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Timming for reverse rotation

T

trojmor

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"I have a 1979 chrysler 360. I

"I have a 1979 chrysler 360. I need timming specs. I have had a problem with engine vibration. My engine runs ruff when I increase RPM in or out of gear. I have replaced plugs, wires, recent head rebuild, rebult distributer, runs hot at RPM over 1800"
 
"You might have a couple of pl

"You might have a couple of plug wires switched, which is damn easy to do on that motor with the idiotic way they ran the wires. Try this:

Warm the motor and idle it about 1,200 rpms.

Using insulated gloves and pliers with insulated handles, remove one plug wire at a time from the distributor cap.

Note the change in rpms. If it slows, good. Put the wire back in and go to the next one.

If you find one that makes no difference, leave it out (for now).

If you find two that make no difference, swap them and see if that helps. If the motor now slows as either one is removed, you're all set.

Jeff"
 
I have all the wires on correc

I have all the wires on correctly. Timming is set. Engine still runs like it is out of balance.

Dave
 
"Marine Engines tend to be &#3

"Marine Engines tend to be "Hard Mounted" to the frame, and therefore, they don't reveal rough running as easily as a rubber-mounted car engine, which can shake and shimmy in it's soft mounts. (That's why it's hard to set timing and mixture 'by ear' on a boat). So if your marine engine is really vibrating noticeably, it's not generally something subtle, like timing being off a few degrees. It's usually something major, like one or more cylinders are dead. I'd check compression and manifold vacuum, in addition to timing."
 
"There are a lot of things tha

"There are a lot of things that could cause what you're dealing with (bad spark, plug fouling, water ingestion, worn cam lobe, carb, etc., etc.).

I'd move to the next phase of Jeff's process of elimination. Bring the warm motor up to 1,500 rpm and kill the ignition. Quickly pull the plugs and look for any that appear too hot, wet (water) or fouled/flooded (fuel). This might, at least, narrow things down to a specific cylinder. If you find consistency in plug richness or leanness, might look at the carb/fuel delivery.

The accompanying temp issue is a little concerning. Although it could be a coincidental/unrelated cooling issue, things that could cause both symptoms (rough-running and overheating) are head gasket leaks, exhaust backpressure/incomplete evacuation of exhaust gases, overheated intake mixture, etc., etc.

Did you replace the lifters when you had the heads rebuilt?"
 
"Did you check to make sure yo

"Did you check to make sure your valve adjustment are not too tight?

Check inside the distributor cap for corrosion, or a crack?"
 
Hope it is not a rebuild. If s

Hope it is not a rebuild. If so you may have a block that needs external balancing. I had one sold to me and found out I had to drill a hole in the fly wheel use a different balancer. It was a cast crank not forged. It vibrated and know one knew what was wrong until I talked to a person at Marysville marine who new his stuff on Chryslers.
 
It is the original engine rebu

It is the original engine rebuilt by my brother in law. He was the original owner. the engine has had this vibration since I perchased it a couple years ago. The boat was sitting unused and I new it needed some work. At the time he seamed to think it was a tuning issue. How did you determine were to drill the hole and what type balancer did he recomend.
 
You need to determine if the e

You need to determine if the engine is indeed a marine or truck engine. The truck engines I believe were externally balanced. Marine engines internally balanced and used a heavier crank (forged) so you could get more compression as they work harder. If this is the case call Marysville marine.They are on line and ask for a tech who is familiar with Chrysler engines. They have always been helpful to me in the past. They sent me a print as to where the hole is located and the correct balancer to be used. You may need your engine numbers to have them check it out. good luck. It was no big deal and worked for me. It is always best to check with an expert on marine engines and not rely on almost an expert.
 
I guess to back up a bit. If t

I guess to back up a bit. If the engine was rebuilt with short or long block (auto or truck) and parts from the old marine engine were used on that block that may be the start of the problem. If rebuilt with same block and crank then may be a different problem.
 
"Both marine and auto 360’s we

"Both marine and auto 360’s were externally balanced and there’s no difference in the rotating assemblies. The 318 and 340’s are internally balanced.

