uberkevin Posted July 11, 2023 Author Report Share Posted July 11, 2023 5 minutes ago, datzenmike said: You can shift into the gears with a screwdriver or wooden dowel. L and Z series transmissions have different 'bell housing' bolt patterns. $250? Get a 30 day return option in writing in case it's crap. They should be ok with this. $250 is ok for a reasonably good 5 speed. I've done the front case swap once.. maybe 8 years ago. I have two L transmissions I can take the case from, one 620 4 speed and one stock 521 4speed. I'd rather not mess with the stock 521 4speed. Good idea on the 30 day warranty. I'll call and ask if that's something I can do. If I can get to it within 30 days to make sure it's in good working order. But after this I'll need a new drive shaft probably, unless this 720 5peed is the same length as the 620 4speed that was in there. Doubt it.. Quote Link to comment
Crashtd420 Posted July 11, 2023 Report Share Posted July 11, 2023 10 minutes ago, uberkevin said: I've done the front case swap once.. maybe 8 years ago. I have two L transmissions I can take the case from, one 620 4 speed and one stock 521 4speed. I'd rather not mess with the stock 521 4speed. Good idea on the 30 day warranty. I'll call and ask if that's something I can do. If I can get to it within 30 days to make sure it's in good working order. But after this I'll need a new drive shaft probably, unless this 720 5peed is the same length as the 620 4speed that was in there. Doubt it.. The 720 and 620 should both be the same longer transmission.... Is the 620 transmission what you had in the truck? If so the driveshaft would have been shortened to suit.... There is a stumpy 5 spd from the mid 80s 720... those are the same length as the 521 transmission.... Also stock 521 transmission isn't the same as the 620 4spd... but at least you have that bellhousing to use... Quote Link to comment
Crashtd420 Posted July 11, 2023 Report Share Posted July 11, 2023 Is the 620 transmission a 71b type? Quote Link to comment
uberkevin Posted July 11, 2023 Author Report Share Posted July 11, 2023 I would assume but I don't see the making anywhere on it. Quote Link to comment
uberkevin Posted July 11, 2023 Author Report Share Posted July 11, 2023 (edited) The drive shaft was most definitely shortened for the 620 transmission. I have the receipt for it from the p.o So what you're saying is I might not have to do anything driveline related. Edited July 11, 2023 by uberkevin 1 Quote Link to comment
Crashtd420 Posted July 11, 2023 Report Share Posted July 11, 2023 2 hours ago, uberkevin said: The drive shaft was most definitely shortened for the 620 transmission. I have the receipt for it from the p.o So what you're saying is I might not have to do anything driveline related. Yes drive line will be fine.... I believe the 71b transmission, with the exception of the the stumpy one I mentioned, should all be the same length.. as long as you have a bellhousing that fits the L series, which you do, any 71b you find will work... Quote Link to comment
Crashtd420 Posted July 11, 2023 Report Share Posted July 11, 2023 2 hours ago, uberkevin said: I would assume but I don't see the making anywhere on it. Does it have a belly pan, Probably not.... that would be like the old 521 4spd... You should see a center plate with a bellhousing and tail housing.... Sound like a 71b to me if the driveline was shortened.... Quote Link to comment
uberkevin Posted July 11, 2023 Author Report Share Posted July 11, 2023 Definitely not a 521 flat belly pan transmission. 71b. 3 Quote Link to comment
datzenmike Posted July 11, 2023 Report Share Posted July 11, 2023 4 hours ago, uberkevin said: I've done the front case swap once.. maybe 8 years ago. I have two L transmissions I can take the case from, one 620 4 speed and one stock 521 4speed. I'd rather not mess with the stock 521 4speed. But after this I'll need a new drive shaft probably, unless this 720 5peed is the same length as the 620 4speed that was in there. Doubt it.. The 521 4 speed is no good for the case swap only the '74 and up 71B 4 speed 620 transmission. The '74 and up 620 4 and 5 speeds are 31.5" long. Most 720 4 and 5 speeds are also 31.5" but as mentioned there are some 26" 'shorty' ones out there. A 'shorty' with an L front case would be the same length as the 521 4 speed, so no drive shaft shortening. Here's a shorty with L front case. Has to be 2wd or there's no speedometer. 1 Quote Link to comment
uberkevin Posted July 12, 2023 Author Report Share Posted July 12, 2023 (edited) Okay so I can only use the front case of my 620 4speed. Makes sense looking at them So I'll swap front cases and bring them the 620 with Z front case as core. Edited July 12, 2023 by uberkevin 1 Quote Link to comment
datzenmike Posted July 12, 2023 Report Share Posted July 12, 2023 Just to be certain... L series... Z and KA series... That middle rib is at the top if the transmission is sitting upright as in the installed position. Engine mounting bolt close to the left side is L series, bolt to the right is Z series. Just remember left is L series 2 1 Quote Link to comment
