engine popping

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Harryb
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engine popping

Post by Harryb »

I have been having a power loss and popping back through the carb. on the port motor. After doing a lot of trouble shooting including changing to a LX301 ignition module and a accel coil that can take a full 12 volts all the time I removed the valve covers and #8 exhaust cam lobe is flat. The motor starts great with the new ignition system, but now that's least of my problems. I was wondering where to get a re-manufactured 318. Lots of them on the internet but I was hoping for info or recommendations from others that have had to replace an engine. Thanks
1987 32 f/b sedan with twin 318's Docked on florida's nature coast
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tundrarules
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Joined: Fri Jul 11, 2014 11:17 pm

Re: engine popping

Post by tundrarules »

Wonder if lack of zinc caused you flat lobe?

http://zddplus.com/about-us/faqs/

I have been running Rotella 15-40 diesel based on Jeff's advice. According to zddp website, it doesn't mix well with the diesel oils. I will go back to straight 30W and add zddp as required. What do you guys think?

No advice on engine...sorry. :ugeek:
1985 29 Sedan
Edelbrock 1409 carbs
Mallory distributors
Pertronix Flame-Thrower coil & wires
780 hrs/eng
TN River, MM 213.8

:mrgreen:
Tranquilo
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Re: engine popping

Post by Tranquilo »

Hey man, sucks you are having ignition problems with your 318. I'm having trouble with mine too here in Miami and all of the mechanics I have been put in touch with suck pretty bad (or never show up)

I found this official Chrysler LM318 service manual today after searching like crazy:

http://www.correctcraftfan.com/Download ... Manual.pdf

I learned a bit already about how it should work for my system since it looks like I may need to rewire a few things (or the whole charging system) since the P/O fell short in the smart & honest depts.

My engine started popping too but it was after getting nailed with a squall and flooding the deck and engine with water during sea trials yesterday. Pretty sure its moisture in the cap.

Anyway, I'll be an expert by the time I fix my boat. My boats are 1973 singles but the electronic control seems to be pretty limited in differences (part wise)

D
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
jmonday
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Re: engine popping

Post by jmonday »

Thanks Tranquilo for the link im doing the same thing you are on the same boat!
River here to day is at 40 going to 45 feet in cinci so had to pull mine to safer water becuase of wire/distributor Issues.
Jeff Monday (Blue Mondays)
1973 28 ft Express single 318 1976 StarCraft Islander 1961 Sea Nymph
Lower River rd
Rabbit Hash KY
ericinga
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Location: Cumming, GA

Re: engine popping

Post by ericinga »

Harryb-

IMO, you should verify compression and run a leak down test on each cylinder. If the compression is good (for me good is 120 - 125 ft. lbs. on an older motor) and the valves are not leaking, you should be ok to replace the cam. Perfect compression is 139 ft. lbs. If compression is low or inconsistent across the cylinders, you should consider an engine rebuild. If the cam has a flat lobe, you've pushed those metal shavings through the entire motor. I would not be surprised to see cylinder and bearing surface scoring.

Many people will tell you an automotive motor cannot be used in a marine application. This is not true. The performance may not be perfect as the auto camshaft is not designed to generate low end torque. The automotive cam will work but will likely be less fuel efficient. The difference is in low RPM valve timing. The Marine application has an earlier intake valve closing timing to generate more low RPM compression and torque. This is similar to the timing in a work truck or high performance motor.

The cost difference between a marine and automotive 318/360 is around $1,500 to $2,000.

My dad was an SAE certified master technician for over 30 years. He installed an automotive 360 in his 26' Marinette. It ran like a scalded dog for the six years he owned it. The next owner turned into a work boat.

I talked with a local engine rebuilder earlier this year about our 318. He called his parts distributor and was able to locate a marine grind cam. I believe the cost was $110. This told me to look for an "RV" grind. This is a high torque application cam. Call an engine parts supplier. National Performance Warehouse is located in Miami.

In the end, be comfortable with your decision. The extra cost for marine engines might be worth the peace of mind if using automotive engines will cause anxiety.

Eric
Eric Spies
1989 32 SDFB
Twin 318s
Lake Lanier, GA
Marinette Boat
Tranquilo
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Re: engine popping

Post by Tranquilo »

jmonday wrote:Thanks Tranquilo for the link im doing the same thing you are on the same boat!
River here to day is at 40 going to 45 feet in cinci so had to pull mine to safer water becuase of wire/distributor Issues.
HA! Perfect. We can start a support group :)

Keep me posted if you find the ignition relay, battery voltage regulator or monitor and / or the 50 amp breaker. I can't find them anywhere and think I have a defect there causing that issue
2x 1973 28 Express - Single 318
New electrical panels, water system and velvet drive
Miami FL & Catawba OH
Fastjeff
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Location: Rock Halll, MD

Re: engine popping

Post by Fastjeff »

Eric:

Was talking with a friend of yours the other night: Peter B.

Jeff
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington
jmonday
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Joined: Thu Jul 31, 2014 2:01 pm

Re: engine popping

Post by jmonday »

I may have a cam for you if needed. It was given to me and i a sucker for free boat parts i may never use.
Jeff Monday (Blue Mondays)
1973 28 ft Express single 318 1976 StarCraft Islander 1961 Sea Nymph
Lower River rd
Rabbit Hash KY
ericinga
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Posts: 170
Joined: Mon Jul 14, 2014 11:21 am
Location: Cumming, GA

Re: engine popping

Post by ericinga »

Hey Jeff-

The name doesn't ring a bell.

Eric
Eric Spies
1989 32 SDFB
Twin 318s
Lake Lanier, GA
Marinette Boat
Harryb
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Joined: Sat Jul 19, 2014 1:56 pm

Re: engine popping

Post by Harryb »

I appreciate the offer on the cam but along with the flat cam lobe the #8 exhaust push rod was bent so the valve has stuck at one time or another or maybe even hit the piston, The motor did pass a compression check with all cylinders between 125-140 psi before I pulled the valve covers. I have been running the engine at idle just to get in and out of port and to help park. I've had a lot company for the start of scallop season and have been using the boat and pushing that cam grit through the motor so a complete re-build or new long block is probably in my future. I was hoping others who had experience with a re-builder could offer advice on where and where not to buy. There dozens offering long blocks on the internet. Thanks BigM
1987 32 f/b sedan with twin 318's Docked on florida's nature coast
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