i will be tearing down my 70 455/365 engine this week or next to check things over before it goes back in my pace car. this motor is going to be stock down to the exhaust manifolds {may change cam to a more modern grind}. i have researched this site on engine info and it seems there is ALOT of spun bearing issues with the bigger olds engines 400/455ci. whats the deal with this? i have done many sbc/bbc builds stock to strokers and have had only one problem with a bad oil pump. this car is not gonna be a hot rod but it deff, wont be babied! are the 455's prone to detonation causing bearing failure? if so is this due to a bad combustion chamber quench area? or guys throwing way to much timing into it? poor oil distrubition? or is it just guys throwing these things together without checking clearances/tolerances. i know all machine shops are not created equal{sp}. i have allways checked EVERTHING i get back from a machine shop and have caught flaws now and again. i just want to go threw this motor once and not have to pull it after the resto is done and the frontend is on it. thanks guys!!!!!
charlie,,,,

 

The oiling system on Olds motors isn't the greatest, and don't like to be revved much beyond 5500 rpm for long periods, or could mess up the bearings. Also, if you have crank machine work done, important polishing the journals before putting things back together.

 

Olds engines were built with rather tight tolerances, and not so good oil return system. If you are gonna beat on it, make sure your rod and main tolerances are at the top of the suggested tolerances (.035 on mains, I believe). DO NOT use a high volume oil pump, unless you get an aftermarket large capacity oil pan, and have work done on the oil return journals and oil restrictors to the rocker arms. If you usually keep it under 5500 RPM's the stock config. is fine.

 

#3 and 6 rod bearings spin most often; the oil feed holes come out at the journal in a bad angle. Cutting a short "trough" instead of just chamferring the hole seems to help. Also, Olds rods are fairly soft and the big end deforms under load. Without enough press fit, the bearings spin. Be sure to get the rods re-built carefully to the small end of spec (2.6242") or for similar money, get aftermarket rods (better approach).

 

jesse442 is right I have 3 engine's that haven't blown up . I would also remove any casting flag in lifter area and at front of block where oil comes through to the timing chain there's a hole, deberr the hole and make it into a tear drop shape also paint lifter area with that orange slippery paint (forget what it's called oil runs off it really fast) it will help oil get back into pan faster.My cars are 4 speeds and they go 5500-5800 no problem just don't hold them there too long

 

My car has original rods in it that were professionally polished and relieved, and they work fine....no idea of horsepower, but my 71 will do around 87 mph approx. 8.10 in the 8th mile.

 

thanks for the info guys

 

The rod and main bearing diameters are to big. Rod and piston weight are very heavy. Cyl block is weak.

Gene

 

for future reference{sp}. how many grams is a oem cast piston and what is the weight {in grams} of a stock rod? who is making good rods at a reasonable price and weight? i beam or h beam. what are the forged aftermarket pistons coming in at for weight. never heard the olds blocks being weak. where are they weak at?thanks,,,

 

I think I read those same threads and was actually getting paranoid, then I said to myself I am glad I went for overkill.. my Motor is done, still sitting in wraps waiting for me to finish the chasis but I am happy I went with the eagle rods, the Icon pistons the arp bolts and now I am even more happy that my builder went the extra mile on my block.. but man oh man I am not planning on beating on it just want it to run well....


IMG_3954 by thunderboat59, on Flickr


IMG_3952 by thunderboat59, on Flickr


IMG_3948 by thunderboat59, on Flickr

IMG_3950 by thunderboat59, on Flickr

 

factory and old TRW/speed pro pistons are 680 grams or more. Add in the 190 gram pin and you have heavy. Stock rods are around 860 grams. Think of how far you can throw a hard ball, now can you throw a soft ball that far?
I take stock rods and take them down to 800 grams. it is hard to take very much off the TRW/speed pro pistons, but every little bit helps. If you get good pistons they are much less in grams. You can check name brands and get the weight. "H" beams are still kinda heavy, but I still take them down to 800 grams. You can also find light weight wrist pins also. It may cost a few bucks more, but you will see a big difference in performance.
you will have to research for pistons, Mahle, probe, SRP, many more. Same with the rods. You should check with the vendors on this site and ROP. Smitty at M&J proformance is a very good one.

