| Author |
Message |
Marty
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 8:49 am: | |
1978 Mci 8, Shutters and dampers working correctly, Total engine and body miles 101000(documented).
I was taking some readings with my laser and found that the drivers side manifold was warmer than the passenger side on start up and stayed warmer until the engine reached operating temperature.
The individual cyclinders on each side measeured close to each other. The difference was side to side as measured on the exhaust manifold. Power seems good.
Where would you start?
THX Marty |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 12:30 pm: | |
Which engine, and is it a TA or NA?
you mention shutters/dampers but then talk about exhaust manifold. You measurements refer to the exhaust manifolds and the individual cylinder to cylinder temps near the exhaust port? |
Marty
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 5:35 pm: | |
Marc, This is an NA. My measurements were taken on each Ex manifold at each Ex port. The cylinder exhaust manifold temperatures were even cylinder to cylinder on each side, however side to side there is a distinct difference.
I don't think it is in the thermostats as the difference remained all the way up until the thermostats opened. Marty |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 6:19 pm: | |
I shoulda stuck my head in the back of the 6V92 to check circulation pattern.
Wonder if, until the engine fully warms up, the decreased temp on the inlet side of the engine Cooling, (if the flow is cross-wise from one head to the other) flow compromises combustion?
Once the engine is warmed up, temps and therefore the combustion is "equalized" and the difference disappears?
Just "spekalating" |
truthhunter@shaw.ca
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 7:49 pm: | |
good spekalation! |
Greg Peterson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 17, 2006 - 8:51 pm: | |
If the bus is a MCI-8 you probably have an 8v-71NA engine. If you are seeing this temperature difference at an idle then it could be the injector and rack adjustment difference between the two sides of the engine.
I have been studying the manuals and the rack and injector adjustment for the 2 stoke DD and it looks like it is “touchy” like adjusting the convergence on an old three-gun color TV (which I did finally master).
If your engine has not been tuned up for along time then one or more injectors on the one side of the engine may be using more fuel and providing the power to turn the engine at idle. This would make that side of the engine warmer. When the thermostats on both sides open up the water flow probably equalizes all the temperatures. I would guess a tune up by a master two-stroke guy like Geoff or Don F. would get the temperatures closer.
I am going to use Dontx number scale to categorize my answer.
Now this is a # 5 answer that is engineering or professor answer. It is not a #1. Answer that Geoff and Don F. could give you.
Even though I read the manual I think I will have a category #1 guy tune up my 8v-92ta.
Especially after seeing a fresh rebuilt 8v-92ta for sale on eBay that has only one problem… A hole in the side of the block. The guy said it probably threw a rod because of an improperly adjusted rack.
But as for converging a color TV … bring it on I will cover all categories can even design the deflection yoke for ya.
Good luck and I think a tune up could not hurt since the manual says it should be done at 100k miles. Next problem is finding some “old guy” that can do it correctly. |
Stan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 18, 2006 - 9:05 am: | |
Greg is on the right track. Different temperatures on a cold engine usually indicate a different amount of fuel. My understanding of the DD rack adjustment is that this is normal. A good mechanic adjusting the rack allows for the change in shape of the long curved rod from the governor to the rack on the opposite side of the engine. When adjusted properly, both racks open the same amount when the engine is at operating temperature.
I have been told many times that tuning a DD 2 stroke is more art than science. Pay attention when people tell you to find an old 2 stroke mechanic to do a tune-up.
I am not a Detroit mechanic so I always paid to have a tune-up done. |