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safe redline for 401 nailhead with 115k miles

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thank you guys for the comments and encouragement...

i am a little angry at myself today as i took a bunch of pics when i was doing this work 2 years ago now, and for the life of me i cant find one of the camera cards some of the pics are on.

i snapped a few this morning to try and show a little work and will continue to look for the card...

here is a pic of the duluth mn - superior wisconsin harbor on my morning commute- 20 below this morning

that is lake superior off in the distance frozen about 20 miles out

also have been busy cutting firewood. i heat house pretty much exclusivly with wood. use around 5 to 7 cords a year. it must be split and put in woodshed by spring to dry over the summer for next winter.

house is much warmer and nicer with giant used windows in, more insulation and new vinyl siding.







Edited by 65wildcatconvt
spelling again ha ha (see edit history)
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here is a picture of what the car looks like generally underneath before painting but after many cold hours in winter lying on your back with a wire brush , drill with wire wheel and various scrapers and screwdrivers to try and clean off as much loose scale and loose rust as possible.

but i always try and remember, "hey my labor is free" what else would i be doing? maybe getting into trouble.

this is a pic taken more towards the front of the car this morning so you can hopefully see what it looks like before and after paint.

tools used on whole project are wire feed welder, cheap 29 dollar jig saw, cheap 29 dollar electric cut-off tool and common hand tools.

as you clean and poke around like a dentist, you can find any weak spots and mark them to cut out if new metal needed.

the front half of the car seems to be in somewhat better shape than the rear... this is really solid and pretty clean by up north standards for 50 years old.


Edited by 65wildcatconvt
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Great car, and good looking pup too.. We had to put down our Husky Lab mix breed back in 2000 and still miss that dog. Anyway, good luck with the car, and all your other projects too.

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ok - i took these pics this morning of work and paint done 2 years ago.

this is a piece of steel welded over the rebuilt rear body mount. i sprayed some primer on it just to protect it as i want to go back and regrind some of my crappy welds when time permits, which is why i held off painting the entire trunk also.

remember my main goal was to keep the car drivable in summer if possible, so may of 2013 after taking out gas tank, rebuilding 4 rear body mounts and painting the rear 1/3 of car, it started to get nice out so i stopped work, put painted gas tank back in and car was drivable over the summer.

the gas tank will not have to be pulled again although there is some small cosmetic work to be done to make rear body mounts look better.

its hard to see but the steel is butt welded and should blend in decent with a little more elbow grease, which i can do as time permits in warmer weather while car is still usable.


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here is a pic of homeade body mount made from 1/4 inch angle steel and a pcs of plate first welded to it inside from the top.

these are the pics i have not found yet so i apologize for the poor photos.

basically i ran steel from the inside of the existing body brace after cutting out all weak metal. then followed the path to where the body mount connects to the inner rear fender if that makes any sense.

after getting this far, i then realized i can make another pcs of plate to tack over the angle steel from underneath, and with patience and some grinding i can most likely make it look very similair to a body brace.

the key thing for me is again, i can do that when free time comes up and car is still drivable.

the silver paint is 2 year old rust bullet, but not painted heavily around body brace as i know i will be working on it more...

any black paint is rustoleum spray satin black which is just sprayed over the rust bullet as time and money permit.



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now when i first got the car it ran poorly, but after getting it home and getting it running strong, but before doing any metal work i ran into a problem.

when acceleratng somewhat hard maybe half throttle or more, the car would have a shudder or almost felt like a wiggle to it.

at first i thought - ujoimt or driveshaft carrier issue or what? it just felt weird...

so when crawling around under the car i yanked and pulled on driveshaft, ujoints etc etc but everything seemed ok. so i just drove the car easy that first summer...

well you guessed it but after fixing 4 rear body mounts, i took the car out in the spring of 2013 and lo and behold 75% of the shudder was gone... now it would only have a mild shudder under almost full throtle starts.

so those rear body mounts were pretty much not mounting anything ha ha.

the rest of the shudder was eliminated as i moved farther up the car the winter of 2013- 2014. will try and post those pics next.






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To get back to the original subject.....DO NOT put off doing the timing chain and gears another day! The original question should have been.....what is the redline on my loose

chain and plastic teeth timing gear?

Edited by Seafoam65 (see edit history)
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Agreed! A worm OEM timing chain is a "non-ticking" grenade for the engine. Definitely "cheaper" than fixing or finding another engine (and then overhauling it before you put it back in). You NEVER know when it's going to "go", either. At 100K+ miles, I would hope it's already been done, but they are cheap enough (parts wise) to replace and then KNOW all is well in there.

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The nailhead as what you call an interference fit engine. A valve in the wrong position in relation to the piston will put the valve through the top of piston in a heartbeat. Especially if your cam gear has lost its nylon covering for the teeth. My engine seemed to be running fine, but I never pushed it rpm wise. Upon tear down, all of the nylon was in the oil pan.


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alright hey thanks to everyone-- so much great info from everyone.

the roads are solid salt up here still for about one more month and my car is up on blocks, so it is staying there until timing chain and tranny maintenance is done.

im not saying i am buying from rock auto . com but do any of you guys have an opinion on what you would buy of the 3 chains offered... they are down to one gear so kind of wondering where to buy a decent set, brand name, etc...

i will pick up a set as soon as i get my tax refund and will probably start another thread about doing a timing chain if that would be alright, i have a general idea but dont want to mess it up as i have not done one on this engine before.

Edited by 65wildcatconvt
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Summitt Racing, search: 'buick 401 timing chain'...may come up as for Ford, but click 'check application' to see Buick stuff. A lot of replacements are sloppy loose and the best ones I have found are old stock from when these cars were contemporary...you can spot one of these from the elongated box vs ones that will fold to fit in one hand, like this one: http://www.ebay.com/itm/1967-1976-Buick-400-430-455-timing-chain-/331156999236?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4d1a7ecc44&vxp=mtr

Gears? Just check that the teeth, keyway and timing mark is clocked exactly like your original.


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The first one I bought was sloppy loose. I sent it back and got one from someone

else and it was tight....can't remember who I got the tight one from. The loose one came from OPGI.

there was a very good discussion on changing the timing chains on these engines on this forum last year. Do a search and you will find it.

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