Moparts
413 Motorhome engine questions
Posted By: 66coronet500
413 Motorhome engine questions - 03/31/13 08:35 PM
I have a 1966 Coronet 500, 318 poly, auto from factory now- no engine and set up for a 4spd. Bought a 413 for 200.00 then found out it was a motorhome engine. WTF- NO REFUNDS. Ok, so now its a budget rebuild with my son. I have 915 heads, Intake, distributor, car style water pump, bigger cam and lifters. Here are my questions:
1. Can I use the rocker arm assy's?
2. Can I use the push rods?
3. Can I use the oil pan?
4. It has a"thick" harmonic balancer, should I change this? Will belts line up?
5. Has a 6 hole crank, can I use my stock 4spd set up?
Thanks!
Posted By: Dodgem
Re: 413 Motorhome engine questions - 03/31/13 11:00 PM
Everything should work.
Posted By: dodgedartgt
Re: 413 Motorhome engine questions - 04/01/13 01:45 AM
I don't know about the rockers and pushrods, but I would be very careful about changing the balancer without tearing down the short block first. I was recently considering a 413 M/H engine myself and got an education from a friend. Many of the M/H and industrial engines had very heavy 4 ring pistons in addition to the LY rods. If there is no "ring ridge", and you have a ring compressor, then at least pull out one piston to see.
If they are the heavy pistons, then you can replace with lighter "car" units and a rebalance will only require removing weight. I'd bet you can bring the rotating assembly to neutral balance, increasing your balancer and flywheel options.
Also, I'm betting you'll need to change the oil pan.
Mike in FL
Posted By: 82ramIndy493
Re: 413 Motorhome engine questions - 04/01/13 03:02 AM
When you say thick balancer are you talking about a external balanced engine balancer? All the 413's I have ever known were internally balanced. I have a 413 M/H engine from a 71 and it has the forged crank balancer. I just recently put a 74 440 from a M/H in a 86 pickup and it worked fine. What year engine are you working with and does it have the extra cooling passage heads and water pump housing?
Posted By: NITROUSN
Re: 413 Motorhome engine questions - 04/01/13 03:15 AM
Quote:
1. Can I use the rocker arm assy's? Should work
2. Can I use the push rods? Maybe depending on lifters and required length needed.
3. Can I use the oil pan? No.
4. It has a"thick" harmonic balancer, should I change this? Will belts line up? 413 should be steel crank. Sounds like you have a cast crank balancer. Mixed bag here so who knows what will line up??
5. Has a 6 hole crank, can I use my stock 4spd set up?
Better double check the crank. If its cast you will need the correct flywheel. From your balancer question you had better identify the crank. Also make sure there is a pilot hole.
It most likely will be a very low compression motor. I would be looking for a better motor.
Posted By: dweller
Re: 413 Motorhome engine questions - 04/01/13 06:55 AM
I've seen MH 413s with that balancer before. It is a special forged crank balancer that is thicker than the standard forged crank unit, maybe for pulley alignment? Not sure? They appear to be internally balanced and the crank is the same as a car forged crank as long as it has the six bolt flange.
Posted By: 66coronet500
Re: 413 Motorhome engine questions - 04/01/13 03:58 PM
1971, I pulled the MH heads and waterpump off and going with car parts.
Posted By: dOoC
Re: 413 Motorhome engine questions - 04/01/13 05:31 PM
Quote:
I have a 1966 Coronet 500, 318 poly, auto from factory now- no engine and set up for a 4spd. Bought a 413 for 200.00 then found out it was a motorhome engine. WTF- NO REFUNDS. Ok, so now its a budget rebuild with my son. I have 915 heads, Intake, distributor, car style water pump, bigger cam and lifters. Here are my questions:
1. Can I use the rocker arm assy's?
2. Can I use the push rods?
3. Can I use the oil pan?
4. It has a"thick" harmonic balancer, should I change this? Will belts line up?
5. Has a 6 hole crank, can I use my stock 4spd set up?
Thanks!
Hi 66 ... got your PM on this topic ...glad to help out.
FIRST ..... how clean is the inside of the motor? MOST I havwe seen are in good shape.... low miles plus when they are used they are worked hard - so very little sludge build-up.
Ok ...rockers are the same. P-rods .....are longer with the goofy heads. NO on the oil pan. The balancer ?.... is a really NICE PIECE ... but very true ... getting stuff to line-up is going to be a bummer. I am thinking about having a custom crank pulley made. Those are INTERNALLY balanced motors ....so a regular car balancer should just slip on. IF you did this ... the TC cover would also have to be changed.
That crank and your 4 speed ? ....IIRC .... the ones I remember looking at DID HAVE a bushing in there.
And as Double N said ..... these motors have patheticly LOW compression ratio. I would take those 915 heads and shave them 60 to 90.
Posted By: Bumbalawski
Re: 413 Motorhome engine questions - 04/01/13 11:57 PM
As it was mentioned earlier, those industrial headed MH 413's have a very heavy 4 ring piston. And they have LY rods. I had a 1972 413MH engine with industrial heads and it had those crappy pistons. Looks like some higher than normal motorhome RPM could break those LY rods with those heavy pistons, and I mean they are heavy and very low compression.
Posted By: 66coronet500
Re: 413 Motorhome engine questions - 04/03/13 04:44 PM
So, I should be able to go to my local salvage yard, find a big block mopar car and grab its harmonic balancer and timing chain cover?
What should I do with the stack of MH engine parts?
Thanks to all!
