345 V8 diagnosis and engine tech

Ive never believed the 'jumped a tooth' theory, why did it only jump once? Ive seen timing chains incorrectly timed before though.
If all the comps are even don't worry about rings and valves.
Holley carbs are a bugger for flat spotting due to sitting for a while and drying out, also the accelerator pump cam can be incorrect. Most petrol Accos were put on gas and bingo no more flat spot. HTH

I wish I had a picture of the chain on the 302. You'd wonder how it had been running in the first place. Between the chain wearing (no tensioner) and the plastic coming off the cam gear (which is only there to shut it up), eventually it'll jump a tooth. Could run like that for ages (Dad's did) before it jumps another and it's now too retarded to run. Wasn't super high mileage either, about 240K's, from memory.

Jarrod.

The carb is now brand new, and it's behaving similar to before we pulled it down. I moved the fuel pump cam to the earlier position on the linkage so it pumps a little earlier but no change. Ether doesn't really make a difference to how it behaves

You say the ignition is all new - did you do the ignition timing with a timing light? The vacuum advance hose should be removed and plugged to set it, otherwise you end up with about 7200 degrees retarded timing and they don't go too good with that.

asw120 wrote: In the past, I have checked it by the "rough" method:

Get either #8 (don't know why IH did that), or it's opposing number at TDC as marked on the crank. I don't remember what a 345 has for this, but let's assume it doesn't slip, like it can on a Holden red motor. Whichever one is at TDC firing position will have both valves shut hard, on the other at TDC, they should both be "rocking" as you rock the crank back and forth.

I'd think a 345 would easily outlast a timing chain, if a 302 Ford does. On dad's Ford, the timing chain was hanging under the crank gear, barely touching the teeth. The plastic coated cam gear teeth don't help, as the plastic breaks up. Car engines tend to have this (AMC / Jeep 360 also comes to mind). I don't know if IH used them. A 350 Chev truck motor I stripped once did not. Hy-vo chains don't last forever, either. Not sure if IH used that, roller, or gears (which can strip - another story!)

I expect you will get more potential answers tonight after people get home from work (I'm at home recuperating).

Blocked muffler also comes to mind, but I don't know how that would affect your compression readings.

I would love a bit of education, myself on this as I keep an eye out for a cheap ACCO.

Best of luck, Jarrod.

you take of your self there Jarrod do what the Doc says and dont get tempted to play until your told dont ask me how I know these things but I get bored real easy

Paul

you take of your self there Jarrod do what the Doc says and dont get tempted to play until your told dont ask me how I know these things but I get bored real easy

Paul

No driving for a week and then no lifting anything over 5 Kg for another 5 weeks after that. I've been home a day and a half and I'm crawling up the walls already. Can't just sleep it off, either due to neck pain. Gonna be a slow month.......

Next door ingnored the doctor's advice - his hernia came straight back! Not gunna happen to me.

Cheers, Jarrod.

Hmmm. theres a reasonable chance we didn't pull the vac advance hose. Will check that. Can you check timing at cranking speeds?

I suppose you could do that while cranking depending on your timing light but the centrifugal advance may play havoc with it as the timing is based on around 500rpm idle speed.
Go back to basics, get the crankshaft back to the timing marks lining up for number 1 cyl, and check when the distributor points open while turning the engine by hand.

mercskeepmeinajob wrote: I suppose you could do that while cranking depending on your timing light but the centrifugal advance may play havoc with it as the timing is based on around 500rpm idle speed.
Go back to basics, get the crankshaft back to the timing marks lining up for number 1 cyl, and check when the distributor points open while turning the engine by hand.

Thats what I would as well

One of the benefits of points is that you can check the static timing with a multimeter or test light.
With the test light just hook to the terminal from the coil to distributor and the other to a power source, light will go out when the points open.
Much the same with the multimeter but may pay to disconnect wire to the distributor and just put one lead on the points wire and the other to ground.
Much easier than trying to guess when the points actually open by looking at them while you turn the motor.
Cheers Steve