1967 CJ5 Dauntless V6 Engine Rebuild

Last year, after driving my brother-in-law's V6 CJ5 which had recently had a valve job, I realized that his V6 had quite a bit more "oomph" than mine. I figured that after 80,000 miles, mine was probably in need of a valve job as well. I took it to a very good local engine builder who took the heads off, only to find out that several lobes of the cam were very seriously worn down, and some of the lifters were in bad shape as well. So....I decided to bite the proverbial bullet and rebuild the entire motor. This Youtube video shows the finished results:



Externally, the rebuilt engine appears stock. Internally, it has been line bored, balanced (both rotating assembly and weight-matched), and ported. Block was decked, heads were shaved, and cylinders were bored to accommodate 231 pistons, yielding a compression ratio of 9.18:1. A custom Comp cam (based on modified 260H design specs) was installed, along with new oversized valves, springs, seats, guides, pushrods, hydraulic lifters, and new bearings throughout. TA Performance adjustable oil pump and Cloyes double roller timing chain & gears were also installed during the rebuild. Original alternator was rebuilt by TAE, original starter was rebuilt by CAS. and original distributor was rebuilt and recurved by Advanced Distributors.

Engine was rebuilt by Thomas Lassman Custom Engines & Performance of Black Mountain, NC.

The newly rebuilt engine idles remarkably smoothly (particularly for a Dauntless!) After rebuild there is no noticeable change in low end torque, and mid and upper ranges have significantly increased power.

 

Nice! If you feel at liberty to share just regarding the engine rebuild cost--which side of 3 grand did it land? More or less? ...or ignore the question.

 

To be honest I drove a friends AMC v8 jeep and really wasn't impresed, my Commando seemed to be just as fast.
My Jeep guru told me that a V6 can chew up a cam and I have replaced a couple of them. Open up the thing and I seemed to be missing a few lobes. Well there is my problem. Probably better than when I had 1/3 of a camshaft layong in my oilpan and a hole in the side of my block.

 

Dave B, Your question re. the cost is actually a good one.....if a bit painful!

The total was north of $3K, in large part as a result of some unfortunately timed discoveries at the machine shop. When grinding the last valve seat of the second head, a crack appeared that required replacement of the head. Problem was, I couldn't find a perfectly matching one to replace it, so I ended up buying a set of 1970+/- heads through the classifieds here (thanks, Oldtime!) and having the oversize seats I'd already bought installed in those. So, I basically ended up having to pay for having two sets of heads machined, as well as the cost of the second set.

Also, decking the block was expensive, but necessary using the 231 pistons in order for the compression ratio to work out. If I were to do it over again, I'd just use oversize 225 pistons, and not have to deck the block. Rotating-assembly balancing is likewise not inexpensive, but it made a huge difference in terms of reducing the engine's vibration level. In addition, the aftermarket parts I opted to use were not cheap.

At the end of the day, I'm very satisfied with the results, but it did end up costing more than I'd anticipated. I figure (read: I'm hoping) that in a few more years, I probably won't remember the cost figures to the extent I do now, but will still very much appreciate how well it runs.

 

maurywhurt, thanks for the additional info. -- I have a Dauntless 225 V6 "odd-fire" in my 1967 CJ5--it's running fine, but nice to know of your rebuild work.

 

It isn't as "cheap" as it used to be to rebuld a motor The guy that did my heads on the Harley did a five angle grind for the valves but he is a bit on the obsessive side and has spent many years building racing motorcycles. He just told Suziuki to cram it after a few races they had him at. They stole a lot of his knowledge and applied it to other race bikes later.
As far as I know he is now a happy guy sitting on the bank of the old Muddy Miss with a fishing pole and still teaches machine work at the local community college.

 

That's a nice engine!

 

All V6 Dauntless engines are nice!

 

Yup! This one is so clean you could eat off it! Mine...not so much, lol!

 

Great Information - I looked on the internet regarding contact information for Thomas Lassman Custom Engines & Performance of Black Mountain, NC and couldn't find a direct number or website. Can you share the contact info? I live about 2 hours NE of Black Mountain and looking to have my Dauntless rebuilt.

 

Care to share your cam spec's? I'd be interested in modern grinds compared to the old stand-by's that have been around for 20+ years.
-Donny

 

VAPepsiGuy, I just PM'ed you with the info you asked for.

Donny, I actually just posted that cam card a couple of days ago on this thread: 231 OF cam specs | EarlyCJ5.com I'd be interested in hearing your thoughts once you've had a chance to take a look at it.

 

how is the engine running a year later? holding up well? do you have a build sheet of what when into the motor?

 

I'm happy to say that the engine is still running great a year later. I never did a detailed build sheet, but a description of what was accomplished during the rebuild is included in the first post in this thread.

 

Awesome good to hear!

 

With the new valves, are you using plain old pump gas with no additives?

 

Yep, just out-of-the-pump premium.