Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans Advertise
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> Main and rod bearing clearances
User Name
lost password?   |   register now

Thread: Main and rod bearing clearances Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Additional Options
Miscellaneous Options

Topic Review (Newest First)
07-11-2019 09:51 AM
Itsjust a 305 Im running h beam rods 7/16 bolts and i been there and done the need more power. My truck is being set up for the 11.00 index class here. And i only have jetting up to a175 shot.

I thought the clearances where a but on thr close size. I well check my rods before i order my +.001 bearing
07-11-2019 09:38 AM
ericnova72 The .0015" is a bit on the tight side considering you plan some nitrous use. If it was mine I'd get the +.001" clearance set and use just 1/2 of it, this would put you at .002"-.0025" clearance.
Splitting sets to fine tune clearance is quite common in the high performance and race engine scene, so don't de worried about it.

Be honest with yourself about that nitrous amount.....the power gets addictive and often leads to stepping it up....more than a few engines have been toasted due to the owners upping the jetting to the max the solenoid will flow.

If you're the type that this would be a possibility, then use the full +.001" set(actually, it would be a .009" under, or sometimes called a .010x")….and makes sure you've got the added RING gap to also handle more nitrous.

If using stock rods, even with ARP bolts, don't run them on the tight side, get the additional oversize there for sure if it measures out tight. Slightly tight a thr rod will only ba acceptable with a race type rod with 7/16" capscrews.
07-11-2019 08:58 AM
MouseFink I have used Valvoline 10w-30 All Season Motor oil in every car I have owned since 1965. I have never had a problem that could be blamed on the oil when using 0.0025” - 0.0030” rod and main clearances.

I spun out rod bearings on two different occasions in my 1969 Pontiac Firebird 400 but that was due to excessive engine speed over 5700 RPM with stock 1969 rods. I resized a set of used 1972 stock rods that did not have a spit-hole, using ARP 3/8” rod bolts, and that ended that problem.

Stock 1955-1963 Pontiac forged or 1964-1971 Pontiac cast spit-hole rods with stock rod bolts are undependable more than 6,000 RPM.

You can successfully use up to 0.0030” rod and main clearance if you have rods without a spit hole in the rod cap. The lack of a spit-hole forces more oil across the rod and main bearing surfaces.
07-11-2019 07:46 AM
2001Blazer4x4 It's fine but I would stay away from 20W50 oil. Use good old 10W40.
07-11-2019 07:00 AM
MouseFink Rod and main bearing clearance between 0.0020” and 0.0025” is ideal.
07-11-2019 06:40 AM
Itsjust a 305
Main and rod bearing clearances

Look for somw help again it seems like my bearing clearances seem a lil tight. My main are betwwen .0015 and .002. I have not checks rods yet bc i ran out of time last night. Was wonding about if this was ok or if i need to get a set of that has the +.001 . my crank is .010 on both mains and rods.

Note this is what i would call a hot street motor and the plans are to u a 100-150 shot as a o **** button at the track when running heads up.

Motor specs are
Copy victor jr intake
Worked over 210cc intake procomp heads
3.5dome pistons at 4.04
3.5 stroke crank thats has a .002 gram bal
Came is 243 int./249 exh at 50 with a .600 int and exh on a 112 lob
Running a .040 head gasket

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 07:19 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.