74 145 with kjet idles lovely but will not rev smoothly

1974Wagon · 2023-07-16T22:37:42+00:00

Who rebuilt the distributor and was it tested?or did you do it yourself

Laurie

Way back in 1976 my 145 with K jet played up in a similar fashion before water was found in the fuel system. The piston was slightly rusty and would not move smoothly from one end of its stroke to the other every now and again making overtaking a non event sometimes.

The bore was ok but was cleaned with WD40 on a cotton bud and looked very clean. I vigoursly cleaned the piston with a piece of old pillow case (rough but not scratchy) dipped in a mix of silicone and moly oil. Reinserted the piston and it now moved freely again.

But the dealer buggered up the 145 during a service about a year later and in a deal I got a new 245.

Bloody cars! They always seem to try a new trick!

1974Wagon

Hello everyone. Thanks so much for commenting. To answer Ramrod's question, I rebuilt the distributor myself using one of Colin Duncan's kits and his guide online. Unfortunately for me, even though the car was built right here in Halifax, the only shop willing to take on a rebuild was Flowtech in Alabama. And that would have been $600US plus the cost of sending a hunk of cast iron in the mail. Out of my league.

As far as testing goes, I have tested flow rates for individual injectors by rigging up a thing made of four plastic bottles and measuring amounts when lifting the plate in the metering head. The four injectors are even and the spray pattern is good.

The valve clearances are good.

I think, as many of you have suggested I may go back to the plunger and take a look. Although, when I separate the distributor from the air metering body, the plunger does drop down slowly. Could this still be a problem? The whole thing was seized and shellacked when I first got it so not really sure how loose it should be.

Perhaps it is worth revisiting the rebuild and looking for tiny specks again?

I will try all of this in the morning I expect. It feels so close after all this time and effort.

Thanks again. Warren

ramrod

There is so much that goes into rebuilding a distributor, which is why they are so expensive to do.

that and there are not too many people still alive around the world that know how to do it

Ex850R

The fuel distribution repair guy is mentioned here and probably in the PINNED section.

He has rebuilt WURs for example.

I've got no memory so others can tell who it is.

One thing that stopped my 78 245 was a crack in the rubber bellow on the fuel distribution set, it would open up when hot,car slowly got slower till no go. Cold it was fine.

Took a while for my expert old! Volvo mechanic to find it, had him puzzled

1974Wagon

Been out in the garage again to check on a few of the suggestions.

The distributor rotor has about 15 degrees play, if that, and springs back. The timing is definitely advancing with revs.

Also, meant to mention before that I fitted a Pertronix electronic ignition earlier in this build.

So, now I should pursue the fuel side of things, right?

I will redo a volume test. Does anyone have a number of litres a minute that I should expect?

I will also examine all the airways and the take a close look at the plunger in the fuel distributor.

And, Snoopy, thanks for the tip on the bellows. I checked that on the weekend and it is tight.

Ex850R

Mine had a crack from dry rot, very fine......hard to see.

I'd swap in a good known distributor if the one you have is unknown, even new parts can be broken.

1974Wagon

Hello again. I did a volume test and the pump delivered just under a litre in 30 seconds. The pump is a Spectra something that I bought new so I hope that is enough.

Also ran the injector test again, and one of the injectors is getting a little less than the others. Switched the line and it was not the injector. Perhaps this points to the fuel distributor too? Although seems like a more likely misfire situation than a low power thing...?

Lifted out the fuel distributor and the control plunger slides right out. Seems free to move.

ramrod

You’ll need to have the distributor rebuilt or swap with a known working one.

also look for a Bosch fuel pump that way it is correct for your application (correct pressures)

Major Ledfoot

ramrod brings up an interesting point - @1974Wagon what type of main fuel pump are you using to replace the original?

jamesinc

Unless you are seeing your pressures drop off away from idle, I'd say your fuel delivery is fine.

1974Wagon

I bought a Spectra SP1252 from IPD a couple of years back to replace the stock pump. As I have mentioned, the system pressure hits a steady 70 psi and the volume is just under a litre in 30 seconds.

This weekend I will hook up the pressure gauge again and watch the system pressure when the revs rise.

Major Ledfoot

1974Wagon
How did you go with this? Any resolution?

1974Wagon

Thanks for following up. For reasons far too boring to go into here, I have been kept out of the garage. I will get back to it as soon as it is possible.

1974Wagon

I managed to make it out to the garage this morning and hooked up the pressure gauge again. Warmed the engine and then watched pressure as revs rode. There is no drop in the pressure at all. Stays steady at 70psi. I assume this means I can eliminate fuel delivery from my search. Volume seems good and pressure remains good. I guess I am onto the fuel distributor again...

jamesinc

How much time have you spent on the (ignition) distributor? I'd check the vac and centrifugal advance and just verify they're working. If it's a points ignition I'd measure dwell also.

1974Wagon

Hello. Thanks for the message. I replaced the cap and rotor and installed Pertronix ignition. The distributor is centrifuge only and I was able to verify that the timing advanced as the revs went up. Is there anything else I should be checking?

jamesinc

Hmm no I think that is enough to say the ignition is basically OK.
In that case yeah I think you might be having to go over the fuel distributor. Maybe it is as simple as debris in the system. The fuel metering pin is supposed to be a precision machined fit, so it should slide smoothly and with no wobble, and if you pull it out of the fuel distributor you should hear a POP, indicating a good seal.

1974Wagon

So. What a journey. The long and the short of it was the piston and the barrel in the fuel distributor. Depending on the orientation it would either be super slick and smooth or, it rotated just a little bit then it got sticky and would bind. I cleaned everything really well and tried again but couldn't get the piston to slide smoothly in all positions. This explains the hesitant acceleration I think.

When I first got this car, it had been sitting in a barn for over 25 years and nobody could even remember what stopped it in the first place. Maybe it was this problem all along?

I got a rebuilt FD and fit it this morning. What an incredible difference. I am up and running and, with a few more tweaks, should be on the road very soon. Thanks for all your advice. I thought you might like to know the outcome. I guess once the piston and barrel are not perfect, for whatever reason, it really is game over.

Major Ledfoot

1974Wagon Thanks for telling us what happened, it all adds to the knowledge base.
Glad to see you got her going and there's another 145 saved.