Check that the vacuum advance is working too, and doesn't have a defective vacuum diaphram. Easy to check this: remove the distributor cap, unplug the vacuum hose from the carb, suck on hose while watching for movement of the breaker plate in the distributor. Seems to me now that my 5.0 in my Ranger did about the same thing when the vacuum pod diaphram ruptured last year
(I think) Timing chain issue... might explain dyno/starting/timing issues..
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Yeah, as we installed the new coil we made pretty sure those were on good and tight.
I'll check the vacuum advance as well.
mrmustangman357
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- Feb 11, 2007
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jerry S
New Member
I too had a problem with chain stretch. It was a brand new double roller chain and it went after less than 500 miles. The stretching was the symptom of something else. It turns out my builder in Pennsylvania did not balance the crank correctly. To remedy the problem forever and ever, I had the whole rotating assembly rebalanced went with a Pete Jackson gear drive.
Well, haven't had a chance to tear into it yet (this past weekend i had to work extra both days and was burnt out, the weekend before I was working on my brother's eagle project which coincidentally kicked my car out of the garage for a weekend). This weekend = no football, work, eagle projects etc... so if i do'nt get to it you can officially label me lazy.
I also had some issues with my daily driver, which diverted some attention.I did tune it some, mostly messing with the carb. The biggest realization I came to was that I believe my '3 minutes running perfectly' was something of an overstatement... I believe it was just idling fast and that smoothed it out. I got it running well enough to drive across town without dying, though it still doesn't want to idle initially.
Ive done most of the really easy stuff too.. checking wire connections, vacuum leaks, etc... didn't find anything too shocking.
Interesting Jerry S... was the chain stretch visually perceptible or was it just something that happened at high rpms/temps and would be tough to tell with the naked eye?
One other question... on newer (within the last few years) Holley Street Avengers, to adjust the floats or change the jets... do you need to buy new gaskets of any kind? The holley recommendations say that in general you do, but I thought they switched to a gasket-less product at some point... could be wrong though.
jerry S
New Member
I had some parts added after I had my car dyno-tuned and the new mechanic noticed it when he re-tuned the car (dyno guys tuned my car so rich that all the coatings washed off the engine bearings). He was having some trouble with the timing and asked why I did not use a new chain when I re-built the engine. He was surprised when I told him it was new.
mrmustangman357
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woodsnake
15 Year Member
Haha, sorry guys I came down with a nasty bug combo this weekend... on monday the dr. said I had bronchitis, a sinus infection and an ear infection... essentially my immune system sucks. Was pretty miserable all weekend up until yesterday morning when the antibiotics started to kick in. I'll update as soon as I get into it, and I promise it'll be soon...
Quick update, finally got around to tearing into the engine somewhat. Timing chain looks pretty good... not sure how much play there's supposed to be, but there isn't a whole lot (looking at the engine from the front of the car, the passenger side of the chain has a little play (maybe an inch back and forth) but nothing major... i think.
Also don't see much in the way of debris/metal shavings.
Tonight.. plan on checking to see if every valve is being opened by the cam and to check for coil bind. Any tips/guidance welcome.
One other last question... if I were to use the movement of the #1 cylinder's rockers/springs/valves as a guide, at what point in the motion of the two would the engine be at exactly TDC? When the intake valve starts to open? When its fully open? Halfway through being open? None of the baove? I still need to find a way to easily verify TDC and mark it precisely on the balancer for tuning it when its reassembled.
I also have a few pics, will try to get them up in the next few days
Also don't see much in the way of debris/metal shavings.
Tonight.. plan on checking to see if every valve is being opened by the cam and to check for coil bind. Any tips/guidance welcome.
One other last question... if I were to use the movement of the #1 cylinder's rockers/springs/valves as a guide, at what point in the motion of the two would the engine be at exactly TDC? When the intake valve starts to open? When its fully open? Halfway through being open? None of the baove? I still need to find a way to easily verify TDC and mark it precisely on the balancer for tuning it when its reassembled.
I also have a few pics, will try to get them up in the next few days
69gmachine
Member
1) An inch of play is way too much (even assuming you mean +/- 1/2" for a total travel of 1"). Although it may be tight on the pulling side at the moment, the slack will cause the cam to advance ahead of the crank then stop, then when the crank catches up again it will jerk it forward. This will explain your wandering timing mark as well as the crappy performance. One cause for a stretched chain (even a new one) is lack of lubrication. Did you coat it with engine lube when you installed it? I also drill a tiny hole in one of the oil galley plugs so that it sprays a mist on the chain. This isn't necessary for a street car, but it's cheap insurance.