Posted By: Greg55_99
Re: 413 Motorhome engine questions - 04/03/13 05:46 PM
Do like I did 33 years ago. Throw away everything except the block, crank and rods. A few nuts and bolts you can keep. The rest is useless. If you’ve got a mind too, I can use the truck rear sump oil pan, pickup and dipstick.
Greg
Posted By: dOoC
Re: 413 Motorhome engine questions - 04/03/13 10:27 PM
Quote:
As it was mentioned earlier, those industrial headed MH 413's have a very heavy 4 ring piston. And they have LY rods. I had a 1972 413MH engine with industrial heads and it had those crappy pistons. Looks like some higher than normal motorhome RPM could break those LY rods with those heavy pistons, and I mean they are heavy and very low compression.
FOUR RING piston ? .... I have heard of them ... but never seen them .... them being CRAPPY ? ... for HP use ... ferr-sure ... but for what that engine was built for ...nothing better !
The heads ? .... again ... they are PURRfect for their intended use ...LOUSY for HP ... but nothing is BESTer for a lower-RPM torque motor.
Posted By: dOoC
Re: 413 Motorhome engine questions - 04/03/13 10:34 PM
Quote:
So, I should be able to go to my local salvage yard, find a big block mopar car and grab its harmonic balancer and timing chain cover?
What should I do with the stack of MH engine parts?
Thanks to all!
As long as the BBM has a steel crank in it ....and the timing marks have not moved .... you should be good-to-go.
""""""""""Do like I did 33 years ago. Throw away everything except the block, crank and rods. A few nuts and bolts you can keep. The rest is useless. If you’ve got a mind too, I can use the truck rear sump oil pan, pickup and dipstick. """""""
For a HP set-up .... you beez uNwrong. But the bolts and nuts ? ... most of those are for the indust motor.
uSeless ? ..... send them to me ! ... I am eventually going to do some low rpm flow work on the heads to get some MPG out of these motors in MH's and tow-rigs.
Posted By: Secret Chimp
Re: 413 Motorhome engine questions - 04/04/13 12:39 AM
... are you hitting the sauce or something, Doc?
Posted By: Greg55_99
Re: 413 Motorhome engine questions - 04/04/13 01:18 AM
Quote:
Quote:
So, I should be able to go to my local salvage yard, find a big block mopar car and grab its harmonic balancer and timing chain cover?
What should I do with the stack of MH engine parts?
Thanks to all!
As long as the BBM has a steel crank in it ....and the timing marks have not moved .... you should be good-to-go.
""""""""""Do like I did 33 years ago. Throw away everything except the block, crank and rods. A few nuts and bolts you can keep. The rest is useless. If you’ve got a mind too, I can use the truck rear sump oil pan, pickup and dipstick. """""""
For a HP set-up .... you beez uNwrong. But the bolts and nuts ? ... most of those are for the indust motor.
uSeless ? ..... send them to me ! ... I am eventually going to do some low rpm flow work on the heads to get some MPG out of these motors in MH's and tow-rigs.
Wish I had come up on you five years ago. I had 413 heads, intake, exhaust manifolds, water pump and housing, gear driven cam, the whole shooting match. I had it in storage since 1980 and got tired of looking at it. I hauled it to a dumpster one night.
Still got the 413.
Greg
Posted By: dOoC
Re: 413 Motorhome engine questions - 04/04/13 07:26 AM
Quote:
... are you hitting the sauce or something, Doc?
SAUCE ? .... CHIMPster ? ... 
Posted By: dOoC
Re: 413 Motorhome engine questions - 04/04/13 07:45 AM
Quote:
Wish I had come up on you five years ago. I had 413 heads, intake, exhaust manifolds, water pump and housing, gear driven cam, the whole shooting match. I had it in storage since 1980 and got tired of looking at it. I hauled it to a dumpster one night.
Still got the 413.
Greg
CHIMPster will be really "swinging-from-da-vine" after hearing this .... 
I am going to spend about a half-a-day PORTING those exh mans !! ...... PLUS whenever I can pick-up some 413's I do .... the last time I was set-up with a swap-spot at the Nats I was told that there was a guy from MI that had FIVE of these motors... some complete some not so much. We made a deal .... and he delivered those 5 motors up to me in nw lower MI ...and he lived just west of Port Huron. .... for 350$ 
Posted By: 66coronet500
Re: 413 Motorhome engine questions - 05/14/13 01:25 AM
Just an update, A guy bought my 413 heads, waterpump, intake and all parts I didn't want for a newer 38 foot 440 motorhome. He wants to build a stroked 440 and use the 413 heads, etc.!
The 413 has a car waterpump, deep oil pan, 915 heads and I hope to have it in the Coronet In June or July.
Posted By: dOoC
Re: 413 Motorhome engine questions - 05/14/13 02:33 AM
did he say what he was going to put the motor in ?
Posted By: 66coronet500
Re: 413 Motorhome engine questions - 05/14/13 04:24 PM
The same MH it came out of.
Posted By: dOoC
Re: 413 Motorhome engine questions - 05/14/13 05:38 PM
So he is intending boring that 413 out to 440-spec AND putting an arm in it ? ...with bone-stock heads ? .... he better not buzz that past 2500 or so.
Posted By: dogdays
Re: 413 Motorhome engine questions - 05/14/13 11:08 PM
Bore it out to 4.25, use stock 383 pistons and a 4.15" crank for a 472, stock 413 rods complete the package. Boring past that will hit water sooner or later.
R.
Posted By: 66coronet500
Re: 413 Motorhome engine questions - 05/15/13 06:21 PM
NO- I have the 413 block. He is using the 413 heads etc, from my engine that I did not use on the 440 in that MH.