Dartswinger70
Well-Known Member
- I want a car that will lay rubber for a full city block... so it would have to be pretty heavy duty...
340 Engine Shake
- Thread starter plumkrazee70
- Start date
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plumkrazee70
Well-Known Member
UPDATE: and not a.good one. I'm not a professional,.but I believe this 340 is toast...
The main and rod journals on the crank have scratches I can get with fingernails. To top it off the rod and.main journals have been cut down
.030 already according to the bearings.
The block has some absolutely bizarre wear in the cylinders. I just don't understand why or how. This motor has literally less than 200 miles on it. It has however been sitting on and off while the car underwent it's "resto" While it was bagged in a garage, maybe moisture got in? Its already bores .040 over.
To be honest, I'm not sure it's worth it to me to bring it .060 over (even if it sonic checked good), buy a new crank, pistons, rods and do all the machine work over. Not sure what I'm going to do and maybe I'm jumping ahead. Gonna bring my dad by this week to get his opinion as I don't think it would clean up with a hone.
Pics of the worst cylinders, they all have some version of the wear. Pics of the bearings and crank.
The main and rod journals on the crank have scratches I can get with fingernails. To top it off the rod and.main journals have been cut down
.030 already according to the bearings.
The block has some absolutely bizarre wear in the cylinders. I just don't understand why or how. This motor has literally less than 200 miles on it. It has however been sitting on and off while the car underwent it's "resto" While it was bagged in a garage, maybe moisture got in? Its already bores .040 over.
To be honest, I'm not sure it's worth it to me to bring it .060 over (even if it sonic checked good), buy a new crank, pistons, rods and do all the machine work over. Not sure what I'm going to do and maybe I'm jumping ahead. Gonna bring my dad by this week to get his opinion as I don't think it would clean up with a hone.
Pics of the worst cylinders, they all have some version of the wear. Pics of the bearings and crank.
plumkrazee70
Well-Known Member
Pics of the crank journal. Rod bearings look just like the main bearings.
mopar head
Well-Known Member
I wouldn`t toss the block, not many around.
Seems that condensation set in and did it`s dirty deed, maybe greasing bores for long term storage would be a good thing.
Good luck with what ever path you take.
Seems that condensation set in and did it`s dirty deed, maybe greasing bores for long term storage would be a good thing.
Good luck with what ever path you take.
Rat Bastid
Dunamis Metron
Polish the crank and send it.
TT5.9mag
Two atmospheres are better than one
Yea crank can be polished, machinist should be able to look at the rust stains and give you an idea if a hone will clean it up. I don’t think you’re that far far off from a nice refresh, the bores being the big determining factor. And honestly the bearings don’t look terrible. They don’t look good but Ive seen much worse.
Inertia
Well-Known Member
The crank can be polished, and many 60 over 340s are running around, I've built a few, including my own 69, I bought new, and wouldn't be numbers matching without 3 sleeves and going 60 over.
Cylinder wall pattern during misc teardowns show no distortion, which I have seen with weak cyl walls .
Ran 12.5 pistons racing at 60 over .
Same pistons trimmed 3 times over the years, about 10.5 now.
Hope it helps, cheers .
Cylinder wall pattern during misc teardowns show no distortion, which I have seen with weak cyl walls .
Ran 12.5 pistons racing at 60 over .
Same pistons trimmed 3 times over the years, about 10.5 now.
Hope it helps, cheers .
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plumkrazee70
Well-Known Member
Good to know on the crank. I thought it would have to be cut. And I thought .030 was the most you could go. What I'm struggling with is buying another set of pistons and machine work for .060 over. The bearings, no biggie that's cheap.
My mind is instantly going towards a junk yard 5.9, re ring, bearings, upgraded cam and ede aluminum heads. Selling my brand new Edelbrock aluminum heads and my la air gap to fund the ede magnums and intake. And Use my la front accessories with the FItech on top.
