(Cracked Block) - Sudden Milky Oil - 351w

Well if one of you guys wants to play around with some motors I have a 351 and 302 (both with bad blocks) that need to find a home.

Waterdog wrote: Is there a reason you can't use roller tappets with a flat tappet cam ? Just cost ? We all use roller rockers to replace the stamped steel rockers.

Roller cams are totally different animal than a flat tappet cam. Different metallurgy, different lobe shape. The roller is on the left, flat tappet on the right:

There is a company based in Turlock CA, Lock and stitch is the name I believe.
They have a process to close cracks in blocks that works. It involves drilling small holes in the cracked area tapping the holes and using the Lock and Stitch process to bolt the crack closed. Sounds strange but it works very well. About 20 years back California had a large freeze that broke engine blocks all over the North State. Lock and Stitch was the only process that permanently fixed the cracked blocks with no distortion issues related to trying to weld Cast Iron.    Might be worth a check., I was an engine rep for Federal-Mogul, Sealed Power calling on all the Engine Shops on the West Coast some built 1,000 engines per month so I had a lot of exposure when the Freeze hit, Lock and Stitch came out the hero in that Freeze and made a good name for the product. I am sure they have a web site that could be checked to learn more.

http://www.locknstitch.com/cracked_engine_block_repair.htm

Link to lockstich

Don't get me wrong having my friends brother rebuild it or rebuilding it myself would have most certainly been the cheaper route, however some additional factors have weighted in on my decision.

I may not have admitted it as a teen, but now that I'm in my late 20's I'll concede to the fact my parents typically know more then I do. That being said when they offer to pay for 80% of a re-man unit I'm sure as hell not going to turn it down.

On top of that I'd rather have a 3rd party engine builder put it together so when it blows up I'm not forever pissed at my friends brother or myself.

Once the long block is assembled, broken in and installed I'll update the '79 Ski Tique Resto-mod Story

Andy, I believe the answer is yes. A flat tappet blank wouldn't survive a meeting with a roller lifter. Different material and treating.

Waterdog wrote: halfnelly wrote: Waterdog wrote: Is there a reason you can't use roller tappets with a flat tappet cam ? Just cost ? We all use roller rockers to replace the stamped steel rockers. Roller cams are totally different animal than a flat tappet cam. Different metallurgy, different lobe shape. The roller is on the left, flat tappet on the right: OK, I know rollers have steeper ramp angles, are and are made from better material and can stand higher spring pressures. I guess the question is will a roller tipped tappet wear through a cast cam. Roller tappets = less friction = free horse power (except for the up front cost of the tappets)

A lot more to it than that.

The flat tappet cam lobe is ground at a slight angle so the pressure from the tappets keep the cam pushed toward the back of the block and prevent the cam from "walking" forward into the cam cover. This slight angle also rotates the lifters to keep them from wearing in one spot. This is the reason that when you reuse flat tappets on a cam they have to be put back in the same spot they came from. Each one wears itself to that specific cam lobe.
A roller cam is ground perfectly flat so the roller lifter sits nice and square on the lobe and you don't want it to rotate. A roller lifter that rotates would be really bad. This flat grind however can cause the cam to "walk" forward so you have to put a thrust bushing between the cam and the cam cover.
That slightly angled lobe on the flat tappet cam would not allow the roller lifter to sit nice and square on the lobe exacerbating the wear that Tim mentioned.

Then the roller lifters are significantly taller than flat. This requires a different length pushrod to get your valve train geometry back where it's supposed to be.

JoeinNY wrote: LeftFieldEngineering wrote: Well if one of you guys wants to play around with some motors I have a 351 and 302 (both with bad blocks) that need to find a home. Those things are anchors, 90 percent of the parts on them would come free with a good junkyard block. If either has a RH crank with wick lines (a 2 piece rear seal) then you can pull the crank out before you junk them but the rest of the long block parts aren't worth much. Keep any marine accessories/brackets or put them up for sale. Then scrap the rest, soon trust me, I had to move around more engines and hoarded parts than I care to admit this week, my back is killing me.

x - 2 what Joe said after using the block the only thing from that picture that didn't go to the srap yard is the cam and roller lifters and not sure why I kept the cam.