GM engine specifications

[jebo53]

I just bought an old 1974 Penn Yan with no motor or transmission in but I was told that a GM 305 or 350 would do the job.<br /><br />I might have found a 350 but I would like to know where I can find the specifications, oil pressure, compression, operating temperature, etc.<br /><br />Also would anyone know what kind of transmission would fit in that boat.<br /><br />The Penn Yan compagny dont exist anymore so it is pretty hard to find any information.<br /><br />Thanks very much to anyone taking the time to answer me.<br /><br />Jebo53

 

[Don S]

Re: GM engine specifications

One thing a person needs to know is the size boat you have, and when you say 'Transmission', do you mean the boat is an inboard setup or does it have an outdrive.<br />Compressions depend on the year of the motor and compression ratio. Temps are usually 180 degrees or less depending on setup. Raw water cooled or closed cooling system. Oil pressures also vary depending on year and type oil pump.<br />Do you know there is a difference between a marine engine and an automotive engine and why there are differences????<br />You need to know that kind of things before starting a project of resurecting a boat.

 

[tommays]

Re: GM engine specifications

i am going to take a WAG but i would think its a shaft driven tunnel drive modle which was penn yans big thing<br /><br />if so it had a V8 hooked up to a velvet drive trans of some gear ratio??? which hooked up to the prop shaft<br /><br />let me know if i am close <br /><br />the best thing you can do is look for the same boat and see whats in there<br /><br />tommays

 

[seahorse5]

Re: GM engine specifications

A lot of those early PennYan tunnel drives used 318 Chryslers with Borg Warner transmissions.

 

[jebo53]

Re: GM engine specifications

First thanks to Don S and to tommays for their answer.<br /><br />Here is more information.<br /><br />The boat is a 1974 tunnel drive. The shaft and the propeller are there. The prop is a 12x14. <br /><br />The motor I am looking at is about 5 or 6 years old but with very little hours on it. I went with this guy for a drive and the temperature was around 180 when driven at 3200 to 3500 rpm but got a little higher when pushed more so we backed to 3500. The oil pressure was 40psi. I know that he had heating problem twice because he broke a belt so the temperature went at top, the antifreeze reservoir emtied and the oil pressure went down to what looked to be zero, so you can see that it is a closed cooling system. <br /><br />Since this is a very small place, there is no other Penn Yann around. By the way this is a 23ft.<br /><br />Thanks again to all who will take time to help.

 

[Red Fuel]

Re: GM engine specifications

The trans you're looking for will either be a borg warner 71C with a 1.2 to 1.5:1 gear ratio with that prop, or a 72C with the same gears. It depends on the bellhousing used with the motor setup. 71's were with older chryslers and omc's and the 72's were used with most newer models. Check ebay.

 

[snapperbait]

Re: GM engine specifications

Jebo... <br /><br />A 350 would be fine as long as it's brought up to marine specs... Also, make absolutely sure the engine is strong and healthy.. That is alot of boat for a 350 to push...<br /><br />A Borg Warner "Velvet Drive", model 71-c or model 72-c with a 1:1 ratio would be the correct trans to turn a 12" pitch x 14" diameter prop, IMHO... This is the exact setup I used to get a "baseline" idea for a correct propeller in my boat which is very similar to a PennYann (21', deep v entry, heavy, straight inboard, with a tunnel)<br /><br /> I also suspect my power to weight ratio would be quite similar to what you propose.. (302, 220hp?, 71-c w/ 1:1 ratio) I ended up going with a 13"x13" four bladed propeller..<br /><br />With a 1.5:1 reduction gear ratio you would have to swap propellers to roughly a 15 to 16" pitch with the same 14" diameter... Another consideration is that there may not be enough room in the engine compartment to accomidate the extra length of the 1.5:1 transmission..<br /><br />For specs on the transmissions that have been mentioned here, check http://www.marinegears.com/catalog/cat-idx-bw.html <br /><br />Good luck..

 

[Sonama]

Re: GM engine specifications

Thanks very much<br /><br />Jebo53

 

[Don S]

Re: GM engine specifications

Don't go rushing into things Jebo: <br /><br />Originally posted 10 October, 2004

 

[Silvertip]

Re: GM engine specifications

You are not worried about the fact that oil pressure went to "0" and it overheated "twice". You had better buy that engine cheap.