Engine Build Pre-Assembly (pushrod length measurement)

 

Next up on the pre-assembly checks to do list is to figure out what size pushrods I will be needing.  To do this I will be bolting the cylinder head on, torquing it to spec, and then setting up the valvetrain for the #1 cylinder.

 

Below is the head gasket installed

 

Torquing the head bolts down in the proper sequence to 75 ft/lbs

 

 

I will be using my solid lifters that I explained in my last blog entry.  Here they are in the #1 intake and exhaust lifter bores.

 

 

 

To determine the pushrod length pushrod checkers are used.  They are basically a pushrod that has a threaded section so the length can be increased or decreased in size.  Because big block chevrolet motors have 2 different size pushrods for the intake and exhaust, I had to get 2 different pushrod checkers.  One that measures 7.5" to 8.7" used to measure the intake side and one that measures 8.5" to 9.8" used to measure the exhaust side. 

 

Before I did this I had gone on to Comp Cams website and was looking at the sizes of pushrods they offer.  I noticed they had a kit for a 454 Engine with their retrofit cam.  I thought I would set my checkers to their sizes and see how they fit. 

Next to do was to set the rocker arm up.  To do these checks I had to swap the normal valve springs for light checking springs.  If the regular springs were used with the pushrod checkers there is enough pressure that they could be bent.

The picture below shows where the rocker arm would sit if the pushrod was too short.  The roller is sitting too far inboard on the valve stem.

 

As the pushrod is lenghthened the roller now sits more in the middle of the valve stem.

 

In order to make sure the pushrods are the right length I needed to see where the roller tip on the rocker is actually riding during opening and closing.  To do this I coloured the top of the valve stem with a sharpie before putting the rocker on.  As I spin the engine over and the rocker, pushrod checker (set to length) and lifter open and close the valves the rocker tip will wear a pattern in the marker.

In the picture below is example of where the pattern should be.  I lucked out and the Comp Cams pushrod set that they have is a perfect fit and provided good results

Pushrod checker set to length

Setting the pushrod checker to the desired lengths

 

  

Below, I am installing the rocker arm on the valve at "zero lash".  This means that with the lifter on the base of the cam lobe (lowest point) the locking nut on the rocker stud is tightened down just until all slack is taken out of the pushrod, no more.  When I go to install the pushrods and rockers on final assembly I will be taking them to zero lash and then turning the locking nut another half turn, which puts a "preload" on the hydraulic lifter.  I will explain more on this when doing the final assembly.

 

This picture below shows a wear pattern too close to the outboard side of the valve.  In this case the pushrod would need to be shorter.

 

When I was done and I was happy with the wear patterns on both the intake and exhaust valves I ended up ordering the Comp Cams push rod set with 7.725" intake pushrods and 8.684" exhaust pushrods.  Once I get the pushrods I will do this test once more to double check correct length.

Engine Build Pre-Assembly (making a hydraulic lifter a solid lifter)

Hydraulic lifters in an engine are pumped up with pressurized oil, in the lifter body, when the engine is running.  This pressurized oil fills the lifter body and holds the inner plunger up against the pressure of the pushrod while opening and closing the cylinder valves.

During my engine pre-assembly I have to perform some measurements obviously without the engine running providing the lifters with the pressurized oil to the lifters.  If I were to do this with my hydraulic lifters the way they are, the inner plungers would collapse, providing errors in the measurements.  So in order to perform these measurements I need to either buy a solid lifter the same size as my lifters or take apart a pair of my lifters and make them into a solid lifters so the inner plunger won't collapse while making measurements.  I had talked to Comp Cams tech support asking them about getting a pair of solid lifters with the same measurements as my hydraulic lifters.  They told me that they do not have any, so the choice was made for me.  I was forced to dissassemble a pair of my lifters and make them into a pair of solid lifters.


First I had to remove a retaining clip that holds the plunger assembly inside the lifter.  It was actually a smaller version of the spiral locks that I used on my pistons.   So because I had the experience from using them on the pistons I removed them fairly easy.  I wish I had a magnifing glass though because my eyes are gettting worse as the years go on......

