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Old 08-14-2012, 09:59 PM   #21
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Originally Posted by REDNAX View Post
...especially as hydraulic lifters are obsolete.
?

Care to comment on this?

I know that roller lifters are a huge improvement, but for a street engine I would still lean toward hydraulic roller lifters rather than a purely mechanical one to avoid having to adjust frequently. Especially in an engine being built for low RPM power.
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Old 08-16-2012, 02:02 PM   #22
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Vaughan, I agree hydraulic roller lifters offer a significant improvement in power and efficiency and are far better suited to a street vehicle.

If anyone would like to go for a new production truck replacement engine from Chevrolet, the HT502 is an aftermarket engine thatís all about torque and towing. Take a look http://www.gmpartsdirect.com/performance_parts/store/catalog/Product.jhtmlPRODID=1116&CATID=1099.html. If you wanted to move to a used standard production multi-port EFI engine, you could install an 8.1 L with its Powertrain control Module (PCM) from a salvage yard. The 8.1 L is a stroked version of the 545/7.4L and has the same form factor (external dimensions, etc.)

But for lower cost improved performance, Iíd just look at a cam like the one I suggested in my previous post and install a set of Thorley Tri-Y headers (most of which are CARB approved). The Try-Y headers are tuned for broad band torque optimization below 4,500 RPMs (unlike most long tube headers that are optimized for peak HP in the upper RPM register. It goes without saying, that you should have good compression and anything that needs to be done in this arena such as rebuild or ring replacement/valve job must be addressed. This sort of thing will yield efficiency and torque where you want it.
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Old 08-16-2012, 03:19 PM   #23
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Originally Posted by Steve Bryant View Post
Vaughan, I agree hydraulic roller lifters offer a significant improvement in power and efficiency and are far better suited to a street vehicle.

If anyone would like to go for a new production truck replacement engine from Chevrolet, the HT502 is an aftermarket engine thatís all about torque and towing. Take a look http://www.gmpartsdirect.com/performance_parts/store/catalog/Product.jhtmlPRODID=1116&CATID=1099.html. If you wanted to move to a used standard production multi-port EFI engine, you could install an 8.1 L with its Powertrain control Module (PCM) from a salvage yard. The 8.1 L is a stroked version of the 545/7.4L and has the same form factor (external dimensions, etc.)

But for lower cost improved performance, Iíd just look at a cam like the one I suggested in my previous post and install a set of Thorley Tri-Y headers (most of which are CARB approved). The Try-Y headers are tuned for broad band torque optimization below 4,500 RPMs (unlike most long tube headers that are optimized for peak HP in the upper RPM register. It goes without saying, that you should have good compression and anything that needs to be done in this arena such as rebuild or ring replacement/valve job must be addressed. This sort of thing will yield efficiency and torque where you want it.
I'm inclined to agree with you, Steve. For a low RPM engine aimed at optimizing torque, I probably wouldn't pony up for roller lifters myself. I was more questioning the previous comment about hydraulic lifters being obsolete. I brought up roller lifters more as a guess about what was meant by that.

I also agree that the Tri-Y's are a good recommendation.
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Old 08-16-2012, 05:15 PM   #24
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Here's the thing about roller lifters versus those with no roller. With the roller, the valve opening and closing rate can be much faster because o the rollers can roll up a steeper cam profile and allow more combustible mixture to enter (intakes) and leave (exhaust) and the same basic engine could produce more power. I wouldn't say that hydraulic lifters are obsolete, but if I were installing a new cam, I'd go a step or two farther and get roller replacement lifters and new valve springs. Comp and a number of other manufacturers offer the whole thing as a kit and the labor costs won't be any more. The only reason to have solid lifters on a modern engine would be a race application in my opinion.

