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freedombro · 12-26-2016, 05:36 PM

Greetings, All.

After having so many (and varied) issues on my last few trips, I decided to invest heavily in my 1986 345, lovingly known as the Unleaded Zeppelin. In the last 12 months I have replaced the entire cooling system, water pump, and alternator. I had the q-jet and distributor rebuilt ($900) by a (seemingly knowledgeable) old school big block expert. I added headers and flowmasters with a full tune-up before my trip to Sturgis for the bike rally. I had a backstage pass for the rig at the Buffalo Chip Campground and was looking forward to hosting some friends who were scheduled to play there during the motorcycle rally.

Immediately, I was disappointed in the lack of increased performance I had anticipated. The route to South Dakota from LA is mostly uphill, and the rig struggled from the start. I didn't expect any speeding tickets, but I also wasn't happy that big rigs were lining up on my bumper during long hauls in the slow lane. At one point, a Highway Patrol pulled me over to free up traffic, and see where I was going. He was cool, and let me slide since I was only two miles from the summit, and I could practically coast to my destination from there...sad.

Then...I started to notice a change in the transmission...I limped into Heber City Utah knowing this wasn't going to work. After a sleepless night in the Walmart parking lot, I located a transmission shop close by and waited for them to open. To make a long story short, we left the Unleaded Zeppelin in UT to get a rebuilt transmission installed and continued on with friends to Sturgis in their van. Bummer.

After retrieving the rig on the way home (and paying the $3000 bill,) I was severely disappointed when 10mph was the best she could maintain up the grade between Vegas and LA. I have run this trip several time before at a 35mph slow speed. I parked it when I got back in August, and have just now recovered enough to consider giving her one more chance.

I am not very mechanical, but I have access to people who are. I need to know if it makes more sense to rebuild the current (original) engine, or install a new crate motor? If that is even the best place to start? Are there other potential reasons for the lack of performance? It seemed to have less power after all the work I had done? What is my best option in crate motors? Any other recommendations or suggestions would be greatly appreciated. I want to keep her on the road, but I'm scared to death, at this point, to driver her around the block!

Thanks for listening.

My name is Keith, and I'm an Airstream Classic Motorhome Addict.

Countryboy59 · 12-26-2016, 05:57 PM

Quote:

Originally Posted by freedombro

Greetings, All.

After having so many (and varied) issues on my last few trips, I decided to invest heavily in my 1986 345, lovingly known as the Unleaded Zeppelin. In the last 12 months I have replaced the entire cooling system, water pump, and alternator. I had the q-jet and distributor rebuilt ($900) by a (seemingly knowledgeable) old school big block expert. I added headers and flowmasters with a full tune-up before my trip to Sturgis for the bike rally. I had a backstage pass for the rig at the Buffalo Chip Campground and was looking forward to hosting some friends who were scheduled to play there during the motorcycle rally.

Immediately, I was disappointed in the lack of increased performance I had anticipated. The route to South Dakota from LA is mostly uphill, and the rig struggled from the start. I didn't expect any speeding tickets, but I also wasn't happy that big rigs were lining up on my bumper during long hauls in the slow lane. At one point, a Highway Patrol pulled me over to free up traffic, and see where I was going. He was cool, and let me slide since I was only two miles from the summit, and I could practically coast to my destination from there...sad.

Then...I started to notice a change in the transmission...I limped into Heber City Utah knowing this wasn't going to work. After a sleepless night in the Walmart parking lot, I located a transmission shop close by and waited for them to open. To make a long story short, we left the Unleaded Zeppelin in UT to get a rebuilt transmission installed and continued on with friends to Sturgis in their van. Bummer.

After retrieving the rig on the way home (and paying the $3000 bill,) I was severely disappointed when 10mph was the best she could maintain up the grade between Vegas and LA. I have run this trip several time before at a 35mph slow speed. I parked it when I got back in August, and have just now recovered enough to consider giving her one more chance.

I am not very mechanical, but I have access to people who are. I need to know if it makes more sense to rebuild the current (original) engine, or install a new crate motor? If that is even the best place to start? Are there other potential reasons for the lack of performance? It seemed to have less power after all the work I had done? What is my best option in crate motors? Any other recommendations or suggestions would be greatly appreciated. I want to keep her on the road, but I'm scared to death, at this point, to driver her around the block!

Thanks for listening.

My name is Keith, and I'm an Airstream Classic Motorhome Addict.

What's wrong with the engine?

freedombro · 12-26-2016, 06:04 PM

I don't know...other than it has way less power than it used to. I don't know what else would cause that, other than the engine? I'm listening, if someone has alternative suggestions.

