1.7L timing/cooling problems

[jackr67]

My 1.7L 1971 FI has been misbehaving lately.

Above 3,000 RPMs I get a nasty ping, running 93 octane and at "factory" timing marks. Before I adjust the timing to try and compensate I want to be sure I'm not overheating or experiencing some other sort of problem.

I have the cabin heating system removed and the doghouse vents to it capped.
The cold idle air valve system is also disconnected and capped.
The thermostat flaps *seem* to be operating correctly, and I can spin the bar to move the flaps with no resistance other than the spring.

I just adjusted the valves and found them to be very close to spec, with only the #4 intake a little tight; it has only been a few hundred miles since the last adjustment.

I'm getting a little blow-by and showing light amounts of oil on the #3 spark plug - I get some smoke on downshifts and when dragging the motor, in case this plays in.

I've played with the mixture screw some, but it's now back to where it began.

The motor was rebuilt less than a thousand miles ago by the PO, a novice, and I'm worried I may have internal bits rattling loose.

Any theories as to what I may have fouled up?
What would be the best direction to go to remedy the ping?

Thanks!

[KaptKaos]

My 1.7 was having similar issues, swapped out the points for a pertronix and it seems to be better. Just filled up on some better gas too.

/bump

[jackr67]

Problem solved.

Spent about an hour and a half driving around the block. I'd do a lap, then adjust the timing slightly and see what difference was made. Turning it counter-clockwise seemed to have no positive effects and made for some rich smelling exhaust.

Turning it clockwise to the point where the center-screw on the vacuum unit hits against the metal clip for the oil filler seems to be the sweet spot. Just before redline I'll get a little clatter, but otherwise it's perfect. This is several degrees (< 5) clockwise from where the "stock" timing marks would have me set.

Is this bad?

Took it around for quite a while last night, then cooled it off and went out again and the adjustment seems to be holding and the car is behaving far better.

[Bleyseng]

The "real" way is to use a timing lite and adjust the timing to 27 degrees BTDC at 3500rpms. The timing is very critical as it is for both the spark and FI trigger points.

Just turning the dizzy till it seems right don't work too well in the long run.

[bd1308]

:agree:

im fighting the same battle, but i dont have any timing marks for my 1.8 L-jet system that I installed on my 1.7

[Scrappy]

Since they are the same engine, except for bore and maybe valve sizes, you can time it like a 1.8L (7.5 degrees at idle-900 rpm)

It ain't brain surgery Britt.............

[jackr67]

Well again, it was timed properly using a timing light to 27 degrees with the vacuum lines disconnected - etc. However, at that setting I got nasty pinging problems.

My concern here is that in order to get the engine running properly (ie, not pinging) I had to adjust the timing away from factory specs, and I was wonder why - is there something wrong that I'm not seeing?

Thanks for all the replies!

[bd1308]

yeah I know. Scrappy is that SLITS/Ron?

b

[Dave at Pelican Parts]

Originally posted by jackr67
My concern here is that in order to get the engine running properly (ie, not pinging) I had to adjust the timing away from factory specs, and I was wonder why - is there something wrong that I'm not seeing?

First, are you sure you're setting the timing the way you think you are? You wouldn't be the first person, for instance, to set the knob on an adjustable timing light to 27 and then use the stock 27 BTDC timing mark. (Not that I've done that. More than twice. )

Next, it is possible that the fan is goofed up. Unlikely, but possible. Check your TDC and timing marks against the template in the timing Tech Article elsewhere on this site.

--DD

[bd1308]

check dwell too. mine was 30 something degrees and it ran like poop and it pinged or something too.

b