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Technical 389 cu. in. Roller SBC Build

Discussion in 'The Hokey Ass Message Board' started by Montana1, Jun 15, 2019.

  1. This thread is going to be a conversation/journey/history about building up to this latest 389" roller motor for the '32 Hot Rod. I'm usually one of those guys who's not afraid to try some things, even if it cost's me a little more than usual. It's been a real learning experience. I hope you enjoy the ride!

    Over the years, I've had several different motors in this car since I built it back in '04-'07. All these motors were stroker motors with a B&M 144 blower on them. The first one was 383", B&M 144 blown, 010 medium-duty truck motor with a mild cam and stock, small valve, iron heads, and a 650 spread bore Holley on it.

    Of course, with a new build you tend to beat on it a bit, and in time I tore a few things up. Some were my fault and some were not. I'll get into that as we go.


  2. I've lost a few cams (four to be exact), back in the days when they were taking the zinc out of the oil without telling us, and I couldn't figure out what in the world was going wrong. This wasn't my first rodeo! I suspected something sinister might be going on behind our backs.

    Each time I'd replace the "flattened" cam with a different one, trying to find the right power and sound I liked. I finally settled on a COMP XE262H. 262 / 270 duration with .492" / .500" lift with 1.6 rockers. It had really good torque and sound, and delivered 18 MPG.

    I even tried one of COMP's recommended so-called "blower" cams and it turned out to be nothing more than a stock spec. replacement cam for a 305 FI, with a wide LSA, which I quickly removed in exactly 2 weeks and threw it in the junk. It was smooth and lazy as Granny's Oldsmobile.

    Interestingly enough, as I went from an XE250-260H up to the XE262-270H cam, it went from 22 mpg down to 18mpg, but the slight rumpety-rump was there and that's what I was looking for!


    Checking the cam and rod bolt clearance. Had to trim a few...

  3. I even cracked a couple of cylinders one time, due to uncontrolled detonation down at sea level, That was my fault because I didn't follow the tune up close enough when I got there. Also, I had too much CR and too small of a cam. That's not a good combination at sea level, but you can get away with it at higher altitude. You can also get by at lower RPM's, but not so well at higher RPM's.

    So, I had them re-sleeved (which didn't workout very well either). The machinist said he sleeved them all the time for the local dirt tracker guys, but it never was right after that.

  4. blowby
    Joined: Dec 27, 2012
    Posts: 8,272

    from Nicasio Ca

    Hole in the fire! Are those flat top or pop ups? Forged? Looks like more of an immediate failure, no other signs of impending danger.
    Montana1 likes this.

  5. Ericnova72
    Joined: May 1, 2007
    Posts: 486


    Looks like KB hypers to me...and that is always where they break.
    They've got no place in a forced induction motor IMO...go forged or go home.

    Sleeves can work fine...but you've got to bore the rest of the cylinders to the next oversize because the sleeve's press-fit distorts the original cylinder to either side of it. Can't put sleeves in a .030" overbored SBC and stay at .030"'ll have a lot of blow-by and oil consumption if you do.
    Two sleeves on one back and next to each other is kind of a deal breaker too. Takes a lot of the strength out of the block.
    Montana1 likes this.
  6. Yes, they were KB Hyper flattops and it was only 5 lbs. boost at sea level. I've run these pistons for many years. I had been to this place several times before, but I didn't give it enough jet and had too much timing this time. It went into a pinging frenzy and wouldn't quit!

    However, the machinist said he had good success sleeving many blocks in race cars and so we installed one in each bank. Interestingly, it only broke two cylinders, and one piston. I probably won't sleeve any more blocks. It ain't worth it!

    I also came to the conclusion that a small cam and stock small port heads easily incite detonation because of the overly high velocity, which increases burn speed and requires less timing. It just got me this time, that's all! That's part of the learning curve...
    Last edited: Jun 17, 2019
  7. So after the cylinders cracked, I built another 383" 014, 2-bolt block and had it bored .030" and decked .020" at a different shop. He set the piston clearance at .0025"-.003" with KB Hyper dish pistons and did a really nice job, but he thought it should have a 600 grit hone job.

