Wednesday, June 23, 2010

Pontiac’s 389ci Engine

Pontiac Overhaul Time

Updating Pontiac’s venerable 389

Story and photography by Jim McGowan

Every time I get involved with an engine project I swear it will be the last one – ever! It’s hard work, both mentally and physically, particularly if you choose to do it yourself. Regardless of what engine you’re building, lots of research and financial decisions need to be made before you start, or trouble will be knocking on your toolbox lid.

Once it’s established that you need/want to rebuild that chunk of iron, you must then decide how you want to build it, how much you can spend, what parts will you use, what shop will do the machine work, etc. The list goes on and on.

The article featured on this page is from the May 2010 issue of Pontiac Enthusiast Magazine.

This ’65 GTO engine was an untouched original until the decision was made to freshen it up. It ran relatively well, had an average compression of around 175 (with a low of 165), but was suffering from blow by, front and rear main seal leaks, a few valley pan and other miscellaneous drippers, plus over four decades of use. Environmental issues were also at play here. It needed a complete going through (there was also a lot more wrong, as you will see). The time had come to clean it up and bring it into the 21st century. I wanted to use a combination of original and contemporary internal parts, but keep the external appearance stock. I did my research (for several weeks) as to what parts vendors I wanted to use, found a highly-recommended local machine shop and the rest is documented here.

I am going to include as much info as possible, but since space is a consideration, and pounding in piston after piston is boring, I must abbreviate the step-by-step assembly project. However, I will include part numbers (when available) and suppliers for your reference. We are starting with a stock-bore 389 cid block, but the basic machining and rebuild process will hold true for any Pontiac (or other V-8).

While gas prices have continually fluctuated, the octane rating here in California has dropped. We are down to 91-octane premium, and it looks like another point drop is eminent. This Pontiac will be street driven about a 1,000 miles a year, so I am lowering the compression from 10.75:1 to 10.25:1 and bumping the cam and valve train up to Ram Air IV specs. The 10.25:1 compression is still a bit high; 9.5 would be better, but for casual pleasure driving it has proven to be OK and the engine sounds healthy. Hardened exhaust valve seats and stainless steel valves will also help with the octane drop. Cast pistons and rings are fine for my driving purposes, as is the bulletproof original Pontiac Arma Steel crank. After careful measuring, it was determined that the cylinders would clean up at .030 over and the crank would be turned .010 under. The block would also be align-honed and the original connecting rods resized and ARP rod bolts installed.

During the tear down we had a few surprises. Two of the pistons had broken rings (the blow by), most of the connecting rod and main bearings were showing lots of copper and the block was clogged with sludge. Probably the reason it was running hot! It’s what you don’t know that grenades your engine. Luckily, the broken rings hadn’t scored the cylinder walls and we had no spun bearings. Timing of the rebuild was accidentally perfect.

Be sure to use a good ZDDP additive in your oil before initial fire up, as most of today’s over-the-counter oils have had this critical lubricant removed by the EPA. Two bottles for safety and then the ZDDP content in the oil should be sufficient, but it’s all chancy now. I used two bottles of Justice Brothers Engine Treatment, which worked well and the cam survived the run in without any problems. We didn’t dyno the engine, but estimate the horsepower to be slightly over 400, with the torque slightly more than exciting!

The photo captions will tell the rest of the tale. My strongest advice on rebuilding your engine is spend the cash on the best parts and machining. You only want to do it once, so do it right!


• Block: cleaned, Magnafluxed, align-honed; bored .030-inch over

• Heads: cleaned; Magnafluxed; bronze guides and hardened exhaust valve seats installed; three-angle valve job; stainless valves

• Crank: turned .010-inch; polished

• Rods: rebuilt; ARP bolts installed, pistons fitted

• Reciprocating assembly:balanced

1 After much agonizing, I made the decision to rebuild my original ’65 GTO engine. Except for machining, etc. that can’t be done personally, the R&R, strip down and re-assembly will be done at home with the help of a few friends. This is the first time the engine block has been removed from the car.