The cup was removed along with a spacer

I found I had to remove the tie-bar that holds the lifter pair together.  The tie-bar rivet was preventing the plunger from sliding out.  Unfortunately they were pressed in so had to be driven out with a punch and hammer.  After doing this I don't think I will be reusing this lifter pair in the final assembly, I will just purchase a new pair (I checked and made sure I could buy a pair first, in case I had to).  Cheap insurance I suppose, instead of trying to return them to the hydraulic set.  I will keep them in my tool box, who knows maybe I'll build another engine.

Below the picture shows all the parts of the lifter laid out.  From right to left: spiral lock, pushrod cup, spacer, plunger, spring and lifter.  The tie bar is above all the pieces.

Next I had to fill the space inside the lifter body that would have normally been where the spring sits.  I got some small washers and nuts to do the job.  This actually took a little while to figure out how many washers I needed to bring the plunger to the same spot (flush with the spiral lock groove in the lifter body).  With one nut and one washer I was able to have the plunger in the exact same placement in the lifter as when the spring was in.

The picture below is a view looking into the lifter with the nut and washer inside

Installing the plunger back into the lifter

Installing the cup and spacer back into the lifter

Installing the spiral lock back into the lifter to hold it all in

And that's it, a hydraulic lifter made into a solid lifter for measurment purposes.  I did the same with the other lifter.

Engine Build Pre-Assembly (Cam Degreeing)

 

The next step in my build is to degree the camshaft.  Some people may say "why not just slap it in there, it's a brand new Comp Cam".  Well, I could do that.  Chances of something being wrong with it are probably pretty small, BUT... I wasn't there when they machined it, packaged it and sent it.  So I want to verify that the cam that came to me is in fact the right one I ordered.  To verify this I have to "degree the camshaft".  Every new cam comes with a cam card that lists all the specific data about when the cam will be opening and closing the intake and exhaust valves, I will be making sure I can get these same numbers.


Below is the cam card that came with my camshaft.  I will be verifying the duration @.050" lift numbers, lobe lift, intake and exhaust centerlines and lobe separation for both the intake and exhaust cam lobes  

 

 

 

These are the tools I will be needing to degree the cam.  A dial indicator and magnetic base, a crankshaft degree wheel, crankshaft turning socket, and a wire pointer attached to the block (I used a wire coat hanger).

 

 

 

First thing to do is to find true TDC (Top dead center) of the #1 piston.  This is the exact point where the piston is at it's highest point in the cylinder.  This needs to be absolutely correct because it is the reference point that all the cam card data is based on.  I know this because during my first attempt at degreeing the cam I must have somehow knocked the degree wheel making TDC incorrect.   I was getting totally wrong numbers and scratching my head.  Finally I started over and found TDC again, after that the numbers were all correct.

 

I rotated the engine over clockwise until I got it as close to TDC by eye.  I then lined the pointer on the degree wheel up to 0(TDC).

 

I then set the dial indicator up on the top of the piston and zeroed the dial. 

The engine was turned counterclockwise until the piston was 0.100" BTDC(Before Top Dead Center).  I then rotated it back clockwise until the dial read 0.050" BTDC( I rotated it back to 0.100" BTDC and then back up to 0.050" to take the slack out of the timing chain).  With the piston at 0.050" BTDC the degree reading was taken from the wheel.

 

 

 

 

 

The engine was then turned clockwise again until the piston was reading 0.050" ATDC (After Top Dead Center).  The reading on the degree wheel was taken again.

 

TDC is the midpoint between the two numbers, so the engine is turned to that midpoint between the results.  Without moving the crank the degree wheel is then rotated so the pointer is then at "0".  The process was then repeated until the number BTDC and ATDC were the same.  At that point the "0" on the wheel should be exact TDC.

2 Lifters were then oiled and put into the lifter bores.

Making sure the lifters were both in the lowest points (valves would be closed). I set the dial indicator up on the intake lifter with a 5" pointer extension on the dial as can be seen in the picture below.  From this point on I didn't seem to take very good pictures of what I was doing.  So basically I followed the camshaft degreeing procedure included with my cam.  I will try and explain what I did.

