Well I screwed up big time. Did it to myself and now have to rebuild a 350 for my SunCoupe. Replaced the radiator, hoses, belts, water pump and some other items. Refilled with water(only) because I wanted to make sure no leaks before adding antifreeze. Well life got in the way and I totally forgot to add it and we had below freezing weather for 3-4 days. So you've probably guessed I cracked my block. At this time I'm not attempting to repair that block but once out I will hold on to it for a possible later fix. So with that said I will be rebuilding another block. Found a 70 short block and it's currently at the machine shop to determine if it will be a useable block. Already know it will need boring as there was alittle water in two cylinders and there is some pitting where it was sitting. So I'm guessing new 30 over pistons. Currently considering the TA 212 cam, TA 1579 Cam bearings, TA lifters, TA stg 1 springs. Staying with the stock intake and stock exhaust manifolds but adding downpipes and duals. Or would the TA 112 cam be more suited for normal driver? I've listened to several sound videos of vehicles with the 212 and they sound great. Currently considering decking block and heads enough to make sure they are straight. But has also gotten advice to not deck and use Fel-pro Blue composite gaskets, and forgo the TA 1602 pistons or Sealed Power ones for some forged Autotech pistons. Comments or Suggestions
The autotec would be best choice. Alittle lighter and closer to deck. Get a fresh harmonic balancer. Or a rebuild. I would suggest drilling out oil sump and getting a later 5/8 pickup tube. And later stamped steel rockers. Stick with the 212 cam or the crower level 3 cam.
The autotecs are the most expensive part too $699 dollars. But as the other gentleman said I could recoup some of that by not having to deck the block and heads. Putting them back in line with the TA pistons. But wouldn't that then require a balance of the crank due to the weight difference of stock pistons versus the autotecs? I have seen plenty about oil mods but no specific thread or videos. Can someone direct me to some? Harmonic balancer....Get new one or rebuilt one no matter which way I go? As for rockers....Are you referring to item 4 page 50 in the TA catalog?
The crank should be rebalanced no matter what, when parts are changed on the rotating assembly. Switching to lighter pistons they will have to take weight out of the crank, which is covered in the price to balance. If they have to add weight on the crank because the new pistons are heavier, that will be an extra charge for the expensive Mallory metal and for the labor to install it.(around an extra $100 per slug that is added)
Thank you Derek. My mind is going about 1000 different ways and on several different issues right now. Just trying to remember everything I need to ask or tell the machine shop to do if this block is good.
If you decide to go with the AutoTec pistons, have the machine shop measure the deck height of the block so you can order the pistons with the correct compression height. And Andy is right, those pistons include the pins and a premium ring set. If you were to order a custom set of pistons the pins and rings are sold separately, a cheap set of custom pistons are around $800 without the pins and rings. If you are going to have them do a cleanup cut on the deck, have them give you the measurement of what the deck height ends up as. From the factory often times the deck height on the sbb 350 blocks were usually at least .030" more than the factory spec! So you can't just assume that the block is what the written down spec is, it needs to be measured. The block is pushing 50 years old so it is possible that it might have had deck machining in its life at one point as well so it could be under the spec. Measure twice order pistons once. That's the deal about the AutoTec pistons, they're made to order so you can change diameter, compression distance to work with your specific combo. Here is what they wrote about them; "AutoTec is a High Quality, Precision Manufactured piston option. That comes at a very respectable price. Our Design Specific Forging allows us to manufacture our parts with less machining time, thus allowing us to keep production cost down. Then pass that savings on to you, the customer. Made out of 4032 High Silicone Aluminum Alloy, it has great wear resistance, a low expansion rate, is very durable, and is very low in friction. These pistons accommodate multiple uses including. Your local auto shop, muscle car restorations, performance street rods, as well as many spec racing classes. They can also withstand mild nitrous kits and small turbo or super chargers. Just about everyone can benefit from the excellent value the AutoTec line carries. Keeping in mind these pistons were originally designed for about 600 Horsepower. In Small Block applications, we have customers that frequently fine tune engines that yield 850+ Horsepower with a bit of Super Charger boost. Bore, Ring Pack, and Compression Distance changes can be made to any shelf part at no extra charge. Meaning that if you do not see your application listed in the guide, we can make what you need without charging a custom price. Every part is made with same high quality machines and tools as our RaceTec line including diamond turned ring grooves, and skirts. Not to mention our parts are 100% made in the USA."