uberkevin Posted July 17, 2023 Author Report Share Posted July 17, 2023 I now have a 5speed for the 521. Needs. Resurface flywheel, new water pump, debating new throw out bearing, new clutch slave, wire from fuse block to alt engine bay harness, trans oil, OG fuel pump, oil filter, install oil pan gasket, front main seal, front case gaskets, Shim oil pump for more volume, reinstall drive line, transmission, engine. Wires from new Matchbox to new coil. torque all bolts to spec. New wire for water temp, new thermostat. Just got ngk plugs and wires, cap an rotor and coil for matchbox. Seems like alot but that's not to bad. Quote Link to comment
datzenmike Posted July 17, 2023 Report Share Posted July 17, 2023 ALWAYS replace release bearing. If it was a water pump no big deal, easy to get at and easy to replace. If the release bearing fails in 6 months you'll be pulling the transmission or the engine/transmission in the snow to replace it. Fuck that shit. For under $20 save yourself the bother. Shimming the relief valve doesn't change the volume output. It increases the output pressure but only when revved up. For more volume get an oil pump from a D21 Hardbody KA24E or KA24DE. I just get them from a wrecking yard. My tired 620 L20B made 17 PSI at hot idle. With no other change than a KA high volume oil pump, it made 29PSI at hot idle. The oil bleeding past the bearings stays the same but if the pump moves more oil the pressure has to go up at lower RPMs. The interior rotors are 13% longer on the KA pumps. They have the same 55-60 PSI top pressure. The new coil has to be from an EI ignition. A points coil will not long survive EI use. 1 1 Quote Link to comment
uberkevin Posted July 17, 2023 Author Report Share Posted July 17, 2023 Thanks for the info on oil pump, I looked in one yard for oil pump from ka with no luck. They had Ka's but non with pump. So I'll just hit the other two yard here. Coil I got is for a 79 620 that originally came with matchbox. ill order new throwout bearing you're right, thank you. 1 1 Quote Link to comment
uberkevin Posted July 17, 2023 Author Report Share Posted July 17, 2023 (edited) Oh! I have no idea the mileage on the l20b I have, I guess If I'm in there I should probably just get a new timing chain kit?? 60$ ITM engine components Timing kit. Edited July 17, 2023 by uberkevin Quote Link to comment
datzenmike Posted July 17, 2023 Report Share Posted July 17, 2023 Set precisely to TDC using the ignition timing mark and turning up to the mark in a clockwise direction. It's easy to over shoot the mark so if you do back it up 1/4 turn and keep trying. Done properly this will place all the chain slack on the tensioner side and the amount can be viewed by looking at the marks on the cam sprocket. This is what you should see... There is a small notch on the back of the cam sprocket and at TDC it should be just below and slightly to the right of the small horizontal line etched into the cam thrust plate behind it. The cam is perfectly timed. This is an L16 so it is set on the #1 position. If an L20B they are factory set on the #2 position. If you cam timing is like above (but on the #2) then the chain is as good as new. No need for the expense of a new kit. I've never seen a worn out sprocket or stretched chain it probably just doesn't happen. However this can't be said for the left and right chain guides and the shoe on the tensioner. They are teflon or nylon coated and the chain does wear into them. 1 Quote Link to comment
NC85ST Posted July 18, 2023 Report Share Posted July 18, 2023 Yeah, here’s the tensioner shoe from my z24 after about 400,000 miles. 3 Quote Link to comment
uberkevin Posted July 18, 2023 Author Report Share Posted July 18, 2023 Check chain slack and wear on chain guides. Slack looks good, guides look good. Quote Link to comment
uberkevin Posted July 18, 2023 Author Report Share Posted July 18, 2023 4 minutes ago, NC85ST said: Yeah, here’s the tensioner shoe from my z24 after about 400,000 miles. There's wear... but not anywhere near this. Haha that's just impressive. Quote Link to comment
]2eDeYe Posted July 18, 2023 Report Share Posted July 18, 2023 17 hours ago, uberkevin said: Thanks for the info on oil pump, I looked in one yard for oil pump from ka with no luck. They had Ka's but non with pump. So I'll just hit the other two yard here. Coil I got is for a 79 620 that originally came with matchbox. Get a brand new, factory fresh unit. https://www.amazon.com/Hitachi-OUP0023-Oil-Pump/dp/B00T3MGEHO/ref=sr_1_fkmr1_1?crid=2SJFD9ABW2MJ0&keywords=ka24+oil+pump+hitachi&qid=1689692283&sprefix=ka24+oil+pump+hitachi%2Caps%2C144&sr=8-1-fkmr1 1 Quote Link to comment
uberkevin Posted July 18, 2023 Author Report Share Posted July 18, 2023 Yeaah should probably. 1 Quote Link to comment
uberkevin Posted July 18, 2023 Author Report Share Posted July 18, 2023 Ordered most everything I need from rockauto. Now I wait. 1 Quote Link to comment
uberkevin Posted July 18, 2023 Author Report Share Posted July 18, 2023 (edited) Picture for rhe hell of it. Redeye! Thanks for the transmission mount. Edited July 18, 2023 by uberkevin 3 Quote Link to comment
]2eDeYe Posted July 19, 2023 Report Share Posted July 19, 2023 You are welcome. Quote Link to comment
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