Jeep Engine Build

[Burgerman]

Leakage into crankcase has me wondering if cylinders out of round. Any block history? Could somebody have excess honed it in the past?

 

[bob w]

Straight from the engine shop. .030" overbore and hone, new pistons and rings. End gap is .018" I assembled it. The short block did sit assembled for 6 months before I put the head on and tried to start it.

About the only thing I can think of is the hone finish on the cylinders in not compatible with the rings.

I've been assembling engines since 1958, Never had this situation before. I've got an email into the engine shop. Awaiting his reply. Not blaming him. Just trying to figure it out.

 

[bob w]

I was just about to pull the engine out and ball hone the cylinders when my very good friend, Terry showed up on his vintage restored (by him) Sportster. He said, "Stop!" there's nothing wrong with that part of the engine.
We spent most of the day verifying everything. Put the head, intake and all the other stuff back on the engine. Wouldn't start. After juggling different push rod lengths and rocker stand shims it started and ran. Push rods that seemed loose at rest were too long on the exhaust side causing the valves to hang open. This thing has short travel lifters and the push rods have to be the right length.
We ran it only for a minute but it sounded powerful and crisp.
After Terry left, I cut up some 8.5mm spark plug wires to fit. I removed the 2" carb spacer and the Holley carb wouldn't fit because of fuel line and linkage interference. So I did the right thing and replaced it with an Edelbrock branded Quadrajet. Don't ask me why.

 

[Burgerman]

Nice job sorting this out Bob. Glad your block is ok. Like powerful and crisp. Good friends rock.

 

[oneeye]

Nice looking engine! Glad you got it sorted out.[cl

 

[smallfoot]

Glad you got it figured out. I had faith it was something simple...

 

[Old Iron]

Glad you didn't finish pulling it apart cause, on the previous page post 300, I said it was the valves not closing.
Had this same thing happen on my 401 Nailhead

 

[bob w]

Yes indeed, OI. I thought I had that area covered. Had the rocker stands shimmed with a slight bit of lash, like for a solid lifter cam. Apparently the hydraulic lifters pump up even at idle, possibly on the starter motor. Must be very short plunger travel in these lifters.

The high zinc 50 weight racing oil I had in the engine might have contributed. Possibly wouldn't bleed out of the lifters at the right rate.

 

[Old Iron]

These non-adjustable rockers are definitely touchy
The ole Nailhead only had 8 thou taken off the heads to clean them up and I ended up having to put adjustable push rods in it.

 

[bob w]

These non-adjustable rockers are definitely touchy
The ole Nailhead only had 8 thou taken off to clean them up and I ended up having to put adjustable push rods in it.

That confirms my suspisions, OI.

 

[Torchie]

[P [P [P [P [P
And learning.
Torchie

 

[zzrodder]

I'm not familiar with the Jeep rocker arm setup, assuming they are not adjustable? Wouldn't adjustable ones be a better route to go than messing with a bunch of different pushrods?

 

[bob w]

zz, if there were adjustable rocker arms available I'd own a set. By selecting correct size shims for under the rocker stands, I got the engine to run. After running a few minutes the lifter plungers seemed to work better. I'm confident enough that I'm putting all the other stuff on the engine and elsewhere.
Two of the events I pan to run do not allow Weld Rodlite rims. Also, I felt the 10 1/2" Mickey's were too wide. I bought the 9" Hoosiers from a Super Stock (or stock class?) racer. The International slots are from Facebook Marketplace. I have to black out the white letters on the slicks to look more period correct. Notice the unilug slots are wallowed out. I had my long time friend and ace machinist Don Groff drill a fresh bolt pattern.
After a lot of scrubbing on the wheels I once again whipped out my trusty tire irons and put 'em together.

 

[Bamamav]

Look good to me!

 

[05snopro440]

Looks like adjustable arms are available. Not cheap, but available.

https://www.boostedtech.com/solutions/accessories/roller-rockers/jeep-2-5l-and-4-0l-harland-sharp-1-71-adjustable-roller-rockers/

https://www.summitracing.com/search/part-type/rocker-arms/make/jeep/engine-size/4-0l-242/rocker-arm-style/full-roller

 

[bob w]

Looks like adjustable arms are available. Not cheap, but available.

I believe they are not adjustable. A big improvement though. If the engine works out, that would be the next modification.

 

[Torchie]

Nice to have a friend like that.
[P[P[P
Torchie

 

[05snopro440]

Looks like adjustable arms are available. Not cheap, but available.

I believe they are not adjustable. A big improvement though. If the engine works out, that would be the next modification.

There are a few options in the links I shared for adjustable arms.

 

[Old Iron]

Adjustable push rods are what I ended up putting in the 401 Nailhead and the 392 Hemi

 

[05snopro440]

There are a few options in the links I shared for adjustable arms.

Although on Summit, one review for one of the adjustable options said they needed longer pushrods as well otherwise they needed a valve cover spacer