weak 351m

Reply Subscribe

Thread Tools

Search this Thread

Jul 17, 2002 | 09:23 PM

dea75

Thread Starter

New User

Joined: Jul 2002

Posts: 8

Likes: 0

weak 351m

[updated:LAST EDITED ON 17-Jul-02 AT 10:53 PM (EST)]I have a 1979 4x4 F-250HD, 351M w/2 barrel(stock), C6(stock), NP203 Tcase w/lock out conversion, Dana 60 front/rear(limited slip) with 4:10 ratio. The motor is an Oriley Auto Parts stock crate motor with about 20k or so on it. From day one it has been a gutless wonder. I recently upgraded from p245/75/16 all season tires to 285/75/16 cooper stt mud tires. The problem being that befor the new tires I had just enough power to slowly crawl over my street curb into my yard to hook up to the boat. Now with the new tires I cant crawl over the curb, but now have to "goose" it to get over and of course tear up the hard earned grass. Point being what can I do to my current 351m on a budget? I only drive the truck to and from work (4 miles away), to the lake now and then (8 miles away) and then through some fairly rough hunting terrain in the fall, so I am primarly looking lowend power/torque. Also since day one for this engine I have had to use premium gas, if not it rattles. I have checked the timing and also the carb (new carb at time of new engine). If anyone has adressed these problems befor and has some ideas please advise.

tks, DEA75

Jul 17, 2002 | 10:52 PM

proford460

Senior User

Joined: Apr 2002

Posts: 229

Likes: 0

From: Comstock

weak 351m

check your dist fly weights and vac advance also make sure advance is hooked up the port vac

Jul 17, 2002 | 11:09 PM

dea75

Thread Starter

New User

Joined: Jul 2002

Posts: 8

Likes: 0

weak 351m

proford:

dist fly weights?

Jul 18, 2002 | 10:02 AM

Kenworth

Posting Guru

Joined: Aug 2001

Posts: 1,533

Likes: 2

weak 351m

They regulate the ignition timing in the distributer if the weights don't work you end up with the low rpm missing, you shouldn't need premium gas in a 351M if its a stock spec'ed engine. If your running Champion spark plugs remove those POS and put in a set of NGK V-power and your truck will run alot better.

Jul 18, 2002 | 11:05 AM

dea75

Thread Starter

New User

Joined: Jul 2002

Posts: 8

Likes: 0

weak 351m

As you might tell I an somewhat new to the actual power plant items in my truck. How can I ck to see if the weights in my distributer are preforming as they should? I beleive that I am using autolite plugs, what do you think? Thanks to all of you that can help this newbe FORD man down the trail to a better running 351M.

Jul 18, 2002 | 02:48 PM

FatChanceSlim

Junior User

Joined: Jan 2002

Posts: 50

Likes: 0

From: Durango U.S. of A.

weak 351m

Another possibility is that when they built the engine, they used a stock cam and stock timing chainset. This will give you retarded cam timing which lowers the available power output quite a bit. If you find they did this, a simple fix is to put in a new double roller timing chainset and install it in the 4* advanced position. This will give you back some more power. Of course, putting in a better cam is the better way, but you might want to try the chainset first.

Otherwise, have you done a compression test to make sure the engine is OK? To run right, you need good compression, a spark at the right time, and a proper fuel/air mixture. Check these, one at a time. The chainset will get the valves opening and closing properly so you get good compression if all else is in good shape. If you're using an old distributor, then your timing advance may not be working right. What is your initial (at idle) timing and when do you get full advance and what is it? I would probably play with the carb last, but a look at your sparkplugs will give you an idea of how the mixture is set.