2 The original Arma Steel crank (#9773383), rods and pistons were intact. The bearings were showing lots of copper and a few were ready to take a spin. The timing on this project was perfect, even thought I didn’t realize it at the time. Two of the pistons had broken rings, but luckily there was no cylinder wall damage.

3 The factory cast 10.75:1 pistons were in good shape, as were the cylinder bores. The bore diameter was checked and we determined that a 30-thousands (.030-inch) cut was all that was needed. Next step: remove the pistons.

4 Before removing the crank, we mic’d all the journals and found that turning them 10-thousands (.010-in.) would bring them back to perfection. The term 10-under refers to removing material from the journal surface, making it 10-thousands under size from stock.

5 Early Pontiac engines came with an almost bulletproof Arma Steel crank, which are popular with Pontiac engine builders. The ID is plainly visible on this part.

6 The factory rods were cleaned and resized to perfectly round and new Clevite 77 bearings and ARP rod bolts installed. Unless you’ve had a catastrophic engine failure or are building a race engine, there is normally no need to buy new rods.

7 After careful measuring, the block is installed on the boring machine and the cylinders machined. Boring makes the holes slightly larger, hence the term 30-over(size). The block was completely stripped and cleaned prior to starting the machining process.

8 After the cylinders are bored, the top of each cylinder is given a slight chamfer to facilitate piston ring installation and to take the sharp edge off the cylinder left by the boring and honing.

9 We began assembly by installing the oil galley plugs. They were removed for the block cleaning, and if not replaced it will dump lots of oil on the garage floor at fire up. It would also mean pulling the engine again to install them. Next, the brass freeze plugs will be installed.

10 The rear galley holes are now plugged and the brass freeze plugs installed. It is important to follow a procedure when installing internal sealing parts and double-check each step. Oil or water leakage can mean having to remove the engine to access the problem areas.

11 Federal Mogul high-babbit cam bearings are now inserted using a special tool. This is something that you should leave to the machine shop if you don’t have the specialized tool necessary. They will install the bearing for a few more bucks. The installation starts at the back of the block and moves forward.

12 The main bearings are now installed. Here we see the thrust bearing being put into place. The oiling holes in the bearings match up to oil holes in the block. These holes keep the crank lubricated and spinning happily.

13 The Viton rear main seal from BOP Engineering is now installed following the supplied instructions. A little filing is required at the top edges to make the fit perfect. Here, we are determining the seal is level with the block surface. Viton has better wear and thermal characteristics than neoprene or the old style rope seal. The BOP rear seal is available in 3- and 3¼-inch diameters. They recommend using a silicone sealer with this seal.

14 The complete reciprocating assembly was balanced at the machine shop. Here we blow out all the crank oil passages before final installation. Notice the beautiful polish job on the rod and main journals.

15 With the crank in position, we used Plastigauge on each journal and torqued the main caps to 120 ft-lbs. The Plastigauge crushed to between .002 and .003-inch, which is perfect for the mains. We did the same for the rods to check their clearances. This is a little extra work, but worth every second for the life of your engine.

16 The two-bolt main caps were installed and permanently torqued down in stages, finally reaching the required 120 ft-lbs. The crank endplay was then measured and found to be a perfect .006-inch.

17 Prior to installing the pistons, the rings were installed in the cylinder bores and the ring gaps measured. They were ideal at between .016/.018-inch all around. We then installed the ring sets on the pistons.

18 There is a small notch in the side edge of each piston, which MUST face the front of the engine. Each bore was washed with transmission fluid and then wiped with a good coating of engine oil before the pistons were installed. Rubber hose was used on the rod bolts to prevent damage to the rod journals.

19 Crane Cams anti-pump up lifters (#99282-16), chromoly push rods (#28620-16), and 1.5 ratio-stamped steel rocker arms (#28800-16, now discontinued) were installed. We soaked the lifters in engine oil for several days to pre-lube them.

20 Liberal amounts of assembly lube were used when installing the cam and lifters. The Ram Air IV Blueprint Series Crane Cam (#969681) was installed followed by the lifters. This cam has a gross lift of .469-inch and provides 16 inches of vacuum at idle for the power brakes. Despite various rumors I’ve heard, the RA IV cam idles nicely at around 800/900 rpm and is very streetable.