All 360 cranks (marine and auto) were cast. The only forged crank that Chrysler made for the LA small blocks was for the 340 (roughly ’68-72). Because the 318’s and 340’s share the same stroke, the 340 forged cranks were, subsequently, used in some 318 marine engines during that time period. This was for strength only. While the weight of a crank can have an impact on how engine torque is absorbed and transferred, it has no impact on compression.

I would strongly advise going through a process of elimination to rule out some of the potential issues that people have suggested in this thread (fuel, spark, heads, cylinders, etc.). While it’s worth confirming that you have the correct flywheel, etc., modifying these components, in an attempt to “balance” the engine, will likely just add another variable into the mix.

The fact that you’re having temp issues should not be ignored or dismissed as coincidence. An engine isn’t going to run hot simply because it’s out of balance."
 
"My M440 vibrated, but only a

"My M440 vibrated, but only a little. It ran hot, but only when operated over 3000 RPM for more than a few minutes. Other than that, it ran fine, for an entire summer. If I ran it at 2000 RPM, it ran at 160F. But a Tune Up and Timing made no difference to the vibration. Upon investigation, this is what I discovered: 25 psi compression in 2 adjacent cylinders, and water on the spark plugs in those cylinders. That was caused by a blown head gasket. Looking further, I discovered 2/3'rds of the vanes on my water pump impeller had broken off, and it was barely able to keep up. (especially at 3000 RPM). That caused the hot running and eventually warped the heads, which blew the gasket. It did not help that the exhaust manifold had also failed and was leaking water into those same cylinders! I Fixed the Pump, the Head Gasket (w/ a valve job for good measure: it’s a 40 yr old motor) and replaced the Exhaust Manifolds, and it ran 90 hours last summer, smooth as can be. The only thing that’s ‘missing’ now, is some money from my wallet. But that’s how boating is. Check your compression, and take a peek at your water pump. Nothing good happens when that pumps starts to fail."
 
"Beuhler Jet is on the money w

"Beuhler Jet is on the money with both his facts on LA engines and his suggestions. Vibration plus overheating almost certainly equals something other than balance issues.

It is, however, possible to re-drill an external balanced 360 flywheel and use it in conjunction with a new damper on the front to change an externally balanced engine to an internally balanced one. I did that, but it is not for novices. I had a top notch machine shop do the work and the only reason I did it was that I trusted the machine shop and it was cheaper (a little) than buying a new flywheel. I was installing a crank kit to make a reverse rotation 360 into a standard rotation 410. Along with everything else, I had the machinist modify the flywheel to accept a much stronger coupling that would take the extra torque the engine makes, so re-balancing it at the same time was the way to go."
 
Thank you all for your input.

Thank you all for your input. I plan to get back to the boat this weekend. I will get back to you after I do some checking.

Dave
 
"Dave, try adjusting the timin

"Dave, try adjusting the timing by ear after the engine is warmed up and see if it runs better. You can usually advance it until it starts to miss then back it off till it's smooth then back it off slightly more and it will be close to correct. Lots of balancers have slipped oner the years and the marks are no longer correct.

Dan"
 
"I would also like to point th

"I would also like to point the best way to set the timing on these old engines. Set #1 at TDC and make a mark on the front pully and timing cover you can see easily, now get an adjustable timing light and as the engine is running at idle you adjust the timing light so the marks you made are lined up and read on the light the number of degrees of timing you have, this is now your inital timing (usually 5-7 degrees. Now rev it up to about 2500-3000 and repeat the procedure, now you should have total advance of about 30-34 degrees, if you don't have good advance your mechanical advance in the dist is not working, this kills fuel economy.

Dan"
 
"..."now you should have t

"..."now you should have total advance of about 30-34 degrees"

That's way too much for a 360. The book says around 26 degrees, max.

Jeff"
 
Buehler Jet

I answered your

Buehler Jet

I answered your question. It was a long answer and it disappeared when I hit the transmit key. I love the result of my project but if you want the details we should email each other.
 
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