The Official 356Talk Forum

Ron, per your comment: Dyno- done, twice. Leak down- done. Ignition timing - done. Exhaust Chem? Do you mean Afr? If so, done.

Latest Dyno pointed to ignition, back to where this all began.

Chuck Watson wrote:Ron, per your comment: Dyno- done, twice. Leak down- done. Ignition timing - done. Exhaust Chem? Do you mean Afr? If so, done.

If Afr = air/fuel ratio, yes.
Let's see the curves; what goes haywire?

Ron,

If the engine accelerates to 4000 RPM but doesn't gain any speed something has to be slipping.
If it wouldn't increase RPM one might look for a tuning problem.
OK I missed on the drum/disc brakes so being an ex race car how about spiders or an axle if it has limited slip?

Norm

Norm, the claim here is that the engine makes "no power under load".
Maybe it is a 'transmission' problem (and I mean that in the general sense of power transmission, not the transaxle), but if so, the dyno curves will rule out a loss of engine power over a certain RPM.

[quote="Chuck Watson"]Today's update (I'm sure you guys are as tired of this as I am)...

Adjusted valves, a few were a little tighter than spec for this cam but nothing major. Tested the car. No change. I did take a close look at the tach during the test drive. Basically the engine does increase in rpm while the speed does not. I went from 1500 to 4000 rpm with less than a couple extra mph. As I think the clutch and drive train are not the problems, my thought is going back to fuel and spark. The motor could rev, but with a low spark or low fuel it wouldn't have much power, right?

Ron, this was my impetus for suggesting something slipping.

Too much confusion on this thread so I give up.

Norm

Norm Miller wrote:Too much confusion on this thread so I give up.Norm

Agreed, so let's remove the variables one at a time instead of guessing.
If the dyno curves say it's not an engine problem we can start chasing possible transmission problems ONE AT A TIME, rather than the 'well, Joe's coupe had a distributor that jumped timing once!' approach.
It's not rocket science, but it should be a scientific examination.

Ron,

Without hands on they are all guesses, cripes someone might have left the dowels out of the flywheel/crank

Take care,
Norm

Norm Miller wrote:Ron,
Without hands on they are all guesses, cripes someone might have left the dowels out of the flywheel/crank
Take care,
Norm

The dyno report would tell us something about that; the curve would flatten at X RPM while engine RPM would increase and dyno RPM would stall.
Much better than guessing whether the gas tank vent is plugged to whether the rear tires are slipping on the rims.
It's a simple concept; eliminate what you can to reduce the variables.
Or is guessing just a great deal of fun? In which case, I'm bailing; have a ball!

Replaced the distributor - no change. I was able to do the slipping clutch test (4th gear clutch drop) and it did grab and stall the engine. And again it did the same thing in first gear as before: increase rpms without increasing speed. So I gave up like the rest of you. Car delivered to my local P Car specialist today. I'll post the findings, when found.

Chuck Watson wrote:Replaced the distributor - no change. I was able to do the slipping clutch test (4th gear clutch drop) and it did grab and stall the engine. And again it did the same thing in first gear as before: increase rpms without increasing speed. So I gave up like the rest of you. Car delivered to my local P Car specialist today. I'll post the findings, when found.

I'm betting on leaking heads.

I'm betting on clutch. If a motor accelerates in first gear without increasing speed, the clutch is slipping. If it stalls sitting still in fourth gear when the clutch is released, the clutch is holding. But in the first case, you have the momentum of the car added to the force wanting to slip the clutch and you are giving it a lot of gas. In the second case you probably are not giving it enough gas to cause it to slip, unless you ride the clutch as you do the test.

I'm guessing it's a loose lug nut on the left rear wheel causing the distributor to jump timing!

Isn't remote troubleshooting fun? I have to get my hands on it to check stuff or I don't really enjoy it.
Some time I'll relate (in the open forum) my troubleshooting as to why the warning horn would sometimes blow when the landing gear was retracted on takeoff in a B-47. I was the Crew Chief. Only took six months, mainly because it was intermittent.

Wes

DaveErickson wrote:I'm betting on clutch. If a motor accelerates in first gear without increasing speed, the clutch is slipping. If it stalls sitting still in fourth gear when the clutch is released, the clutch is holding. But in the first case, you have the momentum of the car added to the force wanting to slip the clutch and you are giving it a lot of gas. In the second case you probably are not giving it enough gas to cause it to slip, unless you ride the clutch as you do the test.

I'm far from an expert here but I would argue that my nose would detect a slipping clutch. It always has in the past.