Author	[Modern View]
DGK 01-20-2013 08:48:58 70.194.131.86 Report to Moderator	Bought 620 in a basket, the previst owner said had knock when he tore it down. Bored new pistons bearings, even idler gear buy hyd pump. Put back together and still has knock. If you put your hand on hyd pump you can feel it. So I took gov. completely out and still have knock. Does it sound like something with cam? Thanks for any help. Doug [Reply]   [No Email]
BushogPapa 01-21-2013 10:37:22 173.88.51.117 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   Get it out and put it to WORK a while...!!! If it not getting any Louder, it is fine... Ron.. [Reply]  [No Email]
buickanddeere 01-21-2013 06:52:57 184.151.63.131 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   Did you actually pull the cam and followers then had them re-ground? [Reply]  [No Email]
DGK 01-21-2013 08:29:16 70.194.128.116 Report to Moderator	Re: 620 knock in reply to buickanddeere, 01-21-2013 06:52:57   No did not pull cam. Bolts were alittle loose on cam gear but didn't make any difference. Just knowing the original owner tore it down because of knock. Sure can feel it on hyd pump. [Reply]  [No Email]
buickanddeere 01-21-2013 08:38:02 184.151.63.131 Report to Moderator	Re: 620 knock in reply to DGK, 01-21-2013 08:29:16   Can't really call the engine trouble shot without inspecting the cam, bearings and followers. After 54 + years of use and abuse, that cam and follower set have to be worn or damaged . [Reply]  [No Email]
gtx1967jewison 01-21-2013 17:10:18 174.253.146.191 Report to Moderator	Re: 620 knock in reply to buickanddeere, 01-21-2013 08:38:02   Surprisingly, of the 15+ 2 cylinder cams ive looked at none of them had any noticeable wear. I think they must be super hard. They also turn about 500 rpm with very little spring pressure. Im sure some are very worn out there though. [Reply]  [No Email]
donmyeil 01-21-2013 06:13:53 74.32.241.119 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   Check the camshaft gear bolts. Been known to come out. [Reply]  [No Email]
MSD 01-20-2013 21:25:32 67.4.60.56 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   Checked the timing on it? Had that happen on one of mine. Just try turning the distributor and see if it quiets down then you know if it is the timing. [Reply]  [No Email]
BushogPapa 01-20-2013 09:50:31 173.88.51.117 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   This is tough..!! The 620/630 have a whole set of Natural sounds, from those huge parts..especially when first started cold..!!! It is not a loose setting on a Valve, is it..? Could be piston slap (when cold) or even a wrist-pin with just a MINUTE amount of slap..(if it is, you may NEVER find it!!).. Flywheel SPLINES AND CLUTCH-Driver FIT are Critical and MUST be Tight, with NO wear.. The Hydraulic pump and Governor gears can contribute to significant noise.. If you measured and confirmed the Bearing Clearances, you should be in fairly good shape, internally.. [Reply]  [No Email]
bigboreG 01-20-2013 08:58:00 166.181.3.52 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 08:48:58   What about the clutch driver and flywheel? Are the splines good on both? You mentioned new bearings, does that include main bearings also? [Reply]  [No Email]
DGK 01-20-2013 10:27:48 70.194.133.169 Report to Moderator	Re: 620 knock in reply to bigboreG, 01-20-2013 08:58:00   Machine shop fitted rist pins bored block. flywheel and clutch driver tight. Cam gear looks good but seems like coming from that area. Pulled clutch side off and checked cam bearing was good. checked other side was good. Plastic gauge rods were good. Just seems like in cam area. I reset valves a couple times. Thanks Doug [Reply]  [No Email]
2-banger 01-20-2013 17:14:11 69.205.113.95 Report to Moderator	Re: 620 knock in reply to DGK, 01-20-2013 10:27:48   id guess rods need to be rebushed for wrist pin but you said they fitted them? i had a late a and driver was off mark on crank it sounded bad and shook.. [Reply]  [No Email]
rla 01-21-2013 04:59:31 162.39.22.109 Report to Moderator	Re: 620 knock in reply to 2-banger, 01-20-2013 17:14:11   Don't forget aluminum pistons can make alittle noise when they are not under load?? Play with your timing alittle.. [Reply]  [No Email]