Timing chain & gears question

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   The '72 360 V8 in my '69 AMX has a fairly concerning coolant leak at the top left (facing the front of the engine) between the timing cover and the block. When running the hot block burn off the wet, but once it has sat for a day or two it starts seeping out. No water in the oil yet, though. Regardless, I'm going to take off the timing chain cover and everything that that entails to fix the leak, but while I'm in there I'd like to replace the timing chain & gearset for peace of mind. 

HOWEVER, I have heard a lot of concerning tales of woe regarding timing gears, specifically, the camshaft gear and how some brands can have an adverse effect on the oiling of the distributor. I have a copy of "BJ Builds an AMC engine" and while he points out that the cam gear he is using has too many slots for oiling the chain to the detriment of the distributor gear, he doesn't point out which brand this is to avoid OR which brand to buy. 

So, since I seem to have a habit of fixing things until they're broken, what is a recommended timing chain and gearset for a stock application? Or should I just address the leaky gasket and don't fix the gearset if it ain't broke? Engine runs great and is strong, but I have no idea how many actual miles it has on it...judging by the buildup of oil/grease/crud on the bottom of the front of the engine, it's never been rebuilt or opened up before.  

Thanks!  

Edited by sweatlock - Jan/25/2015 at 9:05pm

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sweatlock Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/28/2014 Location: Largo, FL Status: Offline Points: 3322	Post Options Post Reply Quote sweatlock Report Post Thanks(0) Quote Reply Topic: Timing chain & gears question Posted: Jan/25/2015 at 9:01pm
	The '72 360 V8 in my '69 AMX has a fairly concerning coolant leak at the top left (facing the front of the engine) between the timing cover and the block. When running the hot block burn off the wet, but once it has sat for a day or two it starts seeping out. No water in the oil yet, though. Regardless, I'm going to take off the timing chain cover and everything that that entails to fix the leak, but while I'm in there I'd like to replace the timing chain & gearset for peace of mind. HOWEVER, I have heard a lot of concerning tales of woe regarding timing gears, specifically, the camshaft gear and how some brands can have an adverse effect on the oiling of the distributor. I have a copy of "BJ Builds an AMC engine" and while he points out that the cam gear he is using has too many slots for oiling the chain to the detriment of the distributor gear, he doesn't point out which brand this is to avoid OR which brand to buy. So, since I seem to have a habit of fixing things until they're broken, what is a recommended timing chain and gearset for a stock application? Or should I just address the leaky gasket and don't fix the gearset if it ain't broke? Engine runs great and is strong, but I have no idea how many actual miles it has on it...judging by the buildup of oil/grease/crud on the bottom of the front of the engine, it's never been rebuilt or opened up before. Thanks! Edited by sweatlock - Jan/25/2015 at 9:05pm

maximus7001 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jun/27/2011 Location: Winnipeg,Canada Status: Offline Points: 1086	Post Options Post Reply Quote maximus7001 Report Post Thanks(0) Quote Reply Posted: Jan/25/2015 at 10:09pm
	If you are going to have it that far apart it would be silly not to change the timing set. My 290 needed a new timing set at 60000 miles when the nylon gear let go according to the receipts that came with the car. It is at 68000 now. These are original miles. It was changed 13 years ago before the reported problems of the gears being made wrong and needing to be modified to prevent engine damage. Edited by maximus7001 - Jan/25/2015 at 10:22pm
	1968 Javelin SST 1997 GMC Safari AWD 2001 Daewoo Nubira SX (Winnipeg only model) 1997 Honda Accord EX (Canadian Model) Winnipeg, home of the Jets.

sweatlock Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/28/2014 Location: Largo, FL Status: Offline Points: 3322	Post Options Post Reply Quote sweatlock Report Post Thanks(0) Quote Reply Posted: Jan/25/2015 at 10:14pm
	Well, I agree - so what's the recommended brand of timing chain and gears for a stock application?

