Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Marine Engine?
Posted by: mgb260
Date: February 16, 2022 04:24PM

Eric, The cams are regular hydraulic cams. It is the lifters that are different. Their 50233 grind is what Chris used. Lunati and Comp Cams have faster opening and closing but unfortunately they don't carry them for the 215/300/340 Buick. They do Buick V6 and Buick 350 and 455 V8's. They may be able to do a custom grind but it would be more expensive.

[www.crower.com]

[www.crower.com]



Edited 3 time(s). Last edit at 02/22/2022 01:27PM by mgb260.


Airwreckc
Eric Cumming
RTP, North Carolina
(137 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: 300 Marine Engine?
Posted by: Airwreckc
Date: February 16, 2022 08:19PM

Jim, thanks for the clarification and information.


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Marine Engine?
Posted by: Wilitrun
Date: February 17, 2022 11:30AM

Hi all,
Here's a short video I shot of the current situation once I got everything shuffled around and organized.
I haven't found any specific information on the marine cam for this engine, but what I've read so far suggests marine cams in general are close to a truck/RV grind in that the torque curve is broader and flatter, and because the exhaust exits below the waterline, the lobe separation angle is wider by a few degrees, to prevent negative pulses from drawing seawater up into the exhaust during idle (a theory that makes sense to me) and the effect it would have for me is that the idle would be very smooth, and breathing at high RPM would be quite poor (this I don't necessarily find objectionable as I really don't want to overspeed the engine, but I may have a problem with my wide-ratio T5 and certainly with a 3.9 axle ratio). With the money I'm saving I don't mind revisiting that part of the equation, though.
The mild concern for me at this point is I'm seeing a slow ramp-up of oil pressure to about 30PSI at a brisk idle, so I'm going to have to look a bit deeper. Compression/leakdown test still isn't done, hopefully there will be time for that this weekend. In any case, this puts the project light-years ahead of where I was at with the other engine, and for very little money, comparatively.

[youtu.be]


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6261 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Marine Engine?
Posted by: BlownMGB-V8
Date: February 17, 2022 12:07PM

For now unless you have a flattened lobe you are much better off leaving the cam alone. The stock cam is not BAD, and the engine will make more than adequate power with it. See if you can find compression specs for that marine engine, maybe run a compression test. You'll note that the factory spec for HP is at 4600 rpm so I would not expect anything much over 5K from it unless you make changes. Definitely fit the 4bb intake if you have one. Your oil pressure is quite good. No real need to even touch that if you don't want to, but you are going to need a different oil filter base. When you swap that, get the TA shim pack and set the end gap on the gears tight. The booster plate is a good addition.

Great find. You'll be happy with that one. Be sure and use oil made for vintage engines.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(4320 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: 300 Marine Engine?
Posted by: MGBV8
Date: February 18, 2022 12:05AM

It's Alive!


88v8
Ivor Duarte
Gloucestershire UK
(1001 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: 300 Marine Engine?
Posted by: 88v8
Date: February 18, 2022 04:07AM

Irrelevantly, but for fun, this car has a marine engine, and it's running backwards.
Was somewhat tempted to buy it but had an attack of common sense.
[bringatrailer.com]

Ivor


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Marine Engine?
Posted by: mgb260
Date: February 18, 2022 10:47AM

Ivor, Corvair stock were reverse rotation and the v8 was changed otherwise it would run backwards!

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