Didn't smoke at all when I ran it on the engine stand. Ran great.Is it worth it too refeshen. Only 1/8 th inch cylinder wall left. Was going to do new rings. Are my cylinder walls going to come apart? Am I going to be over heating alot. Running a 1950 pontiac radiator. Stock 425 cam. Pretty much all stock rebuild parts.
I thought the thin-wall overheat myth had been long busted. Improper honing and surface finish along with inept tuning contribute more to running hot. Did it overheat on the stand? Several engine types have .125" walls or thinner, like late Ford 302 (.090" often in areas). Racers make a judgement call on what power level to run those at or use only for stock duty. Those blocks split right up the middle long before the cylinder walls give. Depends on how much it takes to clean up. If there's no ridge give it a quick wipe with a hone. What do the bores actually measure out at? What's the piston clearance now? Are you open to sonic testing or crack checking? Pistons can be knurled on the non-thrust side as an alternative to a last resort. You're not limited to common oversizes. As an example, Olds 403 racers hone just to cleanup and then order a custom piston (which they use anyways) because there's insufficient room between the siamese bores for a headgasket to hold. Same with BBC's @ 4.600". Pistons are made in .005" increments, or custom to keep using a very expensive block. Need more info!
Alright. I'll have to go take some more measurements. not standing next to the engine right now but I'll get there. But right on. I'm not a engine rebuilder for a living soooo what does block filling it mean. Also can I jus tap into oil passage or tap into one end of the cycle to the other end
The 425s had a thinner wall then the 401 to start. Then add core shift, porosity and 50 years of internal erosion and corrosion, and there are not many 425 blocks left that are up to a .060" overbore. I think sonic testing would be in order to see if it is a candidate. Cheryl
Block filling is filling the coolant passages around the cylinders with Bloc fill a cement type material that hardens around the cylinders to keep them from distorting under heat and load. The block would need to be cleaned by a machine shop with the machinery to clean a block so its clean inside and out. That way the block fill won't move after it hardens and rust won't keep eating the block under the fill. An oil cooler usually gets the oil from where the filter is screwed in the block. The best way is using a oil filter relocation kit that allows you to route oil from the block thru a plumbed line to the filter back to the block. When you run an oil cooler you go from the block to the oil filter to the oil cooler then back to the block. Easy peasy. GL Derek
how about sleeves? or would multiple sleeves cause too much distortion ? I don't know.. just asking, Mine got a sleeve on one cylinder 40 years ago.
Sweeeet. Thanks guys. I did think about putting sleeves, but I can't afford over 100 dollars per sleeve now. Thanks again everyone!
Check about sleeves. I can attest that one can work. multiple sleeves may be a different story. Mines not a performer. Only a cruiser.
Block fill is no more than a couple hundred vs. $800 for eight sleeves, better off buying a better block. Derek
For the reasons Cheryl mentioned, I've prefered the 401 to the 425. It seems that folks are generally more excited about having those extra 24 cubes tho!
Yeah I heard that putting 8 sleeves torsionally distortso a block. But I have seen it done on a hemi and seems to be fine. But old hemis have a lot more cylinder wall so whadda I know.
Depends on if the sleeve(s) are thick or the thinwall type, and how much interference is used. Several thick sleeves makes a block flimsy unless they're brazed in.
Put a parts wanted ad for a 425 block you might get lucky and find what you need for a lot less than fixing that worn out block. GL Derek
I definitely wouldn't spend the $$ on 8 sleeves. There are still blocks around. I got a 401 block and crank for $50...delivered 90 miles...Craigslist horse trading. Crank needs welding, stroker?!?
I ran a 401 bored .125 oversize (so I could use some ancient M/T forged pistons) It was really thin. I sonic checked it and #7 cylinder was around .065. Looking at that block from the bottom side with the pan off and comparing it to the sonic test results cylinder wall thickness was pretty consistent with where the cylinder wall extended into the crankcase. Don't know if they are all that way but mine was. I filled the block with Hard Block to the bottom on the middle freeze plug. That engine was a 4.125 stroker with 12.00:1 compression, I ran it for 8 years in a boat. A piston gave way (skirt broke) before that thin cylinder cracked out.
Although I am very happy with my .030 over 425, I would be just as happy with a 401. In my case, the 425 found me, and it was necessary to bore it .030 to clean up the cylinder walls. I would be happy to pay $300 for another 425 with a Quadrajet and a THM 400. It was a deal that I couldn't refuse. Just don't ask what it cost to (finally) get it running right. If I had taken it to Tom Telesco in the first place, I would have saved a small fortune.
When the block fill hardens, and distorts the block, how are you going to re-machine it to get everything right again when the block is already thin? The time to fill a block is after the block has been cleaned inside, but BEFORE the machine work has been done.
