Author Topic: How to proceed with my 340  (Read 13013 times)

Offline soundcontrol

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How to proceed with my 340
« on: March 03, 2015 - 05:10:11 PM »
When I bought my car 2 years ago, I thought the 340 was a worn out stock engine, since the oil was very dark, smelled burnt, and when I hit the pedal the oilpressure dipped, so the light came on. It was also leaking oil everywhere (on the headers while driving) and headers leaked also, so it really had a clunker feel to it. Previous owner did not know much about the engine he said.


Taking it out and apart now, I find that it has TRW 10:1 forged pistons, a forged crank (maybe someone can confirm this with the picts?) A Crane camshaft HMV 278-2 NC, a pretty mild street camshaft I think. An Edelbrock aluminium intake. The heads are the later 360 model with the small intake valves though. Seems to me that the engine is pretty good except for the heads, called around today and to fix those heads with larger valves and a regular valve job for unleaded gas is around $800-1000. For just a bit more cash I can get Edelbrock heads. Is that a better option for me?


The camshaft chain needs to be replaced, seems a bit loose. Cam and lifters looks good, cam bearings looks good, have not checked the other bearings yet. Should I take the pistons out and replace rings and bearings anyways? I have no idea how many miles is on this engine, but since the cam chain is kinda loose... and the oil is dark, also lots of black oil residue on top of the pistons. (see pict, but I wiped off some to see the numbers.
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new




Offline burdar

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Re: How to proceed with my 340
« Reply #1 on: March 03, 2015 - 05:12:54 PM »
Around here, it costs around $500 to go through a set of stock heads.  There's nothing wrong with the 1.88 valves.  If you aren't racing the car, it's not worth the expense to go to 2.02's IMO.

Offline Chryco Psycho

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Re: How to proceed with my 340
« Reply #2 on: March 03, 2015 - 05:18:07 PM »
You should have done a compression test before disassembly . Can you see cross hatch on the cylinder walls any reason to suspect the rings are bad ? Is there any ridge at the top of the bore ?
 What do the brgs look like ? Wondering why the oil pressure is low , minimum would be a new oil pump
 The crank is forged  :2thumbs:
 Eddy is a step backwards IMO + alum heads will drop the compression by 1 point due to heat loss to the alum , why not get a good head like RHS or similar
« Last Edit: March 03, 2015 - 05:23:07 PM by Chryco Psycho »

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Offline soundcontrol

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Re: How to proceed with my 340
« Reply #3 on: March 03, 2015 - 05:44:26 PM »
I know, I just thought of a compression test while I was taking off the second head... :dunno:
Didn't look that close for a crosshatch, (didn't have my contacts in..) I will look better tomorrow. There is no ridge though, I only thought of changing the rings/bearings because I have it all apart and its fairly easy and not so expensive. I took it apart just to see whats in it and to fix the oil leaks. Gonna check the crank bearings later. It has an oil splash guard also (maybe all smallblock do, I only had bigblocks before).
I will get a new oil pump, the oil pickup was loose also, could have been screwed in a few more turns.


Not gonna race it, so maybe I'll save the cash and just use those heads then. Just want a nice ride until I can afford a Hemi. Since I'm in Sweden everything costs twice as much as you guys pay....
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new

Offline Chryco Psycho

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Re: How to proceed with my 340
« Reply #4 on: March 03, 2015 - 10:17:39 PM »
if there is no ridge the rings should be ok but as you said it is apart so it is easy to swap them out , make sure you use plasma moly , chrome will never seat .
, If you buy a good head like Airwolf or RHS you should have no issue selling them for decent $$ when you are done with them , but that is your call .
 if the pickup was loose air is much lighter than oil so it could have been pulling air which is good & bad news as oil starvation may well have damaged the brgs but that is likely the problem .
 All performance small blocks have the windage tray , but most do not .

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Offline Denison636

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Re: How to proceed with my 340
« Reply #5 on: March 04, 2015 - 12:01:18 AM »
I know that these are the speed pro trw forged piston. I put them in myself. Thing that caught me on yours is the dip in the center of the piston.
Its just a little 340 with a miss

Offline crash340

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Re: How to proceed with my 340
« Reply #6 on: March 04, 2015 - 04:15:36 AM »
I couldnt find anything on RHS's web site re mopar heads?
Greg

73 Cuda
Brisbane, Australia

Offline soundcontrol

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Re: How to proceed with my 340
« Reply #7 on: March 04, 2015 - 05:30:52 AM »
Plasma moly rings, never heard of it, things change, it was 28 years since I took an engine apart last time :)  Good info, thanks!
The oil pickup was so loose that it was moving with gravity when I turned the engine around on the stand, I assume it could move up and suck air then when accelerating or turning sharp....

