Team Camaro Tech banner

1 - 9 of 9 Posts

·
Registered
Joined
·
630 Posts
Discussion Starter #1
Now that I have all of my parts and the machine work is complete on my block and crank I am ready to start the assembly. I would like to do a mock up assembly first to check the following:

-Rod to block clearance
-Rod to cam base circle clearance
-oil pan to crank/rod clearance
-crank bearing clearances
-rod bearing clearances
-crank thrust bearing clearance

Without throwing out a ton of questions can anybody give me a blow by blow description of how you would do this properly. I know this might sound like a goofy request but I want to do this right the first time. I am making some basic assumptions that I need to torque the bearings to their proper torque specs, no rings on the pistons, lubricate bearings and cylinders with oil and do one cylinder at a time and so on. But since there are so many with much more extensive knowledge of engine assembly than I would like to pick your brains a little.

Here are the parts for my short block which may answer any additional questions or why have clearance questions:

-400 2-bolt block .040 over w/ARP studs, decked, align honed mains
-stock 400 crank, magged & polished. Machinists say with standard bearings my clearances will be .0024 main and .0018 rod.
-Scat 4340 I-beam cap screw rods floating(supposedly stroker clearanced.
-SpeedPro H616P Hyper pistons, flat top w/ 4VR(supposed to be 11:1)
-Kevko stock appearing oil pan, 6 quart cap. + filter, 2 trap doors with built in crank scrapers.
-Melling HV pump with pickup welded and set for this pan.

I know this is a long post but wanted to include as much info as I can. Let me know if more is needed. THx!

Tom
 

·
Registered
Joined
·
755 Posts
I have an excellent assembly book that details the pre-assembly process - I just need to find it so I can share the name. I'll look for it tonight.

The big problem I run into with pre-assembly is that to do it right you need the rods/pistons assembled first. Then you fit everything together and grind any rods that need clearance (400 or 383). Then disassemble and balance everything. The problem with this approach is that you can't disassemble the rod/piston easily and may actually damage the piston. This is probably the best argument for floating pins I've come up with. Maybe I'm doing something wrong and there's a better way?

It also seems that there's no way to avoid small dust scratches in the bearings with repeat assembly and disassembly. The last motor I built I accidentally ended up with 2 sets of bearings. They both miked the same so I did pre-assembly with one set and final with the other.
 

·
Registered
Joined
·
630 Posts
Discussion Starter #3
Thx RMR!!
All the info I can gather will be a big help! Have pistons and full floating rods so the assembly/disassembly issue is not problem. The rotating assembly has been balanced as well. I have 2 sets of bearings already and was actually considering doing what you had done but somehow I just can't imagine that this is really necessary and common practice by other engine builders......would get pretty expensive to use onje set just for mock up.

Tom
 

·
Registered
Joined
·
2,372 Posts
Use masking tape to hold the floating pins in place for pre-assembly. The retainers should not be used until final assembly and they are not to be re-used.

-Mark.
 

·
Registered
Joined
·
755 Posts
Here it is: "How to Build the Smallblock Chevrolet" by Larry Atherton and Larry Schreib - it's an SA Design Workbench Book. It helped me a lot and is packed with good pics and a ton of info. Good luck!
 

·
Registered
Joined
·
8,108 Posts
floating pins are nice for mock up, i put my locks in one side of the piston, then slid the pin in and mocked it up, then put the other locks in after. since its a 400 block, and i beam rods (good choice), clearancing will likely be minimal. on my 406, i opted for a small base circle cam, which BTW i reccomend doing, and upon mock up had no interference issues with the cam/rods (5.7 rods). but, when i checked closer, the rods in 1,2,5,6 where only about .010-.020 from the cam, so i clearanced those rods just to be safe (to about .060). with a cap screw rod and a small B/C cam, there may be no issues, but just look closely at these rods. it is unlikely the block will need any clearancing, with i beams, but check anyway. the other place to look at is the rear counterweight on the crank. my moroso pan needed slight massageing for clearance, but nothing major. those are the areas i had to give attention to on my 406, so just kind of a heads up. just give everything a good once over, a couple of times, and you should be good. good luck
 

·
Registered
Joined
·
630 Posts
Discussion Starter #8
Thx for the c-clip tip 68RS406! If I were to go with a new small base circle cam any reccommendations? What are you currently running in your 406? I keep hearing a solid flat tappet is the way to for more power and rpm capabilities. Iv'e posted my combo a couple of times but here it is if you can offer an opinion:

408 @ 11:1
ported 462's w/Crane gold rollers and stud girdles
Edelbrock Torker II(would love to ditch it but!!)
Holley 750VS
ST-10 w/ 2:64 1st
10-bolt w/ 3:90's
power brakes

Would definitely like to have a healthy lopey idle but still have my power brakes functional. I'll consider a canister if I need to and don't mind set the valve lash occansionally either.

Tom
 

·
Registered
Joined
·
8,108 Posts
hey great, hope it helps. as for the cam, i'm running an isky solid roller, .250 at .050, 608 lift, on 108 lsa. i do really like the cam, but it may be a bit much for your combo. i really don't like to reccomend cams, since it's such a personal preference thing, and varies from combo to combo, but for all out performance, you can't beat a solid roller, imo. just don't be afraid to go with a bit bigger cam than say maybe a similar 350 would like, the cubic inches eat up a cam pretty quick. look into cams and check some good manufacturers for suggestions, but just as a rough guess, i would say a solid F/T , .050 duration around .240, and lift in the low .500's. i also like a 108 lsa in these motors, but everything can vary. most any manufacturer will grind a cam on a small B/C, just ask them, isky did mine for no extra. good luck, you'll love it!
 
1 - 9 of 9 Posts
Top