I  replaced the carb. It had a 1.02 from a mustang, I bought a correct 1.08 unit for truck with the correct boosters and no cracks on the emulsion tubes. It was a refurbished unit but I set the wet float height and idle screws myself. Has 48f jets, I didn't pull the power valve though.

The balancer is a brand new Dayco, a better grade than their standard oem  replacement. I checked the marks with a piston stop, I always do that- sometimes new parts are bad. Initial timing was 17°, I backed it down to 15°. I'm running the vacuum advance off the timed port. I set base timing with the vacuum plugged to be double sure.

The timing mark does jump occasionally while watching it with a timing light, but I need to verify if this is a cause or a symptom, like the pop dropping the rpm is flinging the centrifugal advance or something screwy.

Thanks, I know this isn't as sexy as a lumpy cam ;)

I'll double check but the shaft felt better than most 2100/ 4100's I've fooled with. I sprayed around the shaft and base and didn't see a change in rpm either.

The vacuum is strong at idle, until it hiccups and the needle drops 2 hg momentarily. If it were constant or even rhythmic I think this would be easier to chase.

This is as hard to diagnose as it is to decide if I should put my t-5z in this 3 speed baby doll.

I would tend to agree with the thought of an intake valve intermittently sticking open.  You would lose vacuum, and when the plug in that cylinder fires, the pop will come back through the open valve, intake, and carb.   Do you hear the pop through the carb?  Is there any valve train noise when the vac drops and it pops?

Last edited by TimC (3/06/2017 3:57 PM)

TKO- T-5z
I want to bad, it's the sentimentality of cruising my uncle Johnny's ride as he did that holds me back.

Rudi-
I'm with you, it was the vacuum guage that got me thinking a sticky valve was a strong possibility.

TimC-
No valve train noise and just standing under the hood and I didn't put my ear to the airhorn. I'll break out the stethoscope.

I haven't ruled out a rich condition at idle or misfire either, That pop gives a stronger exhaust pulse with your hand near the tailpipe. I had to pick up the 9 year old today so no time to tinker (she hates the truck). I'll get back to you fellas when I get more clues, in the mean time here's the Ranger-



 

Good looking truck, Jon.  You might want to consider the fact that when unka Johnny was young and might have considered it,  nobody had probably ever thunk of a T5Z....otherwise, well, you never know.

​2X what MS says....get new rubber.  Ax Red3511 about old tires.

​BB

I don't know about the ZDDP concentration in synthetic oils, I would posit that its the same as conventional though due to the cutback mandated by the EPA.  I will say this though, in terms of wear prevention and engine preservation synthetic is always going to be better than conventional.  I recently had to pull the heads off my WRX which has 193k on it (wife's DD) and I inspected the cylinders while I was there.  I found no appreciable wear at all.  No ridge, no taper, and I could spin the engine over without the heads using only my hand on a socket on the crank bolt (no ratchet or bar).  The cams, followers, etc. likewise showed no wear I could see.  I have maintained it regularly and have used synthetic oil (Amsoil)  since it had about 20k on the clock.  With the heads reworked and a new timing set it runs better than it has in years.  I fully expect another 100-150k from it, which at the rate my wife drives will be another 10-15 years or more.

Oh, and get a DNA test on that 9 year old of yours.  Something's off there...

Jon Richard wrote:

I'll do some research on synthetic oil and flat tappet cams, you talked me into it you silver tongued devil 😎.

And no DNA needed, her biological daddy drives a Honda and wears Mr. Rogers style sweaters...

Well then you're doing the Lord's work and I leave you in His grace and favor. 
 

TKOPerformance wrote:

Well then you're doing the Lord's work and I leave you in His grace and favor. 
 

Bwahaha!
Trust me I'm trying to get her converted- classic rides, not Bibles 😉

Synthetic oil/ flat tappet cams-
It appears you need ZDDP in both synthetic or conventional oil with non roller cams. There are both on the market specifically blended for older cars. I think I'm going with Valvoline VR1 conventional, not because it's conventional it just rates really high. I read Amsoil Zrod is good stuff too.

I haven't been able to find Amsoil locally... is it only available online?

1)  Jon Richard.... Ohhhh Man, that truck.  My advice:  drive it with those tires, and when they explode & leave you on the side of the road, sign the title, tuck it up above the sun visor, then PM me and tell me where it is.  I'll take it it from there.....

2)  Michael H.... I have attended the last 4 Bashes, and at each one, Don has enlightened me about Amsoil.  I believe he is involved, somehow.  Perhaps he will chime in, or you can PM him.

3)  J R:  Do I see a jen-you-whine AWANA derby car?  I have "assisted" in the creation of those for years.  Maybe I should have used Amsoil on the wheels/axles.  I never could get those thing to go fast.  Knowing my limitations in the speed arena, the kids and I always went for style.

I buy Amsoil locally; there's a Chevy dealership here that sells it.  I think that you just need to find a local "dealer", which is often just a guy who sells their products out of his garage, etc.  Here's a link from their site that should be able to help:

http://www.amsoil.com/locator/map.aspx

Yeah, no telling how gummed up things got sitting dormant in that barn for three years, I might snake a bore scope down a plug hole to see if the sea foam and risoline had any effect.

And you're telling me! I have two other projects sitting on blocks, victims of my mortal enemy WYAIT