If I had a motorhome and I planned to keep it for the foreseeable future and I wanted or needed to upgrade the engine: I'd probably go for a low mileage 8.1 L fuel injected engine from a salvage yard, install a towing cam and the tri-y headers. It would involve some work and research, but is probably the best option (versus staying with the same engine or doing a conversion to a diesel).

I'd also replace the transmission with a 4L80E or 4L85E transmission. If you had a wrecked doner vehicle, you could probably do the whole thing for $6,000. That['s a guess on my part, but I used to be a mechanic and I'd be doing the work myself.

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Old 08-20-2012, 03:15 PM   #25
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Not sure if a roller cam would be good... never retro fitted one to a BBC, but hear good things about roller rockers. The lack of sideloading on the valve tip is worth the effort and would reduce valve stem wear.

I read a great article on upgrading the Big Block on Campfire Clicks/This Old RV and the guy was very detailed and gave the MPG improvements etc... but the site is down/gone... anyone know if it moved?

One thing for sure, is I will be saving for one of these to maximise efficiency and get the carb setup right...
Holley Performance Products Holley Wideband 02 Controller with Gauge*534-201
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Old 08-20-2012, 04:01 PM   #26
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Found the new site!

Drivetrain improvements that actually work > CampfireClicks.com | Online Community for RV Owners, Classifieds, Forums, DIY, How To's, Reviews, Member Profiles, Blogs

Just in case its disappears again, here is the body of his info:

Hello Everyone, I wish to relate a project that has been ongoing for two years & too many dollars to comfortably recall. My84 Windcruiser p-30 motorhome is in very good condition except for the running gear. one of the first things to go was the transmission (due to pulling a heavy trailer to florida a couple of times). after buying a TCI trans & converter, I equipped it with a derale vented deep trans pan & GM red stripe vacuum modulator. Take note for all transmissions use Trans Guard additive imediatley! Results are a veritable sucess as I tow a 12000lb trailer most of the time now with not even a wimper from the tranny.

The next item was a set of ceramic Hedman Hedders, these are attached to summit 2.5" "x" pipes (NOT an H pipe) After this are a set of "DNA" stainless mufflers about three feet back from fhe "x" and After these are flowmasters exiting through Gibson turndowns in front of the rear tires this system is very free flowing & at highway speeds is not audible inside the coach and still lets the engine breathe.

The addition Harland Sharp ROLLER rocker arms with a 1.8 ratio gives .040 increased valve lift & frees up around 25 HP or more while reducing heat buildup. A Weiand "peanut" port Action Plus manifold and Edelbeock 650 Thunder series carburetor ( tighten the secondary one quarter turn tighter to stop the bog). A split plenum carb gasket from edelbrock & K&N filter element.

My ignition is a jacobs RV series computer & coil this unit has an inclinometer that supplies the coilwith 525 volts for up to 55 seconds for climbing hills & I have never had engine knock running regular gas. Along with jacobs ceramic plug wires, cap & rotor & advance curve kit using the middle springs & NGK plugs gapped at .060, completes the top end. I recently had the pleasure of removing the oil pan to install what I think was long overdue for

All chevies is a one piece oil pan gasket, at this point I modified the oil pump by using a time tested method by removing the oil pump bypass spring & placing a Holley jet or 1/4" spacer behind it,this has always resulted in a ten to twenty pound increase in oil pressure. (Only do this on a good pump as it wont help you if your pump is worn out & high volume pumps do not need any mods). While apart the stock cam is advanced four degrees with a double roller timing chain set and cam button to stop cam walk. Up front is a TEAM "G" aluminum water pump which weighs 10 lbs less, moves 15 gallons more a minute while using less HP to turn it no need for the bypass hose but use a 180 degree new style "Safety" thermostat.

Try to get fresh cool air into the engine, I used flex dryer exhaust hose covered with insulated ducting covering it, ahead of this is a 600 cfm air pusher providing mild boost to the carb (dont laugh it WORKS). All this may seem a little extreem to some but I am a hot rodder still & I couldn't resist playing with this to see noticeable seat of the pants results & I'm overwelmed with the "NEW" Motorhome!

