Performance expectations of Robert Davis 3.0l

[daveb]

willing to bet your throttle is not opening fully. BTDT

[alaskajosh]

willing to bet your throttle is not opening fully. BTDT

Thanks for weighing in, Dave.
I haven't driven it since summer so my memory is hazy but I'm sure my rpm's on the hwy were up around 2700+... shoot, I'd better not say for certain. I just don't remember. But suffice to say things seemed to be opening up.. Is that what you mean?

Thank you for your good advice, Zayante. I think I'll give that vaccuum test a shot--

What would you guys do with those compression numbers? 140, 120, 140, 150. That was a cold engine, BTW. I agree it must be at least a contributing factor.. Does it warrant a rebuild? What would you do?

Thank you, gents!

[yorker]

I would exhaust all other possibilities before I even considered doing the engine. Check the throttle linkage and make sure you have the full range of motion when you press the gas pedal. Make sure you don't have any issues with the timing. Make sure there is no crushed section in your exhaust. Check your fuel lines and make sure there are no issues there. If those are cold compression readings I wouldn't be too worried yet. Do a leakdown test yet?

[alaskajosh]

I thought I'd follow up on this issue as it unfolds and resolves.

Investigating, I did find a pretty bad exhaust leak from a badly cracked manifold. That wasn't helping matters.

Then, long story short, I upgraded to the carb that RD recommends. The Weber 38/38 in place of the 32/36 the po had installed. I've only driven it a little since but I think I can say I'm well satisfied at this point. It's pretty quick and only bogs down a little on the steepest, longest hills which I don't hold against it.

With my 3.8 diffs I run approx. 3000rpm at 60mph. It sounds happier at around 2800, 58mph, which is a fine speed for a vehicle of this nature. It would easily do 70+ if I wanted to listen to it scream, which I don't.
It jumps off from a stop with plenty of zest.
Bear in mind mine's much heavier than the average 109 with a winch bumper, camper top, and more.

Haven't been off-road since the upgrade/tune but imagine it will only be better and it was never bad.

I'd enthusiastically recommend this engine upgrade. As a GM family engine, it's understood and accepted at you local parts counter or junkyard and a neat fit.

Edited to add: I spoke with RD today and he said there is a lot more power there to be tapped.