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



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine> First BBC, urgent help with timing!
User Name
Password
lost password?   |   register now

Thread: First BBC, urgent help with timing! Reply to Thread
Title:
  
Message:
Trackback:
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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
08-05-2010 07:38 PM
bbcguy140 but like every one else said it dont matter where the rotor ends up at #1 cause all u need to do is just change the locations of the wires. i just prefer to have #1 in the factory location it makes it easier to put the wires on
08-05-2010 07:33 PM
bbcguy140 wow man that looks pretty bad would definately affect compression. and no the valves will not fall into the engine if u take out the rockers and push rods cause they are held in by retainers that are held into a groove machined into the top of the stem held by the pressure of the spring. youd need to take the heads off in order to get the valves out. so dont worry about loosing the vaves into to engine. and the best way ive found to get the distributor lined up in the factory position for #1 is to get the engine to compression. and i always line up the mark on the balancer with the 0 mark on the scale. that is where the piston is all the way up in the cylinder. then i pull the distributor and line it up with the number one tower on the cap then turn it counterclockwise back just a little before #1 then drop it in the hole and twist it clockwise a little till the gear lines up then it will be lined with the correct tower. then i bump the starter to get the oil punp shaft lined up till the distributor falls down all the way then ur golden. after all that i normally get the engine back to tdc on #1 to double check the alignment. its never failed me. so give it a try. sorry about the wordiness of this but it takes alot to explain
04-15-2010 03:06 AM
F-BIRD'88 Stock GM rockers and valve springs are not compatable with high lift cams.

Long slot style rockers are required. Replace all the push rods and all the rockers.

Valve spring compressed coil clearance at full lift and retainer/seal guide boss clearance at full lift must be verified.
First you need to verify the actual cam lobe lift of the cam that is in the motor. Don't assume the cam in the motor is the specs shown on the cam card. Measure the cam lobe lift off the push rod with a dial indicator. .320" The lifters must be inspected for wear.
The cam and lifters are probabily trashed now too.

I'll bet you will need a new cam+ lifters + long slot rockers+ pushrods+ correct springs+retainers and seals.

Do not use gasket sealer on the rocker cover gaskets. It is not nessessary and the sealer ends up stuck in the engine oil passages blocking oil flow.
Engine bearing damage, cam lifter wear and noise etc etc etc.

Who ever put this motor together is a hack.
04-14-2010 07:12 PM
S10 Racer
Quote:
Originally Posted by Forza1
How straight do the push rods need to be? I rolled them over glass, and one will need replaced for sure. The other two roll pretty smoothly, but if I get eye-level with the glass, I can see a slight(hair thick) bend to them. Should I replace them?
It would be worth some peace of mind knowing you have new straight ones. They are not that much $$$ and new ones will save you from having to do it again. If possible, go with the 3/8" diameter chrome moly pushrods.
04-14-2010 02:49 PM
Forza1 How straight do the push rods need to be? I rolled them over glass, and one will need replaced for sure. The other two roll pretty smoothly, but if I get eye-level with the glass, I can see a slight(hair thick) bend to them. Should I replace them?
04-13-2010 01:30 PM
Forza1 OK, gotcha, thanks. I spoke to a cylinder heads shop yesterday and he wondered what could have caused it, he suggested maybe a valve binding. However, I read if you don't de-burr the oiling hole in the pushrod cup, it can lead to cracking. Plus they look like older rockers to me. It's my only car so it's kind of a chore getting to the parts store but I will keep everyone updated.

-D
04-13-2010 01:19 PM
S10 Racer
Quote:
Originally Posted by Forza1
By "rocker slot", so you mean rocker arm? Or is this a specific part of the rocker arm? I've never heard the expression before.
With any aftermarket higher lift cam than stock, you need to check and see that the slot in the rocker arm is not hitting the rocker stud when the valves are open.
04-13-2010 01:17 PM
richard stewart 3rd the slot that the stud comes through
04-13-2010 01:03 PM
Forza1 By "rocker slot", so you mean rocker arm? Or is this a specific part of the rocker arm? I've never heard the expression before.
04-13-2010 05:55 AM
redsdad
Quote:
Originally Posted by richard stewart 3rd
Hi,
just unbolt the rocker & replace it
Not so fast. I put a very mild cam in a 396. Even so, the rocker slots bottomed out on the studs, causing similar damage to what you see here. Closely examine the valve end of the slots and the studs to see if yours are bottoming out. Then buy a set of rollers.
04-13-2010 02:55 AM
Forza1
Quote:
Originally Posted by S10 Racer
With that compression, you should be running the highest octane pump gas you have in your area.
Thanks for the heads up, I plan on running 93. However I didn't think it was too bad considering the aluminum heads. I used to have a LS1 with alum. heads/cam and the compression was 11.2:1 and it ran great on 93 octane. But that's a completely different engine.

I know the car needs valve seals, and I'm wondering if I should just get a cam kit for $350 and change my cam, rockers, lifters, timing chain, push rods, seals, etc... I don't really have the tools for precise measurements and clearances.

-D
04-12-2010 06:52 PM
S10 Racer
Quote:
Originally Posted by Forza1
Hey, I'm glad you mentioned this... Can you tell me how mild or wild this cam is? I attached the cam specs sheet below. I don't understand how it says .320 lift, shouldn't it be more like .530, esp with 1.7:1 rockers? Or am I reading it wrong?

I know it's a 4-bolt main block, forged crank, forged pistons, 10:1 compression, aluminum heads(I was told edelbrock? I'm not sure where to look for the edelbrock stamp at to verify), Performer RPM intake manifold, Chevy 427 "dump truck" exhaust manifolds, and someone bolted on an Edelbrock 1407 carb. I don't think I can fit long tubes, and I feel like the carb is way too small for a 454. If I get it running right, will "shorty" headers and a 850cfm carb wake the car up? I have no idea what kind of power it should be making.

I will do the timing tomorrow and let you know how it goes. Thanks for the advice, I'm learning a lot of this hands-on stuff as I go. Anyone have a good link to a DIY valve seal install?

-Dustin
With that compression, you should be running the highest octane pump gas you have in your area.
04-12-2010 05:57 PM
richard stewart 3rd Hi,
Look like GM rockers, A guy at work had this happen all the time 67 chevelle 396, just unbolt the rocker & replace it, roll the push rod on a piece of glass to be sure it's straight, & make
sure it's not clogged also.
Rich
04-11-2010 01:36 PM
Forza1 Well I found out the cause of the weak compression on the passenger side, and so the plot thickens...


So on a whim, after I set the crank and rotor today, I decided to pop the valve covers before I buttoned things up. The drivers side looks fine, but it looks like 3 pushrods on the passenger side pushed through their rockers. I attached a pic below... Can anyone ID these rockers by looking at them? I guess I'm going to need to replace the pushrods too. If I unscrew the rocker arm, will the valve fall into the cylinder? What's the procedure for this?

Thanks everyone for your help so far!

-D
04-11-2010 06:48 AM
Rhansen the .320 lift is lobe lift, multiply it by rocker ratio to get valve lift (.544)
BTW that looks like a relatively conservative cam for a big chevy.
This thread has more than 15 replies. Click here to review the whole thread.

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 04:02 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.