Yes I would do it again. There are no drag strip time slips but I now move along with the big pushers with ease & the BEST part is gas mileage averages 11 to 13 mpg bobtail & 7 9 mpg towing my Nomad around florida for car shows. I hope this article will help anyone curious about these improvements.
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Old 08-20-2012, 11:21 PM   #27
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MPG tips..

Did a little digging and found some interesting comments out there on the 454 and MPG...

Carbureted big blocks are a real challenge. Hi flow intake and exhaust help. A good pre-emulsion carb, like the right Holley that has been torn down, trued and detailed helps. I've done that and can gain up to 10% on the carb alone. The timing chain and gears wear and stretch, losing MPG. It can matter anytime over 50k to 75k on big blocks, maybe sooner depending on oil and change cycle. The proper camshaft makes a difference. Matching ports between intake manifold and head is important. I've custom timed each cylinder spark to it's own TDC and gained MPG (due to crank inaccuracy common in older big blocks). Gears are important to keep cruising RPM's down. Watch tire pressure. Cruise control only works on flat roads, overreacts on hills. A vacuum gauge does not do it. You can see high vacuum in a lower gear but get terrible MPG. Tests were done by the EPA, DOE and others that found driving habits can reduce MPG up to a third. Towing my 5th wheel, I use a ScanGauge for an instant MPG readout to tell me when I'm doing good and when I'm wasting gas. Lower speed and coasting are big factors to stretch MPG. I got mine at scangaugesales.com

Read more: How Many Miles Per Gallon Does Your Motorhome Get?
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Old 08-22-2012, 01:37 AM   #28
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I'm so glad that this thread has started it has provided so much good information. There are a couple things that I have not figured out quite what to do. If you add oil and transmission coolers do you size them large enough that you can discontinue using the ones in the radiator or should you keep them in the circuit. I assume when it's time to buy the coolers if I give the manufacturer my horse power and weight they can recommend the correct size and here in the deep South is it wise to put thermostats on those coolers to keep them from running too cold. Any thoughts would be helpful.
The other thing that I been thinking about is the radiator fan that is mounted to the engine. If I understand it right on some of the newer pickups they are using a mechanical clutch that is connected to a PWM circuit from the computer which will give you a fan speed proportional to the amount of cooling you need. Is it possible to adapt an old viscous clutch fan and I think you would just use a on-off thermal switch to control it.
Just a little info on my motorhome, I have installed a Holley EFI throttle body system on it. I've been happy with results so far but I don't have too many miles on it yet and I need to get it out on the road to fine tune the fuel and spark map. I changed to a wide band O2 sensor which makes it easier for me to get the fuel map right. The other thing I did was add a knock sensor and sure enough if I tap on the side of the engine lightly with a hammer the spark will retard. I haven't proven it in the real world yet but I'm hoping that it will allow me to switch back to regular gas, I don't think the compression on a 1982 engine is that high you couldn't run on regular. I think at the time the technology may have been too complicated or expensive to have spark retard as standard.
The reason I went to EFI was to solve the way to common problem of fuel starvation. But what I found may have been the root cause of the whole problem after I installed the throttle body system. I replaced the back electric fuel pump and I noticed that I was seeing bubbles in the clear glass filter that I put in the gas line. I assumed it was just cavitation because I have no back pressure on the gasoline going to the sump tank mounted in the engine compartment. Eventually the electric fuel pump died and I traced the problem to where the fuel pump lead tapped into the 12 V at the distributor. They used a very heavy gauge wire that was size wrong for the snap on connector and it had corroded. They took the heavy wire gauge and put about 12 feet of it looped up in the wiring harness on the side of the engine and came out to a resettable fuse and then I believe it may be as light as a 18 gauge wire on back to the fuel pump. Because this is a pulse power load is hard to tell if the voltage drop is excessive to the fuel pump. Now that I had a good connection the bubbles in the gas line went away, I would never figured this out if the pump had not completely quit. The way my rig is laid out the generator is very close to the fuel pump and I think what I would do if I had a carburetor is pick up 12 volts at the generator connections, put an in-line fuse and a relay to keep the voltage drops at a minimum.
Regards,
Bill
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Old 08-22-2012, 08:09 AM   #29
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Thanks for posting Bill... great info!
You are going to post some pics of course?
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Old 08-22-2012, 08:12 AM   #30
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Anyone have any experience with one of these systems?