    I didn't care for that because I never liked a slick cylinder surface, but I thought I'd give it a try. I prefer a 320 grit hone instead, but he said that was too coarse, 600 would be better. Personally, I think 600 grit hone and rail rings might work well in a Honda Civic that spins 9500 rpm. :eek:

    But anyway, I put in all new parts and had him balance it thinking this might be a good motor. This motor ran good, but it NEVER sealed up! It drank oil like a "drunkin' sailor"! It only got 200 miles per quart of oil and fouled plugs every once in a while, but it never smoked.

    After about a thousand miles of it, I got mad and beat on it for about a 1/2 hour. I figured it would either live or die! When I pulled off the exit ramp it was a little warm on the gauge (200*). It started squealing and when I looked down, there was no oil pressure and it quit.

    The wife looked at me and said, "What do we do now?" I told her, "If it starts, we'll drive it home!" To our surprise, it did! The oil pressure came back up and everything looked OK, so off we went. After that beating, it got about 500-600 miles to a quart of oil. I thought we were making progress.

    I will say that I had a FRAM filter on it and I think it collapsed or something. I went home and changed the oil and filter, and did some research and found out there were some issues to that affect. I switched to WIX after that.

    I ran this set-up about 10,000 more miles over the next summer. It ran fairly well in spite of the many issues, and believe it or not, it got 20 mpg with a small cam and small heads.

  8. In the summer of 2012, I acquired a new set of IK 180 BRODIX heads, so I began to install them. When I pulled the old heads off, every cylinder was scored. When I took the pan off there was a puddle of cast iron chips in the bottom about 2 1/2" - 3" dia.

    When I pulled the rods and mains, everything was showing copper. When I pulled the cam and lifters, they were well on their way to going flat. I was just about sick! Surprisingly, the crank was OK. The machine shop was supposed to have cleaned everything and made it ready for assembly, but obviously they missed something.

    I was in a pinch now and had to get the car running, so I ordered some .040" over KB 135 dish pistons, rings, XE262H Comp cam and lifters, new rod and main bearings and went to work.

    I proceeded to hone it to .040", but some of them didn't clean up at .003" clearance. A couple of them had to go out to .005" and .006" clearance to clean up. It clattered a little when it was cold, but it went away when it warmed up. I know that ain't right, but it got me by for 7 years and 60,000 miles!

    This time I used a 280 grit to rough it in and then finished it with a 320 grit. Ironically, that motor started off at about 600 miles to a quart of oil and after 2 dyno pulls it went to 1200 miles per quart! I NEVER had an SBC get that much!

    Besides that, the .040" over pistons were about 25 grams heavier than the .030" over and the balance was way off. I was able to cut them down about 10 grams, but the motor always shuddered at about 4000 rpm and it just wasn't smooth at any rpm.

    Believe it or not, that 385" motor was my best running build to date! It made 592 torque and 465 HP with 4# of boost and got 18-19 MPG. That motor was a torque monster and a blast to drive!

    Then last winter it started drinking oil again.




    Surprisingly, these .040" over pistons still look like new today, except for the carbon on top.

    Early Ironman likes this.
  9. After the 385" motor started drinking oil, I started looking for another block. I have two of them back in storage that need machining, but I needed it right away and I wasn't going back there for several months or so.

    Fortunately, I found an 010, 4-bolt block that was bored & honed .060", decked .020", align honed including main studs, and ready to go. It was at a local speed shop where I winter and the customer decided to go LS and I got it for the price of machining. What a deal! ;)

    At first, I was a little leery of the .060" over bore thinking it might run hot or something. As it turns out, it seems to run just fine and maybe even a few degrees cooler than the 385" did. I've let it idle a few times for about a half an hour or so, and it only goes up to 205*-210*. I think that's a pretty good indication of how it will respond sitting in traffic somewhere.

