New Dart SHP burns bearings

New Dart SHP block, all new rotating assembly, roller cam, Crower roller lifters. Top end is Dart aluminum heads w/ T&D shafts. Kevko 1097s pan and 10552 pump. Motor was broke in and all was fine. Track packing and hotlaps was good - good oil pressure and water temp. Started last in heat, finished 3rd. Third lap of the feature it explodes. Rod came out front left of block. Looking is crack journal that can be seen are burnt up. Bearing clearances were good when put together so that is not the problem. Main torque was per install paper that came with block.

As mentioned this block was brand new. It came "ready to assemble" - bored/honed to 4.155, cam bearings installed and freeze plugs installed. I put in the 1/8" plugs in the lifter valley and the 1/4" plugs in the back, front, oil filter boss as the install paper called for.

I have the feeling I messed up by not using restrictor plugs in the front 2 that are for the lifters. Everything leads to it being that. A search (that has came too late) shows Moroso sells a plug kit and says it for use in the SHP when using roller lifters, but some other tech sites say to never restrict this block. The tach was at 7800 and it exploded middle of back straight - let me add that it had no oil leaks prior - which leads me to believe that the oil was all up top starved the front of the motor, regardless of the priority main oiling that block has.

Any thoughts?

dry sump oiling or wet, sounds familiar to one I killed with no oil temp at start of race

Oil temp is so important, especially when it's all new and tight.

He has a mod so it is wet sump

I haven't messed w/ the SHP but a few things to double check. Pan to pickup clearance, also some guys say the kevko box pans don't do a good job of keeping the oil around the pickup.

You say it was "ready to assemble" Do you know if they line honed it? Some shops say its required others say bore/hone/deck is all that's required.

Did you guys dyno it? Cut any filters apart? Always cut filters after the first time hammering on it be it on the dyno or at the track. And then again the first time hammering on it at the track.

The only way to know is take it apart. If it kicked out a rod cap I'd be looking at the rod bolts.

You didn't say what rods or bolts you used or whether the rods were checked for roundness and proper bearing crush.
I don't know by your description if were oil related or assembly issues however the rest of the bearings and carefully checking of the rods will at least indicate to you if the problem was systemic or isolated.

Either way I feel for ya. It's a sick feeling to lose a brand new engine you had high hopes for and on a good run to the front on top of that.

Have used this same model pump, pan and pickup on 3 other motors with no problems. Not sure if block was line honed or not. Rods were new Olivers. We always warm our motors up before running them, the lineup procedure used at Devils Bowl lets a motor warm up.

This motor was not on the dyno, but first started with a screen on top of a WIX Gold filter and ran off and on about 25-30 minutes, screen was clean and filter was clean. The screen and another Gold filter was put on and ran about the same amount of time, once again all was clean. Now when I say clean, there was some lint from shop towels but nothing metal that would show as a problem. The oil was changed and WIX race filter was put on. A total of 10 quarts of XPR 20w50.

Let me add that the final time we checked the lash (valve covers off) just bumping the motor over would cause oil to shoot out of the pushrods about 2 feet. Seriously. Looking back at that is what makes me think it was sending all the oil to the top.

Some more research shows Mullins sells their race ready prepped SHP blocks with restrictors in them. For those not familiar with the Bowl, if you are one of the top running fast cars you will be making laps hooked up and wide open, with little rpm drop except at corner entry if you are running low. I am thinking it had enough oil pumped to the top that it starved the lower front of the motor.

Hoping to have it out later this week and will get a better look.

Bill, I assume it was a roller? Do you know what size your lifters are and the finish size of the lifter bores?

Reason I say this is excessive clearance there will really effect how much oil is lost if there wasn't restrictors in the block.

Not saying I know much about the SHP block and if they need restrictors , but lifter clearance has been an issue with lot of lifters as they vary a ton on sizing and easy to get excessive clearance.


Check this out to see what I mean: https://www.youtube.com/watch?v=SpfOKr3B3FA

Crower 66292 roller lifters, .842". Do not have all my notes here at home, but it seems it averaged .002 on clearances.

I don't have any experience with that style of block, but I have seen what you are talking about with leaving the restrictors out happen.I put restrictors in every block, then drill them to the size I need.With dart blocks ,cometic gaskets and brodix heads I check all water ports,oil drains etc... in all three to make sure they line up.

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Originally Posted by LateModel B23

Crower 66292 roller lifters, .842". Do not have all my notes here at home, but it seems it averaged .002 on clearances.

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I maybe wrong on this as I don't mess with engine much any more, but I do think Crower's lifters are more on size then many of them as many are smaller like .840 to .8405 so on a pre-machined block that just takes the lifter bores out to specs can be loose. Many blocks come small on the lifter bores from the factory due to lifter size variance. So just be sure to check that out when you get it apart.

The other thing to look at is the lifter valley as many of the blocks are made to be used with a dry sump and don't have much for drain back holes and usually need to be drilled or opened up. My Alum dart had instructions to drill a single .625 hole at the back of the valley in front of the dizzy for a wet sump. That is what I did and I fought oil pressure fluctuation at the end of the straight, thought it was the oil pan but long story short after to blew up I did research and had to open up the lifter valley as it was a drain back issue and after that solved the problem. This was years ago so not sure if they have changed the instructions or if a SHP has a fairly sealed off valley or not. But check that out.

On the lifter bore dumping oil... Carl at CNC is always harping on not using the 3 hole cam bearings because of all the bleed off, maybe without the restrictors and the loss of oil through the cam bearings it could of starved the bottom. Let us know what you find, I would like to get a SHP in the next year.

SHP block have an open valley area. Oil drain back is not an issue with the valley wide open. I have never used oil restrictors in a SHP block. The lifters are designed to be the restriction to the top end, as long as no one modified the lifters. What rod, rod bolts, bearings were used?http://i873.photobucket.com/albums/a...pspm7lpbwk.jpg

Check the drain holes in the ends of the heads, many times the gaskets, block and heads don't line up.Also the crankcase pressure is tring to exit thru the same holes that the oil is draining in to.

If your running roller lifters the restriction is built into the lifters and no restrictors should be used if your lifter bore clearance is between .0014 to .0019. In most cases on circle track engines I put a small groove on one side of the lifter between the oil band of the lifter and feed hole on the lifters on the drivers side because there is not enough oil to cool the rockers and springs. And you want to put restrictors in LOL. Some guys don't have a clue how oiling works on roller lifters !!!!! I have machined and sold well over 250 SHP blocks and to date never attempted to restrict any oil to the top end. and to date no problems. If your running cam bearings with 3 holes there is a lot of bleed off on all 5 journals get rid of them, Having all the oil return on top of the crank is not the hot set up JMHO. What did you check your bearing clearances with ? Who's lifters are you running ? Lifter bore clearance is key when trying get control of windage. I will not move a block out the door unless I have lifters in hand to check oil clearance. https://www.youtube.com/watch?v=SpfOKr3B3FA

I think he mentioned which lifters he was using.

I wouldnt trust the machining on a purchased block, brand new or not.

Not saying the SHP blocks are not good, but...everything should be thoroughly checked and i mean thoroughly.

Also the quality of machining and finishing is key.

Can't tell from pix ,does that block have a drain in the right rear corner where a stock block does?