Thanks!

Waipio Rim · 12-26-2016, 06:52 PM

Before you give up on the engine, get someone to run a compression test. That will tell you whether the performance problem is inside the engine or is being caused by an ignition or fuel problem. If the engine has good compression, we can start guessing in earnest.

tjdonahoe · 12-26-2016, 06:57 PM

If replacing ,go with a crate motor, check the compression, carburetor? Distributor and timeing...The 454 has been known to score a rear piston because of enclosed space area holding the heat ..

68 Overlander · 12-26-2016, 07:14 PM

Certainly worth finding the real problem before considering a new crate motor, which is a rebuild anyway.

Waipio Rim · 12-26-2016, 07:32 PM

In the meantime, and since you have already had most everything else rebuilt or replaced, here's my guess: catalytic converter(s)?

PaulnGina · 12-26-2016, 07:44 PM

I know this sounds simple, but......

Make sure the plug wires are installed in the correct order, and check/set the timing.

Isuzusweet · 12-26-2016, 07:52 PM

There are many factors that contribute to perceived engine performance or lack there of; transmission performance, bad wires, plugged exhaust, leaking intake, bad carb.

Your transmission has the final say on performance as it transfers engine performance to driveline motion. You may have a strong engine, but if the transmission is old and tired it will seem as if the engine is bad. Since the transmission went bad it would have tainted your perception of engine performance.

Now you got the transmission rebuilt, but by who (an Allison dealer?) and did they used the correct torque convertor? Did you do a proper break-in of the rebuilt transmission?

As a previous poster stated I would first start with a compression check before deciding on an engine replacement.

As for engine rebuild or replacement? A crate engine is a NEW engine, not rebuilt! Yes, you can get rebuilt engines from your local Goodwrench dealer that come on a crate, but a "crate" engine is a new motor.

A rebuilt carburetted 454 is the lowest cost way to go and is plug and play. A crate 502 with fuel injection is not plug and play but any competent shop would be able to complete the conversion. The rebuilt 454 will give you okay power, torque and the usual mpg but the 502 would increase power, drivability, torque and fuel economy; but at a greater initial cost.

Cheers
Tony

ijustlee · 12-26-2016, 08:14 PM

Just a guess but maybe your timing advance isn't working? 454's are pretty good engines and you should be able to pull long grades in second gear unless you are over weight by a lot. Are your secondaries in the Q-jet working? If they don't open that could cause the lack of power you describe also. If your engine doesn't use oil on long trips it is probably going to last for years. A worn out engine will have a lot of blow-by and use oil, that's when you think about replacing it! A burnt exhaust valve or two is a repair in my universe. Funny story, years ago I tuned up a 454 in a one ton duelly with 56,000 miles on it owned by a lady who bought it new and towed a heavy fifth wheel. She drove down from Canada and had me check it out for the trip back home. We went for a test drive up a steep grade and when I floored it she got a puzzled look on her face and asked me "what's that noise ?" when the secondaries opened! I questioned her about this and she said that if she had to push the accelerator that hard she would get a bigger engine! Yep, over 50,000 miles of towing. I would buy a used truck from that woman!

freedombro · 12-26-2016, 09:21 PM

Thanks to everyone for the input.

I now have a list of things for my mechanic to ck before I move forward. You guys rock.

Cheers!

Keyair · 12-26-2016, 09:49 PM

Welcome to the Asylum, Keith, my name is Steve, and I too am an Alumamotohomeaholic...

Something is wrong with your Motor, unless your brakes are stuck on.

On my Maiden voyage, from KS, to CA, my 454 pulled my 345 up and over the Continental Divide with authority and aplomb, and whilst I knew it was working, it pulled up some serious backcounty grades with the 4 barrels howling out load at 35mph. This was no Freeway haul I was on. The motorhome has about 7000 miles on it's JASPER re-manufactured unit, and pulls hard.

Tony's advice is sound, as always.
Compression tests will tell you a whole lot, and a leak down test is an autopsy.

A crate motor makes sense, if only to minimize downtime and shop storage costs. If that is not a issue, get your original motor built by one of the numerous shops in LA.
If money was no object, I would stuff a '92-98 5.9 12v mechanical Cummins in there.
Otherwise, with the CA smog you need to pass, go with the 454.
Tell whoever rebuilds it what it is going in... so you need a well built 4 bolt main unit, with an RV cam.

