About to begin the planning for rebuilding my 401. First step is ensuring the block has no issues. I have stripped the block bare and will be bringing the block to the machine shop for the following: 1) Sonic check cylinders to ensure sufficient material for boring 2) Measure bores - I have done initial measuring and the bores don't appear to be overly worn, but #8 is worn exactly 0.010" (explains why there was only 100# in this cylinder when I did a compression test), so I want someone with more experience working a bore gauge to confirm, so I can decide on piston size. 3) Magnaflux block - the shop I plan on going to also provides Sonafluxing. I have no experience with sonafluxing so I don't know which is a better option - any thoughts? 4) Hot tank the block 'cause its a mess and there are lots of deposits in the water jackets Any other block inspection items should I have done? Once I am sure the block is good I will be planning the build and will be seeking additional advice. Thanks Doug
if its a street motor and you only going .020-.030 over bore, hot tank yes all that other stuff is not needed, unless its free. put the money in a nice set of custom lighter weight pistons. just my opinion and something to think about. good luck with your engine build.
Yep,,, hot tank it first.... I took a 401 to a machine shop once, got it hot tanked and there was a foot long crack in the water jacket to the outside that was covered with grease..... I would not bore it any more than absolutely necessary ,,,, to prolong block life... .010 over can usually just be honed... be sure to clean out the inside of the rocker arm shafts... lots of crud in there....and the oil galleys at the cam bore.... and the head V's....
More than one block has cracked on the side from a freeze-up! They can be repaired, but it'll cost ya. Many shops don't do hot-tanking any more. Hazardous chemicals. Spray washers are the modern replacement. Some even bake all the grease off first. Another cleaning option is shot-blasting. That'll clean everything done to shiny clean metal.:grin: The cam and lifter bores will need to be honed since the shot beats them up. Local shop charges $150 for the whole cleaning process. It'll look like new. Just a spray wash cost me $60. Definitely measure bores first. I had one with 0.008" wear that just barely cleaned up with a 0.020" overbore. Cylinders wear unevenly. Boring is the only method to get the bore centered and round again. Honing is for finishing. Sonic testing for wall thickness probably isn't absolutely necessary if you only expect to bore 0.030" over. Curious what it'll cost you. If it's a little thin, you can partially fill the water jackets with epoxy block fill to stabilize it. Keep us posted, we need a good build thread again!:TU:
So you had .010 wear on the diameter? If so thats only .005 a side which isn't enough to cause low compression itself. Perhaps the cause was with the valves? I'm far from an expert but this process has served me well. I like to take 5 measurements on the bores. I measure top to bottom (intake to exhaust) starting about 1/2" down from the very top of deck. Then midway down, and then at the bottom near end of piston ring travel. Next I measure front to back, (or left to right looking at the bore) again at the top then midway down. Most of the wear will be top to bottom. Document the readings on a chart for each cylinder. Then you start to see where the worst wear is and/or how uneven the wear may be which starts to paint a picture of how far you have to go on over bore. I like to go armed with this data to the machine shop if for no other reason to educate yourself and prepare for the outcome. They need to verify your dimensions but at least you can talk somewhat intelligently about it. This also lets them know you are taking an interest in being involved up front and can lessen the potential for them to try and cut a corner behind your back. Never assume anything with a shop unless you have a "lot" of experience with them. Stick your nose in regulary (but professionally) for updates and ask questions. If they don't like that take your business somewhere else. It seems that for evey success story dealing with an engine shop there is a horror story. One more tidbit, ask the shop who specifically will be doing the work on your engine. Bigger shops usually have youngsters in training and I personally do not want them learning on my projects. Its OK to request a veteran if you think its necessary. It might increase the price a bit due to labor increases but thats money well spent. Trainees are supposed to be supervised but we all know that doesn't always happen in real world. In my limited experience, when the goal is over boring to the minimum required, the shop will bore the worst cylinder based on dimensions and visual (scoring, rust, etc)and see where it cleans up. At that point they stop and you buy new pistons based on the closest stock over size available. Once the shop has the new pistons in hand to verify exact size, they can finish the bore process. They will probably need to true up the "deck" or head mating surface a small amount. Just make sure they go the minimum required.
