I am going to rebuild my 351 Windsor engine (mild street use ) , it is already bored + 30 with recent re-bore I will be renewing the pistons due to the previous builder butchering one of the pistons, what i want to know is it ok to re-use the original connecting rods or should they be replaced with new Also whats the best technique for pin instalation , warm the rod end or freeze the pin Thanks Dave
For a press pin they make a rod oven that heats the small end and lets you slip the pin in. Any machine shop should have one that builds engines. Very common operation. For your rod, why would you think you needed to replace it? Is it damaged? I always have rods checked for straightness, new bolts (especially in a 351W rod, weakest part is the bolt) and resized after bolt replacement. You have the weakest of the 351W rods with the square cut across the rod bolt seat that narrows the rod between the bolt and journal. The football shaped rod bolts and round cut for the bolt to set in is much stronger. If you plan to do anything but cruising, I would replace the rods with aftermarket H beams. Even the cheapest of the cheap Cat brand H beams with 8740 bolts is better than a stock rod. SPark
Hi, I have to replace 1 x rod as it is bent, but was advised to replace all with new as i am replacing the pistons anyway normally i would reuse any good stock rods on engines that use circlip pistons , just thought there might be an issue on old press fit, thats why i was advised to renew The rod bolts are straight with the football (oval Type ) heads Thanks Dave
Scat press in rods are a cheap insurance . More strength, better bolts. My last build, my machine shop charged me 60 bucks to press off the pistons and reinstall the new rods. It was cheaper than resizing the old rods and buying ARP bolts. I paid $ 239.00 for the Scat rods. Off ebay.
Use to put the rod in a vise,and heat the small end with a torch until it turned blue,but not till it got red,and then set the piston on,and hand pushed the pin through.Air cool.
A second vote for either SCAT 4340 forged material or Eagle "SIR" 5140 material I-beams (the sportsman type stock appearing) in the $250-275 range. Made from much better material than the stock rod, has better strength bolts and is a capscrew design instead of thru-bolt and that eliminates that bolt head notch that really weakens a stock rod in a really bad area. The cost of cleaning, inspecting, adding new ARP bolts, and resizing the stock rods is going to get you within spitting distance of a new aftermarket set....the slight savings in reworking the stock rods isn't worth the fact you still end up with a rod that has a million cycles on it already, and has a known performance weakness(that bolt notch). Unless you are shooting for over 600HP a fully machined H or I-beam race type rod is complete overkill...and they tend to be on the heavy side which can negatively impact with crank balance leading to an expensive heavy metal added balance job if piston weight and crank choice isn't all figured out in the planning stage..
Sure it's Ok. Take them to a machine shop. It's cheap. It will be really cheap if you replace just the bad piston.
I would have a job to find one or two pistons the same make, they are flat top with 4 valve relief , no brand markings apart from + 30
I've always just pressed the pin into the rod; never heated the small end as have always been a bit nervous of affecting any heat treatment the rod might have received during manufacture -but when pressing the pin in, I always use a pilot to make sure that the pin can't get cocked as it's pressed through the rod. You can see the pilot in the first photo It's a couple of thou' under the size of the pin that's right above it. There's a capscrew clamping the pilot through the pin to the mandrel on the press. I've done loads of rods this way, never had a problem yet.
Take it to your local shop and show them.....machinist see a lot of different parts come through the door and can often tell what brand something is just by looking at it.
I went with an entry-level Scat rod on my last build, the builder recommended a full floating rod. I found the rods on eBay, less than what Summit had them by around $20. Definitely show the piston to your builder, you can buy them as 1 most of the time. Have him look them all over and give you a recommendation on what rod you should use. Hell.. have him install the pistons on the rods too, give yourself a break.
I keep going back to this engine when I get chance, this is my first Ford V8 so I am learning from advise / books /internet What I have now found is that the pistons were assembled correctly on the rods, whoever put the engine together made the mistake of wrong cylinder numbering They used the odds on the left bank (from front ) and the evens on the right instead of 1234 left and 5678 right all the rods/caps are numbered so when I re arranged them on the bench in the correct numeriical order with the bump on the rods inwards all the piston notches faced forward I have also found that all the pistons are not of the same manufacturer , on the skirts 2 are slightly more pointed at the bottom I removed the broken piston from its rod and the good piston from the rod I thought was bent, I don't have an hydraulic press so made an extractor and used the threaded bar with the bearing races from a bush extractor kit the first one I heated then pushed the pin out the 2nd I did cold and it came out just the same as the heated one Now I have the rod off that looked to have a bend in it if I clamp it to the other loose rod it appears to look straight so I cant understand why the crank would not fully turn What I intend to do is to clean everything and install the rods and pistons without rings one by one and checking the rotation as I go So with the bores and pistons being good and the correct way round could I get away with 2 new matching pistons opposite each other and a replacement rod that way it will be evenly balanced
Must have been a chevy guy. Make sure when you reassemble you have the connecting rod facing the right way. One side of the connecting rod should a chamfer on it, that side faces towards the cheek on the crankshaft.
Since they are just cast pistons, if you can get two single pistons with similar weight and top crown configuration to go along with replacement stock rod you won't even need to rebalance it. The replacement rod can be weight matched to the bent one, and if the new piston is no more than 20 grams each heavier or 40 grams lighter you are fine, well within the factory balance window and no sense spending stupid money on a "high speed plus/minus 1 gram" balance job. You'll never feel the difference and the engine won't care. You will find that once you price two replacement singles that you are very close to 1/2 way to the cost of an entire new set that will already be matched. Full sets of flat top cast hypereutectics are in the $140-150 range, singles are $30-35 each. Hypers fit with the same clearance as regular cast, and the set ought to put you close enough on balance to not even worry about it. If the factory figures a 50-70 gram window on bob weights for balancing, why does any cast piston motor need a "precision balance" in todays age of CNC machining??. Pistons in modern sets are all within 3-4 grams across the entire set. People get suckered into way too much "VooDoo" about engine balancing.
I use one of these puts no stress on the piston. http://repairguide.autozone.com/zne...0c152/80/06/7c/fc/medium/0900c15280067cfc.gif
I can get a full set cast pistons over here same design at a reasonable price so was thinking to buy set and just use two as its difficult to buy separate
The Jalopy Journal
