were clevite bearings used?

sven

 

If he bought the rotating assembly(rods, pistons, crank) then it is slowboy's fault because they should check rod bearing clearances before selling the stroker kit, but if he only bought rods and pistons and reused his stock crank then Joey should have check the clearances himself and he is at fault. Plain and simple in my opinion. So my question is Joey did you buy the crank, rods and pistons of the kit from Slowboy or did you only buy the rods and pistons, and reused your stock crank?

 

This is incorrect.

These clearances cannot be checked unless one has the block itself present, which SBR obviously does not and never did.

 

I had asked the same question on post #27 (page 2) and still have yet to get a response although SBR has made several posts since then.I guess you will have to "BUY" one of their kits to find out........

 

A word of advice to all who contemplate purchasing and installing a stroker kit on their own:

Never assume that these parts will fit perfectly into any given block, period. They may appear to fit perfectly, but a deviation in recommended bearing clearances by so much as a couple of thousandths is enough to create a world of problems.

If there isn't enough clearance, the oil won't be able to coat the bearing surfaces and you'll get what appears to have happened to Joey. If there is a little too much clearance, one gets what amounts to a large oil leak. Even one bearing with too much clearance will leak oil and starve the others.

The vendors who piece these kits together have no way of knowing how the parts will fit once they are in YOUR block. I'd also recommend putting a micrometer to the rods and crank journals prior to installation. If you find one rod or crank journal that is inconsistent, stop what you are doing and make a phone call.

Before buying anyone's stroker kit, inquire specifically about what you're getting, especially with the crank. I'd prefer a kit that had a crank that was new (or one that proved true with a minimum of attention), and checked for straightness. If the crank is not new, inquire about how far (if any) it's been turned. Because of these considerations, the lowest price does not necessarily guarantee the best deal if you get what I mean.

Be advised!

 

SBR advertises ACL bearings with the 2.1L destroker kit.

 

It came with ACL bearings.

Since I did not measure the rod bearings I will never know for sure what happened.

I still think if a vendor supplies you with the crank, rods and the rod bearings they should be the correct ones.

 

What's the consensus on ACL bearings vs. Clevites?

 

I think I can add another possiblity of why this 2.1 failed. Pictured here are bearings from an engine I assembled earlier this year. The owner of the car made a huge mistake on his first oil change. He jacked up the car on the oil pan. It was driven for two weeks before he brought the car back to me with a complaint of an engine noise (rod knock). When the car came in it had no more than 30psi oil pressure. The pan was bent and restricted the oil into the pump. The rod and main bearings where swapped for new ones, crank hand polished, pan dented back out. Car left with 110psi oil pressure and has been running like a champ since.

The pics of the bearings in this thread look like the ones I posted. Both suffered low oil pressure. If the engine was assembled with clearances that where too tight the engine would not have turned freely during assembly. I doubt that was the case. The bearings did not have too much clearance. If they did a rod knock would have been heard upon start-up. And there is one more thing about these bearings that support my view. The bearings farthest from the pump 3/4 will look better than the two that are closest 1/2. This is because 3/4 get more oil pressure than 1/2 would in a low oil pressure situation. I have seen this pattern in many other motors that suffered low oil pressure. The end of the oil gallery will get pressure first and feed 3/4. Then when there is enough pressure 1/2 will be fed as well.

Now whether or not you guys buy my diagnosis Is not really important. But what is important is you guys that are building your own motors or having motors built should be having the cranks NITRIDED. Factory 7 bolt mitsubishi cranks are not nitrided at the factory. As such they are very soft and will not live through any type of film stregnth loss. They spin rod bearings very easily. Look at the pics of the bearings I posted. They are three times as bad as the ones posted from the 2.1. Yet the crank suffered no damage.

 

This is the only reason that I had a respected local shop with lots of 4G63 experience build my shortblock stroker. I have built a lot of engines, my father used to run a blown alcohol dragster in NHRA on a nationally competative level, so he has built a LOT of engines, but niether of us had built one in the past 4 years. It was worth it to have a guy who builds them day in and day out to asseble the short block, I know that he has a supply of diferent bearings on hand and he mics everything. It was just worth the peace of mind.

 

Why would you need a block in order to check rod bearing clearance?

 

It is up to the person assembling the engine to double check, not the vendor.

NEVER ASSUME ANYTHING when building an engine. Well actually check that, I assume that everything clearance is wrong and all prior machining is incorrect. Then I double check every clearance.

Every set of rods I have ever seen in my life has had at least one that had at least one end over a gram off.
~1/4 of the rods have had a taper on the large end from the factory (I'm not talking about stock) and had to be resized.
Depending on the intended use of the engine I have increased the side clearance on many of the rods.
I have seen too tight of a pin clearance on a few occasions.

That's just getting started on rods only............YOU need to check everything properly. If you don't know how then research and learn. All the information is readily accesable to anyone willing to search. If you can't handle that do not touch your own engine.

 

The 2-2.5 thou main recommendation claimed to be ideal for everything from street to race is not true and is too general. Need to consider journal and housing size and material, , quality of component, application. Almost always in racing things get tighter.... as tight as ~ 5 tenths of a thou for warm weather or pre-heated aluminium block race engines. That makes the listed "ideal" upper limit 500% of actual.

 

Because I don't ***ume anything when it comes to fitment and tolerances of reciprocating assembly components. Been there, done that!

 

You're measuring the rod journal, the rod big end bore, the bearing, no assumptions. You don't need the block. You need the block for main bearing clearance, not rod bearing clearance. Maybe you misread rod bearing clearance as main bearing clearance.