on it. No clue the current condition on it. I bought the sister truck to that one a year ago and then they both ran great
Wayne at Ol2stroker channel just had one listed for sale not too long ago. That's who I bought this one from