Some suggestions...
Good reading..
http://www.airforums.com/forums/f159...4-a-95118.html
http://www.jasperengines.com/

Naper · 12-27-2016, 03:43 AM

Assuming your motor was running ok before the modifications you should concentrate on the items that were worked on, carb distributor etc. My guess its something simple. Wouldn't be the first time a mechanic didn't adjust the the throttle linkage properly. Find some one who works on old cars a hot rod guy would be best.
If your 454 is beyond repair a new crate motor is the only way to go, cheeper in the long run, less down time and a 2 year warranty.

bobmiller1 · 12-27-2016, 07:10 AM

Wow...a lot of good input here...listen before you change that engine do a couple of things, compression check, timing check, distributor vacuum advance check, and a vacuum leak check, use a smoke machine if you have to...get back to us with the results and we can move forward from there. Regards, Bob

r carl · 12-27-2016, 07:22 AM

One of the first things to check is to be sure the secondary's are opening in the quadrajet.

USAtraveler · 12-27-2016, 01:07 PM

As you've confessed, Keith, you are not a motorhead. No big deal. Most of us aren't, including most of the people on this forum. Asking for advice here is a crapshoot. But you live in a place that is the engine mod capital of the world! An online check of shops in the LA area, with follow-up on Yelp, will give you list of shops that are highly qualified to diagnose what may be wrong with your current setup. You can even find specialists in repairing 454's. Until you do that, you are just wasting sleep worrying about whether or not to replace the existing engine IMO.

chriscraw · 12-27-2016, 06:05 PM

Basically it comes down to cost versus performance pleasure. As an owner of a 1991 350LE for which I paid more than I should have, every dollar input into the rig must be valued against pleasure output!
I sympathize with freedombro....having also tried to slipstream a semi on an uphill climb I decided that it was time to review my options. Understanding that even when new, the 454 TBI engine was underpowered when hauling 16,000 pounds of steel, half an oak tree and a weeks output of DuPont’s Corian, I set my expectation sort of low. By low I mean towing my VW Rabbit up a 1 in 3 incline!
Here is my reasoning. By far the best option to improve performance would be to replace the 454 with a Cummins diesel/Allison 6 speed combination. I located a “donor vehicle” but, after adding-up the costs of the conversion (excluding replacing the Onan gas generator with a diesel), I would need to budget around $15,000 of which 2/3 rds would be labor. I met with a guy who had done just this in a 310 (allowing him to cruise at 70 mph towing his FJ Toyota!). He thought that the $15K number was conservative.
So to the crate alternatives. There were 2 options here, one was a 454 and the other the 502 HO. Although the 502 HO option was extremely attractive, it was expensive. In comparing this option to the 454 crate and the 454 rebuild, I should add that in each case there were costs for upgraded ignition and Banks headers and Flowmaster exhaust. However, allowing for the same amount of labor to remove and replace engines, the 454 crate option came out to around $8,000 and the 502 HO at $10,000.
Finally, the rebuild option was analyzed and allowing for the same “add-ons” (both the crate and rebuild options added another $211 for a Crane 134112 camshaft, and the rebuild also added an upgraded hi-flow water pump), I calculated that the rebuild option will cost me some $7,000. As you can see, these findings mirror Tony’s comments.
So right now, the engine is in Dallas (re-bore, pistons, bearings, valve gear etc., brake and steering work. Checking the transmission, new torque converter etc. Can’t wait to hear that rumble and see the VW in the rear-view camera (yes, it works!)

cliffcharb · 12-27-2016, 07:47 PM

I would start with the items you've fixed first, mainly timing. Verify the obvious, plugs wires etc, then verify proper timing. Vac advance needs to be unplugged to set initial. Then I would make sure the advance is working properly, easily done with a timing light. How well do you know the mechanic that did the repairs? Lots of folks forget to disconnect the advance when setting initial, so you end up running extremely retarded, thereby reducing power.

Isuzusweet · 12-27-2016, 07:57 PM

Quote:

Originally Posted by cliffcharb

Lots of folks forget to disconnect the advance when setting initial, so you end up running extremely retarded,

Who are you calling extremely retarded???? I resemble that remark!

Gregsch · 12-27-2016, 09:20 PM

You have already received a lot of great advice here from folks with real world experience with rigs just like yours. All sound advice. I will add my $.02 worth. Back in the 70's I had a 383 magnum engine that I added a cam, headers, reverse turbo mufflers and a Holley carb. It actually ran worse than it did when stock. High performance parts all have to be matched to work together. Add to that the fact that your engine was designed to have systems to control pollution and you have a very complicated scenario. 454's are the most common motor in the hot rod world. Find someone who modifies these engines all the time and have him help you.