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RV Engine Rebuild


October / November 2005


Our tired old 454 finally bit the dust.  On the way back to Florida it started backfiring under load, and losing power climbing hills.  Fuel economy dropped and oil consumption went up.  Started overheating again too.  The most minor problems I can imagine causing all this would be:  a partially clogged radiator and/or a defective fan clutch; some issue in the heads involving valve stem seals and either a burned valve, or a head gasket leak; exhaust manifold cracked or gasket blown.  All this in addition to the known rear main seal leak.

I saw basically two options for repairs.  Option one was to just fix specific problems, which would involve fairly extensive diagnostics, pulling the radiator, and likely a partial engine disassembly of one or both heads.  The labor I guess would be about $1500 for this.  Add parts expense, and we're talking easily spending $2k, maybe more.  The result of this would be a good running engine with 74,000 miles and still a rear main seal leak. 

Option two was to replace the engine.  I shopped around and considered a factory long block, a complete crate motor from GM, a Jasper engine, etc.  If money was no object we'd have a 502 GM Crate engine.  What an awesome engine  515 lb/ft Torque, 320 HP!  But the engine alone cost $6k, plus other parts and labor we'd be spending way over $12k.  Way too much.  Jasper was also too expensive.  They wanted over $4k for just the stock long block.  After much local searching, I found a local shop here in Tampa, Engine Lab of Tampa,  that specializes in complete engine rebuilds for stock and high performance applications. 

Engine Lab of Tampa made a great initial impression.  I visited their facility, met the owner Dave Deegan, saw their operation, and I was sold on them.  All that remained was to get a quote.  To my surprise their quote was the lowest cost of any I had considered -- $5,250 for complete job remove, rebuild, reinstall.  Of course, this is the LOW estimate, many other components may need to be repaired or replaced, but the same would be true for all other options so this number is good for "apples to apples" comparison with the alternatives.  Warranty is 24 months, 24,000 miles on the long block, and 90 days, 4000 miles on other misc. replaced parts.  So, on October 20th we left our coach with them, and checked into an Extended Stay hotel.  Projected completion was NLT November 1st. 

After several days the rebuild was progressing well.  We discovered the primary engine malfunction was a burned valve.  Also a number of other problems; worn cam lobe, damaged rod cap, exhaust manifold leaks, burned spark plug wires, leaky oil sender unit, defective sensors, TBI needs service, leaky water pump, partially blocked radiator, etc. etc. etc. 


Technical details of the job

Here's what we planned to have done. 

  • Complete engine rebuild plus the following (all at extra expense of course):

  • Balance the rotating assembly (a nice touch for this big engine, cost $300 extra)

  • Replace factory cam with CompCams kit K11-302-4 (includes cam, lifters, springs, timing gears & chain -- this cam was recommended by CompCams for my application, about $280 extra)

  • Radiator rod out and recondition

  • Replace water pump

  • Replace all hoses (surprisingly the belts were in great shape - must have been new when I bought the MH)

  • Replace plug wires with MSD 8.5mm high performance RFI suppression wires

  • Replace stock exhaust with Doug Thorley headers

A few items we added along the way:

  • Clean TBI unit, install TBI service kit

  • Replace the starter

  • Dave didn't like the little aluminum heat shields that came stock, so he recommended some high-tech fabric boots that slip over the sparkplug boots and extend about 8 inches out over the wires.  They're sharp!

  • Service automatic transmission and replace stock fluid with full synthetic for cooler operation and wear reduction

  • Replace the oil cooler hoses (were leaking)

  • Replaced about every sensor and sender on the engine -- Oxygen sensor, oil pressure (was leaking) water temp, fan switch, engine temp sensor for computer, etc.  May as well do this now, no added labor expense just parts, Cost about $180 but prevents problems down the road.

