ERE-383 #77


ERE 383 #77
Rebuild of 4-bolt main GM 350 with LE heads & Cam

READY FOR THE DYNO

We are starting with a pretty good running 350LT1, (4-bolt mains).  It already has a nice set of LE heads and an LE camshaft.  Attempting to figure out why the motor had a noise at high rpm and lacked the full power punch that was expected of it.  Also converting to a 383 stroker while she is here at the shop.


Crane gold 1.6 ratio self-aligning rockers with 7.2" pushrods.  Nice components.  The poly-locks look to be just barely threaded on the stock rocker studs.  (No-harm no foul).  I tested the thread engagement and it's about 5 threads.  Taller rocker studs will be needed.


The self-aligning rockers need a lot of valve tip in order to keep from hitting the retainer or keeper.  This looks ok but very close to hitting.

The rocker poly-lock nut slightly rubbed each rocker but eventually clearanced itself.  This is pretty common and again no harm-no-foul.

Each valve retainer had slight witness marks from hitting the rockers, (probably happened at high rpm).  This would cause the rattle sound.  Nothing is broken or overly worn but I'm sure eventually a rocker would have fallen off the stud or a spring would have broken.

There is a bit of fine metal pooled in the lifter valley that probably came from the rockers and valve retainers.  All of the lifters looked good visually except #1 intake lifter was difficult to remove from the lifter bore.  Some valve float pounding?

The combustion chambers look excellent!!

Pistons and bores look good too.  No oil burning.

The oil pan looks great!  No debris what-so-ever.

I don't know this label but it's probably GMPP replacement 4-bolt block lingo.

This would not be from the factory...the HV oil pump.

It's a very nice bottom end.

I'm happy to see the builder has the windage tray installed.  The HV oil pump is prone to cavitation but the windage tray will certainly minimize the risk.

The pump had the 3/4" pickup RTV'ed in place and you could easily move it and pull it out.  But the system worked.  The bottom end looks to be in good shape.  The pickup stayed in place until I pulled it.  I have installed pickups like this in the past but with 3M boat calking.

Nice 4-bolt mains.  Rods were balanced by evidence of the buffing on the lower cap.  
Next on the to-do list is to get the block to the machine shop and order a 383 rotating assembly.


Upon further tear-down and inspection we find #1 intake and exhaust cam lobe wiped.  That is the cause of all the fine debris.  The lifters were ok.  Maybe a soft cam core?


Oh boy!  I've never seen this before.  The builder installed all of the right side pistons/rods backward.  #2,4,6,8 were facing forward.  The piston dots were facing rearward.  But this error did not seem to cause any damage.  The pistons and rods looked great.  The cylinder bores looked great.  The only problem I can detect with the running of this motor was possible valve float at high rpm and the cam lobe damage.

The crankshaft does not spin freely.  The main bearings must be gummed up or tight.  Upon removing the crankshaft it looks as though the main bearings are scratched up with dirt, (from the cam lobe wipe).
Project moves into the parts combo phase:

Callies 1-piece rear main seal Dragonslayer crankshaft.

Callies 6" Compstar H-beam rods.

Mahle premium D-Dish piston with 1.5mm rings.

Callies has 4 crankshaft on the shelf assigned to me.  Now it's time to call for one and have it balanced.  (1744g).


I use a pro 3-beam scale and a cheap flea-market digital.


The Mahle SBC125030I16

This scale is used as a 2nd check.  It's 1 gram high.

After weighing all parts individually I weigh the piston/pin/lock/rings all as one and make sure it matches the sum of the individual parts.
Piston 432.0g, Locs 2.2g, pin 117.0g, rings 35.0g = 586.2g...then rods 450/174g, King bearings 39.0g.  (6g for oil) = 1744g


The block is still at the machine shop but I'll get the pistons and rods mated up in the mean-time.


Callies/Compstar 6" H-beam rods.

Mahle -16cc D-dish piston #SBC125030I16

Checking rod bearing clearance I start with torquing up the rod, (.005" stretch or 80ft-lb).

The Callies Dragonslayer crankshaft rod journals mic out at 2.0990".

King rod bearings installed.  The 1st rod to the left was using standard size on top and bottom which gave .003" clearance.  Then after mixing .001" and standard it came out to .0025".  That is more like it.  All 8 rods then received standard size for the top and a .001" under for the bottom.  All came out to .0025" clearance.

Now file fitting the Mahle piston rings.