For technical info's sake, a piston appx. 22 grams lighter would not require a rebalance 'if' the crank is already balanced. That would only change the balance formula by 1%. There are times I'll swap lighter or heavier pins in order to save the expense of a balance if I trust the previous work, but keep in mind that most will and should disregard any previous balancing work regardless.
Thanks for the information guys. Still waiting on word from machine shop about block. Time to get the engine out of my car they will need the heads anyway
Not sure how far up you reached to pull that 22 gram number but if he switches to AutoTec pistons that would be around 150 + grams per pistons less weight. And factory balancing is less than optimal but in there defense they only meant for these engines to see less than 5,000 RPM most of the time without going past 5,000 RPM when Grandma drove it. I would recommend rebalancing even if he re-used the factory pistons. I have seen rods weights in a sbb 350 as much as 80 grams difference. Spending the little bit on balancing would go a long way getting a smoother running engine for the service life of the rebuild.
I figured that if the OP began weighing components and crunching numbers, he would catch the generality to my example and the mistake. Safe assumption to double check things on any build and don't accept everything with complete accuracy until you're totally satisfied. I did not state that his crank was or wasn't 'only' factory balanced. I'm stating that you can take the same balanced crank to several different people and it will show up different things, depending on what they are using and how they choose to make corrections. If it has been balanced by one aftermarket shop and he's satisfied, there might not be any discernable corrections needed to about 1% of the total bobweight. The rods and pistons could easily be weighed without the immediate shop charge that happens when the crank is spun up on the machine. Likewise, just weight matching the components goes a long ways towards the less than full effort builds. Also even on a crappy OEM engine, if you run it all the time to +5k rpm and never see evidence on the bearings...how far out is it? I know you are splitting hairs with my comments because maybe I'm splitting them with yours...now re-reading yours, that wasn't the intent. I think it's obvious that I'm making the suggestions based on knowing the history of the engine and it's prior life.
So while I'm waiting and needing to gather other items. 1. Which Petronics ignition? Or similar? 2. What is closest RED to original available today? 3. Exhaust using stock manifolds? Duals from stock back and mufflers. Stock mans with gasket or not? 4. Already have Autometer gauges to install. 5. Anything else
1. Nothing really wrong with the old distributor, but pertronix does make a points eliminator kit at a decent price. 2. I used duplicolor DE1653 paint. I like the way it looks. 3. Be sure to grab those 2.5" downpipes you mentioned. $115 a pair. If you can have your exhaust surface on the heads and the manifolds milled flat, there shouldn't be a need for gaskets, if only high temp sealant, and only a light film of it. Buick didn't use anything from the factory, but that was when the metals were new 40+ years ago. 4. Neat. 5. That pretty much covers it I think. Oh, use coolant.
This one will have coolant in it the second all the house clamps are tight!!!!! I'll deal with leaks if any...
put some el cheapo parts store drain pans under the hose connections under the car for extra insurance against spillage.
Nooooooooooo, water only until you confirm there are no internal cooling system leaks! If you go with a flat tappet cam, while you're breaking it in, run water only then check oil for signs of water in the oil after the cam break in procedure is done. If all looks good, drain 1/2 of the water and fill up with anti-freeze. If you have anti-freeze in the engine upon initial start up and you do have a coolant leak into the oil and don't see it until the cam break in procedure is complete it could be to late, anti-freeze likes to eat bearings!
Ok water it is.....But I'd like to question something. I have a dirt track race car friend that says to startup without water? Bring block temp to 140 and cut engine off and let it cool back to ambient. Anyone every heard of this? Would that affect cam breakin?
You really should break in cam at one time not restart engine. So I would not do what your friend says. And how does he know it’s at 140 as the sender reads coolant temperature . If there’s no coolant there’s nothing to sense.
I had never heard of that before. I know cam break in is crucial. He says he uses a temp gun to check temperatures. (I'm not doing this so no further discussion is needed)
