4.2L Stroker Build

mythorath

Member
No sound when engine is cold, only shows up when engine has fully warmed up.

I think I'm going to try to pull the oil pan and check the rod bearings to see if anything is going on down there. (I think a bearing is being / has been destroyed)
 

mythorath

Member
Well I spun a rod bearing.




20181101_183106.jpg


I'm thinking this was caused by a blocked oil passage or something similar. All of the other rod, and main, bearings looked fine and dandy. Could also have been miss-assembly, this was my first engine build after all.

Very slight scoring on the crankshaft. Going to take it into the shop when I get some time and money to see if the crank and rod are salvageable.

Looks like the car is sitting for a few more months.
 

6 Shooter

Well-Known Member
IMHO, spun bearings come from not enough oil in the gap between the bearing and the crank journal. Can be caused by bearing wear, improper torque
on the rods, or the bearing being too tight upon initial installation due to improper bearing size vs the size of the crank journal at that location. Generally, the rod bearing clearance should be about 0.0015 of an inch which allows enough space for oil to lubricate. Another possibility is inadequate assembly lube in the bearing when the motor was put together OR, NOT priming the motor with oil prior to first crankup.

Another possibility is long term wear of 100,000+ miles and not changing oil frequently enough.
 

mythorath

Member
Sorry for the lack up updates, kind of got side tracked in life for a bit.

The bearing didn't actually spin, just shifted a bit. After talking to the machine shop we think I just messed up the install on one bearing somehow (or there was a defect that I didn't notice).
Machine shop measured everything and they just had to polish the crank and install new bearings.

I got the engine back in the car, it seems to be running great! (even with the stock tune still loaded)

Currently having a problem with a transmission leak. I think it's coming from one of the transmission cooler line connections on the transmission.

Once I have the leak figured out I'll start tuning the car, once I learn how to tune the car that is...(I have all the hardware for it)
 

Sideshow Bob

Active Member
I know what your talking about. I've been working on mine for 9 years now. Thanks for the update I just dropped my block off at the Machine Shop I'm looking for any thing to watch out for on my build.
 

mythorath

Member
From my limited experience I would offer up these tips:

Be as clean as possible during the assembly process.
Inspect each and every bearing very carefully (replace even if you see a speck of a defect, this is likely what caused my first build to fail)

I think the biggest problems I ran into while assembling / installing the engine for the second time were the trans and oil dipstick tubes. I forgot to install them on the engine before installing.
Oil wasn't bad to get back on just had to pull driver side exhaust manifold off.
The trans dipstick tube I had to modify to install, I couldn't reach where it bolts to the back of the engine. (just install it back on trans before putting trans back in car)
 

Steve A

New Member
Hey myth, the learning curve is always steep initially but by the time you get done you'll be a seasoned veteran. One thing I would recommend is that anytime you have the engine and transmission separated change the rear main seal on the engine and the forward pump seal in the transmission. Just cheap insurance. Obviously your rear main seal is new so that wouldn't be needed.
 

Sideshow Bob

Active Member
What was the problem with the 918 valve spring? They are the right upgrade for our heads. That's what I have ordered for mine. I know they need some machine work to get them too 130 lb Seat pressure but I don't think that requires a lot of work.
 

mythorath

Member
From what I remember my machinist said the springs were too strong, and there was risk of damaging the head or valves.
He was also taking into account which camshaft I'm using. (which is a very mild cam), and the fact I'm reusing stock valves, and non hardened pushrods.
My machinist did all the math and found that the new springs were the right spring for my specific setup.

I'll see if I can get some more info for you in the next few days.
 

mythorath

Member
Short update!

So you know how I took the engine back out a second time to fix that bearing?...

Well I had to take the engine back out for a 3rd time. Had a transmission leak that I just could not fix for the life of me. After I got the engine out I found out I broke the trans dipstick tube...pulled an engine to fix a dipstick tube. I will say that I don't know if that trans dipstick tube is replaceable inside the car though.

Got that done last weekend. got the engine dropped back in the car 2 days ago. and I plan on actually putting it back together over the next few days. Hopefully I'll get to take it for a drive soon, and not spew trans fluid all over the streets. Then I can finally do something about the inside of the car.
 

Sideshow Bob

Active Member
Thanks I'm not sure what needs to be done to get the 918 to work yet but hardened pushrods is one of them. I think they have to machine the pocket but stock valve will work. I'm using them on a 224 / 224 cam for boost.
 

Spdricer

Active Member
Short update!

So you know how I took the engine back out a second time to fix that bearing?...

Well I had to take the engine back out for a 3rd time. Had a transmission leak that I just could not fix for the life of me. After I got the engine out I found out I broke the trans dipstick tube...pulled an engine to fix a dipstick tube. I will say that I don't know if that trans dipstick tube is replaceable inside the car though.

Got that done last weekend. got the engine dropped back in the car 2 days ago. and I plan on actually putting it back together over the next few days. Hopefully I'll get to take it for a drive soon, and not spew trans fluid all over the streets. Then I can finally do something about the inside of the car.
Show pics of like ur work area and stuff
 
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