Greetings ! I just re-acquired a 1968 riviera gs. So what would be the opinion of those that know , should i tear it down to do the mods for a motor that is close to factory specs as a rebuild will allow and will remain so. I ask be because motor does spin. Was rebuilt 1000 miles before it broke down. Parked the car 30 yrs ago due to overheating on frwy then crapping out . Would not start since then. Pulled the plugs and and found metal melted to 2 of them.Pulling heads see whats damage is first. Will do a visual of the bores . Will also remove oil pan to clean. Thanks
Do the mods. You could stay with the factory oiling to the heads, rather than going to oil through pushrods, (saving cost of pushrods) but the cost of doing the oil through pushrods is very little for better valve train oiling, and overall, the mods mostly are the cost of drill bits, burrs, 5/8 oil pickup and labor. A very small percent of the overall build, but great benefit to even a stock spec motor.
I would wait until you hear if the heads are cracked or not. I also fear that the melted metal you have found on two of the plugs is from the pistons. If so and they are what has distorted enough to lock up the motor then you will likely need to sleeve those two bores. Are these two pistons next to each other?
If you are doing a rebuild I would just do all the mods. Follow Jim Wiese's "Oil Mods tutorial" he states at what power level some of them are needed so there are a few that are optional. If it was that hot, there is a good chance the heads are cracked. 400/430 heads are quite crack prone. Greg
Might as well just go with a 455 block more options for pistons, and if you go with a older 455 oil mods may not be needed. Machine work costs are the same on either block. Melted spark plugs means lots of heat and detonation.
Buick thought it was important enough to open up some of those oil passages on every engine they built after a certain date.
Got the engine out and driver side head off and it dont look good. #1 and #7 had a large amount of aluminum debris.looks like a complete tear down is in order.Sure hope the engine is still rebuildable
The 5/8 inch oil pickup. Was that only on the 1970 Stage 1 455 engine? Just wondering, I assume the 1970 455 GS Base engine has a smaller pickup, which I have. I wonder if it's worth the $$$ and effort to upgrade to the 5/8 pickup? My 455 was rebuild to Stage 1 specs 11 years before I bought it from the previous owner. What's your opinion?
Volume over pressure, wins every time in oil supply to bearings. The oil wedge that provides "lift" and "separation" between the bearing shells and the journals, as well as the cooling that greater flow from volume provides is the "life" of the rotating assembly. (You need a certain amount of pressure, but the flow provides a greater benefit of cooling, flushing and less breakdown of oil from heat). Buick engineers realized this and and made it a focus going forward. (realize the short few years any engine would be used in production, vs the bean counters trying to save every penny) and the many years people have done everything to extend the life of these designs. But, to do any oil mods that your engine lacks, will require a tear down, to facilitate boring the oil passage from the pickup tube mount (bottom of the block) and forward to the oil pump, beveling the radius' from the supply bore in the block, to the oil pump and other passages, as well as the oiling to the cam tunnel and lifter galleries (per Jim Weise's oil mod specifications), my opinion is do it all, as the money and time spent is in your best interest, than to piecemeal the mods. If you are "going in", go in all the way... So, after nearly 60 years, implementing all that has been learned and understood, into any build, stock or "purpose built" engines, is worth every penny and pound put forth in any build/re-build. Better to put in "extra", than "leave anything on the table". But it is always easier to spend another persons, time and money, when it costs you nothing. So I try and provide as much as I know, (with all the knowledge of +70 years of family mechanical engineering, innovation, and and drag racing of three generations) with the caveat that each person decide for themselves what will work for them. Hope this helps.