The target it .019" 1st ring and .016" 2nd ring.
Stay tuned.  The block should be finished soon and the assembly will begin.
Now the job is to clearance the bottom of the cylinders for the stroke.  I do this by hand and then mock up a rod/piston combo and see if there needs to be more clearance.  Then POR15 black paint.

This is the drill bit used for block clearancing.
POR-15 Engine black

Here are good views of the rod clearance at the bottom of the bore.

Now onward:  Measuring for main cap bearing clearance.  King 557HP bearings and stock 4-bolt main caps to cradle and support a Callies DragonSlayer crankshaft.

Most of the caps required a mix of .001" under and standard size.  The crankshaft main journal size mic'ed out to 2.478"

QC photo of the oil gallery steel ball plug in place.

Cam bearings being hammered into place.

Main thrust bearing feeler gauge at .004" and then total crankshaft endplay at .007" with the rear main cap torqued to spec.

Lunati camshaft from Lloyd Elliott.

Stock weep-hole oil galley plugs installed for cooling of the timing set.

This is a GM extreme timing set, (being re-used).

Serial number of the Callies crankshaft = 147295

Double check of the ring gap in the actual bore as opposed to the bore gauge tool.  

Here is how I check piston to bore clearance.  I use a feeler gauge.  A .003" fits and the .004" does not.  Mahle spec is .003 to .0035".

Photo to the left shows the pistons at.008" in the hole.  The block is not zero decked.  I ask that it be decked to about 9.010".

Photo above shows feeler gauge of .018" (rod side clearance).  All rod bolts torqued to .005" stretch. (80ft-lb).


Camshaft degree check.  Intake centerline is at 110* which matches the cam-card.

LE installed new valve springs.

New Comp rocker studs #45012-16. The self-aligning rocker passes the check here.  Good clearance between rocker and retainer.

And here is a pretty good witness mark of the rocker tip on the valve tip.

This was the lifter guide for #1 int./exh.  I replaced it with a take-off in good condition.

Crower 66330-16 hydraulic lifters and new spider.

Reusing the Comp 7940 pushrod, (7.200")

All of the rockers have these clearance/interference marks.  Right now it looks like there will be no clearance issues.

Getting ready for the engine dyno.  GMPP dual-plane intake manifold.

The previously used pump is the HV to the left.  I'm replacing it with a SV M155 but with a high pressure spring.  The refurbished oil pump drive gear is shown on the left and the old gear on the right.

Rod-bolt clearance with the windage tray.

Stock 3/4" pickup installed by freezing and then pressing on.

Oil pan hammer message for #1/#2 rod clearance.
Oil pan on and painted.

Oil pump and system pressure test:  Cold oil @ 60psig with rather low speed drill.

I spin for more than a few minutes until most of the rockers show oil up from the pushrod.

Setting up for dyno:  First I need to make sure my TDC is accurate.  The LT1 does not have an aftermarket pointer available and so I make due with a gen 1 small block Chevy pointer from ATI. 

I use the piston stop method and it stops at 20deg BTDC and ? ATDC. (no marks on damper after TDC).

And so I just find the 1/2 way point and it should be TDC on the pointer/damper.  Here is the tape I use which comes from my wife Nancy's purse.

Then I set the distributor in place with #1 on the compression stroke at about 36 deg. the fine adjust when on the dyno with the timing light.

Look closely and you'll see "Neutral" written on the rear main seal housing.  I've installed the wrong flywheel at the dyno and that is a pain in the butt to stop the session and swap to the proper flywheel.  This might help me reduce errors.

On the dyno at Jim Morgan Racing Engines [Morgan International]

Power falls flat at 5000rpm and above.  Wondering if the valve train is not up to snuff?

The next day:  Swapped to 7/16" studs and rockers....still flat above 5000rpm.

A few days later....new distributor, coil, ignition, Carb....still flat.  We will get to the bottom of this.  Going to try new valve springs and head back to the dyno.

Verification of pushrod length.  Here is the trace from the 7.200" pushrod that has been being used in the engine and it is more than perfect.

After buying a few tools, (it's about time I invested in cylinder head tools)....I checked as found install height.  It is 1.840" (that gave 140# spring pressure).

Here is my spring pressure checking tool.  This is at 1.790" and that is 155psi.

These keepers put the spring at 1.790"

Here you can even see where to valve spring retainer was sitting previous and the new height.  The valve stem has a witness mark from the old keepers.

 Ellwein Engines 2017