You may remember me from posts like the squid that ate my transmission. I built an engine and have pretty much solved various problems like leaks and oil pressure and oil temp. It is a 2056 with a 73 web cam + 2.5°.

I had to do some work on the heads. I was shooting for about a little over 8:1 compression, and while I have some uncertainty of deck height I am certain of the head chamber volume all matched to 69 cc ( I would say milliliters). According to CB Performance that would give me a maximum of 8.4 compression.

That is the set up here is the problem. On load I hear a ticking sound, with maybe a tinkling high tone. There are several alternative sources of rattling, but it is coming from the engine bay. The gas here is generally 91 octane. I have enriched the MPS to deliver A/F to around 11:1 at load with part throttle and that has not cured the problem. After break in the car turned more difficultly with the starter so I wonder if the cam may be producing better dynamic compression. The heads overheat if I push air down the road at 70 - they generally don't at 50. Timing is stock.

Question 1. Is this knock/ping/pink(UK)?

Question 2. What are my best options and how quickly must they be instituted. The car is grounded for now.

3 - Thanks!

The pinging, overheating and hard start is indicitive of an advanced timing situation. Have you double checked the timing?

I have, and it is at 27 degrees at 3500. I was going to play with backing it off some, but am lately getting mixed messages about that. One problem I have is I am not certain what pinging sounds like. I think I am hearing it though. Thanks

What distributor?
What fuel source? What carbs? What is the setup on the carbs?

the engine most likely does not need as much "all in" timing with the raised compression. back it off and find what the timing it likes under load and then work the dizzy to get idle and all in timing set up.

Glad you asked. This has run me from pillar to post in an interesting way. I am learning a lot, but can do that when the snow falls and the salt vampires hit the road.

I am running D-jet. I rechecked my scraps of paper and compression has an upper limit at 9.7 if I completely mressed up and have no deck height (doubt) down to 8.7 if I did the deck height right at 40 thou.
I am running gas from a Stop and Go that advertises recreational gas with no ethanol. Force of habit with old cars. 91 octane, but I now realize that ethanol might be good at boosting octane, snd I might be able to get 93 elsewhere at a name brand.

I added a 6AL cd ignition and I thought about adjustable retard - just right for me - to go with it, but the red box only lasted about a couple of weeks. New out of box but off warrantee due to stashing away.

I finally got the D Jet to play nice. I find the car runs better a bit leaner, but right now the car cruises at 12:1 and is pinking at 11. Charge cooling isn't going to do it for me.

I am guessing I have flame fronts moving unevenly in the squish zone after ignition. I may buy one of those microphones you attach to different places and drive around with head phones.

I came so far. The car runs like a champ. Help!

I would say the problem is the D-Jet system. Unless you have a modified brain it will probably never work well with A: larger engine and B: a different cam. I have seem several that had the brains reprogrammed by a shop in LA and those engines also had a larger throttle body inlet, larger injectors and larger fuel pump. They did not idle well or run at part throttle but ran like stink at full throttle making about 145 HP or so. In a car that weighed 1800# they worked well.

I would suggest getting Webbers, better distributor and tune it that way.

Any chance you "upgraded" the oil pump during your rebuild?

If so...oil pump clearance to cam gear.....?

Just a shot in the dark..



Stu

I did - I checked. Thanks Stu. Lots of clearance. See next post.

Thanks to everyone that chipped in. I love my 914 but was ready to stop driving it indefinitely. But we thought we would back off the timing. I have an adjustable timing light -sometimes it even works. Odd. The mark at 27 degrees BDC shows up at idle, and when you rev the car it doesn't change - it sort of looks like it moves but only a degree or two.

So I swapped in the distributor from the 1.7 with a pertronix trigger. Ping is gone. Wrong dizzy for the car, but the ping is not intrinsic to acceleration any more.

There ought to be a big thanks banner that you can add from the cute little icons, but in the absence of such i shout: THANKS!!!



Now to rebuild a dizzy or find a better one.