I have a 48 Sedanette that I'm restoring and will be installing a 71-73 472 engine and a TH 400 transmission. I'm currently working on the 472 rebuild. This is the first time to restore this engine. If there is anyone in this forum that has made a similar engine swap, I'd like to discuss your experience. I'm also new to this forum so would like suggestions to items in this forum I should review. My first specific question to this engine follows: The timing gear had what I would call ex-stream wear. The top of the gear teeth on the cam gear were reduced to points. Any suggestions at why or what would have caused this ex-stream wear?
Those timing chain sets are famous for that failure mode. The original cam sprocket had plastic teeth, which may fall off any time at this age. Just put on an all steel roller timing set and forget those problems.
A TH400 trans this age also has failure possibilities. The seals (on the pistons that drive the clutches that connect the motor to the wheels) age and may let clutches slip, with disastrous results. Bruce Roe
This engine was loaded with carbon. My guess is the timing gear was largely responsible for this. I've miked the rods and main bearings. the rods were 1.5 clearance. That seems good. The mains were 2 to 3 clearance. That seems to be high. What do you all think? There is a very small ridge in the top of the cylinders. I'm considering putting in a new timing gear set and putting the engine back to gather. The person I bought the engine from thought maybe the engine had about 80,000 on it when it was removed. I'd like all the input and comments I can get. So fire away!! I also have a source for a fuel injection system for this car. Its the type that showed up on Cadillacs after 1975. I'm also open for motor mount suggestions.
I'll include some pictures in the next post.
If there is interest I'll create a photo and comment section of the build progress.
Those 70s open loop Electronic Fuel Injection have reliability problems, and little advantage over a Qjet. Not recommended for new installations. An approach some people use, is to adapt a modern closed loop EFI to work with the 70s intake manifold/injectors/throttle body. The 70s GMC motorhome people have done a lot with EFI 403/455/500 engines. You can see some info on 70s EFI on my PHOTOBUCKET.
I don't have websites handy, but try some searches on GMC MOTORHOMES, look for EFI. Russ Harms has a huge amount of info on his Old & Cad fuel injection conversions to modern closed loop, programable systems. There are also some MAF based systems that work with hardly any programing. good luck, Bruce Roe
Trying a picture link again. If this doesn't work can someone guide me to the instructions for doing this.
Looking for suggestions: I want this car to be a driver. I'm going to replace the timing chain, cam, lifters, rocker arms and new bearings. I don't know about the pistons yet. This engine is the 71-72 type with soap dish pistons. It came with a quadrajet carb. My goal is to keep the cost down and as I said earlier create a good driver.
What suggestions would you make for the parts I need. All suggestions will be considered.