Peterman Posted May 9, 2015 Report Share Posted May 9, 2015 First of all thanks for all the help I've gotten reading this forum so far. You have gotten me running again a few times already. I purchased a 74 620 automatic about two months ago and since then I've put in a new starter among other things as the old one was worn out. In the last couple days I have found it more and more difficult to start and am just getting grinding sounds. I pulled the starter off last night and the flywheel is worn down all the way around as far as I can tell. I was wondering how far the starter should engage the flexplate (mine is only engaging about a quarter of the width of the plate). Also, would this result from something misaligned or a missing shim? I tried to post in the classifieds as well but had some issues- anybody in the Seattle area have a flexplate for an l18 they want to sell? I want to get this sweet truck back on the road and have a feeling a new flexplate is needed! 1 Quote Link to comment
datzenmike Posted May 9, 2015 Report Share Posted May 9, 2015 Well let's look back some. The starter was replaced... could it be the problem? Was the old starter the cause of the ring wear, maybe? Is there a thin engine plate between the automatic and the engine block? There should be. The starter should sandwich it against the transmission when bolted up. If the ring gear is worn there is no easy fix, the transmission or the engine will have to come out to get at it. If you have the original engine, any L16 or L18 flex plate will work. If your engine has been replaced with an L20B you will need an L20B specific plate. You can identify the engine you have by looking along the top edge of the block where it meets the head, directly behind the dip stick handle. If you have an L18 you want a 5 bolt wheel, if an L20B you want a 6 bolt. Here is the link to the correct classifieds forum.... http://community.ratsun.net/classifieds/category/5-drivetrain /?sort_key=date_added&sort_order=desc You are cleared to post there. 2 Quote Link to comment
Peterman Posted May 9, 2015 Author Report Share Posted May 9, 2015 Thanks Mike. I'll pull the starter and check to see if it's functioning tonight as well as the other things you mentioned. I'll update with my findings 1 Quote Link to comment
datzenmike Posted May 9, 2015 Report Share Posted May 9, 2015 Verify your engine. Lots of things can be swapped in 40 years. L20B flex plate is different (6 mounting bolts) 1 Quote Link to comment
Peterman Posted May 10, 2015 Author Report Share Posted May 10, 2015 The engine is an l18 still. I took a look at the starter and saw a retaining ring holding another ring on the shaft of the starter that was preventing the gear from extending far enough. I took off the ring and the problem is fixed. Starter is solid. 1 Quote Link to comment
datzenmike Posted May 10, 2015 Report Share Posted May 10, 2015 There are many starters for the 620 and of them, they are divided into manual and automatic, although I can't see the difference as the starter ring is the same for either flywheel. Well, what ever it takes to get it going I guess.... 1 Quote Link to comment
Peterman Posted May 10, 2015 Author Report Share Posted May 10, 2015 I thought it was strange that the design on this starter would prevent it from fully engaging the flexplate. Quote Link to comment
datzenmike Posted May 10, 2015 Report Share Posted May 10, 2015 AFAIK all manual and standard flywheel teeth are the same and in the same location so all starters should work. A factory Nissan starter is likely $200. Auto stores have them rebuilt cheap or get knock offs from China and sell them for $60. Quote Link to comment
Kmralvarado Posted September 7, 2017 Report Share Posted September 7, 2017 Well let's look back some. The starter was replaced... could it be the problem? Was the old starter the cause of the ring wear, maybe? Is there a thin engine plate between the automatic and the engine block? There should be. The starter should sandwich it against the transmission when bolted up. If the ring gear is worn there is no easy fix, the transmission or the engine will have to come out to get at it. If you have the original engine, any L16 or L18 flex plate will work. If your engine has been replaced with an L20B you will need an L20B specific plate. You can identify the engine you have by looking along the top edge of the block where it meets the head, directly behind the dip stick handle. If you have an L18 you want a 5 bolt wheel, if an L20B you want a 6 bolt. Here is the link to the correct classifieds forum.... http://community.ratsun.net/classifieds/category/5-drivetrain /?sort_key=date_added&sort_order=desc You are cleared to post there. The L16 and L18 flex plates are the same? I am looking for a 5-bolt L18 flex plate but can't find it anywhere. Would the L16 work fine? 1 Quote Link to comment
datzenmike Posted September 8, 2017 Report Share Posted September 8, 2017 The L16 auto flex plate after April '71 will match the L18. This is when the new 3N71B was introduced to replace the older Borg Warner automatics. I don't know if the BW flex plate will work but the 3N71B will 1 Quote Link to comment
Charlie69 Posted September 8, 2017 Report Share Posted September 8, 2017 There are many starters for the 620 and of them, they are divided into manual and automatic, although I can't see the difference as the starter ring is the same for either flywheel. Well, what ever it takes to get it going I guess.... On the automatic starter is clocked different then the manual starter. The automatic starter sits with the solenoid close to the engine block the manual starter lays with the solenoid away from the block. I will take some pictures of my L20B automatic I have in my 520. Quote Link to comment
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