More on the "small FE" idea....

[TomP]

I must disagree on the tow rig Quadrabog idea, I think unless you are talking a CobraJet Mustang towing a Jet Ski the thing will be running with the secondaries open getting the 4 mpg that Chevy trucks get.

I think a better idea is a 4180 carb like used on 302's and 351's in the mid 80's. Annular discharge primaries. I am going to stick one on my stupid wagon's stupid 332. It gets excellent mileage already (over 20) but has dismal power. I did try a top speed run with the car but ran out of clear highway before 90mph and that took forever. The stock Holley 2V carb is tiny, like the primaries of one of those 390cfm 4 barrels.

[drdano]

Blair!  Hurry and get that thing on the pump and get us some data before this becomes a Holley/Autolite/QuadraCrap holy war!

[chris401]

And most of the early blocks will only bore 4.080" safely. A decent 4" + bore cast piston will make a less expensive use of parts already there.


I was partly guilty of making my post wonder off topic. My point was all you need is a set of decent cast pistons to make a small cube FE run and perform fine on the street. Using stock rods and stroke will be more than adequate to drive the Interstate, town or pulling a trailer. From what I have seen a builder or salesman will try to steer you into spending money that you may not need to spend. It is probably from lack of personal expexperience instead of any sinister intent to rob the customer.

[CaptCobrajet]

My test may not cure the carb debate.  Mine is a 70mm EFI throttle body on a Streetmaster with injector bungs angled in right at the valve cover rail.  I'm not a guy who will try to sell anybody anything if I don't know it will work, from experience.  I hold the opinion that that a tightly clearanced, coated, hypereutectic piston is probably the best choice for an endurance tow rig. JMO.

[chris401]

I hold the opinion that that a tightly clearanced, coated, hypereutectic piston is probably the best choice for an endurance tow rig. JMO.

That is the type of response needed. An inexpensive piston to use with what you have. Adding an extra $200 for off set crank grinding then buying rods or an extra $350 for custom pistons defeats the economy build idea. I would like to see a 1.86-1.875 piston produced for the same cost as the low compression 1.816".

$50 crank polish or $175 turn, $150 pistons and $175 bore will get the foundation for a basic build done. Then look at rod prep, decking, line hone ect.

[CaptCobrajet]

I'll go for the $175 bore, but then you gotta hone it.  A correct hone job is $350 minimum.  The cylinder hone job is HUGE, even if you use cheaper parts.  I used the Mod rods and dime-a-dozen crank so I could get a zero deck using 390 pistons without cutting the deck to death.   If you had to buy a 390 crank, turn it, and resize the rods, a zero value core with an offset and 400 rods ain't much different.  I believe in being cost effective, but some major items have to be good for a real good piece.

[Joey120373]

The cylinder hone job is HUGE, even if you use cheaper parts. 

Very curious about this, I know that a "propper" cylinder hone is crutial, but I have a feeling that that the gurus are doing something different than the standard "plateau" finish that most machine shops use.
Not expecting anyone to give up trade secrets here, but if there is substantial HP to be had by a specialized home job, I may very well bite the bullet and ship the block off to get it machined, rather than taking it to my local guy who will just throw a run of the mill power home on it.

[CaptCobrajet]

First thing is: use a honing plate.  Most shops have never seen one for an FE.  Next, know what to torque it at, then take the CARE to get it straight and round........VERY straight and VERY round.  Then you gotta put the proper crosshatch in it, both for the "underneath" and the plateau.  Depending on the use, I use different profiles on the finish.  Some stuff needs to seal instantly and run fast for the short term.  Some stuff needs to seal before burnish and run forever.  The method is different.  That is as specific as I will get here, but if you never believe anything else I ever post here, believe that a hone job can make or break a successful build.  Not just power wise, which is real, but in terms of the long haul.  Ring seal, ring life, and piston life are all affected by the cylinder prep and finish.

[chris401]

The $175 included hone. A smaller shop with less overhead can get away with that. $350 seems about right when I lived in DFW, at that time customers or my stuff didn't get the attention or knowlage your shop would probably provide.

[CaptCobrajet]

Hmmmm.  You should poke a bore gauge in one and see what you have sometime.  Sometimes stuff will get by, but it can be much better.  Some machine shops really get it......some never do.........

[Katz427]

I just would add to what Blair has stated here. If you ever get the chance to look at a cylinder wall freshly honed under a scanning microscope as I have, you would not believe the difference in a honed cylinder and a correctly honed cylinder. It is night and day and easy to see why. Also you are able to understand why piston ring manufacturers specify that one follows their directions for correct honing.

[chris401]

I trust the man doing my next cut work. If he does says something I think is wrong I will more than likely try it at least once.

[Barry_R]

Bore gauge will tell you something - but nowhere near everything.  An incometer will tell you a great deal more about bore geometry - and will show you a lot about the limitations of even a very good bore dial tool.  A profilometer will tell you a good deal about bore finish, an acetate "print" from the bore and a microscope will tell you even more in three dimensions.  You can spend your career studying cylinder wall characteristics - and some folks have done just that at the OEM and supplier levels.  At the machine shop level the best we can generally afford are the bore gauge and profilometer.  In a past career I got to see the better equipment in service and it was eye opening to say the least.

Bore geometry and surface finish are two different inter-related things.  With common hone processes and equipment (like the fairly new Sunnen SV10 I own) you are faced with two options.  You can run vitreous stones which break down and give a nice bore finish - and you "chase" the geometry.  Or you can run diamond stones which give a nicer geometry and "chase" the bore finish.  They use different coolant in the machine, so its difficult to swap from one to the other unless you own multiple hone machines.  I chose to run the diamonds since FE engines are very thin walls and consistent geometry is harder to achieve.  We use a multi-step hone process to get to the desired finish.  All of our engines get two torque plates installed before honing.

[CaptCobrajet]

Real world translation=get it VERY straight and VERY round (bore geometry), and get a proper finish for the task (diamonds, traditional , whatever gets you the right finish for the intended use).  I would like to have two hones.....one diamond, and one old school.....but I can't justify both sitting here most of the time.  If a person takes the time, and the right method, you can get there without a diamond head.  I choose the old stones, and extra time.  The diamonds get the hole straight quicker, but then you have to do a lot of honing to justify the cost.  I don't like the finishes with the diamonds as well, JMO, so I do it how I do it, and it works.  My stuff is not fancy.  I rely heavily on method.  I use the A/Stock crowd as a meter.  We seem to get our stuff as good or better than the other guys who run A/SA, and money or machine is no object to some of those guys.

[winr1]

If using a 390 crank with rod journals turned to 2.310 and offset ground the same amount as the 352 crank

It would increase the 390 crank .125 making it a 3.905 stroke ... correct ??

Resulting in 1.6375 comp. height if the deck is 10.17 .... ??




Ricky.