hurt the 401 nailhead!!! need ---9:1 forged pistons/bearings

pulled the motor out of the car to finish painting the car. i decided to pull the motor apart just to replace some gaskets. WELL... i will need rod and crank bearings, machine the crank, already.010 under. and going to swap out the pistons and rings for a forged set with lower compression. had a faulty oil pickup a few months back and didnt think it did any damage. well glad a didnt spin a bearing. the motor had no noise at all.. no knocks. do they sell clevitte bearings for a 66 401? anyone running 9.0:1 forged pistons? tring to get this car painted and put back together before i get married in july. really like to have it finished in march. just sold my 53 international to pay for paint and some new engine parts..

Paul
66larkgs

 

why 9.0:1 do you want to run 87 gas and not 92

 

i am going to be bumping up the boost from 7psi to 10-12 psi. i have a friend in conn that hits his nailhead with 15 psi at times with meth injections.
i just want a nice friendly compression ratio. i am not building a race car but a real nice driver with a turbo that will make TONS of torque and when i want to bump up the boost i dont want to have to worry about to much cylinder pressure.
paul
66larkgs
turbo buick nailhead

i saw you stroked yours, what did you use for parts?
what type of pistons and from where

 

Paul, that's a bummer....
Rod bearings are the same as a 455. I don't believe any of the major manufacturers make MAINS for the Nailheads, but it's been a few years since I checked. Tom T (Telriv) would know what the current offerings are.

Joe has a thread titled 'having a mini stroke' with details about his build.
http://v8buick.com/showthread.php?t=217336&highlight=mini+stroke

.....JE pistons in Joe's build. Diamond is another supplier of custom pistons.

Edit: specify MAIN bearings

 

Well,,,, if,,, you buy a full set of pistons... you can use the regular stock spec. forged ones and a set of composition gaskets to come up with a cr very close to actual 9 to 1....
Buick advertised 10.25 to 1 for 401/425's but when you check ''actual'' they are closer to 9.25 with the old steel head gaskets that were normal back then at about .020 or so thick... with a gasket that is .o35 -.o40 ,, you will be close to the 9.0 that you want....just dont mill the block or the heads....
Double check those cam bearings,,, to make sure you did not spin any of them... do,,, do,,,,do replace the cam bearings... they are THE oil pressure....if you dont,,, the engine will have low oil pressure from the git go....and it will only get worse....acquire a old cam and make you a reamer tool out of it to use for reaming the new bearings in case the new bearings are too tight.... all you have to do is cut a L shaped cut into each bearing journal , to the right , so the tool will cut as you turn it to the right with a ratchet as you ream the bearings....
Replace the oil pump... it has had metal chips run thru it... the oil filter will not get all of them out of the oil....
Use zddp additive each and every time you change oil and filter....
Back in the old days, I have seen mechanics lower compression by using 2 steel gaskets stacked one on the other.. and painted with aluminum paint.... but this makes it really hard to remove the heads later because the paint ''glues'' them to the block.... not fun if you have to pull a head.....

 

thanks Walt. didnt know you were going to have so much boost, that engine will make mega power,nice.

 

When I calculated it, I came up with around 9.9:1 with a steel shim head gasket, and around 9.3:1 with a composite gasket.

Paul, what kinda cam are you running? Have you looked at what kind of dynamic compression ratio your combo would provide?

 

Andy's numbers are about what I've come up with as well.
Stacking steel shim head gaskets is done by the Turbo Regal guys..... but you would have to stack 3 of them to equal one 0.045" composite gasket.

With forged replacement pistons being in the $600+ range, I can't imagine customs with a lower CR would cost much more.

DCR numbers start to become irrelevant when you are adding boost. But they will give an indication how it will perform off-boost.
You'll have to decide if you want nice, crisp throttle response before boost (higher CR and mild cam), or maximize performance under boost with a lower CR (8:1) and run high boost levels.
I'm curious what the turbo experts would recommend!