Eddie, with all the work you have done to your short block, why use stock main cap bolts?? ARP all the way.
Also see the distance between the pan rail and the main cap. See how it necks down, that is why I say a weak spot. To be strong I say it should be just as wide as the main cap all the way to the pan rail.

Gene

 

Not sure where the .035" number came from, as sounds more like a spark plug gap to me. I'm usually looking for about .002" on the front mains, and maybe .003"-.004" on the rear thrust. Maybe missing a zero on the original response.

 

This is correct. BBO main bearing failures are almost always the result of a heavy reciprocating assembly on a weak crankshaft in a weak block. Works fine at low RPM for street driving, but push it hard and the block isn't stiff enough to control the crank movement then bearings & journals get damaged. Rod bearing failure is frequently caused by too tight clearance.

Bill Trovato's book explains most of these issues and how to minimize them.

 

good info/responses guys, wanted to do a 69 4 spd hurst clone and run a built 455 after my vert project is done. seems it would pay to get a ultra light rotating assy from one of the aftermarket companys out there. or maybe just stick a 434 stroker sbc in there lol,,

 

Gene, we think alike, and I did use ARP bolts through out, this picture was before I dropped them off, he wasn't "thrilled" and he said it isn't as easy as just changing the bolts LOL but they replaced the bolts, retorqued and rechecked the clearances, and I completed another might as well, same reason I went to Harlan Sharps LOL... I also used a "stock" milodon pan which actually holds 1 quart more than an oem stock pan but in a better configuration than a toro pan, but still I only have 6 qts....

 

The Machinist also cross drilled the crank, chamfered the holes, and did some work to the bearing oil holes, restrictors etc ... he was a really good guy, and I had to kinda trust him as this is waaayyyy over my head on what the motor needed, I wanted roller tip rockers and he said if your going roller than it's harlan sharps and that means bigger studs and non stock valve covers... he fabricated block off plates for the performer aluminum manifold, welded them in and machined the surface, port matched the runners and also machined off the edelbrock name and then blasted the manifold so it looks as cast.... cheaper than finding an original aluminum olds manifold... I also went with SFI approved damper and flywheel but not for racing I guess I just wanted the best "insurance" didn't mean to hijack the thread but after reading those threads I too was worried thinking holy crap, I spend 5 grand on a motor ( not to mention I provided a lot of parts too) and I can end up very easily with a spun bearing etc ... That said the 350 that was in it would rev very nicely always had great oil pressure and even after 100K miles blew very little smoke ( a little at start up) never even thought about spun bearings etc.

 

I am considering making mine a 4 speed convertible clone that is why I had the motor painted red.... My Motor is a 69 455, and it does have the nodular crank etc and "supposedly" those motors had higher nickle content or something that made them a better block, I also used the C heads with the valves done and some minor porting and polishing, matching etc...

 

NOT the nickel myth again!

This has been disproven by metallurgic analysis by members of this forum.



- Eric

 

oooopppppssss LOL yes sorry about that ....... anyway it is a 69 Block.... and ya know nuthin can be finer when you have a sixty niner...... Engine Block...

 

If thinking of going big cube small block, get hold of a 350 diesel block, as lot's of meat to work with. Some go 440 on these, no problem.

 

You'll get no argument from me on that point.

- Eric

 

Seems a lot of guys have built the diesel block.. to tell you the truth I really don't know enough about it, or "designing" engines etc , I had mine built, I went with heavy duty stuff not so I can race it but so it will hold together and be the best it can be. I got SFI rated flywheel because i like my feet LOL... and i was thinking the 455 has a lot more torque etc I am sure I would have been fine with the stocker but it was Might as well fever LOL.

I was reading a lot of stuff on another failed engine thread, and I am actually Glad my builder said we will max the compression at probably 9-9.5, when i said I think my 350 has more than that now, and a stock 455 was over 10 he said do you want to be safe or sorry? torque is what your gonna feel in the seat of your pants and your not racin..... well I can not wait to get further along on my project...