ccowx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Nov/03/2010 Location: Yukon Status: Offline Points: 3510	Post Options Post Reply Quote ccowx Report Post Thanks(0) Quote Reply Posted: Jan/25/2015 at 11:22pm
	The leak you have, are you sure it is between the timing cover and the block? I have seen and experienced more leaks between the intake and thermostat housing, which leaves a puddle on the top of the timing cover. I would check there first. Second thing is that the timing gear issue as far as oiling the distributor and cam camshaft gears is mainly one of the oiling passage through the gear to the distributor gear being blocked with flash. Regardless of what gear you buy I would make absolutely sure it has a clear passage through to the distributor gear. If you find the leak is not with the timing chain cover, you may not have to do much at all. Chris

74gremx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/18/2009 Location: Adelaide, Aust Status: Offline Points: 949	Post Options Post Reply Quote 74gremx Report Post Thanks(0) Quote Reply Posted: Jan/25/2015 at 11:26pm
	We see a few timing cover leaks like you have described here in Australia, but it is due to corrosion, not just a gasket. So prepare to have to replace the cover. I have seen people try and weld them up, put epoxy paint on the inside, glue stainless plates in, or stuff a rag in the hole with a hole punch to stop the leaks.
	1970 Javelin 360/727 1974 Levis Gremlin X 304/904 1964 American Convertible 1974 Matador wagon (parts) 2016 Holden Cruze Equipe 2014 Holden Colorado "Don't mistake activity for achievement".

sweatlock Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/28/2014 Location: Largo, FL Status: Offline Points: 3322	Post Options Post Reply Quote sweatlock Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 5:46am
	I have fixed the T-stat housing w/ threaded studs on the intake manifold and a new gasket - no leaks there. You're probably right about the corrosion and I do have a spare timing chain cover waiting in the wings. In "BJ Builds an AMC" the author shows a photo of a cam gear with multiple oiling paths and recommends not to use it and get another set - he doesn't mention which brand it is to avoid or, better yet, which brand he does recommend. So I thought I'd ask to see if anyone had a recommendation on either a specific set to go with or perhaps one to avoid. Thanks

69 ambassador 390 Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Nov/22/2009 Location: Peoria, AZ Status: Offline Points: 3539	Post Options Post Reply Quote 69 ambassador 390 Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 8:54am
	SA gear makes a good one. We use them all the time and have yet to find a bad one. They make them for Milodon. We still check every one of them but have yet to find a bad one.
	Steve Brown Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special

AMXTSY Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jul/08/2014 Location: central IL Status: Offline Points: 445	Post Options Post Reply Quote AMXTSY Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 9:17am
	There was factory police interceptor package for the 390 motors that included a double roller chain and gear set. These are still available as NOS. Maybe, something like this exists for a 360. Just a thought... Bruce
	Bruce Carothers Champaign County, Il. AMO # 9928

mmaher94087 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/01/2008 Location: Arizona Status: Offline Points: 1690	Post Options Post Reply Quote mmaher94087 Report Post Thanks(0) Quote Reply Posted: Jan/26/2015 at 9:52am
	".. prepare to have to replace the cover." X2
	Mike

SC397 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5480	Post Options Post Reply Quote SC397 Report Post Thanks(2) Quote Reply Posted: Jan/26/2015 at 11:49am
	They ALL need some work to suit me. Start by making sure that the oil feed hole from the cam lines up with the transfer slot on the back side of the timing gear. Second, make the transfer slot going through the gear is actually there. Third make sure there is no timing chain feed slots at the the oil transfer slot. Fourth - it is my preference to have minimal number of feed slots to the timing chain. Here is the timing gear from the Comp Cam kit along side Engine Pro set. Engine Pro used to be SA Gear. Anyway, same part numbers stamped on them etc... Oil holes that go to our precious distributor gears.. The Comp Cam diameter is .185" (#13 drill) and a stock cam measures .191" (#11 drill). Hopefully, it doesn't make a huge difference. But.... The oil slot in the Comp Cam timing gear misses the hole by half a hole. The True Roller is the second picture is not as bad but still is not centered up. These are shown on the Comp Cam Here is a old original stock gear on a original stock cam. Guess what... they line up. Amazing. Here is what I did to fix the Comp Cam gear to line up with the oil hole. Here is the front side of all three. The original stock gear doesn't have the oil slots. I guess the aftermarket put them in there to spray oil on to the timing gear. Interesting that the True Roller only has 2 slots and the Comp Cam gear has 6. I braze all but one of the extra oil slots shut on the timing gear. Edited by SC397 - Jan/26/2015 at 11:52am