EZ-EFIô Self Tuning Fuel Injection System (Base Kit)
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Old 08-22-2012, 09:37 AM   #31
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I've done a lot of tuning of the stock GM PCM using a wideband and logging/tuning software and hardware manufactured by EFILive. FAST is one of many Competition Cams companies. They produce good products and stand behind their products.

Tuning an EFI system basically involves getting the look-up tables for various manifold pressures and RPM combinations dialed in by logging fuel to air mixture data using the wide band oxygen sensor with a laptop computer. For general purposes, you want the engine to run at a stoichiometric mixture (optimum AFR of about 14.7:1 for gasoline). Startup enrichment and full throttle enrichment may also need to be adjusted and set up in the EFI's computer. On systems that incorporate spark control with or without knock retard capability, the spark tables must also be set up in a way that mimics the centriugal and vacuum advance of a traditional distributor.

There's a learning curve to all of this but it can be rewarding and fun.
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Old 08-22-2012, 11:32 AM   #32
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Brad,
Don't know about EZ EFI, but see post #10 here on a swap to a Powerjection system:

http://www.airforums.com/forums/f159...arb-55577.html

It would be good to hear how it has held up over time.
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Old 08-22-2012, 01:02 PM   #33
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More good info, this is turning into an awesome thread!

All this talk of EFI, make me want to throw the Carb away and put a system on... but here in California it STILL has to pass smog, and few of these aftermarket systems are CARB complient.

Maybe I should do the TBI conversion rather than stress about the carb!
I have a complete 454 from a 1990 Suburaban, and I also took the whole TBI system, including the harness and ECU, with the plan to swap the whole thing into a Blazer...



I hear its not difficult, but I would need to swap the Airpump system too.... and the 1990 had a single serpentine belt, as well as everything on the engine being transposed... ie on the 1990 the AC compressor is on the right of the engine and the Alternator on the left... on my 1987 Suburban and my Airstream, it reversed..
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Old 08-22-2012, 01:17 PM   #34
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Quote:
Originally Posted by dadstoy View Post
Keyair, do you know what the specs are on your RV cam? Also, do you know if there are any marking on the outside of the heads to tell what they are? I'd sure like to know which ones I have.
Dean,
Still looking for my cam sheet... I know I have it somewhere!

The head castings are marked in 2 places most of the time.
Here is a shot of one of the casting marks, clearly showing a 781 and Pass, meaning passenger car...
This one is on the underside, but there is another set of numbers cast on the heads on the top between the rocker pedestals and the valves.



Look up your casting numbers here..

Big Block Chevy Engine Parts casting numbers and Identification
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Old 08-22-2012, 04:48 PM   #35
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I do my own mechanical work on the motorhome because if I paid shop rates I simply couldn't afford to have an RV. For most of my life I only had one vehicle so that prevented me from being much of a gearhead if you have to drive it to work the next day. But now I have four vehicles and with all the good information on the Internet I feel like I can do a lot of the work myself. The reason I went with the Holley system is at the time it was well documented and a lot of support over on the Chevy forums and the amount of changes I had to make were minimal. One of these days I want to write a blog about this experience so I can remember what I done and how I did it.
One thing with a EFI system you have to throw away that old air pump because the air will completely swamp out the O2 sensor. I don't know how older cars in California are tested but the way I understand it in the rest of the country they only sniff the tailpipe at two RPM settings. If you have your fuel map optimized it will fail because of too much NOX but the quick fix is just make those particular RPM settings a little richer to keep the cylinder temperature down. Because of the age and weight of my RV I don't have to do emission testing even in a nonattainment area like Austin.
If I were to do it again I would most likely try to transplant a complete system out of the junkyard and perhaps use a megasquirt controller because I like the idea of accessibility to all of the software and the ability to make your own enhancements. The downside is with both Holley and megasquirt, you nearly need to have a second controller as a spare because if you have a failure you're not going to pick one up at AutoZone.
Regards
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Old 08-22-2012, 08:07 PM   #36
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Hi Bill,