There were a few delays, hurricane Wilma, parts delivery delays, etc.  On the final installation the starter failed, and we had to install a new one.  I'm glad it failed then, and not a week later!  The job was finished about 5pm on Friday, November 4th.  I was there for the final test drive with Dave Deegan.  I really like the way the motorhome is running, and Dave was really pleased with the results of their engine build too.  I've always been somewhat of a hot-rodder, and I couldn't see spending thousands of dollars and ending up with a stock engine.  I'm glad that we warmed it up a little!

Dave's shop does a lot of high performance work, and this influences everything they do.  They pay great attention to detail.  The regular long block rebuild included .030 over pistons, 3 angle valve job, a lot of precision machine work.  One example of attention to detail; they spin the completed engine and do a compression check on each cylinder. 

I can't wait to test this engine out on the mountains when we head west again next summer.   My hope is to greatly reduce downshifts from OD into 3rd, pulling most easy grades in OD at 70mph.  On the really steep grades, this past summer we sometimes found ourselves all the way down in 2nd gear at 35 - 40mph.   It would be great to climb most grades on the interstate highway system in 3rd gear at 60 MPH.

Where are the Pictures ? 

click here  For pictures of the engine rebuild

Total cost?  With everything I added to the job, the total cost was around $9,100.  Yeah, that's a lot to spend on a 10 year old motorhome, but we do plan to keep it a LONG time.  With any luck, we'll get $1000 or so back from our warranty...

Will the Warranty Pay Off?


We do have a "warranty" on this RV.  It's the "CSP", Continued Service Plan, purchased through the Good Sam club.  These warranties are quite restrictive on what they cover, especially on older coaches like ours, so we were only expecting them to cover a small part of what we had done.  They cover parts that have sudden mechanical or electrical failure, not normal wear and tear.  Our most realistic hope is that they'll cover the burned valve, the starter, and pay for the standard hours those repairs alone would have cost.  We made the claims and as of this writing (November 6th) we are waiting for their response. 


What's Next?


One of the very few things the Engine Lab doesn't do is exhaust systems.  I plan to order a Flowmaster 70, Big Block II muffler to install in the next couple of weeks.  I'd really like to open up the exhaust more to let that cam work.  Also have a tachometer on order.  Would be nice to know the RPM's.  When I visit Brazell's next summer maybe I'll get them to put it on the dyno so I can see what she'll do :-)


The story continues.  The following are excerpts from the daily blog where I commented on our continuing repairs:

Saturday, November 5th 2005:

Yippee!  New engine installed in motorhome, and it runs like a scalded dog.  Chris may write some to update on details of the last few days, but I'll mostly tell you about events of today, and the new engine in the MH.

Lots of Bad Luck -- But Mostly Comes Out Good

As you'll recall from reading last month we had our motorhome engine rebuilt.  The Engine Lab of Tampa, owned by Dave and Susan Deegan, did a great job.  However, because of hurricane Wilma, some parts delivery issues, and unexpected problems, completion was delayed by a few days.  Dave was really great about it, keeping me informed all along.  On Friday it was done, and I went for a final test drive with Dave.  Everything went great, and we were very happy.  We left the RV parked there over night and were going to pick it up the next morning.

The next morning we picked up the RV and headed out for MacDill AFB FamCamp.  Within just a couple minutes I smelled wires burning and saw LOTS of smoke coming out of the dash! I pulled over and grabbed the fire extinguisher.  Luckily there was no fire, just a lot of smoke.  It was coming from behind the TV set, which is mounted in the center of the dash above the doghouse.  We were SO disappointed!  And the shop is closed until Monday.  So we decided we just needed to keep our cool and work on the problem.

Lucky for me I'm fairly handy with electrical wiring (former AF Avionics tech about 20 years ago).  I pulled out the TV and right away we saw the problem.  A wire bundle ran across the dash behind the TV.  One of the wires had burned completely through its insulation for about 2 feet. It got so hot that it melted several wires around it so they all stuck together.  Thank God it happened this way, instead of causing a fire!

I pulled the dash apart and followed the wire bundle to a connector, then on to the fuse box.  It was all the wiring for the dash AC and heater.  I disconnected the wiring bundle so it wouldn't burn any more, and we could start the MH and drive away, then I put the dash back together and we moved on down the road.

