For the mechanics

[birdy3897]

Timing for a 2.5L 120hp(1978). Here we go again, it should be a simple procedure but it is kicking my a.... I got the motor at TDC for sure and I set the distributor in so that the rotor is pointing at the #1 wire terminal. When I get the motor to start up (roughly) I can't get the motor to run right in the range of the timing tab on my timing cover. The advance seems to be working right as when I throttle it up it advances. The motor will run pretty smoothly when I adjust the distributor but not great and when I adjust the distrubutor to get the motor to smooth out the timing light is showing it is way advanced, about 2 inches at idle before the timing tab! Could my distributor be a tooth off? And if it was couldn't I make up for it by adjusting the distributor so that the number one terminal is lined up with the #1 on the cap? Another thing I should point out is that the distributor does not have points, but pertronix conversion kit?

 

[Capt Ken]

Re: For the mechanics

So you are sure the #1 piston is up all the way when the timing mark is TDC? I can't remember if the old 2.5's was internal balanced or external. If the front pulley is an harmonic balancer like the V8 and V6 engine, they can slip on the hub and not line up.

 

[Don S]

Re: For the mechanics

Why don't you just try moving it one tooth and see what happens. The worst that could happen is it won't work.

 

[lilmandavis]

Re: For the mechanics

why was the dist out? is it points? could it be the wrong rotor?

 

[bruceb58]

Re: For the mechanics

Having the distributor a tooth off will not matter. it just means you would have to rotate the distributor to compensate for it.

You have the spark plug wires in the correct firing order? New plugs, rotor, cap and wires?

I looked over your old posts and see you have been doing a lot with this engine. Perhaps you need to go back and check some of your past work to see if everything was put together correctly. For example, did you ever figure out why you were getting water in cylinder #4? Was it the bad head gasket? Did you replace the head gasket that you reused?

 

[birdy3897]

Re: For the mechanics

Yeah, the work I did before on the motor was done correctly. I now have good compression and there is no water gettng into the cylinder. The motor ran ok before I checked the timing but not as I expected. It doesn't have very good acceration and won't idle without chugging badley below 850-900 rpms. When I put a timing light on it, it was no where near the timing tab, like 4 inches advanced. I found TDC ( for sure) and adusted the distributor to the number one cylinder. The firing order was also checked (1-3-4-2) and correctly hooked up. For some reason when I adust the timing mark while running underneath the timing tab it doesn't want to run, almost stalling.It only runs decent when it is way advanced. I wonder if it could be my distrubtor is junk? Is there a way to check it? I know the mechanical advance is working because it advances even farther when the rpms are raised. Also, the plugs, wires, and cap only have a few ours on them.

 

[birdy3897]

Re: For the mechanics

I was thinking of buying one of the electronic distributors and seeing if that solves the problem. The distributor I have now is pertronix converted(no points).

 

[whywhyzed]

Re: For the mechanics

Was the cam out?
Cam to Crank timing ok?
Choke opening ok?

 

[birdy3897]

Re: For the mechanics

Cam to crank timing seems good, at TDC in the number one cyclinder the valve sequence looks perfect with the valve cover off. Yes, the choke is working correctly.

 

[calwldlif]

Re: For the mechanics

As you change advance carburator
settings need checking.
If you have put all the
valve train parts in correctly
then you have a carb problem.
Vacuum leak?
dirty, mis ajusted carb
plugs fouled

Try resetting carb idle and mixture alittle at a
time as you little by little get the timing correct

 

[Don S]

Re: For the mechanics

Cam to crank timing seems good, at TDC in the number one cyclinder the valve sequence looks perfect with the valve cover off.

Does this mean you can look at the valves and tell by looking at the heights of each valve if the cam gear is a tooth off on the timing? Man, I wish I could do that, I have to pull the timing chain cover off and see if the marks align.

Have you done any testing? Things like compression test? vacuum gauge test while running? They will help locate engine problems that can't be cured with timing carb and valve adjustments.

 

[birdy3897]

Re: For the mechanics

Thanks guys, calwldlif was right, after I got the distributor in correctly my idle problem is the carb. I found a weak battery which I believe was making my pertronix ignition mess up the dwell and it wasn't sparking very good, I charged the battery and presto! I messed around with the settings on the carb and it smoothed right out. I also found gas leaking very slowly so I think it is time for a rebuild. Can I get a rebuild kit for a rochestor 2bbl? Are the pricey??

Thanks again for help everyone8)

 

[Don S]

Re: For the mechanics

In other words, ya got LUCKY.
There is no dwell on a pertronix ignition, dwell is the angle (in degrees) the POINTS are open.
Hope you have better luck with a carb. They can cause explosions and fires if you don't know what you are doing.

 

[birdy3897]

Re: For the mechanics

In the instructions for the Pertronix it says it automatically adjust dwell. I guess thats just another selling point if there is no dwell.I'm not sure what was the problem. I had TDC without a doubt on the compression stroke of the #1 and for some reason it would not time close. I guess you could say I got lucky because the last time I did it worked. It still baffles me, it is easy to say I was doing something wrong but .... well it is ok now that's all that matters. I seen the carb was getting wet around the base and found it to be gas so I figured I would just get the kit for it and clean it up. I have worked on many carbs before with good success but who knows after the timing ordeal!

 

[birdy3897]

Re: For the mechanics

Compression was 120-125 on all four cylinders. I know they have to be within about 10-15% but isn't that kind of low, I was told it should be around 145-160? Probably just hours of use?

 

[calwldlif]

Re: For the mechanics

It is not uncommon when a new "tight" motor that
the carb idle settings have to be increased.
As the motor runs in the idle will have to be
reduced.
Sounds like your carb is bad anyway,
the problem you have with timing idle
is commond