I need some advice please, I pulled my '67 400 engine to replace frame pads with the new TA ones, clean the block thoroughly, paint it, replace all gaskets and get a valve job. I knew beforehand that this engine had been rebuilt, but not to what extent. I didn't want to have to do much to it since I have very little money and the engine ran well but seemed underpowered. So I took the engine out and the first thing I discovered was the lifters were the after market ones and were very loose in the lifter bores. I could feel them moving ever so slightly side to side when I wiggled them and they pulled out very easily. I compared them to my lifters from my 455 and they are smaller in diameter. I also saw scoring on the cam bearings and the bearing were installed incorrectly with the holes at 9:00 and 2:00. The oil slinger was missing as well (another quality machine shop! :af: ). So I decided I will get a cam kit since I wanted a better cam anyways. I can live with that. The bores look great. In fact you can still see the cross hatch marks on the walls. When I pulled the head I found that the water jackets in the block have A LOT of sludge and sand in them. Hmmm maybe I should flush this out, I'm still ok with that. But when I took off the oil pan I found some disturbing writing on the crankshaft throw. (see picture) I haven't measured any clearances yet (ran out of plasigauge) but I plan on measuring the rods and crank clearances. Now I'm wondering if it would NOT be a good idea to leave the bottom end alone and just do the cam and heads like I originally planned? If the clearances check out OK even with the crank being maxed out, should I just go with the top end rebuild? This engine will be used for daily driving on the highways and weekend excursions in which I will get on it for some fun. I had planned on rebuilding the bottom end in about a year or two at the most. I do have another engine, a complete '68 430 that I picked up at a local junkyard for $75. I have never turned it over and don't know if it can. My plan was sometime down the road to bored my 400 out to 430 specs and use the pistons/rods from the 430. Now it looks like I will have to use the crank, soon. But I don't know the condition of the 430, but I will pull it apart this weekend to find out and post what I find. Those are all the facts, what recommendations does anyone have? The only money I have to spend on this engine/car is from the sales of my Buick stuff (see my listings in parts for sale :laugh: :Brow: ) Thank you for taking the time to read this novel :boring:
Todd- I'm NO engine expert, so this is just my opinion in your situation. I would follow your gut and leave the bottom end alone if has been running fine. definitely replace the cam bearings, oil slinger, etc. Worst case scenario your out some minor parts and your time. It's a driver so you should be fine. Sending an engine out during the summer might take a while at the shop unless you know someone.
I assume your reffering to the fact that the crank is .030 on the mains and .040 on the rods. The "455" writing is prolly there because 400/430/455 cranks visually look the same, have the same size and stroke, so most crank shops will call any BBB crank a 455. Pop some rod caps off and look at the bearings, if they are ok, run it. While I don't grind them that far typically in a rebuild, that's just my personal preference, and there are certainly some solid reasons why reducing the size of the mains and rods can be beneficial. I just don't do it because your not going to ever grind that crank again.. your at the max undersizes. JW
I plastigauge'd the rod and main bearings and they looked pretty good. The average for the rod bearings was .0015 - .0018 and mains were .0015 - .0017. The rod bearings do say .040, I didn't think they made them that size. Someday I'll redo the bottom end, and since I have two spare cranks in good shape, one of which has never been touched I'm not to worried. Another question, since I'm not having any machine work done to it other then new cam bearings, whats the best way to clean the tops of the pistons without removing them from the block while at the same time not getting gunk into the rest of the engine? Lots of carbon deposits. Thank you for all your advice guys I appreciate it!
Acetone will take the carbon right off,go to local Home Depot and pick a can up,it doesnt leave a residue either. Thanks
Scrape the heavy build up and vacuum it. Acetone or Lacquer thinner is the best solvent. Make sure to put a little oil back on your cylinder walls. I would say that crank is fine to run and done after this time.