 

with that i am running low boost 7-12 psi i dont want to be below the 9.0:1 - i want to drive it as a driver and with not enough compression it will be a dog @ 1000-2000 rpm's.i am thinking 75% driving on the street ,25% track and autocross. i think i will most likely autocross more than dragracing just because the xcross is closer. i am hoping depending on what piston i am running to be in the 9.0:1-9.3:1 compression ratio. i do have a new set of .040 composite gaskets and will be buying a set of forged pistons. i have never heard of stacking head gaskets but it makes sense. i pulled the cam out and check the bearings and they were worn but not wiped. i will be putting in new cam bearings and a new turbo cam. i wouldnt mind mini stroking it .. how much more power do you think you made with the mini stroker setup you built?

Paul
66larkgs
turbo 401 nailhead

 

its hard to tell, did some other things like better heads one step bigger cam. glad i try it once but would not do it again, not worth it. my engine builder had some used rods that he was kind enough to give me at the time.

 

i spoke to the machine shop today and he highly rec ross pistons. will be ordering pistons within the next day or so. Has anyone has comp cams do a custom grind cam ??? i emailed them and havent heard back yet but they are ussally pretty quick with a response. Block is just getting a ball hone to put a little cross hatch but the cylinders are all perfect. i will be touching up the head ports but just gasket matching and cleaning up casting. i firgure if i am make alot more power it will be with boost and the right cam for the turbo.

Paul

 

When I emailed Comp about a custom grind they got back to me within a few days. Maybe it'll talk a little longer since its so close to the holidays. The only thing the guy I spoke with mentioned, was that it usually takes them a few days to get the core in stock.

 

Just be advised,,, When I had a problem with a comp cam,,, they had a real beligerent, arrogant attitude about it... after about 20 minutes of this,, I finally gave them a railroad chewing out....but they did send me another cam....:Brow: :Brow:

 

i got a lot of custom cams from comp, always by phone. docs right i called a few times just to get some info the guy wasnt very good. i would call back for a different salesman they were good. comp has a new thing were they harden the cam it costs more but well worth it.

 

Back in the day, the term used was ''flame hardened'' then later the term was ''tufftriding'' and then all the aftermarket cam makers came out with all that ''run it up like a B29 bomber engine'' , horse puckey.....ou: We were taught to just start a engine and ''let it idle'' untill it warmed up , then set the timing, carb,, ect. and dont shut it off untill it loosened up some....never, ever lost a cam doing this.... obviously better made cams back then.... not better grinds, but better made cams.....

 

block is off to the machine shop tomorrow. He was backed up a month before i could drop it off. I guess thats a good thing. i have not ordered the pistons yet but will be shortly due to i want the machine shop just to double check everything before i order $800 worth of pistons. If anyone needs a set of .030 cast pistons they have very little run time and maybe 2 miles.. $100 shipped. i am excited to get this motor back together but i think it will be early march before it is all back together. came to term with the colors of the car where it will be two tone a dark red and even darker red. i have the rendering and would like post for opions.
Why question is should i paint the engine the same color as the car or a powdercoat most of the engine black and heads black and finned valve covers,valley pan ,in the red or chrome.
Thanks as always guys

Paul
66larkgs
turbo 401 nailhead

 

Paul i would like to be first in line for the pistons that your selling (im sure you will need to move that to the for sale section under the board rules). thank you. dan

 

i didnt want to break any rules but i figured i would rather give a great deal to a fellow nailheader and not someone just searching forsale section buying cheap parts and than reselling them.
Paul

 

well i would love to have them for when i start rebuilding the motor in the 66 gs vert im restoring for my mom. i picked up a running 65 401 to get the car on the road but im definatly gonna need pistons for the original motor.

 

just got the .040 401 back from the machine shop. Had it balanced and a set of custom ross pistons,total seal rings.ARP main studs install, ARP rod bolts and ARP cylinder head studs that i am going to install tomorrow when i start assembling the engine. I cleaned up all the ports on the heads and just got rid of all the flashing from the casting process. we dropped compression to 9.2:1 and looking to hit it with up to 15 psi boost. i can post up some pictures before i assemble.i was thinking of doing a step by step assemble with pictures to document.Cant wait to get this back in the car and hoping to have it in the car within a week or two.
the motor took 5 months at the machine shop.. was starting to get ichy for it back
Paul
garret t67 turbo
on buick 401 nailhead