Thread: newbie bbc owner in jetboat

Tweet

Hi, this is my first post of what will probably be many.... Let me first start out by saying that this is my first BBC and I absolutely love it. Im currently running it in my jetboat.Im running a 1979 mark iv 454 with 049 heads. Im not sure what if anything has been done to the engine other than I know that its a Hardin Marine engine... It came with a dual point Mallory dizzy and Holley 850 double pumper. Holley mech fuel pump and Hardin Marine log/snails exhaust.
After the first season of owning the boat/engine which ran pretty good, I wanted to do some upgrades. During the winter I ditched the Dual points and added a Pertronix unit. I went ahead and ditched the old looking Accel wires and install a set of Pertronix wires too. When it came to spark plugs I took my set out which were Autolites (which im not a fan of) and hit the parts store. I found out there that the previous owner install the wrong plugs which were the bigger plugs. I ended up going with the smaller NGK yr5s gapped to 35. The engine really liked the new additions. Start ups were quick and it ran smooth from idle to about 4200 which was my max rpm. After those mods I found a good deal on an intake and installed an Edelbrock HIGH RISE dual plane intake to replace the very low rise stock iron anchor intake. I couldnt believe how heavy that thing was! Bolted up the Holley and the rat like it even more. The engine had more overall pep than before. (Im not sure about how much hp was gained but Id like to say it was noticeable). The last modification was a to the jet pump that got the boat out of the water some which let my motor spin a little higher on the top end from 4200 to about 4700rpm.
Ok, so thats where I am at now.
I ran this set up going on year two with no problems.
I should note that when I first bought the boat I did a compression test and all cylinders were close to the same, with only the #8 cylinder being about 7.lbs lower. That spark plug was a little heavy on the oil too.
On the subject of oil I run 10-30 synthetic blend along with some Lucas oil that a buddy gave me to try. He claimed it made his jet run better so I gave it a try. My engine always made some valvetrain noise so just for kicks I added the Lucas stuff while the engine was warmed up and running. I noticed right off the bat that the engine quieted down and seemed to run smoother. I definitely heard some ticking go away about 30 seconds after adding the stuff.
Anyways not trying to be an infomercial here....
So this year I did no mods.... Everything running as usual except the valvetrain noise has been getting louder lately. From about idle to 3k everyting sounds fine.... then from about 3500 on up it chatters. Chatter goes away when I let of the gas.
I did some research and found out that I could adjust the lash on this BBC so I went ahead and did that. While I was in there I checked for correct torque on head and rockers. I have a hydraulic flat tappet cam with stock stamped steel rockers. Single valve springs with dampeners.
This is what I noticed while in there... When I removed the rockers I could spin the valve springs. I mean that I could spin the springs with my fingers. Exhaust and Intake springs.
Is this normal?

Welcome to the forum. We'll let some of our BBC experts like Pat, Dave, and others give you a professional opinion, but my first thoughts are that the valve springs are just tired. Your valves might also be tuliping, sucking into the heads a little. Boat engines run at 4500 or so rpms all day long, and that is like taking your car and going down the expressway at 100 mph hour after hour. Boat motors age much faster than car engines because of that fact.

Now we'll see what the guys who really know have to say.

Don

hey thanks for the quick reply. Yeah I know it asking alot for a Big block to run in a jet. Im not sure when it was last rebuilt either. Its a weird feeling to full throttle a big block. I try to be good on my stuff too though. I never stab the gas and I dont tend to full throttle it for a long time because Ive heard bad things can happen for long periods of wot. I tend to limit it to 30 sec max wot runs. I can get on plane around 3k and I like to cruise there. I live next to a pretty big lake so long trips are a plenty.

Ok thanks..
Ive checked the rockers and pushrods for wear and they look fine. I have some pics if interested?
Could I just install some new springs in it to get me through the end of this summer or ?
I measured my valves and they are 1.5 o.d. and it looks like 1.880 installed/not compressed.

Sorry Pat, I thought Dave was a BBC guy. There are tools you can buy that allow you to change valve springs with the head installed. You pump compressed air into a cylinder, then you use the tool to release the valve keeper. You can shim the springs to get some more tension on them, or replace them with new ones. Pat can advise better on that though.

