I've got a '71 swinger with a 318 and power steering so the water pump connection is on the passenger side and the timing marks are on the driver side. I have a 340 that I want to swap out but it has the water pump connection and timing marks on the front cover opposite the 318. Can I just simply swap the cover, pump and balancer or are there gonna be issues, do I need to keep the 340 balancer and re index? Haven't really dug into just glanced at it a little this evening and was curious what the best solution would be. Any help appreciated. Thanks.
Timing cover 340/318
- Thread starter ktcnn94
- Start date
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Yes, keep the 340's original vibration balancer with the engine.
Use the original timing chain, water pump, cooling fan, radiator, alternator and power steering parts from the original 318 and bolt them onto the 340. Just make a new mark for TDC on the 340 vibration damper to match the new marks on the other timing cover. Just paint a line on the damper with white out or white or silver touch up paint on the original 340 balancer to match up with the other timing chain TDC mark.
Side Note: The early oil pans (pre 69) had a different seal for the oil pan with 6 nipples and the later one had the 2 nipples and wide rubber flange on the gasket for sealing. If you run the 340 oil pan, you need to get the gasket kit for a 68-69 318/340 to get the proper oil pan end seals.
If you decide to use the oil pan for the 318, then order a gasket kit for a 70 and later small block to get the proper oil pan end gaskets that seal to the timing cover and rear main.
Either the old or new style oil pan will work on the engine, you just need to get the proper gaskets for the pan.
Basically what you are doing, is converting an engine that came with a cast iron water pump to the aluminum water pump. But you have to keep the original vibration damper for the crank in the engine that you are using....
When they changed the water pumps in 70 they moved the radiator outlet to the opposite side, and the timing marks 90° so they wouldn't be blocked by the water outlet.
69_340_GTS
Well-Known Member
The timing marks are not 90° different. It is some odd number of degrees. Best solution is that once the covers are swapped, use a piston stop to find true TDC, and then properly re-mark TDC on the balancer.
Captainkirk
Old School Mopar Warrior
Use timing tape.
Rapid Robert
Well-Known Member
easiest would be to swap just the pump. the early iron pump is thinner so space the WP pulley forward to restore alignment or source a shallower pulley or if you're going the other way get a deeper pulley and you can space the alt a bit forward/backward as needed and Mancini sells crank pulley spacers to move the pulley forward. I lost track on which way you are going (early/late or late/early). Do what you need to do to restore belt alignment. You can see the marks with the pump/hose on the same as the marks side just aim the light at exactly the right angle or a said fab a tab on the other side/find exact TDC/new white paint mark on that side. best would be to as said change pump/tcover and dampener (not sure if there is a balance issue between these 2 engines) to keep in mind
If you don't use the proper pump with the proper timing cover, the timing marks are blocked by the water pump outlet for the lower radiator. The timing marks had to be moved when the lower radiator outlet changed sides...
It is not recommended to mix and match vibration dampers from one engine to another. Keep the vibration dampers with the original crank that they came with from the factory...
Well, a lot of good ideas, I'm gonna tear into it today and see what I find. Heck with it being a 71 block it may already have the markings on the balancer in the right place and just have the wrong cover on it, idk for sure till I get into it. Thanks for the help, always get good answers here.
Rapid Robert
Well-Known Member
Actually you can see the marks with the nipple both on the same side, you gotta aim the light just right & I did that with an 83 318 in my 65 dart with an early (dr nipple) pump to match my dr side rad nipple. On the second part what I was meanin to say but probably said it wrong was what you said (I hope!) that the same type of balance dampener needs to stay with what it came from so as to not mess up the balance.
fishy68
Tyr Fryr's Inc.
A buddy of mine has a 340 with a newer timing chain cover and old style water pump and it's nearly impossible to get the light aimed right to see the timing marks cause the inlet and hose are right in the way.
I cked out the 340 cover and balancer today and with number one at TDC the mark is on zero so it is a balancer that goes with this cover, that being said this is a '71 block so that would mean this balancer is not the one that came with engine as it has an early cover on it, am I correct in this thinking that this is possibly not the balancer that came with this engine or crank unless of course it's an early crank also. Don't get me wrong I appreciate all the thoughts and help but I'm thinking it may not matter which balancer is on it, who knows if it's the original one anyway as old as it is, hard to know what it's been through and had changed over its existence. Thanks again, any more thoughts please.
Marcohotrod
Well-Known Member
it is not the damper that came on a 1971 engine, 1970+ had timing on drivers side. the issue is do u have a 1968-1971 forged crank (internally balanced) or a 1972-3 externally balanced cast crank. all 318 and 340 cranks will go in any year 318 and 340 block. the 340 cast balancer is easily identified by a counterweighted front that has "for 340 cast cranks" cast into it. early 318 engines had forged cranks and later had cast, and they are all internally balanced. so 1970+ 318 dampers and 1970-1971 340 dampers are the same
daredevil
Well-Known Member
I was thinking this could be also.
Rapid Robert
Well-Known Member
I ain't a balance guru but I'm thinking swapping balancers could open a can of worms (especially between 318/340). I'd k.i.s.s. & swap in the 340 & keep the tcover/balancer on it as is & just find true TDC & fab a new tab for the pass side & make a white paint strip on the dampener OR pull the dampener & swap tcovers (then no need to fab a new tab) & reinstall same dampener & make a white paint mark on the dampener on the pass side & you're set. You could locate one of the early bolt on timing tabs that go on the pass side like this one, very nice guy member whitepunkonitro sold me then no need to even mess with the tcover/balancer. EDIT If the 318/340 dampeners ARE both internally balanced then by all means find a 318 one & a tcover with the marks on the pass side, install em & you ARE set! checkout the balance situation & go from there. MORE EDIT Marco has you covered on the balance issue
ok, I went down to the garage and looked at the "balancers" they both look the same as far as design or build. they are both about 1" thick and about 7 1/14" in diameter, basically flat with a couple of partially drilled holes in them. the 340 one is off and I don't see any markings on it like 340 cast crank only, the 318 one is still on the engine. I don't have a problem at all with finding exact TDC and marking the 340 balancer/dampner to use with the 318 timing cover if that's what is best that doesn't bother me at all, but obviously if they are interchangeable i'd rather have one with the correct mark on it to match the timing cover. thanks again for the advice fellas.
Marcohotrod
Well-Known Member
thats why the correct term for a unit on an internally balanced engine is vibration damper-damper is balanced like a tire-those are the partially drilled holes u see. as u know unless u want to change to a 1969 or earlier radiator u need the timing marks on the driver side. a balancer/damper is used on an externally balanced engine. look at part numbers for an aftermarket damper such as the Fluidampr from moparperf-p4452775, fits internally balanced A engines-273+318+1968-71 340. on any engine it is a good idea to check the timing groove in the damper to exact tdc
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