Overheating / Timing Issue

[neilbardsley]

[Meissen540]

Neil,
Before you spend a lot of time chasing this, are your sure your gage is relatively accurate? You can check it with some boiling water and a cooking thermometer that you know is good. I have had bad Gage's and senders more than once. They do go bad, and in the case of the sender, it usually goes to the red zone when it's failing.

Also, the engine is at "normal operating temp" when the needle is straight up at the 12:00 position. How far to the right, measured in needle widths is it when you are running hot? Or are you in the red? Just looking to quantify the amount of "running hot" is.

Maybe Justin will move this to the correct forum.

[356JAGER]

Neil,
Sounds like you found the problem if it cooled down after adjusting your fan belt. Was the 'smoke' oil smoke (blue and stinky), moisture (white) , or from an overly rich mixture (black-sooty) ? Did it go away ?
Tom is correct about checking the function of the gauge prior to chasing other aspects. If your distributor returns to idle consistently, it is not likely to be the culprit.
I set my timing at 3-5 degrees BTDC static with a light and then check and adjust it with a light for 30 - 32 degrees advance at 3k RPM. They usually
match up without further adjustment. Don't know why you can't get your plug wires out of the cap unless they are corroded. In any case tug and twist harder until the come out and if anything breaks simply replace the lot, a good thing to do occasionally in any case. Make sure your valves are properly adjusted to cold specs, your points and plugs are gapped properly (a good opportunity to read the plugs for any variance and indication of other issues)
and finally that your carbs are adjusted and balanced.

http://ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

If you replace your plug wires, make sure your get the extended Bosch plug connectors as they make removal much easier.

Hope this helps.

Cheers,
Joel

[neilbardsley]

Yes I'm very happy that my temp gauge in the car is correct. I have an infra thermometer and it matches with the temp gauge in the car. My gauge shows F and it matches the top end of the engine but the sump is often hotter. This car has had a amp meter and temp gauge added but it are very useful.

The smoke was white. I've checked everything now. The values, new spark plugs (gapped correctly), the dwell to 50 degrees. Carbs adjusted using a colour tune and by ear. However, when I set the timing the TDC mark on the pulley was jumping either side of the line on the case. In the past when I've set it's been more like a blurred image.

I must admit this took me a bit longer to do then normal as whoever had set the timing before I had the car hadn't trusted using an advance on the light so had set a second mark on the pulley. Judging from the service history of the car this may of been Jack and I read about some others on the registry who don't trust digit advances. I don't see any reason not to so I tippexed the TDC so that I didn't mix it up with the other mark.

Anyway the car is in with a shop getting some rust protect on the underside and I've ask them to check if they agree with me that the timing is unstable.

[S.J.Szabo]

[neilbardsley]

[Jack Staggs]

Neil, I don't ever add additional marks to the pulley. I trust my timing light, and test it from time to time. We will set timing between as low as 30* to as high as 37*, depending on the engine. Erratic timing, particularly at higher rpm's can be due to many causes. Binding of the locating post to the points can happen, but very rare to me. Point float can occure if the spring blade has been overheated, causing it to lose tension. A dwell test at will reveal this at higher rpm's. If the high tension spring between the dist drive gear and dist is missing, or a replacement spring of lower tension is used, the drive gear may bounce up and down, causing timing to shift, as the gear is cut on a slight angle. An optimum measurement is given for end float to dist drive to dist, with NO spring, but is rarely needed to be shimmed beyond the standard shim except for racing purposes, exceeding 6k rpm. This correction would require removal ot the third piece. If end play of the crankshaft exceeds acceptable values, variations of timing will occur. If dwell is stable throughout the rpm range, this may be an issue. Check timing with the clutch depressed the entire rpm range. If variation is reduced, crank end play may need to be corrected. Finally, your dist may need attention. Missing shims, binding of advance weight etc. Timing can be CRITICAL to temp!!! Of course, too high compression ratio, low octane fuel, jetting, fuel pressure, float level, belt tension, sheet metal & pre heaters, air seals, spark plug heat range, clogged oil filter(inside and outside), oil consumption, intake leaks, and MORE come in to play. I don't know what has been done to your car since it was under our care. IIRC, we worked on it 2 or 3 times, only needing general repairs, servicing, and addressing customer complaints. I may be wrong here, as we service many 356s
I hope this helps.
Jack