21 Here’s the Crane Ram IV valve springs and retainer kit (#28308-1) and a valve spring installed height measuring tool from the PROFORM/Specialty Auto Parts line of engine building tools. Checking valve spring height will help prevent coil bind as the spring compresses when the engine is running.

22 Hardened exhaust valve seats and stainless steel valves are now almost required today, and will protect the combustion areas using today’s 91-octane (or less) premium fuel.

23 We’re using a Fel-Pro engine gasket kit from Ames Performance (Ames #N575). These are self-sealing head gaskets and are top quality.

24 The assembled heads are now installed. Small dowel pins on the block hold the head in place as you install the bolts, but it’s a good idea to screw one bolt down tightly to ensure the head doesn’t slip off. The head bolts will be progressively torqued to 95 ft-lbs.

25 With the heads secured, the valley pan can be installed. A cork gasket is used as a seal and the edges peened around the circumference for a tight fit to prevent oil leaks. Two bolts in the center of the pan pull it down tightly.

26 With any open holes covered with tape to prevent stuff from falling into the block, the engine was installed into the car. Now all the other parts needed to fire this beauty can be reinstalled.

27 With the engine secured and ready to fire, we can now set the valves. We’re using a Proform valve lashing tool (#66778) on the Crane Cams adjustable 3/8-inch Poly Locks (#99788-16). This early Pontiac engine has pressed-in 3/8-inch rocker studs, later models have 7/16-inch studs and can use roller tip rockers.

28 Before buttoning up the valve train we poured some oil into the rockers for pre-lubrication. Just a little will do the job until the high-volume oil pump from Ames Performance starts pumping. The oil filter was also filled with oil before we installed it. We added two bottles of Justice Brothers Engine Treatment that will assist during initial cam break in, and then filled the crankcase.

29 I added two bottles of Justice Brothers Engine Treatment to the initial fire up oil for the cam run in. This was added insurance due to the lack of ZDDP in today’s engine oils. Once the engine has a few hundred miles on it, I’ll change the break-in oil and filter.


  1. Nice, and thanks for sharing this info with us.

    1. Skullcandy Jib True. Best cheap wireless earbuds for $30. Skullcandy just recently put out its most affordable pair of true wireless earbuds yet. The best cheap wireless earbuds you can buy today. JLab JBuds Air. The best cheap wireless earbuds overall. Best cheap true-wireless earbuds in 2021: Top AirPods alternatives for $100 or less. Best noise-canceling under $60. Mpow X3. $60 at best budget wireless earbuds.

    2. The best cheap mechanical keyboards according to online reviews · The best gaming keyboard of 2020 so far with a sleek design, solid aluminum frame, and genuine Cherry MX key This Gofreetech keyboard has an excellent 4.7 star rating, so if you're

    3. the best gaming laptop for those on a tight budget. For the price, you'll get a great value on entry level performance Best cheap best laptop budget 2021: At a glance · How to choose the best cheap laptop. best Laptop Price in USA, UK online at USA, CA, GB brings you amazing discounted prices for Laptops..

    4. The Logitech G602 is in our opinion one of the best wireless gaming mouse models in the market today best wireless gaming mouse. If you have the budget. Best Cheap Wireless Gaming Mouse Under $30, $50, and $100 · Best Wireless Gaming Mouse.

  2. براي اين کار يا يا که طراحي سايت در تهران و بهينه سازي وب سايت مي توان بهينه سازي و مشاوره بهينه سازي و سئو را تا مشاوره بازاريابي آنلاين و سئو براي دو

    افزايش رنک گوگل
    و افزايش بازديد و همچنين شبکه تبليغاتي را دارا مي

    باشد و در افزايش پيج رنک گوگل دارد شرکت تبليغاتي و کانون تبليغاتي و معرفي سايت به گوگل و طراحي سايت تخصصي و طراحي وب سايت تخصصي است و در ادامه مي توان