    Here's the specs on this motor. It has a 4.060" bore and a 3.750" stroke, making 389" cu. in. I always said my next motor would have a roller cam, so I chose a mild 264*-270* retro-fit hydraulic roller from Comp. It has a lift of .487" and .495" with 1.5 rockers. I chose 1.6 roller rockers to net .519" and .528" lift at the valve.

    The crank is a Scat 3.75" stroker with Pro-Comp H-beam rods. The heads are IK-180 hand ported, street heads with 2.02 & 1.6 valves, beehive springs and 73cc chambers. Pistons are Forged ICON 9926 +.060, with 18cc dish yielding a mere 8.9 to 1 compression ratio. That should be good for about 4#-5# of boost on mid-grade. This is a daily driver.

    Here's a couple of pics...


    Last edited: Jun 21, 2019
    Desoto291Hemi likes this.
  10. gary kessler 1932
    Joined: Apr 16, 2010
    Posts: 83

    gary kessler 1932

    You must have lots of money if you r buying that much shit!!
  11. Most of this stuff came from many years of collecting, just like everyone does. A piece here and a piece there. I had almost everything but the block, pistons & rings, and cam & lifters. :cool:
  12. Back in December I broke a rocker arm stud. I was on a trip and I pulled in to a gas station. I filled up and pulled out of the way to write everything down. When I hit the start button I heard it snap. I pulled the valve cover off and took it apart.

    I called a friend in the Springs to see if he knew of a speed shop in Pueblo and he told me he'd call around. In a few minutes he called back and said that Bob had a screw in stud and he'd be over in about 30 minutes. Sure enough, Bob came to the rescue! Thanks Gene, Bob, Tammy and Caden for all the help!

    It took a couple of hours for everything and I was back running again. Here's a picture of my Grandson helping me change the stud...

  13. Today I learned something about an SBC that I never knew!

    When I got this .060" over block last winter, I got it for the price of the machine work. If you read this far, you'll know that it was bored, honed, decked and line bored and ready to go. The guy was going LS and I got it cheap.

    Well, this motor always made a loud screeching noise upon start up. I couldn't figure it out for the longest time, but I've heard this noise on a few other cars. I always thought they needed the starter shimmed, but never had to do it myself.

    So, I got to studying this problem and couldn't find any answers. Finally I ran across a couple of guys named "modifieddriver" and "tfeverfred" here on the HAMB. They were talking about the starter being too far away from the ring gear. Could it be?

    I don't have mine apart, so I don't know how much I need, or what direction I need to go. After thinking about what these guys said, I realized that my starter gear might be too far away from the flywheel, because of the line boring job, which raises the crank away from the pinion gear.

    So, I was ready to mill .100" off the top of the starter nose cone where it meets the block. Then I read where "tfeverfred" said to just shim the outboard side of the starter, which would move the pinion gear closer to the ring gear.

    I took a wild educated guess and put a .060" shim on the outboard bolt only, between the starter and the block. When I tried it, it was smooth as silk! Thanks to the vast knowledge of the HAMB, "modifieddriver" and "tfeverfred", I'm back in bidness!

    Here are the links to their conversations:
    Post #8
    Post #19
    Last edited: Jan 28, 2020
  14. This was very interesting to me,,,I am always in when it comes to engines .

    Montana1 likes this.
  15. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 424


    In most cases when you line hone a block you only remove .005 from the bottom of the main caps and then bring the housing bore back to standard size so in theory your only raising the crank .0025 which I’ve never seen affect ring gear clearance. I have heard stories of sbc engines having the starter holes in the wrong place or some don’t have the duel pattern and guys try to wing it and drill and tap the second hole and mess it up. Either way I’m glad you got it worked out.