In my mind that is the cheapest quickest way to get this thing back on the road. It's not a numbers matching car and far from original.
Inertia
Well-Known Member
Many here would agree, and offer shipping to send the 340 to them, lol
Rat Bastid
Dunamis Metron
You can turn your rod throws down to SBC small journal which is 2.000 inches (nominal). Or Honda journal size which is 1.885 IIRC (nominal).
If you could get .040 or .050 under bearings you can turn the crank that far. The issue is they’d never sell many of them because most don’t know you can go that far or further.
Back in the “day” undersize bearings all had the same size steel backing. They just made the overlay thicker. I was told there was issues with overlay migration and the like.
Now they use thicker backing and keep the overlay the same thickness across the under sizes.
That's not wear in the cylinders. That's where that block sat up with water in it and it rusted. Looks like somebody did run a hone through it though. That was nice of um. Dang man. Sure am sorry.
plumkrazee70
Well-Known Member
The hone was from when it was rebuilt in 2012ish. I rebuilt the motor back then. It has less then 250 miles on it. What gets me is where the water came from. Makes no sense to me.
That's a good question, but that's what did it.
Inertia
Well-Known Member
Is it all cyls or a few ?
In high humidity, -: engines "breathe" thru open valves, with seasonal/temp changes.
That's how fuel tanks get water in them .
Marine engines in particular .
Not all that uncommon, here anyway ,
I think I posted that in another thread, thinking it was here. I hate being old .
Cheers .
In high humidity, -: engines "breathe" thru open valves, with seasonal/temp changes.
That's how fuel tanks get water in them .
Marine engines in particular .
Not all that uncommon, here anyway ,
I think I posted that in another thread, thinking it was here. I hate being old .
Cheers .
plumkrazee70
Well-Known Member
Yea. It's a big bummer.
.040" and possibly .060" bearing are available same with pistons , crank polish or turn and polish , bore and hone & parts and labor , assemble yourself . Should get by for under $1000 , sucks but its still a 340 and cheaper than a from scratch 360
So did you ever pinpoint what the shake was?
plumkrazee70
Well-Known Member
No,.the point of the tear down was to replace lifters, then the mechanic said he didn't like what he saw on the cam lobe wear. Then he found glitter in the oil (see bearing pics) and also in the filter.
So I decided to tear it down to find the source of the metal (still undetermined) and found the water situation. So one problem just snowballed into another.
I'm dropping it to the machine shop tomorrow to have it sonic checked and magna fluxed. When I was cleaning the oil off for transportation, I saw rust flakes coming out of the water jackets, when I rotated the engine on the stand. But we'll see what the machine shop says.
TT5.9mag
Two atmospheres are better than one
I think you’re getting a little ahead of yourself. Your engine is not junk, and as of right now you should still be considering a refresh IMO. Every cast iron engine on earth has rust flakes in the water jackets, that’s not uncommon at all. Let your machinist have a look, make a plan and follow it. If he says it’s junk then move on to your 5.9.
plumkrazee70
Well-Known Member
You're right. My wife had to talk me down as well. I'll keep everyone updated on what the outcome is.
plumkrazee70
Well-Known Member
I just want to get it back on the road quickly, have it be reliable, make decent torque for a fun street car and do it as cheap as possible. Lol.
TT5.9mag
Two atmospheres are better than one
Cheap or inexpensive is fine. We all work on budgets but with an unknown “junkyard” 5.9 you could be in exactly the same spot you’re in right now. They aren’t all gems. Keep the modifications to a minimum have good quality machine work done, assemble with a mindset towards absolute cleanliness of the parts and you’ll be fine.
I don't see anything nasty except for those bores. Did you say you were already .060 over?
plumkrazee70
Well-Known Member
No I'm at .040 over now. I guess I got scared when I looked down the coolant passages and saw the rust. But I got to have the professionals give the final doag before jumping the gun. It's going in tomorrow.
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