Help needed with cam timing-Ford 312 RR |
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 902 |
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Posted: June-30-2024 at 2:11pm |
Well, it's been too many years for me to remember how to time the cam, and I've lost the picture I had:
Ford Interceptor 312 Y-block reverse rotation. This setup substitutes 2 constant-mesh gears for the timing chain. There is a particular way to set the marks on the gears, and I'm hoping someone knows...thanks.
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1994 Ski Nautique "Riot"
1964 Dunphy X-55 "One 'N Dun" 'I measured twice, cut three times, and it's still too short!" |
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Fl Inboards
Grand Poobah Joined: January-20-2008 Location: United States Status: Offline Points: 2084 |
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Call Nautique Parts.com and ask for our old friend Woody, ill bet he knows something about it. 910-247-6201
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Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise.
1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3669 |
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I have pretty good engine parts sources, I tried to chase this issue today to see what could be found. No Luck, I can verify the 312 and 292 Y blocks share the same timing sets so use both engines in your searches.
The 292 timing chain set up is odd. the sprocket marks both face the Left side of the engine on set up and the chain has 2 marks on it for alignment with the two sprockets. The Gear Drive your unit uses may have an odd set up like the chain drive. (left side in engine talk is always determined when you are standing behind the flywheel looking forward towards the front of the car. So looking at the engine from the actual front the Left side would be on the RIGHT, looking from the front. IF you happen to have the cam card for the cam in your engine you should be able to rotate the engine with the heads off but cam connected and use a micrometer to measure the actual cam lift in relation to the camshaft and work backwards to the proper timing set up. Kind of like Dialing in the cam in reverse. But you need the specs on the cam. Any New Cam for a 292 or 312 should come with a cam card as a starting point. Then of course you would need to know the reverse rotation firing order. There is a Ford Y Block Forum, Y Blocks Forever, Maybe one of those members will have the information needed? Best of luck. Mark
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 902 |
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Thank you both for the advice and replies.
Removed, inspected, the cam. It is in excellent condition. Lubed and reinstalled. The heads are still on but the valve train is out. Pressurized each cylinder just to check. Good. So I've decided not to trust the timing marks on the gears, and bust out a degree wheel and dial indicator. Let's see what that yields...
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1994 Ski Nautique "Riot"
1964 Dunphy X-55 "One 'N Dun" 'I measured twice, cut three times, and it's still too short!" |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3669 |
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It would sure help to find someone with knowledge of that gear drive timing set to get you started. I could not find any of those sets available for sale so treat it like gold, there are no replacement parts.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10860 |
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Since Mourning Wood has 2 threads on the same subject going on at the same time, here's a link to the other thread where it sounds like he talked to a real human voice a few days ago that knows these RR Y blocks and got the info he needed and he'll post what he does as he gets it all put together
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MourningWood
Gold Member Joined: June-13-2014 Location: NorCal Status: Offline Points: 902 |
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Sorry for double thread-was feeling desperate....
Bakground-engine went together great. Lined up "0" mark on cam gear with TDC punch mark on crank gear. As I began installing pushrods and rockers, and setting lash, it became increasingly difficult to rotate. Had rockers on/off about 5 times. It was very hard to do a compression test, and with 8 park plugs in it wouldn't turn over at all....so.... Off cam the heads, touched up by machine shop, reinstalled, same result. That's when I went hunting for 312 RR cam timing info with no luck. Made a couple phone calls (thanks again Keno) and got some tips, but still no definitive answers. So... Still without a 'cam card', I gathered my dial indicator and degree wheel and ended up retarding the cam by one tooth. Reassembled, it cranks over now even with plugs in. It should run. Will double-check the valve timing events before I button it up and try to start. But we're moving the ball down the field..... As of July 6:
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1994 Ski Nautique "Riot"
1964 Dunphy X-55 "One 'N Dun" 'I measured twice, cut three times, and it's still too short!" |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3669 |
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In some engines the valves can hit the pistons when cam timing is off, it does not take much of a touch to bend the valves. I don’t know the Yblock engines so maybe they are not an interferance engine.
I can’t think of anything else stopping your ability to rotate an engine spark plugs removed. I think I would put the brakes on till you find a definite cam gear alignment. Some like the dots to align with each other so one is at 12 am and one at 6 pm, others have you set the crank at 12 am and the cam at 12 am. As Ken mentioned who knows what they decided on the 312 based on how goofy the timing chain sets up in that engine. To be safe back off the rocker arms to close all valves while making any changes. Plugs need to be out since all valves closed would be difficult to rotate.. I hope someone can give good advice on this timing mess.
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