    گفت واژه ياب همچنان واژه ياب فارسي و واژه هاي تخصصي و واژه تخصصي پزشکي و واژه تخصصي مهندسي هستند و همه چي درباره بازاريابي اینترنتی و همه چي درباره بازاريابي آنلاين و درباره بازاريابي اينترنتي و درباره بازاريابي آنلاين مي باشند که بهينه سازي و سئو و آموزش بهينه سازي و سئو و آموزش سئو و مقالات بهينه سازي و سئو و مقالات سئو و سئو چيست و آموزش کامل سئو و آموزش کامل بهينه سازي و سئو که هستند و بازاريابي ايميلي و ايميل مارکتينگ و آموزش بازاريابي ايميلي و آموزش ايميل مارکتينگ و مقالات بازاريابي ايميلي و

    مقالات ايميل مارکتينگ مي باشند و بازاريابي

    و آموزش بازاريابي اينترنتي و

    آموزش بازاريابي آنلاين
    و مقالات بازاريابي اينترنتي و مقالات بازاريابي آنلاين و بازاريابي آنلاين هستند اما

  3. And yet Hall never acknowledges that need for mature consideration, instead focusing on his desires and hoping they come true. They're never answered: the song ends with no game, not even a meeting between the two players. He wants more, but that want isn't enough without putting in the work to make it a reality.
    engine overhaul gasket set

  4. نوفر منظفات خاصة بالسجاد والموكيت وهى منظفات بخارية تعمل على ازالة البقع مهما كانت بقع نتيجه المواد السائلة او المواد الدهنية بسهولة ويسر كما لا تسبب اى اضرار الخاصة بالسجاد والموكيت
    شركة تنظيف

    تنظيف منازل

    تنظيف سجاد

    تنظيف شقق

    تنظيف مجالس

  5. Bolsos Michael Kors Rebajas está por delante del paquete con el nombre de la firma de EE. UU. En la categoría de accesorios de lujo y ropa deportiva.
    Michael Kors Bolsos son premios codiciados, pero están disponibles en varios lugares.
    Bolsos Michael Kors Outlet comprado en su tienda tiene una garantía limitada de un año.
    Michael Kors Väska är identifierbar i både slankhet och elegans.
    Michael Kors Väska Rea betyder ett oerhört öga för smak såväl som stilighet.
    Michael Kors Väska Rea erbjuder den eleganta kvinnan ett utmärkt tillbehör att sticka ut.

  6. I am pretty much pleased with your good post.You put really very helpful information

    โปรโมชั่นGclub ของทางทีมงานตอนนี้แจกฟรีโบนัส 50%
    เพียงแค่คุณสมัคร สล็อตออนไลน์ กับทางทีมงานของเราเพียงเท่านั้น
    สมัครสล็อตออนไลน์ >>> Goldenslot
    สนใจร่วมสนุกกับ คาสิโนออนไลน์ คลิ๊กได้เลย
    มีทั้งคาสิโนออนไลน์ หวยออนไลน์ ฟุตบอลออนไลน์ สล็อตออนไลน์ และอื่นๆอีกมากมาย

  7. Thanks gan, materinya sangat bermanfaat sekali ^^
    Agen Togel Resmi Situs Agen Online | Daftar Togel Online Pasaran Resmi Terpercaya

    Cracked Version is a useful place where you can easily find Activators, Patch, Full version software Free Download, License key, serial key, keygen, Activation Key and Torrents. Get all of these by easily just on a single click.

  9. Facing difficulty installing your Netgear N300 wireless router setup. Immediately connect with us as we assist to fix all setup issue with your Netgear device.

  10. 스포츠토토 It’s hard to find knowledgeable people on this topic, but you sound like you know what you’re talking about! Thanks.

  11. 스포츠토토 This post is very simple to read and appreciate without leaving any details out. Great work!

  12. 카지노사이트 To a great degree lovely and captivating post. I was hunting down this kind of information and acknowledged examining this one. Keep posting.

  13. 카지노사이트 Just wish to state your own post is really amazing. The actual clarity inside your publish is actually just nice as well as we could presume you're a specialist about this topic.

  14. Hey If you find it difficult to write content for your website and also for the jabber server. I myself try to write my essay for my website and they provide me with much better content than my expectations.