Thanks for the advice I should have clarified my plan for this engine as it might dictate what advice is provided. This is the original engine for the '65 Riviera I am building. I would like to build the strongest engine I can without destroying the streetability of the car. This will not be a factory restoration and this car may see some minimal track time. I will be upgrading components where I can (forged pistons) to ensure wherever this build takes me, I won't need to redo anything I already did. My plan is to have all machining done by the shop and perform all assembly by myself. The first step in my build process is to ensure the block is good. I have no history for this engine. I bought the car and other than a quick inspection (compression check and one nice long burnout on my driveway) pulled the engine. Once I am comfortable that I will use the block I can plan out the entire build on paper. I expect to post the build plan when it is completed for review by this forum; before I move to the next step. I am hoping for some solid direction from this group along the way. To address some of the items raised in your responses: I added sonic testing to the initial list of work as it appeared to be a step highly recommended by this forum when it comes to these engines. Sounds like I don't need to have this done if it will take less than 0.030 to clean up the bores. Also, I was planning on epoxying the block up to the water jackets anyway. There is a significant amount of deposits in the water jackets of the block and I thought hot tanking in something caustic was the only way to clean this out. Will spray washing clean this out? I am less concerned with grease removal, as with a little work and engine brushes I can clean off most of the grease. The magnafluxing was added only to be sure there are no cracks hiding that I can't easily see. I thought this was a normal step for a rebuild. Don't want to assemble everything and find out there was something hiding; waiting to break I have already measured the bores but wanted the machine shop to double check my work (this was my first time with a bore gauge). I measured each cylinder in 6 places starting 1" in the hole and then working my way down to 2 other measurements; staying within the path of ring travel. Each of the 3 measurements was made front to back and then side to side. I have it all charted and plan on bringing it with me to the machine shop. I only plan on boring what is necessary to true up the cylinders. Other work (decking) is also in my plan, but only what is necessary to true up the block. One of the other reasons for this initial step is to give me a sense of how this shop operates. Consider this as a test to see if they can meet my requirements. I plan on asking lots of questions about other work I have planned to see their reaction. I do have one recommendation from someone currently having an engine built at this shop. Their opinion was the shop was "full of old guys"; I thought that was perfect. Thanks again for all the advice. I will keep you'll updated and will start a build thread when I have the plan figured out Doug
i filled my block up to the water jackets too. i ended up putting an oil cooler on to keep the oil pressure from falling when hot.. the block needs to be really clean for the filler to stay put.
What do you mean when you say, "I have filled my block up to the water jackets too"??? What are you using for block filler???
yes when i got on it the temp would rise more than before, the bottom of the block cools the oil. the water temp was fine.
sorry about my mistakes on this post,was hit in the side of head and face at work with a 40 oz beer bottle, thought i was allright just sore. i guess i still have some side affects. guys please help correct me if need to. thanks
Doug, this sounds like a great build! Tom T (Telriv) is in the Northeast, you should touch base with him. Performance Nailhead builds are his specialty.:grin: Here are some details on acid cleaning the water jackets: http://v8buick.com/showthread.php?t=143365 http://v8buick.com/showthread.php?t=204599 Erik documented his performance build in this thread....reading these 10 pages will keep you busy for a while! http://v8buick.com/showthread.php?t=115156 Contact him for the epoxy block filler too. He can find a supplier in your area. Joe, aka GSGTX, has used some unique options on his builds....the lightweight pistons and a stroker crank to name a few. He has one of the better performing Nailheads on this board. :TU: This is gonna be a great thread....:beers2:
Walt, Thanks for the links. I have seen many of them, but not read thoroughly. Other than parts inspection the build may not make much progress other then planning. My goal is to spend the next couple of months planning what work I want done and what parts I will use. Come March, I hope to be moving forward with machine work and purchases. The ultimate goal is to have the engine sitting on the frame rails by the end of the Summer. That gives me all winter to get the rest of the car ready for initial startup (currently it is completely stripped).
Guys..... For the record.... There is nothing special about this epoxy. Its just that most people are not exposed to the underbelly of mining and know how to get these mining equipment supplies. In the biz it is called "backing material" and is used for installing manganese wear liners in cone (rock) crushers. There are several trade names because is white labeled for many different suppliers although I am only aware of 2 different manufacturers- Copps and Locktite. If anyone wants to buy some locally in your area, just send me a PM and I will give you the contacts of dealers in your area that sell it. If you want more technical information click here: http://www.coppsindustries.com/products/aggregate-and-mining-crusher-backing/ Also- I didnt invent this idea, and I'm not the first person to have done this. Block filler has been used for a long time in drag race engines that do not require a cooling system. The use of this epoxy backing is a secret weapon used in reducing weight from the older cement type filler that is traditionally used. The "partial" block fill (up to the large freeze plugs) was on the suggestion of our beloved Telriv to add rigidity back to the block. I understand this has been done to numerous nailheads besides mine without effect to cooling efficiency and without any other issues. On this note, I feel inclined to add my own disclaimer: in that if you decide to go this route (and I do believe doing this is a good thing for our nailheads) is that you do so at your own risk and understanding! Erik
my oil pressure would go down after i would run 1/4 mile off on the street,it was summer time and a fresh engine. didnt wait long went with an oil cooler, no more problems. we had to bore the block .035 over, thats why we did the filler.
On our '66GS car that we race the block is filled to the bottom of the outlets for the T/C cover. This is at LEAST a 3/4 fill. At the end of the track, this includes the drive from the pits, waiting in the staging lanes, performing the burnout, running through the 1/4 mile, then making the turn, heading to the timing tower to pickup the timing slip, we usually glance at the oil temp. gauge & the oil temp. has NEVER gotten above 200*. We didn't add a cooler because the extra plumbing required, the addition of a cooler & being the "Nail" pump is NOT a high volume pump we decided against it. So far all has been OK as far as we can tell.
it was a new engine maybe thats why, l shift at 5400rpm tops.oil pump should hold up.i know in your race car your shift points are alot higher,what kind of times and mph are you at now?
