Twin Chrysler 318 Engine Survey Question

[anora1984]

Greetings, we are looking to purchase a 1979 Trojan 30 Express, we had the mechanical survey, the pre-survey and haul out. The mechanical survey found one of the Chrysler 318's had some low pressure. During the sea trail, the owner would not take it above 30rmps. He usually cruises around 22rpms. The mechanical surveyor, told me he was concerned that the owner would not take WOT at 40. Owner states port engine is original and has 3508 hours on it, the STBD has been rebuilt in 2001 and has 880 hours. Everything else has check out well. How concerned should we be and approximately how much should we negotiate down for the unknown status of the WOT of the engines. Thank you. I am a complete newbie.

[prowlersfish]

It just could be just the owner's fear of running an engine hard even though they may be fine. ( seen it more than once) And of course, they could be hiding something. When you said low pressure do you mean compression or oil pressure? What are the numbers and one or both engines?

[prowlersfish]

As far how much to negotiate down, that's a hard question to answer. I guess it would depend on the selling price. If it was going for say 25k I would ask for maybe 5k for need repairs or fix it and re-sea trial and be allowed to go wot. Now if it's a 5k selling price your not going to knock off that much if anything at all . I don't have a clue to the boat's condition or price so just threw some numbers ot there.

Still like to know what "pressures" are off

As far as running wide open I think you should be allowed to open it briefly. I can understand the seller not wanting to run WOT for a long time. Normal cruise on these is about 3000 for most people and wide open 4000 ( I would be ok with 3800 or so)

[anora1984]

Thank you for the replies. I'm still waiting for the mechanical survey paperwork, but he mentioned it was "compression" that was low. I don't have the numbers yet. The price was originally listed for 28k, before they dropped it 24k, we made an offer of 21k pending survey. I should have the survey in hand today or tomorrow and will have some numbers then. Below is the listing.

https://www.yachtworld.com/yacht/1979-t ... s-7932730/

[prowlersfish]

When you get the numbers I will give you my opinion The oat is on the higher en price wise. Bt it looks to be in better condition the most. also has radar. Was the engine rn before the compression test? Has it been sitting ? Any engine photos?

[captainmaniac]

For what it's worth, if I was selling I would have concerns with someone wanting to go WOT for multiple reasons. First, I don't do that to my engines and while I realize some people may be thinking of it as a diagnostic,

• a) some people just think that's how you run a boat (esp. if they have only operated an outboard powered runabout in the past)
  b) I don't want to sell my boat to someone if that's how they are going to treat it
  c) the engine IS 40+ years old, without rebuild, so if they break it, they are gonna just walk away and its gonna cost me a lot

So I think you need to find a middle ground between you and seller.

I have an F32, and I'm running 360's. Similar to what Prowlersfish has said, cruise on my (and likely your potential) engines is optimized in the 2800-3200 RPM range. If you can run it at that for extended period and not see anything funny, its probably okay. If you can creep up to 3500-3800 and run there for 30 seconds to a minute and then back it down - with owner permission - it can give you more confidence in the engine and maybe not freak them out as much as WOT would.

FWIW, I cruise at anywhere between 16 and 22 knots in that RPM range depending on wind / wave / loading conditions, and I have almost 1900 original hrs per side. I have cranked them up to 3500-3800 a couple of times - for 2-3 minutes to make a bridge so I wasn't stuck bobbing in 6-8' seas with a really short fetch for a half hour for the next bridge, and for 5-<10 minutes to outrun a storm to make harbour before 40-60 mph winds and massive downpour hit (the rain wasn't falling - it was going sideways!). Did an experiment once back in 2007 and pushed to 4000 RPM to see what it would do (27 knots), but otherwise never over 3800 for the past 22 years and only did that in emergency situations.

From testing at less than WOT revs hopefully you can assess if the engine is a problem today, or will be good for a bit. Compression numbers Prowlersfish is asking for may tip the scale.

But rest assured - if that engine has over 3500 hrs on it... its not likely gonna go another 500 hours without needing a rebuild. You are most likely looking at rebuild some time in the next few years. Doesn't necessarily mean drop offer by rebuild cost but maybe a bit for 'tired' engine, and budget over the next 3-5 years to cover the cost of the rebuild, if you really like the boat otherwise.

[anora1984]

Here is what I got from the mechanical survey:
ENGINE – CHRYLSER 318 PORT STBD

ENGINE OIL LEVEL: OK OK
TRANSMISSION LUBE LEVEL OK OK
COOLANT LEVEL: OK LOW
DRIVE BELT: OK LOOSE
SEAWATER PUMP: OK SIGNS OF LEAKAGE
CIRCULATION PUMP OK OK
OIL PRESSURE(AT DOCK) NORMAL NORMAL
CHARGING (AT DOCK) NORMAL NORMAL
WATER TEMP (AT DOCK) N/A N/A
W.O.T. RPM N/A N/A

COMPRESSION (WARM ENGINE) PSI
1- 145 2- 155 1- 130 2- 145
3- 145 4- 145 3- 120 4- 130
5- 150 6- 135 5- 140 6- 130
7- 135 8- 150 7- 130 8- 130


ADDITIONAL FINDINGS

1) BOTH ENGINES HAVE OIL LEAK NEAR #7 CYLINDER HEAD BANK

RECOMMENDATIONS:

1) FILL STBD COOLANT RESERVOIR TO NORMAL LEVEL / MONITOR FOR LEVEL CHANGE
2) ADJUST STBD DRIVE BELT
3) CHECK OUT CAUSE OF LEAKAGE ON STBD SEAWATER PUMP / REPAIR AS REQUIRED
4) FIND OUT W.O.T. RPM WITH ENGINES TOGETHER AND INDEPENDENTLY

[prowlersfish]

I feel one engine while having high hours still may have some life left. The boat has been used and that's a good thing. Compression while a bit low on it is still in specs. I would still want to see wide-open rpm if just for a second or 2. I don't like doing one at a time. Need more info on the oil leak.

Here is the specs you can get the manual on this site ( will post the link later)

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