I rotated the engine clockwise until maximum lift was achieved (dial indicator reverses direction at max lift).  The dial was zeroed at this point.  The engine was then rotated counterclockwise to 0.100" on the dial (taking slack out of timing chain), and then rotated back clockwise to 0.050" before max lift.  The reading on the degree wheel was recorded.   The engine was then rotated again past the max lift (zero on dial now) to the 0.050" mark on the closing side.  The reading on the degree wheel was recorded again.  The two numbers are added together and divided by 2.  This is the intake centerline result.  In my case was 106 degrees

To find the intake duration.  Making sure the intake lifter is on the base circle of the cam lobe (closed) the dial was zeroed.  The engine was rotated until the intake opened to 0.050".  The reading was taken off of the degree wheel.  The engine was rotated again until max lobe lift was achieved, This was also recorded.  The engine was then rotated again until 0.050" before closing ("0" on dial).  The reading was taken again off the degree wheel.  To calculate the "Intake duration @ 0.050" lift" is the first reading plus the second reading plus 180.  In my case I came up with 242.5 degrees, which is off by 0.5 degrees and close enough in my opinion.  The intake lobe lift I measured was bang on at 0.319".

To measure the exhaust lobe numbers I moved the dial indicator setup over to the exhaust lifter and repeated the same procedure.  The exhaust centerline I measured was 113 degrees.  The "exhaust duration @ 0.050" lift" was 248 degrees.  The exhaust lobe lift I measured was 0.330".

To calculate the lobe separation is calculated by adding the two centerlines together and dividing by 2.  So in my case 106+113/2= 109.5. 

It took me a few times to get the hang of this procedure, but after doing it the second time I am happy with the numbers I got and they matched the cam card numbers within 0.5 a degree.  I think I am going to go through it one more time before I finish assembling the engine just to be sure.

More Engine Parts...

 

I picked up another package from Summit Racing with some more engine parts. 

 

The Distributor I chose is the MSD Pro Billet Ready to Run.

Holley Street Avenger Carburator.  870cfm, electric choke

Edelbrock Performer RPM Air Gap Intake Manifold.  I chose the powdercoated black version, I think it'll look good with the red of the engine block.  I also picked up some intake gaskets and ARP intake bolts

Engine Build Pre-Assembly (plastigauge rods, cam and timing set install)

 

I have already determined the connecting rod oil clearances in previous posts using the dial bore gauge.  In this post I used Plastigauge to verify those results. 

 

If you look closely in the picture below you can see the small strip of Plastigauge placed on the bearing.



I used a set of vice grips to secure the crankshaft from rotating while torquing down the rod caps.  If the crankshaft were to rotate while torquing the rod bolts the Plastigauge strip on the bearing could be ruined

 



 I did the Plastigauge checks on each rod pair at a time.  The picture below shows tourqing of the #1 and #2 rod caps

 

#1 piston installed without the compression rings for now.

 



 

 

Below shows the results of the Plastigauge.  It's hard to see in the picture, but I got readings of about .002" when compared to the chart on the Plastigauge package.  All 8 rods checked in with similar results.  Which is fairly close to the dial bore gauge results within .0005", so I am happy with that.



The other rods and pistons were installed and checked too

After the Plastigauge check was done on each pair of rods.  I then wiped the Plastigauge off the crankshaft, put some assembly lube on the bearings and re-installed them and torqued down again.

The crank was then spun around a couple times to make sure everything spun freely with no interferences

 

 





After all the rods were Plastigauged, I installed the crankshaft gear using a brass punch slowly working it onto the crank.

 



 

 

Next, I pulled the camshaft out of it's box and installed the cam gear.  I installed the cam gear at this time to make sliding the cam into the block easier. 

 



The cam bearing journals were lightly lubed with motor oil at this time and the cam was slid carefully into the block.

The cam was then spun a few times to verify that it spun freely.

The cam was then pulled out and lubed liberally with some cam and lifter assembly lube.

 The timing chain is then installed.  To do this the cam gear is removed, the chain is put around the gear.  The chain is then wrapped around the crank gear.  The cam gear can then be bolted back onto the camshaft.  The Timing dots need to be lined up before the cam gear is put on.

 

The picture below show the timing dots lined up in the 6 o'clock and the 12 o'clock positions

 

I then started getting the engine ready to degree the cam, I installed the cam degree wheel, magnetic base and dial indicator and a degree pointer made from a coat hanger.  My next post will be degreeing the camshaft.  This is done to verify that the comp cams manufactured this camshaft correctly and to the specifications that are included on the cam card that came with it.