It helps a lot. I was able to track down the original Buick engine re-builder (John Chamberlain). John re-built the engine in 2012. However, this engine currently only has 3,500 miles on it since the re-build. I sent him an email asking this question about the enlargement for the 5/8 in oil pickup and oil passages. I know John upgraded the 455 to Stage 1 specs. I just don't know if he enlarged the oil passages and 5/8 inch oil pickup. Since I joined the Buick forum 2 years ago, I've read about the short comings of the 455 oiling system. Another reason I when to Amsoil Zrod synthetic for my oil lubrication. I had a very good discussions with the Amsoil engineers. Just waiting to hear back from John. Appreciate all the info you have provided me and your years of experience with Buicks. Thank you. VET (Navy)
I think the 5/8" pick up tube was possibly added on late late 70 builds but for sure on 71 on the block itself and pickup tube. I could be wrong but I have "read" the 70 Stage 1 had a little higher pressure oil pump spring? Iv'e finally learned to not believe every thing I read though.. Vet you need to re read Jim W's 4th down oiling mod posts on this "Street/Strip 400 - 430 - 455" engine thread to catch up..
I'm thinking John Chamberlian did the oiling mods or the most important ones on your rebuild. He knows his Buicks..
#1 and #7 are on the same plane of the intake manifold, along with #4 and #6. Where did the aluminum come from?
Just finished reading Jim's oiling mod post. Jim did a super job of explaining what all goes into this work, pictures are a fantastic help. I'm sure John did this Oiling Mod but wanted to check with him first. I've been working with him for almost two years now and I know he is a very good Buick engine builder. In fact, I sent him my 8.2 differential for a rebuild. I'm a retired machinist. As I read over Jim's drilling method using a 5/8" Dia drill bit, it can be challenging to keep the drill straight in an existing hole you are trying to enlarge. This is what I do to make this process easier. (1) I use a 3-flute 5/8" Dia counterbore with a 1/2-inch pilot or machine the pilot to fit into the existing hole diameter. (2) The benefit of a 3-flute cutter, it doesn't grab the existing hole when you start drilling because it has 3-fluts that are flat bottomed instead of a sharp pointed drill bit. (3) Once you drill (counter bore) the hole several inches deep (3 to 4 inches). Install your regular drill bit to finish the drilling operation. Because you have counterbored the hole to 3 or 4 inches deep at a 5/8" dia., this will act like a drill bushing and keep your drilling straight. (4) Because your counterbore has a pilot that fits into the existing hole (1/2") to be enlarged, this will maintain the correct line of direction to be drilled. (5) The pilot works very good on holes that are set at an angle. (6) I like to use a variable speed hand drill, so I can start my drilling at a slower speed to start the hole enlargement process. This keeps the drill from chattering when starting the drilling process. (7) As a lubricant for cast iron, I've found kerosene works very well and gives a much better finish than drilling cast iron dry and also helps to reduce heat from dulling your cutter edges. Kerosene also works very well when you have to hand tap threaded holes, reduces the force required to tap a threaded hole. (8) I find this particular Hand Tapping wrench very good to maintain the threading process in a straight line. The long handles give you more torque leverage when using pipe taps. (9) A picture of a 5/8-inch Dia, 3-flut counterbore. (10) Last picture is the pilot that fits into counterbore. (11) These tools can be purchased from McMaster/Carr catalog.
Let me know how it works and if you run into anything unexpected. Make sure if you have a drill gun that can take a 1/2 inch Dia counter bore shank. VET, thanks for giving it a try.
I just got an email from John this morning, confirming he always does the complete oiling mods that Jim W recommends. I was sure he does this but I had to make sure because I love to crank-up that Big Block. VET
You should start your own thread, these are conflicting issues to the original guys post.. And things are gonna get confusing to the OP
It's just a different machining technique. I don't believe it will confuse anybody. The end user can use Jim's way or try my way. I'am just using a counter bore to do the drilling and Jim is using a drill bit. If you read my method, I only start with the counter boring method and finish with the long drill bit. The only difference is using the counter bore tool to start the drill process and this method keeps the drilling/counter boring in direct alignment with the 1/2 inch hole by using the 1/2 inch Dia pilot that's attached to the counter bore tool. Most guys most likely not use my method because that have to spend more money for counter bore and the pilot. It's another option that can be implemented if one chooses to use it. VET