That's true, the sniffer test is done at idle and something like 2500 RPMs. Motorhomes over 8500 pounds are exempt from the dyno test. The catch is there is also a visual check. All OEM smog equipment must be present and working. I'm still confused about an engine swap to a later year. I just read the DMV requirement and it states that no modification can be made that degrades the smog emissions and the smog equipment for the original year, make and model must be present...what if you put in an engine 10 years newer? Smog checks are done once every two years except for those vehicle the state wants off the road, such as my MH, it has to be smogged every year. I'm due again next month...sad! My problem last year is that it had too much NOX at idle, then when the tester adjusted idle mixture to pass, it would not pass CO at 2500 RPMs.
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Old 08-22-2012, 08:20 PM   #37
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Quote:
Originally Posted by Keyair

Dean,
Still looking for my cam sheet... I know I have it somewhere!

The head castings are marked in 2 places most of the time.
Here is a shot of one of the casting marks, clearly showing a 781 and Pass, meaning passenger car...
This one is on the underside, but there is another set of numbers cast on the heads on the top between the rocker pedestals and the valves.

Look up your casting numbers here..

Big Block Chevy Engine Parts casting numbers and Identification
Thanks Steve. I've been doing a lot of Internet reading...for whatever that's worth. The casting number of the block only determines what year range the block was manufactured, the cubic inches and whether two or four bolt mains. However, many casting numbers state that they could be two or four bolt mains. Most folks say the only way to know how many bolts is to drop the pan and look. There is another number on the front of the block above the timing chain cover that can give more info. I tried like crazy to see that number on my block...no way. My casting number is 14015445. A lot of folks also state that the PASS code on the front of the block which most say means passenger car, doesn't mean a lot, they say GM put that block in a lot of trucks.

I'll look for the casting number on my heads someday when I remove the valve covers to replace the gaskets.
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Old 08-22-2012, 08:27 PM   #38
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Hey Bill (shelocta),

I think you mentioned you have an '82? Which floor plan/size do you have? I think I looked at the Holly site for their EFIs, but I don't think any were CARB compliment. Tell us a little more about in Holly EFI installation and how that went!
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Old 08-22-2012, 08:39 PM   #39
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This is my understanding of the smog rules here in Ca.
Anything gas powered before 1975 is smog exempt.
Anything diesel powered before 1998 is smog exempt.
Anything diesel powered and over 14000lb is smog exempt..

Dean is correct about the smog rules for a post 1975 gas powered vehicle.
All original smog equipment should be present and functional.
Any modified parts need to have a CARB AO number, eg, and intake or exhaust manifold, altho I am told there are acceptable exceptions.

Putting a TBI system from a later vehicle is fine, but then the smog is judged on that era vehicle... ie, put a TBI system on from a 1990 vehicle and it will be judged on 1990 smog levels.
Put a complete engine in and that is what they judge it on...
So the trick would be use a pre- 1998 Diesel vehicle for the donor, if you are under 14,000lb... of if you have a 345... sky is the limit!
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Old 08-22-2012, 09:57 PM   #40
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This might be of interest to the folks in Calif.

http://www.bar.ca.gov/80_BARResource...uidelines.html
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