1979 400 engine build w/pics
#5
#6
Here's a quote from another guy that has nearly the same set-up:
"Just stuffed mine in the truck this afternoon. I'm using almost the same exact setup except for a Edelbrock Streetmaster intake and I'm sure my cam is a little different. I should have it fired up and tested next weekend and I can tell you more.
I'm right around 9.3:1 with TMeyer Pistons, fel-pro headgaskets, and the 2V heads. I'll also be using an eddy 650 & long tube headers.
Based on conversations with Tim and desktop dyno I'm expecting right at 400 ft/lbs and about 375 hp, all on the bottom end. It would be better with a dual plane intake but this one was free. I would also prefer to use a set of the Aussie heads but it's just a truck motor, and I think it will do fine. I bet yours will be the same."
"Just stuffed mine in the truck this afternoon. I'm using almost the same exact setup except for a Edelbrock Streetmaster intake and I'm sure my cam is a little different. I should have it fired up and tested next weekend and I can tell you more.
I'm right around 9.3:1 with TMeyer Pistons, fel-pro headgaskets, and the 2V heads. I'll also be using an eddy 650 & long tube headers.
Based on conversations with Tim and desktop dyno I'm expecting right at 400 ft/lbs and about 375 hp, all on the bottom end. It would be better with a dual plane intake but this one was free. I would also prefer to use a set of the Aussie heads but it's just a truck motor, and I think it will do fine. I bet yours will be the same."
#7
Did you seat the thrust bearing ? You should always give the crank a firm, but not hard hit with a 3 pound or so hammer with a piece of brass inbetween to get it seated right, front and back. Then check it with a dial gauge. Just prying the crank when torquing the cap is not good enough. How much lifter preload did you come up with ?
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#12
Lifter preload should be .020-.060 max. I always go for .020-.030. What do you mean by 180 and 200 ? The push rod should only depress the lifter plunger .020-.060 at that cylinders tdc. The valve train geometry will probably be way off with that much shim and a stock length. Are you trying to use stock length push rods ? Keep in mind most if not all aftermarket cams will not be ground on the same base circle as a factory cam so a stock length push rod is probably not ever going to give you the correct valve train geometry. Did you put a light weight checking valve spring on, mark the valve tip with some white greese or something that will make a pattern and turn it over carefully watching that the lifters plunger didn't compress any and look at the pattern of the rockers sweep in the greese on the valve tip ? With that much shim I'd be worried the rockers full sweep might be way too far from the center of the valves tip. It is very important with a non adjustable valve train that the machinest set all the valve tip heights to within .010 or your lifter preloads will be all over the place, something to always check when you get your heads back.
#13
We measured clearance between top of valve and rocker arm, with lifter depressed and on the back side of cam lobe. Clearance was between .180 and .200 after we shimmed the rocker arms with the .060 shims. Before we shimmed the rocker arms, the clearance was only about .080-.095 and the rocker arm was barely sweeping the edge of the Valve tip and looked like it would have sheared off. The manual said clearance should be between .15 and .20. Now the rocker arm is sitting alot closer to the center of the valve tip. Is this correct, or should we check clearance a different way? This is my first build, but the guys helping have build many motors, although mostly 460's.
#14
As long as there is min .020-.060 max preload on the lifter plunger at tdc and the rocker sweep isn't too far off center you should be ok. I'd go back and check the preload the right way, checking that way does absolutely nothing as far as being sure of actual preload at tdc. In other words you couldn't say at this point how much preload you have in any of the lifters at tdc, which is very important. .060 of shim, stock length and the geometry comming up right is at best wishfull thinking. The more you shim the worse the geometry gets, at some point you have to change push rod length. Shimming or grinding should be only for fine tuning if your tip heights aren't all equal.
You need an adjustable push rod and a light weight checking valve spring in place of your valve spring to find your right length push rod. Put the cylinder on tdc. With the engine on a stand you can eyeball the rocker tip while adjusting the push rod till the rocker tip is a little above center of the center of the valve tip being careful to not compress the valve, you want to keep zero lash. Run it through a cycle watching the lifter plunger as you go, you don't ever want it to compress the plunger while doing this. Take the rocker back off and look at the pattern on the valve tip, adjust the push rod as necessary till the pattern is centered. Then remove the push rod, measure it with a dial caliper and add to that figure for a hydro cam the preload figure .020-.060 (I use .030) and that will be the new length you need. As long as all the valve tip heights are equal then you won't need any shimms or get into grinding fulcrums. If you can't get the right geometry you can introduce a shim into the equation and then find push rod length from there but there is no need to muddy the waters with that at this point.
You need an adjustable push rod and a light weight checking valve spring in place of your valve spring to find your right length push rod. Put the cylinder on tdc. With the engine on a stand you can eyeball the rocker tip while adjusting the push rod till the rocker tip is a little above center of the center of the valve tip being careful to not compress the valve, you want to keep zero lash. Run it through a cycle watching the lifter plunger as you go, you don't ever want it to compress the plunger while doing this. Take the rocker back off and look at the pattern on the valve tip, adjust the push rod as necessary till the pattern is centered. Then remove the push rod, measure it with a dial caliper and add to that figure for a hydro cam the preload figure .020-.060 (I use .030) and that will be the new length you need. As long as all the valve tip heights are equal then you won't need any shimms or get into grinding fulcrums. If you can't get the right geometry you can introduce a shim into the equation and then find push rod length from there but there is no need to muddy the waters with that at this point.