I recently went to a junkyard to find another 5.0 for my 91 f150 supercab. the old motor had close to 240,000 miles on it and I had noticed a dramatic loss of power over the last few months. Anyway, I got the motor with only 48,000 miles on it and switched over all my accessories from the old one to the newer one. After installing the motor, I went to start up and it started, but with a lot of popping sputtering and back firing. I hated to do this, but I finally had to bring it somewhere to get it checked out, because I could not get it to run right for anything. To make a long story short the mechanic finally called me and told me that the reason that it wouldn't run was because it was a 351, not a 302, as I was told that it was. When I got it back it ran great, very strong. But, after the engine warmed up it pinged real bad. When I checked it it was set at 18 btdc. I moved back to the 14 degree mark that is called for on a 302. The pinging stopped but, I also lost a lot of power. I guess I need to find the correct ignition timing for a 351 cleveland on a 95-97 model.
thanks for any help

Johnny

 

I would think you have a 351 Windsor, not a Cleveland. A Cleveland certainly wouldn't have bolted up to everything as easily as the Windsor. Your mechanic changed the firing order to get your truck to run, as is necessary when switching over to a 351W from a 302. As for the pinging problem, it could be several items. Someone who has swapped a 302 for a 351W may want to add to this. My immediate thoughts are that you are now trying to feed a 351W with a 302 engine management system (computer and sensors). It is likely that your engine is running lean, as your computer still "thinks" its feeding a 302 when you actually have 49 more cubes. I don't know if the systems are capable of compensating, or if you'd need to consider changing the computer and other sensors (MAP, TPS?) before your engine will run correctly. Again, my immediate thoughts. Someone else who knows more about these swaps could provide more information, I'm sure.

 

thanks for your reply. would you happen to know the timing setting for this motor
thanks
johnny

 

The base timing setting, with the SPOUT connecter removed, should be like most other FORD's, 10 degrees. For the computer situation, the difference between the 5.0 and 5.8 has to be in the way that the computer pulses the injectors according to the spark/fire order....right ?
Phil

 

jmac:

You know, the more I'm thinking about this, the more I'm starting to wonder if you don't have a 302. You say that the engine you bought bolted in, and all of the accessories bolted up to it, correct? Did the lower intake manifold bolt on with no problems? If so, I'm thinking that the salvage yard sold you a roller-cammed 302HO, like the type used in the Mustangs and some T-Birds. The firing order on the 302HO is the same as that of the 351W (both are different from the standard, hydraulic flat-tappet cam that originally came in your '91), which may have led your mechanic to believe that you had a 351W. I would start by positively identifying your engine, and then checking your computer for error codes. I know some of the 302's had knock sensors, and some didn't. Is it possible that your '91 had a provision for one, and the replacement engine doesn't? Phillip is right on the timing, be sure to disconnect the SPOUT before checking timing. 10 degrees BTDC is a good figure. My '85 302EFI actually calls for 8, but I run 10. There are some guys on this board that report that they are running up to 15, or so, with no problems but I'd stick to about 10 (with the connector disconnected). As for the injector sequencing, it is true that your injectors will now be firing in a different order (if you're now running a 302HO or 351W). This can be solved by switching around some PIN connectors at the computer, but I wouldn't bother. Previous posters on this subject have reported that they can see no real difference. Basically, the fuel charge fires into the intake, and while it doesn't linger directly over the proper cylinder, it's still sucked in by the intake valve of the cylinder that needs it at the proper time. Best of luck with figuring things out..... !