2) The best way to check for TDC is to rotate the crank until the #1 piston hits a stop from both directions. The center of the two marks (on the harmonic balancer) is TDC. Once that is determined you can time the cam to the crank. Alternatively you could use a dial gage, but for most people a stop is easy to fabricate and the results are easy to see. Since the cam timing events are being driven by the chain, and are subject to the relative position of the crank gear to the cam gear, there is no way to use the valve timing events to determine TDC.
Do places sell piston stops? Our first few attempts at home-made stops proved to be an unproductive hassle, though we weren't as committed that time. Though with some more thought/effort I'm sure we could figure it out and I will not put it back together without knowing exactly where TDC is on the balancer.
When I said an inch I did mean about a half inch each way but I was estimating on memory from last night... I will make a physical measurement of the play (maybe even a video) of it tonight and post it. As you say, its very tight on the other side, but there is some visibly noticeable slack on the other end.
We didn't drench it in oil but we did put break in lube on it as per the installation recommendations. We have had this timing issue since basically day one though, so it'd make sense that if it stretched (assuming my memory of the play is accurate) it did it so during break in.
The creating my own oiling hole concept is a cool idea, might look into it.
Out of curiousity (as it appears its not the best way to physically check), where in the intake valve opening/closing sequence would 0 TDC be?
Just got home and measured it... and my eyes weren't lying to me last night. At least half an inch of play, but probably closer to an inch. Pics below.
Could be somewhat hard to see (and i'm sure the ruler moved between measurements, but if you just use the scale you can see it).
Could be somewhat hard to see (and i'm sure the ruler moved between measurements, but if you just use the scale you can see it).
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woodsnake
15 Year Member
69gmachine
Member
Both intake and exhaust valves must be on their seat on the compression stroke at TDC. Since the valves are closed for several degrees of crank rotation, you need to refer to your cam card to know where they open and close as the intake has just closed and the exhaust is getting ready to open. If your crank gear has multiple keyways you can advance or retard your cam timing.
Get a new high quality timing gear set, coat it with good engine assembly lube, then prime the engine using a reversible drill before installing the distributor. There are many manufacturers of good timing sets for these engines in the U.S, Canada, Germany and Australia. If it's made anywhere else, keep looking. It should either be a double roller or one of the new designs from either Ford, Yates or Roush (one of these is high dollar).
Get a new high quality timing gear set, coat it with good engine assembly lube, then prime the engine using a reversible drill before installing the distributor. There are many manufacturers of good timing sets for these engines in the U.S, Canada, Germany and Australia. If it's made anywhere else, keep looking. It should either be a double roller or one of the new designs from either Ford, Yates or Roush (one of these is high dollar).
woodsnake
15 Year Member
I've read thru this a few times now, and am still convinced it is a coil binding issue.
Even though the timing gear exhibits more 'stretch' than I would like to see, it is not so loose that it will cause all the symptoms you are describing.
That being said, you need to isolate the two components, "carb" and "engine".
There has to be a cheap, use able carb on your lcoal craigs list for under a hundred.
Also, you should have one of these:
Proform 66787 - Proform Universal Degree Wheel Kits - summitracing.com
This will show you all of your camshaft timing events, as they happen. There is also a video available to buy, and probably something on you tube as well.
When I was going to school the mantra was "symptom to system, componenet to cause".
Your car runs like crap, why? Is it a fuel problem, or a timing problem?
Prove or disprove the carb/fuel system. Then, get back to the engine.
Even though the timing gear exhibits more 'stretch' than I would like to see, it is not so loose that it will cause all the symptoms you are describing.
That being said, you need to isolate the two components, "carb" and "engine".
There has to be a cheap, use able carb on your lcoal craigs list for under a hundred.
Also, you should have one of these:
Proform 66787 - Proform Universal Degree Wheel Kits - summitracing.com
This will show you all of your camshaft timing events, as they happen. There is also a video available to buy, and probably something on you tube as well.
When I was going to school the mantra was "symptom to system, componenet to cause".
Your car runs like crap, why? Is it a fuel problem, or a timing problem?
Prove or disprove the carb/fuel system. Then, get back to the engine.
woodsnake
15 Year Member
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