Ok yall I bought the Dart SHP block with the one piece rms and my question is did you guys block off the oil galley underneath the #5 rear main cap? If so what size plug did you use? I know the DART block oil system has been redesigned so I wasnt sure if it needed to be plugged like the factory blocks are. I couldn't find one small enough so I opted to plug it with a 1/2" plug in the oil filter opening instead. I had my reservations doing that because I dont know where else that passage went besides the #5 cap. What I did was run compressed air in the oil filter opening and plugged the other side with my finger and do not hear any air coming out in any other places. What do you guys think? Is it ok to plug it there instead of under the #5 main cap? pics enclosed

Here is the opening under the #5 main cap. Couldnt find a plug small enough to fit there



I plugged it here instead

 

Unless you are running a dry sump I would not plug those passages as there will be now way for oil to go from the oil pump to the filter.

Also no need to put sealer between the rear cap and block as that block is a one piece rear seal block not a 2 piece rear seal block.

Going from bolts to studs will change your housing bore diameter and block should be aligned honed as they will tighten up to about .0005 see it all the time on those blocks.

 

thank you for the information. Why is it that the oil galley needs to be plugged on factory blocks?

 

That plug on the OEM SBC's allows oil to be filtered and if left out oil will go the path of least resistance and not flow through the filter.

Dart blocks have better oiling then the OEM blocks.

 

sounds good enough to me. I guess I will pop that plug back out. Thanks for the information. As far as that sealant goes some guy told me to put that on there, I guess he thought I was using a two piece rear main

 

When you put the Main studs in did you follow the instruction the came in the ARP box??

 

Yes, hand tight studs in block and arp lube on washers and threads and torque in 3 increments to 80ft lbs for 7/16 studs and 45ft lbs for the 3/8 studs

 

Disregard my last pm. Carl did my block but its two piece design and may be an older oil system design? I thought i didnt have a plug there under 5th cap

 

Oh ok, I went ahead and took the plug out. Thanks for your help guys

 

Did you miss the foot note where it says,

when changing from factory fasteners to high strength fasteners, Clamping force and tolerances will change, Therefore it will be necessary to check the main bearing bores for proper size and out of round condition ETC.


Going from a bolt that you torqued to 65# and now going to a stud that has much more clamping force and is torqued to 80# and not checking the housing bores you may be in trouble.

 

I checked the main clearances and got .0015" across all mains. You think I should mix and match the bearings with one std bearing and one . 010" over to get to. 0025"?

 

.0015 is on the tight side. If your using Bearing go with an X bearing as it will give you .001 extra oil clearance.

Going with a STD. bearing and a .010 will give you .005 clearance which is not good.

What are you using to check clearances with??

Good luck with your build.

 

I used Plastigage to check the clearances. I know people hate using plastigage but i used it on my last engine build and had no issues. The bearings looked pretty good. Since this will be a turbo motor the ring end gaps I'm going with are .020" top and .016" second.

 

Plastigage is more accurate then some of the cheap bore gauges some guys use.

 

my first builds were on .0055"x Bore dia for gaps and did ok. Showed slight sign of butting and eating the cyl wall. So i'm at closer to .0063x bore now

 

Is that for the top ring only?

 

Yeah top, the 2nd is just abit wider. I was at I think .023/.025 and now run .026/.028 top/second

 

I always thought that for blown motors the second ring had to be narrower than the top ring to minimize blowby

 

Some do that. Some say top ring gets much hotter so it expands more, shrinking up the gap so starting with more top gap will narrower down when running. I'm not sure. I just know it seems to be working for me. I never had bad blowby unless intake mani didnt seal up

 

The ring manufacturer recommended number seems kinda narrow and I've heard horror stories of ring end butting causing wall damage or cracked rings. I may open up mine to similar numbers as yours. Better to have a little more than not enough .

 

Exactly. More wont hurt power