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Hi, just rebuilt my 93 351w after a coolant problem, replaced head gaskets.
She will start on first turn and idle fine but if you give it some gas it won't rev smoothly and when you take your foot from the gas the revs don't drop off straight away, when I take her on the road there is no power at all and it dosn't sound right.
I'm pretty sure I have all the pipes in the correct places.
Any suggestions would be greatly recieved as in England there are very few garages which will look at American vehicle let alone that I would trust.
if you had the valves redone, or even mixed up the components from cylinder to cylinder or used a thinner head gasket, the most likely problem is that they need to be shimmed on the platform that holds the rockers to get back the proper preload the hydraulic lifters need. shim kits are easily available and easy to install.
to check, with the valve covers off, put a cylinder in tdc with both valves closed and see how far you have to loosen the retaining nut for there to be play in the rocker. you'll prolly see some that are way too preloaded, hanging open, and will need shimmed.
Maybe a few plug wires are crossed up, so the firing order is wrong? My experience is with older carbureted 351W's, but it sounds like a timing issue. Distributor off by a tooth, or vacuum advance not working perhaps?
I will check these things tomorrow(sat) but I have checked the plug leads and all the valves went back to their orgininal seat, does anyone think it could be something on the egr?
Hi, thanks for the idea's, I have checked the timing and that is fine(could not do the propane test thing as it's in a van and there's not a lot of room and you can't tell if the gas is being sucked in the carb). I have removed the upper and lower inlet manifolds which seem fine but cannot rebuild because couldn't get any new gaskets, hopefully they will arrive next week and i will try again, any idea's of checks to do while they are off to save time later? or parts to change which could avoid earlier problem?
Allan
Hi, thanks for the idea's, I have checked the timing and that is fine(could not do the propane test thing as it's in a van and there's not a lot of room and you can't tell if the gas is being sucked in the carb). I have removed the upper and lower inlet manifolds which seem fine but cannot rebuild because couldn't get any new gaskets, hopefully they will arrive next week and i will try again, any idea's of checks to do while they are off to save time later? or parts to change which could avoid earlier problem?
Allan
What is the timing, since you checked it? Initial, final, and at what RPM does it top out at?
What is this propane test you speak of? Are you suspecting a vacuum leak on the intake?
Last item - you mention a carb? I'm confused - isn't it fuel-injected? If it's a '93, it should be throwing 'check engine' codes.