Reliability of auto B18 B20 valvetrain in rebuilt AQ

"Very knowledegeable newbie he

"Very knowledegeable newbie here tackling a vintage AQ 110 motor rebuild, needing some feedback.... I've rebuilt a B20 auto engine with performance mods, but am now finding that penta marine has alot of different parts -- many with prices one can only laugh at (e.g., $1050 retail / $880 "wholesale" for a "marine" camshaft),

<<WAKE UP PENTA! -- if you can't be reasonable on prices, you will lose sales!>>

Concretely, the differences in the valvetrains seem to be that the marine cam is flatter, with the valve stems being about 1mm longer to compensate. Theoretically, this is better for durability at the stable mid- to hi- RPMs one sees in boating. BUT, when one can get the FULL valvetrain for a car at less than half the cost of a marine cam... well, hey boaters, I'm willing to either: A) have a machinist 'flatten' my new auto cam to match marine specs, or B) sacrifice a little durability and drive my runabout more like a car!

Can anyone out there boating a rebuilt AQ 100 110 130 etc. (B18 or B20) with the FULL automotive spec valevetrain (cam, followers, valves) give us a performance/reliability report?"

"i ran a b20 straight out of a

"i ran a b20 straight out of a car with no problems. you can take your cam in and get a marine grind, the marine valve springs are stiffer and the timing gears are metal in the marine engine probably to compensate for the higher valve spring pressures."

I am running a B20 with a &#34

I am running a B20 with a "A" grind and no problems. I am using the marine timing gear and springs. It's 1 year 20 - 30 Hours so the jury is still out for me.

"This is good news, along with

"This is good news, along with finding that a cam blank is very affordable.

So then, is the "A" grind the same thing as a "marine" grind, or are there some differences? Where (in US) can you recommend having a marine cam grind done? Have there been updates to the cam spec based on current knowledge?

Anyone using the solid (hydraulic) lifter set?

My engine was found fitted with a fiber timing gear (assumed replacement part): have there been reports of fiber gear failure when using the marine spring pressures?"

"Woddy the "C" grind i

"Woddy the "C" grind is the Marine as far as I can tell. Do a search of past posts to read more about this topic. Here is some links of the reading I did on the subject. I can't say anything about the fiber gear but the lifters are solid not hudraulic. Most change lifters with cam for proper breakin.
http://www.1800philes.com/
http://www.classicmotorsports.net/news.php?cat=5
http://www.volvo-1800.com/distributor.htm
http://www.swedishbricks.net/faq/volvofaq.html
http://www.volvoclubofbc.com/links/resources.html

I will try and find a spec sheet for the cams."

"Woddy I found one of the cam

"Woddy I found one of the cam spec sites.
http://www.turbobricks.com/resources.php?content=camspec
This site says the "P" grind is the boat cam.
Myself and others have pulled "C" cams from thier marine motors. My machine shop grinds the "F" as standard prodcure (20yrs). I am running "A" on my boat.
Confused yet? Add this article to your choice.
http://my.boatus.com/consumer/poweroutage.asp
It tells of water backup in the head from cam spec. Please let the board know what you do and how it worked out."

"A boatload of resources there

"A boatload of resources there Gil, thanks. That valve duration overlap issue is an eye-opener. Guess the safest bet might be to find specs for original marine "P" cam. I can see why "A" might be an OK bet too, since it is low lift, short duration. How is your power curve / torque? Size of boat?

Still, I have a freshwater runabout so might be able to handle a "C", if safe. In a Volvo-issued performance bulletin I have from 1965, the "C" cam was referenced as an upgrade to the early B18 auto engines. It was later the stock cam in the B20 autos. But for penta engine use?...wondering if a "C" would be safe enough from dreaded exhaust valve cracking due to exhaust water ingress.

Will search posts, but does anyone have teardown reports from marine engines running a "C" cam over the long-term?"

Woddy Your welcome for the in

Woddy Your welcome for the info. I am happy with the "A" grind. I have a 1975 18 1/2 ft Starcraft cutty. It is light for it's size. I had a "C" cam in it when I got the boat and the machine shop ground a "F" spec. on the rebuild. I was also happy with the "F" but broke the nut that holds it in because of a water pump failure. I can not tell the difference of the two grinds. Lots of power with both of them. I was planning to regrind my "A" to a "F" but in my case I wont because it may be a waste of time. I don't run that fast and only use it for fishing. Good luck with the rebuild. Gil