So, getting ready to do the rebuild on a 3.4L to replace my 3.1. I talked to a performance machine shop just to see what the cost would be. During the discussion, the guy mentioned that there is a problem with the crank having end play that is of course worse with a manual transmission since the clutch is pushing in on the end of the shaft. He mentioned a 0.005 shim that is made for this problem since it is common to this engine block. Anybody have any information about this apparent common problem and how to check this?

Trying to decide whether to do the rebuild myself or have a shop do it. Thanks...

 

I've been playing with these engines for over 13 years, and have never heard of this.

 

The thrust bearing is most likely to be worn out, that's something you cant shim. I've also never heard of the 660 having an inherent "end play" issue. This would be a good time to find another engine machinist and check the end play, if out of spec, replace main bearings(in a nutshell).

 

ive encountered this on the 4g63 engines , but never a 660 , basically the thrust bearing would get so worn it would start wearing into the crank creating excessive clearance even with a new thrust bearing

if ur crank does infact have excessive clearance king bearings makes thrust bearings with a wider/thicker thrust surface , just not sure if they make one for the 660

 

Great, thanks.. I will be taking the block and heads to a shop for whatever machining is needed. I plan to replace main bearings, rings, cam bearings, and maybe cam and lifters. Just not sure if I would have the shop do the block build up.. Sounds like this is a non-issue with new main bearings being installed.

 

deffinatly call delta up for a cam and lifter set , when u start assembling the engine let us know and ill give u a few lil tricks to do

 

Cool... I am trying to decide on what cam to get.. This is my daily driver so I want to maintain gas mileage... The original 3.1 from the factory got 36mpg at 70 freeway... The 3.1 in the car now is a GM rebuild which only gets about 23 to 24mpg. As far as I know the 3.4 I got out of a yard is bone stock.. Not sure if I should consider the cam as bad (haven't pulled it to look at it) and replace it.. The shop I talked to said I could go just slightly more performance than stock but not much or mileage will drop off.. I am not at all knowledgeable on cam ratings relative to lift and duration so maybe Delta can help with that unless someone on here has a recommendation..

I should say I am not as concerned about performance since this is my daily driver (a little more zip but not sacrificing the mileage) and I am doing a "rolling restoration" on it.. Performance improvements will be dedicated to my 67 SS/RS that I have in complete restoration process.

 

get a delta 252 grind , a 260 cam wont drop off milage really with a good tune

 

Sorry, the part about the 260 threw me... So, get a 252 to have slightly improved performance without affecting mileage? If you were put a number to it, what is the stock cam in relation to 252 or 260?

Thanks...

 

Sorry about getting off the original topic a bit.. Thanks Project89.. I had forgotten I did a thread about the cam earlier this year and the extra info you gave me then.. Anyone interested in the cam issue can go to my other thread..

https://www.thirdgen.org/forums/v6/6...3-1l-3-4l.html