Don

Originally Posted by Itoldyouso

Sorry Pat, I thought Dave was a BBC guy. There are tools you can buy that allow you to change valve springs with the head installed. You pump compressed air into a cylinder, then you use the tool to release the valve keeper. You can shim the springs to get some more tension on them, or replace them with new ones. Pat can advise better on that though.

Don

On old airplane recip's in the Navy we had to pull the rockers and springs for inspections - had a length of heavy nylon rope, the woven kind, that we fed into the cylinder with the piston down, then rotated the engine to bring that one up toward TDC to fill the space with compressed rope and hold the valves. Liked it better than air, as on those big old cylinders you could sometimes overcome the compressed air charge breaking the keepers loose. Never done it on a car engine, but some 1/4" rope should work fine, I would think.

Originally Posted by Itoldyouso

Sorry Pat, I thought Dave was a BBC guy. There are tools you can buy that allow you to change valve springs with the head installed. You pump compressed air into a cylinder, then you use the tool to release the valve keeper. You can shim the springs to get some more tension on them, or replace them with new ones. Pat can advise better on that though.

Don

Aww geez Don.....you put a knife right through my heart!!!!!I'm the guy who deals with the superior BB, the BBF!!!!! But I am gonna get Pat to do all the machine and setup on my new one.... Pat's one heck of a guy, gonna build me the Ford that'll whoop up on his goat!!!! Anyway Don, no offense taken, here on CHR I've been called things a lot worse then a BBC guy!!!!--and I only wish I had the kinowledge on engines that Pat does!!!!

normal ? no it is not .... sound like time for some valve train work new rockers they get mark that looks like this C in them from the valve stem s in time the rocker moves in and out of lash springs that loose will suck the valves in the head s sounds like a valve job and better valves as well DAVE ?? is a bbf guy

well it would be nice for a up grade on valve springs .your going to have to loose the ex rotators to put a better spring in well i would any ways may be some work with the heads on engine could be done .as for asking for a bbc to run at wot all day well 3500 is not asking to much from a bbc .so you need some good stock valve springs .a tool to compress the valve spring on the head .a way to put air in the head . a rubber head hammer to give the springs a good tap to un seat the valve locks as they take a set and will not come off just get pushed down with the valve spring .a good time at this point for new valve seals . yep it is a boat.. i am sure he as some rope how you hold the valves up is up to you but first un seat the keepers first

I'll mix a little thought for you---

Change the springs( In a jet boat engines are easy to work on) now and run it for the month then take it down over the winter---I have seen engines in jet boats hammer all the valves up into the ports so bad from heat/detonation from pulling all that power/load at lower rpms---the loose springs could be a sign of that

And I do BBC, BBF and others also!!!!!

We started going strictly to stainless steel valves because even on heads that we had rebuilt we were seeing short life with regular valves. They were pulling into the heads. It added about $ 10 per valve to the cost, but we never had another comeback after doing that. Boats are just a totally different animal than cars, even though they are using essentially production line car engines in most cases.

Don

Do these look about right?
http://www.summitracing.com/parts/HR...n/?prefilter=1

yes the 98515 spring and i concur with my esteemed colleague . MR J Clayton . yes boats are not USED the same as car engines . boats are hard on Valve train . i wish i could say i did not know not one thing about boats.... BUT i work at a boat yard one of the biggest in mich over two miles long.. EZ 6 boats a day i work on from 17 foot to very big $$$. even lot of the cheap valves are a mix of alloys some what S steel the new Sbc are very thin from chevy new and most of the time the stock intake valve can not be re ground less you need a new blade to shave your face with. they sure will pull threw the head but if the springs are weak the best valve can go to cup

ok so I am really confused now.........
I did some research and reading and come to find out that I have rotators on the exhaust springs side.... Do I ditch these or run them again? Do you ditch the rotators and run the antirotator with the springs previously mentioned in the earlier post?
Also, how do I figure out what correct spring rate I need or is that not critical in my case? If someone could direct me to the correct part, Id really appreciate it.

THEM ARE STOCK SPRING S you have a stock cam ? use them just put them in .. . if your going to put a better spring in more for hi rpm them you would ditch the EX rotator eliminators how you want to do it thats up to you if your pulling the heads at the end of the year then that is time for the upgrade