WOW, what a day! We still need to get the wiring harness replaced, and more importantly find the cause of the problem.  But I'm going to do without the dash AC for a few weeks.  I'm tired of the RV being in the shop.  We spent 14 nights in the hotel, "away from home" and we're very happy to be sleeping in our RV tonight.

She Runs Sweet!

I really like the way the motorhome is running, and Dave was really pleased with the results of their engine build too.  I've always been somewhat of a hot-rodder, and I couldn't see spending thousands of dollars and ending up with a stock engine.   So, we warmed up the engine a little bit.

Dave's shop does a lot of high performance work, and this influences everything they do.  They pay great attention to detail.  The regular long block rebuild included .030 over pistons, 3 angle valve job, a lot of precision machine work, etc.  I won't list all the details here.  In addition, I added a few items like a stronger cam, headers, balancing, etc.  Full details see the link below.  I'll also be adding a Flowmaster muffler in the next week or two.  Can't wait to drive it up the mountains out west next summer :-)  That'll be the ultimate test!

Thursday, November 10th 2005:

The new Flowmaster muffler arrived yesterday late, and I installed it today.  One snag had to be overcome (why can't it ever be simple?).  The custom exhaust shop that was going to make me a pipe had loaned out it's 3" expansion tool, so I had to go hunting.  Not many shops carry 3" pipe, so I had to drive about 50 minutes North, 2 hour round trip. 

Anyway, I got the muffler installed about sunset and cranked up the engine.  Sounds very good, a little loud but it shouldn't be noticeable inside with the windows closed.  I picked a 70 series muffler because it was narrower than the 50 series, and would fit better where the stock one was.  In addition it's supposed to be a little quieter than the 50.  Glad I got the 70, imagine the 50 would have been too loud.  All I need to do tomorrow is install one hanger to give it some support, and retighten the bolts on the collector. 

Tomorrow I'll get to check out the RV's performance.  I'm leaving for Biloxi MS to meet up with Chris and her dad.  The VA is going to do the cataract surgery next week, so it doesn't make much sense for them to travel back to TX and have to return.  Glad that gas prices are down!  I saw regular at $2.29 today. 

Saturday, November 12th 2005:

Well, I've just had an eventful 2 days...

Good news:  Our Good Sam Continued Service Plan "CSP", otherwise known as an RV extended warranty, paid off on the burned valve!  They figured the burned valve and defective starter at about $1200 (a low figure, but at least they're paying).  We have $250 deductible, so they're sending me a check for $950.  Cool

Bad news:  Yesterday I headed out to meet Chris in Mississippi and everything was going great for about 2 hours.  Then, the RV "hiccupped" going up a hill and lost power.  That was about 4pm.  The Engine Lab was still open so I called David.  Lucky for me Saturday is a work day this week, so he told me to bring it in.  I drove 2 hours back to Tampa and stayed last night in their parking lot.  First thing this morning Greg talked to me about what happened and examined the RV.  He concluded that it might be a dirty fuel filter.  There's an inline canister filter under the frame towards the back. Greg pulled it off and dumped it into an oil pan.  Take a look:

Yep, that's a bunch of rust isn't it!  So we think we solved the problem. :-)  I'll check the filter in a week or so to ensure that we don't have a lot of junk in the tank.

After leaving the Engine Lab I drove up to Northdale and visited my Mom.  Then headed out north.  Right now I'm in Chiefland and the RV ran fine all the way here.  Of course, now I'm paranoid, so I'm hearing things every few seconds!

First check of gas mileage, 7.1 MPG.  I'm thinking this is a little low because of all the "testing" I've done on the throttle, not using the cruise control during break-in, some idling at the shop, lots of city driving, etc.  Will continue to monitor.  If we never see  8 MPG I guess I'll still be happy because of the added power.  I was hoping that increased efficiency would give us an increase in both power and mileage.  Driving in the South East I was previously getting about 7.4 MPG pulling the toad (no toad on this trip).