    Sent from my iPad using The H.A.M.B. mobile app
    ottoman and Montana1 like this.
  16. Yes! I thought it was a small amount of metal removed too, and it probably was. The same starter worked fine on the other blocks, that's why I was reluctant to mill it off. So, it could be just an accumulation of tolerances. I know the timing chain wasn't loose or sloppy. I don't know, I never had to do this before, but I'm glad it worked too.
  17. When you put a starter on a Small Block Chevrolet, leave the belly pan off, use an 1/8” Allen wrench to measure between the flywheel teeth and the stater pinion shaft. Most of the time the distance is too far away and will require a shim under the outside mounting bolt only. An old GM mechanic showed me this trick and it has always worked. Starters are quiet after setting the 1/8” gap correctly.

    Sent from my iPhone using The H.A.M.B. mobile app
    Kan Kustom and Montana1 like this.
  18. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    from SW Wyoming

    Has anyone had trouble with the starter bolts working their way loose when using a shim under one bolt? I'm not arguing at all here, just curious if anybody has had issues with that.
    Montana1 likes this.
  19. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,835


  20. Thanks Truckdoctor, I saw that you can check the clearance with an allen wrench, but I don't have a belly pan on my bell housing. It's full circle and I cant see in there, that's why I took an educated guess. I don't want to take the bell housing off right now.

    I figured at the least, I would be able to see if I was going in the right direction or not. I was fortunate that I was. I will say this, the next time I have the transmission out, I will make a closer adjustment of the starter. I thought it strange to only put a shim on one side, but it worked. I'm happy with that.
    Kan Kustom and Truckdoctor Andy like this.
  21. I read an article about the bolts coming loose when they don't run the brace on the front of the starter up to the block. I don't know if I ever seen that brace except in pictures. I've never had them come loose. They say it can break the nose cone if the bolts come loose, especially on a high compression motor if it kicks back.
    Kan Kustom and Desoto291Hemi like this.
  22. Here's a picture of the brace...I imagine it is the first thing to go when there is a problem. Probably can't get to it when you run headers.
  23. fastcar1953
    Joined: Oct 23, 2009
    Posts: 2,835


    Just installed a new engine in my truck and had starter noises. First time for me also. Been messing with sbc for 35 years. Never used the brace either, just lucky i guess.
    Montana1 likes this.
  24. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    from SW Wyoming

    I am a big fan of the starter brace, having once had starter flex issues that were cured when I reinstalled it. Lots of initial advance can put a heavy load on a starter. I like the piece of hose for positive cable protection, I'll have to stash that away in my mental file.
    Kan Kustom and Montana1 like this.
  25. Looks like good work,,,,yes,,,brace helps as well.
    Like you said,,,young,,,,first thing thrown away,,,LoL.
    The bolts came loose on one starter for me ,,,damaged the bolt holes in the block ,,,oh boy,,had to do some serious stuff to fix that .

    In the past,,,,I worked on (owned ),,several SBC,,,,,never had any problems with the starter grinding,,,,,except once.
    Then I learned that sometimes they are out of tolerance and would make a horrible noise .
    Starter shim was the cure !

    Kan Kustom and Montana1 like this.
  26. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,465

    from Brooks Ky

    Nice thread.......thoroughly enjoyed reading it!
    Montana1 likes this.
  27. I like the starter braces with a bolt to the block starter. I use a '55 Chevy bellhousing on my car with a truck starter, those have always been secure with the 3 large bolts. I have to go under it sooner than later, may as well as install the brace.
    Montana1 likes this.
  28. I had another rocker stud break this past week and I think a couple of hydraulic roller lifters were giving some problems. They were making some extra noise, so I was going to adjust them up a little and when I did the stud fell off in my hand... I'm glad I found it in the shop.

    I've been talking to a couple of guys, but no one seems to know what the problem could be. I never had this before, so I started to do some research and found some neat stuff right here on the HAMB about Howard's / MOREL lifters.

    Here's the thread for the rest of the story (starting at post 19). You will find it interesting:

    Anyways, I have it running again and it's doing much better.
    Kan Kustom and pprather like this.
  29. chevy57dude
    Joined: Dec 10, 2007
    Posts: 6,908


    Hope you get it sorted out. You've gone through a lot with it.
    Montana1 likes this.

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