351 strokers are a ticking time bomb?

[Jman142]

So I came across a dude today who stated that 351w that turned into stroker motor are ticking time bombs. He said he talked to a guy at a reputable machine shop who said the crank journals are 1/4 bigger on the stroker crank and that the extra mass on the journal which was suppose to help for strength, in reality made it worse because of the extra weight. He said it put to much stress on the main bearings..now I know that there are plenty of 351W stroker motors out there running fine, I was just wondering if this is even a real world problem people have had, or is suppose to be common knowlegde when building a 351 SM

 

[Rick 91GT]

Never had any issues building any of the large cube strokers.

Crank journals....same size as stock 3" 351W or 2.75" Clevaland main for Race blocks.

Rod Journals...2.0" and 2.10" are the popular sizes, Chevy journals.

 

[Modular2v]

who ever told you that really needs to get their head out of their a$$

 

[BaXTeR3221]

Yea i've never heard of anyone having problems with them. I've heard more issues w. 347's than 351's.

 

[zenboy99]

Don't 351W have oiling issues at high rpm because of the 3" mains?

 

[streetflossin]

no sir not anymore, all the oil issues been resolved, all the newer stroker kits you buy will come with file fit plasma moly rings. the problem was that the older kits came with the wrong kinda rings.

 

[Rick 91GT]

Actually yes with a stock production block a 3" main 351W block still has some oil issues due to the way the oil travels in the block. The front lifters starve for oil, but you can tap into the main oil feed then tap and plumb extra lines in the lifter valley going to the front lifters. There are also bearings out that can help keep oil in the mains, but machine work and clearances become more critical on a high rpm 3" main motor.

The type of piston ring has nothing to do with the oil issues associated with a 351W.

 

[streetflossin]

your right i didnt read this whole questions, i only read oil and 351. but also for stroked 351 oilring/pin intersection problems were solved years ago. The problem was the wrong ring selection

 

[Jason 302]

I actually stopped at my local machine shop today. I know the guy fairly well, and he has a 72 351 block that has been bored, decked, align honed, and stroker clearanced. I didn't ask for a price. He also has a 393 crank. I was thinkin of using this combo with some 408 H-Beam rods and custom SRP/JE pistons. I'm going to wait until I get my 306 put in, then I might fit that into my ranger one day once the 393 is done.

 

[Rick 91GT]

The 72 block is a thick wall block and you can make some serious power with it, I have seen them with 800hp and no issues. I've doen quite a few few 4" stroke motors in those blocks and they do not need any clearacing until you swap in the slightly taller ARP2000 rod bolts.

 

[zenboy99]

I've been looking for one of those blocks for a long time.

 

[Jason 302]

The 72 block is a thick wall block and you can make some serious power with it, I have seen them with 800hp and no issues. I've doen quite a few few 4" stroke motors in those blocks and they do not need any clearacing until you swap in the slightly taller ARP2000 rod bolts.

Did they switch to the 9.503 deck height by that year?

 

[seijirou]

I don't see how the slight increase in weight from larger journals at the centerline of the crank is going to to put extra stress on the main caps if the crank is balanced properly.

It's weight that's at the outside of the rotating assembly that's going to make the crank want to flex.

 

[Rick 91GT]

69-70 9.48
71+ 9.503

 

[70lightning]

Stop hanging around chevy mechanics.