  15. تتميز شركة الرحاب بتوفير عدد كبير من الخدمات المنزلية كمكافحة الحشرات وطرد الحمام وتركيب التكييفات من خلال عماله مدربة على أعلي مستوى وبتكاليف مناسبة جدا للعملاء
    شركة تركيب طارد الحمام بالرياض
    يلجأ الحمام إلى إنشاء عشه في أماكن معينة من المنزل؛ كالأسطح، أو الشرفات، أو عند النوافذ، وهو ما يسبب الكثير من الخسائر المادية، كما أنه يمكن أن يكون وسيلة لنقل الأمراض، لذا يوجد الكثير من الطرق التي يمكن من خلالها طرد الحمام، وهي على النحو
    يتمتع الحمام بقوة سمعية كبيرة؛ فهو قادر على سماع ترددات الأصوات التي يعجز البشر عن سماعها، وهذه الميزة يمكن استخدامها لتكون وسيلة جيدة لطرد الحمام وإزالته من الأماكن التي لا يُحبذ تواجده فيها، عن طريق استخدام جهاز الألترا ساوند الذي يصدر أصواتًا شبيهة بأصوات الحيوانات المفترسة المتنوعة والمسجلة مسبقًا. يتمكن الحمام من سماع الأصوات المزعجة التي يصدرها الجهاز بمجرد تشغيله داخل مساحة على شكل دائرة نصف قطرها 4,000 م، وبالتالي فإنه سيعتقد أن في محيط المنزل خطر فيقرر الابتعاد
    شركة تركيب مكيفات بالرياض
    لقد ازداد الطلب في العصر الحالي على التكييف بشكلٍ كبيرٍ جداً بحيث تعدّدت الأنواع والأشكال للتكييف، وقد ازداد الطلب عليها بشكلٍ كبيرٍ جداً بحيث أصبح التكييف والتبريد يستهلكان جزءاً كبيراً من فاتورة الطاقة في العالم، سواء كان هذا على مستوى المكيّفات المنزلية أو التكييف والتبريد المستخدم في تطبيقات أخرى كالمصانع والخدمات الصحيّة وغيرها، وبفعل هذه التطبيقات المختلفة تنوّعت أشكال التكييف بحيث يمكن لكلّ شخصٍ أن يستخدم النوع المناسب له ولاحتياجاته

  16. VenuePro has 14 modules and it collaborates with both specialists and owners from the industry. The program is constantly being updated. Venue Management Systems

  17. We can provide all the assistance you need to set up your business in Mauritius in accordance with the Business Registration Act so that you can focus on your prime goals and let us handle the rest. Mauritius Business Registration

  18. This is the right blog for anyone who wants to find out about this topic. You realize so much its almost hard to argue with you (not that I actually would want…HaHa). You definitely put a new spin on a topic thats been written about for years. Gretuff, just great!
    Click Here
    Visit Web

  19. when it comes to choosing indoor skiing london for yourself, it's entirely dependent on what you are searching for.

  20. I’m so happy to read this. This is the kind of manual that needs to be given and not the accidental misinformation that is at the other blogs. Appreciate your sharing this greatest doc.

  21. I dugg some of you post as I cerebrated they were extremely helpful very helpful

  22. Very well written article. It will be valuable to anyone who employess it, including me. Keep up the good work – looking forward to more posts.

  23. Ꮋi there Dеar, are you genuinely visiting this weЬ site dailу, if so afterward you will aЬsоlutely tаke good knowlеdge.

  24. Hi, i tһink that i saw you visited my weblog thus i came to “return the favor”.I’m attempting to find things to impr᧐ve my websitе!I suppose its ok to use a few of your ideas!!eacһ time i used t᧐ reаd smaller articles or reνiews ᴡhich alsо clеɑr their motive, and that iѕ also happening with this piece of writing which I am reading here.

  25. I have to voice my affection for your generosity for folks that have the need for assistance with this important theme. Your special dedication to getting the solution along appears to be extremely helpful and have constantly allowed associates like me to achieve their aims. Your amazing valuable suggestions can mean a great deal a person like me and especially to my colleagues. Thanks a ton; from all of us.