Cam questions
 

I got some questions.

Back ground. 4.3L V6 engine with internal balance shaft.
Came out of a '93 S10-Blazer and will go into a '87 S10-Blazer after I rebuild it. The '87 is my off-road toy. I am rebuilding it due to a spun #1 rod bearing after 190,000 miles of service.

1) I keep seeing "Not for Computer controlled engines". What's that all about? How does a computer controlled engine differ from a none computer controlled engine in regards to the cam? Is the only difference the lobe for the mechanical fuel pump?

2) Does the internal balance shaft make a difference as far as cam selection?

3) Anybody know what years GM put Hydraulic roller lifters in the 4.3L V6? Or rather did the "93 have them.

4) Do you have to do anything special to go from hydraulic lifters to roller lifters?

Any and all help is greatly appreciated.
Thanks,

RE: Cam questions
 

Go to the "compression ratio" topic, then page 2, then scroll down to Swarts post on "Rebuilding your 262..." then bring it up. Hit print and it will answer ALL your questions. Good luck.

RE: Cam questions
 

4) Hydraulic lifters must be pre oil filled before installation. Best of my knowledge here. Good luck.

RE: Cam questions
 

#1 - They state this because some computer controlled engines may not run optimally with a high lift and/or long duration cam without modification of the fuel/spark/maf tables.

#2 - It won't affect the choice of cam so long as the cam has the drive gear for the balance shaft.

#3 - I believe hydraulic roller lifters were first installed on the CPI W code motor in '94.

#4 - I do not think that anything was done differently, but you may have a different lifter retainer in the lifter valley... Plus the cam will need to be of roller design to fully maximize the benefits of using roller lifters. Benefits include reduced friction, reduced wear, as well as the ability to run steeper ramps on the open & close sides of the lobe.

RE: Cam questions
 

Thanks.
I am going through that link posted in the Compression thread. Looks very familiar.[8D]

I'll have to do some checking to see which block I have. The intake is off, and it looks like I may have the roller lifters based on that thread and the pics. The more I read that thread, the more important it seems to be to identify which block I have.

I think I have the heavy crank, rodsand pistions, but will have to verify that tonight. Will the heavier crank, rods, and pistions be better for 4x4 and towing?

I dont remember if it had the tranny supports on the bottom of the engine or not. Although I am having a problem with the flexplate in the '93 at the moment. It is hitting the starter (I think) under heavy loads. So either it is cracked (I bought the cheap version), or the bolts have walked out, or the tranny bellhousing is cracked. The '85 block doesn't have the tranny support brace bolt holes, however there is a support brace on one of the tranny middle bolts on the passengers side. It was a real pain in the butt to get that bolt in and out when I did the engine swap. I'll post a new thread on this.

RE: Cam questions
 

Judging from the pictures "heavy" means the weight of the crank and not necessarily "heavy duty". In a "light" crank a crank throw is drilled out. The article explains what versions were made for "heavy duty" use.