Cylinder taper tolerances
 

Does anyone know off hand what the cylinder taper tolerances are for a 351W? This simple rebuild is truning into a nightmare if I have to get this thing take to .040 over.

The best I can tell on the ridge after pulling things apart is it's at .003 or .004. I couldn't get the feeler guage to catch on the ridge because it's a very eased edge.

It's been over 30 years since I last did this and I don't have any of the tools at my disposal I once did. Also, any tolerance specs for the crank and rod journals would be appreciated.

I understand the best way to go would be .030 or .040 over and add in a stroker kit with new rods, pistions and crank but then I have to add all sorts of things like stud girdles, windage trays, etc...... and I'm simply not looking for that much HP!

Thanks!!

Max. cylinder bore taper for a 351W is 0.0010.If you're going to replace the entire rotating assembly,a storker kit isn't that much more money.It all depends on what you want out of the engine,and the vehicle it's installed in.

Hope that's a typo .:-X03



Hastings says there rings will seal up to .012 taper . That's a lot of expanding and contracting even at 1500 rpm .

An old farm truck being patched up might do OK with a 4 or 5 thousandths taper but I would hate to go over .003 on the road even as cheap as I am .

You can run a motor a long time if you valves are still sealing and your rings are still ringing .:-X04

big vann,

Thanks for the info. I actually figured things out today. The tolerances for this engine are right at the edge. I also started checking the crank main and rod journals and they are also too close.

The best option is not the smartest option and the stroker kit is the smartest option for the money. Pricing out a just better than stock rotating assembly is more than a 393 stroker kit. I talked it over with the business manager at dinner and she seemed to think it was better than sinking money into an engine that was not a solid effort.

Napa will clean, bore the block with a torque plate, and install new freeze plugs and cam bearings for a decent price. I am interested if anyone knows of a good Machine shop in the Tri Cities area of Virginia that could do a better job than Napa. If I'm gonna drop the coin needed to do the rotating assembly, heads and whatever else, I just want to make sure it's a good shop. Napa may be a good shop......I don't know enough about this area and I want to make a good decision.

Thanks!

Actually it is more than a typo,it's a mistake!You're right I wouldn't go over 0.03 either ,although it's been done.It's cheaper and easier to do it right the first time.You'll love the torque of a 393.

What a mess! Tried to post something this morning and computer downloaded some crap. Took the whole day to get it removed. Not sure what happened since I was in the middle of typing a post.

The whole original thought was to do a simple hop-up job. I had a 351 out of a '69 Mach1 in 1980 stuffed into my 66 mustang. I figured if I could just do it a little better than that, I would be happy. I was trying to avoid the rotating assembly because of the extra cost and hoped a hone and new rings would do the trick. My original 351 had the 66cc chamber 289 heads on it and ran great with a ridge cut, hone and new rings. Trouble is I didn't have the car for any duration of time after that since I sold it about a year later. Then it was wrecked and that was it.

Since I'm keeping the slick, it was decided to actually do the right thing. What I wanted to do and what needed to be done was the thing that needed to be settled. To spend everyything I was and not take care of something that could cause issues was not the right thing. Anyhow, I'm old enough where my needs and wants won't hurt me....too much. :-X21

Glad to hear about the torque. Makes me worry about the back end of the truck being so light though. We decided to not lower it and that makes the extra HP harder to deal with and not burn up tires. The wheel wells are staying stock too.

I'll try and keep an update running when we get started. Just got to get the machine work done and the extra funds for the changes.

Later