Denison, I think mine are older TRW's, I believe that engine was done in the late 90's. Then the car has been in parts for a long time before I bought it. What is that thing on the side of the timing chain on yours? I did not have that.
Looked at RHS, did not find any Mopar either...



Edit: Actually, l looked at Summit for the pistons, they look like mine here:
http://www.summitracing.com/int/parts/slp-l2316f30/overview/make/dodge
« Last Edit: March 04, 2015 - 06:36:32 AM by soundcontrol »
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new

Offline Chryco Psycho

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Re: How to proceed with my 340
« Reply #8 on: March 04, 2015 - 08:09:07 AM »
That is a chain tensioner available from Mopar , not a production item
RHS used to offer LA heads
Mopars W2 heads are awesome but very expensive as everthing is different for them from intakes rockers & headers & valve covers

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Offline soundcontrol

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Re: How to proceed with my 340
« Reply #9 on: March 04, 2015 - 02:28:52 PM »
Aha, I think I'll just keep my heads then, for now. Expensive is not in the budget and I'm saving up for a new Hemi anyways.
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new

Offline 73restomod

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Re: How to proceed with my 340
« Reply #10 on: March 05, 2015 - 09:43:49 AM »
Indy cylinder head bought the entire RHS small block line from them awhile back. Brand new they are about 1000 ready to bolt on.

Offline jimynick

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Re: How to proceed with my 340
« Reply #11 on: March 05, 2015 - 11:19:29 PM »
Use some plasti-gauge when you remove a main and rod cap to check the clearances. .0025 is a pretty good # and if they're too loose it'll leak oil pressure internally. Also check to make sure the rods were put in with the chamfer to the crank weight side. Plasma moly refers to the coating now used on the rings and it's much superior to any prior ring/coating. Also, make sure the ring gaps are "clocked" properly and not stacked above each other as that'll make it burn oil and lose compression. You won't actually lose any compression using an aluminum head, they're just more tolerant of compression and the rule of thumb is, as CP mentioned, that you can run one higher # compression-wise before you get into problems with detonation. That cam chain tensioner is the cat's a$$ and they run about $35-45 here and prevent the dreaded 340 cam chain noise/stretch. Good luck with it! 

Offline soundcontrol

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Re: How to proceed with my 340
« Reply #12 on: March 06, 2015 - 07:33:59 AM »
Hmm...looking at plasma moly rings on Summit now, according to the pistons, L2316, the bore is 4.070, (I checked the standard bore is 4.04) and my pistons are marked 0.30. I cant find any rings with 4.070, only 4.060, and 4.030. Clearly some error in my skills here... or the Summit search engine is bad. Since Im used to metric, am I adding up the numbers wrong here? It is a decimal increase in the inches numbers right?
It would suck to order the wrong rings and ship them to Sweden.... I was looking at Sealed Power rings, and I check other brands also.

Thanks jimynick, that chain tensioner seems like a good investment.
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new

Offline soundcontrol

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Re: How to proceed with my 340
« Reply #13 on: March 06, 2015 - 03:55:29 PM »
I mailed Summit and got the answer that theese 2 rings are what they have in that bore (4,070).
(And I could not find those by searching their website at all.)



http://www.summitracing.com/int/parts/slp-e-286k30/overview/
http://www.summitracing.com/int/parts/uem-4000am8-070/overview/


Says "moly" only, not plasma moly...
Strange, 030 over standard bore, isn't that a very common bore size?

« Last Edit: March 06, 2015 - 04:19:27 PM by soundcontrol »
/ Ken
Restoration thread: http://www.cuda-challenger.com/cc/index.php?topic=102525.0
topic=108917.new#new

Offline jimynick

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Re: How to proceed with my 340
« Reply #14 on: March 06, 2015 - 05:19:34 PM »
No, it's not a common bore size here in GM land where the standard sizes run 4.00 to 4.060 for a 350 sbc. Check the parts books to finds a size that fits another application. As long as the size and thickness are correct, it doesn't care what it's installed in. Moly is the operative word here and plasma only refers to the method they use to deposit it on the ring.  :cheers: