Venturing into performance upgrades for an AQ271C

[PiratePast40]

Re: Venturing into performance upgrades for an AQ271C

Awesome - didn't want to see someone running full speed on a project and then have to hit the brakes.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

waiting for the weather to warm up a bit. pulling the motor without heat is not fun.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

weather is hear. motor comes out this weekend.

need to assemble an A-frame in place around the boat.

psyched......

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

motor is out. due to other projects, didnt get it mounted on the engine stand yet. will happen shortly.

 

[captmello]

Re: Venturing into performance upgrades for an AQ271C

No Pics????

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

havent uploaded them to my webshots account yet. will do so later tonight

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

here is a link to my webshots page.

http://community.webshots.com/album/582479054oAGiOJ

took the day off to pull the motor apart today. cleanest engine I have ever pulled apart. now to find a blast cabinet to strip of the sheet metal. going to start scuffing the existing paint on the flywheel adapter, etc.

 

[captmello]

Re: Venturing into performance upgrades for an AQ271C

Looks good. What upgrades are going with? Vortec heads/new intake, new cam? roller cam/lifters/rockers?

I'm thinking of freshening up my 350 soon as well, but I don't have the experience...So I'm watching you.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

going with all the above as well as a 2" carb spacer, and ultimately a set of CMI E-top tubular manifolds/headers

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

just spent a BOAT unit at Summit Racing. The cam was cheap compared to carb tuning items, roller rockers and gaskets. Have a pile of primed and painted parts in the garage.

 

[captmello]

Re: Venturing into performance upgrades for an AQ271C

I saw they had the "Extreme Marine" cam/lifter kits for 700-1000. Did you buy one of those? Why/why not?

I can see where this could start adding up...

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

the Comp Cams extreme marine flat tappet kit for cam and lifters is only $200. add $40 each for the head gaskets, $340 for the roller rockers. add another $300 worth of gaskets, carb stuff, timing chain, oil pump, etc. and we have $980

I kept it flat tappet vs going with a retro roller.

 

[captmello]

Re: Venturing into performance upgrades for an AQ271C

Ouch, your halfway to a re-manufactured long block.

So, you're staying with the flat tappet cam and lifters, but going to roller rockers. Was this a budget thing or what. Sorry to sound dumb, but i'm just trying to understand which of these mods are really necessary, and which are not.

Thanks again for sharing your project.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

none of them are "necessary", however I will most likely be building a 383-406 short block in a year or two, so the remainder of the upgrades are building a foundation. Cam and heads are the majority of the power upgrades, the roller rockers are could have been just roller tip, however the best reduction in valve train friction comes from the fulcrums.

Plus, they look cool.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

UPS truck brought me two boxes of goodies yesterday from Summit Racing. realized my exhaust gasket was qty 1, not a set of 2. so ordered another exhaust gasket, and a carb mounted throttle bracket. the old cast-iron manifold had two mounting bosses for the throttle bracket/coil mount, the new aluminum manifold doesnt. May weld on a few bosses to the manifold, vs the carb mounted bracket. not sure yet.

Camera broke yesterday - wont power up with batteries (but will when tethered to computer). sorry no pics for now.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

so far, its been a weekend from hell. load up the car friday morning with heads, intake, boxes of parts from summit, tools, fiberglass supplies, etc. drive the 85 miles to my bud's place where the engine block is.

go to install the new cam, oil pump, etc. the oil pump intermediate shaft is not in the box of parts. then looking at the heads, there are a few broken dampers. could see a few of the valve seals with damage from the broken dampers.

drive the 85 miles back home, grab my valve spring compressor, hit the speed shop for an intermediate shaft, a set of valve springs, and a set of valve stem seals (for a size I assumed the heads were machined for - based off what the prior owner stated they were machined.) get back to Sturgeon Bay, pull the valve springs, and the valve seals are the wrong size. the valve guides were machined to .500 not .562"

Saturday morning, head to the only speedshop in a 100 mile radius that is open, grab another set of valve stem seals.... drive back. spend an hour making a valve stem seal pliers...... damaged the first one, so the longblock sits without heads.

off to the local speedshop to have them install the valve seals on Monday. will spend the remainder of the day working on the engine mounts.

 

[captmello]

Re: Venturing into performance upgrades for an AQ271C

sorry to hear about the troubles. Sometimes you just wish you had stayed in bed...

Hopefully, those will be the worst of your problems. I was suprised to see you hadn't had the heads gone through by a machine shop.

I store my boats 30 min away, just on your side of the river in fact. It makes it that much harder to get things done.

Hope you have better luck with the motor mounts.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

spent an hour scraping carb gaskets. someone in the boats last 24 years installed an 8.5 power valve and changed the secondaries to 85's. carb should be 2.5 power valve and one 80 and one 90 secondary jet.

that explains the fuel consumption at part throttle.

carb going back to a 2.5, however I will have my trusty vacuum gauge handy when I finally fire it up to be certain. will be starting off with the stock 74 primaries, and then converting to 90 secondaries for the initial tuning point. the designers of the holley carb were geniuses. can not get much simpler or easier to tune than a holley carb.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

got the heads installed this weekend. forgot the roller rockers the first trip north :facepalm:

after heading back up with rockers in hand, measured the pushrods with the sharpie process.

so, the witness marks are just south of center, so I will be looking for slightly shorter push rods


here is a link to the sharpie process http://www.circletrack.com/techarticles/ctrp_0609_pushrod_length/viewall.html

worse case, if I cant find a hardened shorter pushrod, will run stock length. better to be just a tad too long, than too short.

 

[Scott Danforth]

Re: Venturing into performance upgrades for an AQ271C

update.

pushrods came in, so I thought time to set lash.
borrowed a priming tool, rotated engine a few times and set the lash using the 8-stop method with priming between stops to keep the lifters pumped up.



Ran into slight obstacle, the stock iron manifold had bosses for mounting the bracket that holds the throttle cable, coil, and circuit breaker. the new manifold does not. New manifold also only has the spreadbore mounting pattern and not the Holley 4150. so I will need an adapter.

I picked up a generic carb mounted throttle bracket and plan on the spacer/adapter. not sure I want to use this, or make a custom spacer/bracket/etc out of aluminum plate to mount the stock coil bracket, etc. leaning toward the later if I have the right thickness on hand.