351w timing issue? maybe?
Thread Starter
|
Freshman User
Joined: Dec 2012
Posts: 35
Likes: 0
351w timing issue? maybe?
Fellas, I have a 79 f-150 and somewhere along the line someone put a 351 Windsor with a Holley 4bbl carburetor , the engine starts and runs idles fine. However when you rev it up it shakes something awful. Similarly I put it in reverse/drive to move it the other day and whenever I gave it some gas it would shake pretty bad and then almost cut out and it actually died a few times.. could this be an air fuel ratio issue? Timing? Thanks in advance!
Senior User
Joined: Apr 2012
Posts: 324
Likes: 0
From: Spencer Mountain, NC
Are you sure the firing order is correct. The correct order for a 351W is 1-3-7-2-6-5-4-8. The firing order for a 302 is 1-5-4-2-6-3-7-8. If your engine is set up with a firing order for a 302 the engine it will will crank and run but not to its optimum. You could also have a timing or carburation issue.
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
Since the 351W never came in the truck how the motor perches and motor mounts are installed is where I would look first .. For example if the previous owner cobbled something together using motor perches that weren't intended for that motor it could have broken a motor mount .. or maybe there is missing motor mounting hardware .. Do we know if this motor transmission combo was ever run successfully in this truck prior to you getting it ?
Posting Guru
Joined: Aug 2010
Posts: 1,761
Likes: 8
From: Knoxville, TN
True ... though why someone would cobble something when the mounts are identical for the 302 which *did* come in these trucks would be a bit of a mystery if that ends up being it ...
Can you describe a little more what happens when it "shakes"? Is it misfiring or does it seem to be unbalanced at higher engine speeds when you rev it? In the latter case, it could be that someone installed the balancer for a late-model 302 that has a 50-oz imbalance instead of a 28-oz imbalance, etc. If the former, then look to mixture or ignition.
Can you describe a little more what happens when it "shakes"? Is it misfiring or does it seem to be unbalanced at higher engine speeds when you rev it? In the latter case, it could be that someone installed the balancer for a late-model 302 that has a 50-oz imbalance instead of a 28-oz imbalance, etc. If the former, then look to mixture or ignition.
Thread
Thread Starter
Forum
Replies
Last Post
TheJunkMan
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
1
Jan 18, 2011 08:48 PM
me123
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
5
Mar 7, 2006 06:45 PM
