Refurbishment of David Ralph's LT1-383 Blower Motor
This is an excellent motor.  A builder in Connecticut put it together originally and they used quality parts and the workmanship is top notch.  The motor has ingested roller lifters, (Comp "R").  My duty is to diagnose problems (if any) and put her back together.

The motor is built around a very solid foundation.
Callies Dragonslayer crankshaft and Oliver forged 5.7" rods.
The pistons are SRP brand and have held up quite well.
The rings are top-of-the-line Total Seal with AP gapless top ring.


The motor as delivered.  Very nice piece.  ARP head studs, Eagle splayed main caps, Callies crank and Oliver rods.


The motor was putting out some massive horsepower.  The owner said 600+ rear wheel HP.  This is with the help of an ATI huffer.


The valve-train was the only problem with the combo. Bent pushrods and broken roller lifters caused some damage but nothing major.  A few dings on the crank and underside of #7 piston 


Some left over debris.


The crank is in very nice shape and simply needs a polish.  The Thunder Racing keyed LT1 hub was dang near welded onto the snout though.  It had to be machined off.  I think the hub should have been honed a bit to fit onto the Callies crank snout.


The SRP piston looks to have held up quite well.  The Total Seal rings are part number MS3690-35  The most expensive set of rings known to man.  The top ring is designed for severe nitrous and blower applications.


I sent the block off to Brinkley Auto Machine for a health check and cylinder hone.  No cracks detected.  Very good and square deck.  Mains OK.  Cylinder hone complete.


I cleaned the block after Brinkley finished his work.  Hmmm, that rust needs some engine black paint.


How's that?


Block is in my shop, clean and dry and oiled.  I use the same cam bearings that the original builder had in this block, (Dura-Bond).  I measured all the cylinder bores (without the heads on) and they were round and at 4.0295".


I need to measure the crank for bearing size.  The original builder used Clevite H-series bearings. (one bearing half standard and one bearing half .001 under for the mains and rods).  That was an excellent choice.  The crank measures 2.4480" on all the main journals and 2.0990" on the rods.  The rods certainly need .001" under bearings.


I'll order a few sets of Clevite H-bearings, Standard, .001" Then get this thing up and running.
Also have the Total Seal rings on order and hopefully a custom cam from A.I. 


Now in order to spec out a custom cam, (from Advanced Induction), I need to know the engine combo specs.  The heads cc to 62cc and the pistons are 24cc D-dish so static compression ratio is around 9.3:1


Here are the heads after refurbishment by Brinkley Auto Machine in Forestville MD.  Brinkley did a valve job and installed the valve springs to the exact specs on the CompCams box, (spring #978-16, 403lb/in spring rate, installed at 1.850" for 126lb seat).


This is the GM extreme LT4 crank sprocket damaged by heat when taking off the hub.  A new sprocket can be purchased separate from DAL for $46 bucks.  Part number 14088784.


If possible, I always install the crank sprocket when the crank is out of the block.  It's just easier.  I do have a very nice hub installer that will press that thing on like a knife through hot butter but it's on now and should never have to come off.


Now this is the 1st step in measuring for main bearing clearance...having a clean and ready block.  The original builder used a mix of std. and .001" Clevite H-series bearings which is exactly what I'm going to use.  They didn't just slap this thing together.  It was assembled very well with great care.  Let me show you some of those nice details.....(next thumb)


The oil passage opening to the main-thrust bearing is modified to allow oil a direct shot to the Clevite bearing oil hole.  Nice touch.  I'm now doing that with all of my motors.


I started out by swapping out 3 of the ARP main studs with the longer windage tray Milodon studs.  This allows for use of the stock windage tray and that tray is essential for good oil pressure.  You guys who say your oil pump sucked the pan dry probably and actually had aerated oil, (if you didn't have a good windage control system).


So I started out with .001 bearings in top and bottom and then all caps are torqued to spec.  The crank main journals are all 2.4480" so that's what you subtract the bearing dial bore gauge readings from.  #1 was 2.4498,  #2=2.4496, #3=2.4497, #4 not measured and #5 was 2.5000.    I already know that's a bit too tight so I didn't even measure #4.  Those readings give the following clearances---.0018,  .0016,  .0017, #4 not measured, #5 .0020".  So I did the same thing only this time with .001 and standard bearing shells in each position accept #1.  I kept the .001/.001 bearings shells in #1.  Final clearances, #1=.0018, #2=.0020, #3=.0020, #4=.0020, #5=.0026    


Now I set the crank in place and torqued all the caps accept the thrust.  This is where you make the 2 thrust bearing caps share the load.  You see what thrust is without the bottom cap, (.008"), then torque the bottom cap and hope that it is close to the same, (.008").   If you get .005 or so then the 2 thrust shells are not sharing the thrust equally.  You just de-torque and try again if that is the case.  The crank end-play final is .008" which is a bit on the high side but the fix is regrinding the crank.  I think .008" will be ok.


The crankshaft is in for good.  Now onward to measuring rod bearing clearance.  I can do that to get ahead of the game.  But that's as far as I can go.  Total Seal rings are the hold up.  I ordered them more than a week ago and still do not have them in hand.  As soon as I get the rings and also the Ai custom cam this motor will be finished.


Piston #7 is the only piston that was damaged by debris.  These gouges on the edge are deep but pistons can live in a strong engine with things like this.  I'll buff the gouges a bit.


Really cannot take the gouges out or a lot of material will be removed.  I buffed the area just to make things smooth.


So now it's time to measure all 8 rods for bearing clearance.  To do all 8 rods takes me hours.  It requires inserting the bearing, torquing to spec, measuring the rod with a bore gauge and subtracting the crank rod journal measurement from that.  Also need to clean the rods and pistons and goop up the bolts with Oliver thread lube.  These 7/16" Oliver/ARP WSB bolts require .0053" to .0058" stretch which should be achieved by 30ft-lb then 40deg.


I'm using the same bearing sizes that were in the rods.  Standard and .001 mix. These are Oliver forged 5.7" rods and are very high quality.  They are not the "billet" rod but they are damn good rods.


Put the bearings in, torque to 30ft-lb, turn the bolt another 40deg.  That is a lot of torque.  At amounts to around 90ft-lb.  I'm not using the torque wrench to crank the bolts 40deg. but I eye-ball it with this breaker bar.


Then check the bolt stretch.  I get .005 to .006"


Now we bore-gauge it and come up with .0018 to .0023" between all the rods #1 through #8.  That is very good. 


All rod/piston combos ready for rings and ready for installation into motor.  Hey Total Seal!  Where are my rings!?


May 9th:  The Total Seal ring set arrived.  Part number MS3690 35, (gapless top ring, advanced profile, napier 2nd ring.  $300+ bucks for these rings.  This is the top ring combination (upside-down).


Here is how the top ring combo would go into the piston.


Here is a Napier 2nd ring.  The Napier has a little scraper lip.  The top and 2nd rings still need to be file fit.  To give me an idea of what to gap them at I put the old rings in the bore and measured what gap was used previous.  They had .034 top and .030 2nd.  I'm going to duplicate that.


All rings filed and stored in their bore.


Now to install the rings onto the pistons.  The top gapless ring, (which was gapped at .034") goes on first.


Then the thin ring goes under the thicker ring.  The thin ring looks very much like an oil ring.  Total Seal has a nice warning tag on these thin top rings.  "Warning, these are not oil rings---don't mix them up"  or some such words.


All rings on.  Pistons stored in order.


All piston/rod combos installed.


Just wanted to show you the oil pump drive.  It's a nice bronze gear.  The original engine builder did a top-notch job.  Many nice little details were put into this motor.


Another neat touch from the original build is tapping the front of the 3 oil galleys.  The local machine shop, Brinkley Auto Machine does the same thing.


Now I have David's LT4 extreme duty timing set installed and this photo shows TDC during cam-degree set up.


I've run into a big snag.  The cam degrees around 8 deg advanced for both intake and exhaust lobes.  It's cause could be the cam but more likely it's due to the timing set or crank nose/sprocket key.  This photo shows me pressing on a different timing set.  I'll degree the cam again with this timing set. 


It still comes in 8 deg advanced.


I tried numerous other crank/cam timing sprocket combos and still no luck.  Now this photo shows me pulling the cam.  I am going to stick another cam in and see if the timing is still messed up. (to rule the cam in or out as the cause).


It's still off even with a known good cam.  So I stick David's new Ai cam back in and I use Cloyes double roller crank sprocket at 4 deg retarded and also this Hex-Adjust cam sprocket set at "zero".  The cam then degreed very good, (107 ICL when the cam card calls for 106).

I'm stuck for now.  I'm sure David wants to keep his stock water pump so I need to get the GM extreme timing set to work.  I'll pull this Cloyes double roller set and re-install the GM extreme set and try out different cam gear pin retard bushings.  


OK, here is what was in the timing set. . . a cam pin off-set dowel pin bushing.  This looks like a 2 deg. bushing.


I have a set of them in my spare parts drawer.


I installed what looked like a 6 deg. bushing and set it "retarded".


After trying all the different bushings and re-checking timing about 30 times...I settled back on the 6 deg bushing that was first selected.  The cam card says 106 intake centerline and I get 105 deg.  That is very close and as close as I can get.


Now cleaned the head deck surface to get ready to install and torque them to spec.


This motor uses head studs which are very good for blower motors.


Both heads on and torqued and rocker studs and guide plates on.


And the timing cover with new seals.  


While we wait for GMPP LS7 race lifters, I can at least check that the pushrods are the right (or wrong) length.  Magic marker the valve tips.


Install rockers and give 1/2 turn pre-load.


Very happy here!.  Perfect geometry.  I actually colored the witness mark with silver magic marker so that the camera could see but that's where the mark was made.

Now as soon as the hydraulic lifters arrive from Scoggin-Dickey this motor is 100% finished, (although I still need to install an ATI damper and button up a few other things such as the rear main seal).


The lifters arrived from Dal.  These are the new "race" LS7 hydraulic lifters.  They soak in 30w oil overnight.


Here is my favorite oiling set up for a stock oil pan LT1.  The stock windage tray and the high volume, high pressure big block Chevy M99HVS oil pump.


To fit around the big body oil pump you have to take tin snips to the windage tray.  I grind and wire-wheel the trimmed area to make sure small slivers don't fall into the oil pan later.


This tray won't clear the rods on a stroker motor unless you use the longer Milodon main studs.


Sometimes you have to bend the tray up and away from the rod bolts.  In this case I did not have to do that.


That M99HVS oil pump comes with the drive shaft and the press-on pickup.


www.Karl-Ellwein.org 2007, Ellwein Engines 2007, , email Karl Ellwein