Engine clean up

claudio

claudio

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I have a 69 pontiac firebird with a pontiac 350
Engine on stand and disassembled ( well crank rods n pistons still there.....
Everything else removed)
Want to know how to clean sludge from internals with out removing the crank shaft
Want to clean oil galleys and in side block also how can I dress up cylinder walls They have some surface rust
Any do's and do not's.......

Thank you in advanced
 
dont know how you are going to do that without removing the crankshaft, the oil passages go to the crankshaft.
are you measuring the bores to see if they need to be machined, same thing with the crankshaft journals, not measuring anything?
 
Ok had friend come by and he looked at my motor
Rust bad in cylinders it's in area where piston makes power
So block will have to be punched out
After further inspection I found a 4 0 on all the pistons
Block is 40 over what is limit on bore size for pontiac...?
What is the standard bore size...??

I found another pontiac 350(1970) that I'm inspecting now it to has bad rust stains in few cylinders(not as bad as my 69 block) and top of pistons pitted. I try to measure the ID of cylinders of both blocks and I think I did it wrong.... They both came up as 3.86 3.87 it is third number that kept changing but definitely 3.8 on both blocks...????Only one of the eight pistons has numbers on it {2270P STD-S and an arrow to FRONT } the rest just have a single number and letter. This block is a 1970 pontiac 350 with five motor mount holes.... If I can save it can I use my 69 heads on it...??
Any major differences between 69 and 70 engines...??
Thank you again
 
the bore of a Pontiac 350 is 3.875 . You would have to have the block sonic checked but a 400 has a bore of 4.120 and has the same stroke. The two years 69 and 70 are basically the same, heads will fit. (92 Sunbird LE is correct you are limited to .060 which gives you a 365)
http://www.wallaceracing.com/boresizes.htm
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The maximum oversize bore for a Pontiac engine is .060" regardless of the original bore size. The maximum OS bore for a 350 CI Pontiac engine is 3.935" for a total displacement of 365 CI.

Block would need to be sonic tested as Mel said to see if the block can handle that overbore.

Doug in P.R.:cool:
 
Ok thank you
The 70 block is standard bore so I can open it further...
I have 69 350 heads at machine shop already
Can I use them on a 400 block..???
Are all bolt holes the same on 350 and 400 blocks{timing cover -oil pan -oil filter adapter - motor mounts bell housing bolts etc.}
Also I have gaskets oil pan oil pump cam n lifters timing set hei distributor and more all new and for pontiac 350.... Can any of it be used if I got a 400 block...??
Thank you
 
Good morning
Bin looking for more 350 blocks but not much luck I have seen many 400 and 455 blocks. I've heard of putting 350 heads on 400 block but I don't know what heads.
Every thing I have is for a pontiac 350. My heads are almost done(at machine shop) trany(pontiac 350 auto) at trans shop...
I can take my 70 350 block to machine shop but then my bill grows bigger
Spend money on a 400 short block and put together using my parts..???
Just don't know of the differences between 350 and 400 block aside from cylinder size....?
Thank you again
 
the 350 and 400 blocks are the same as far as attaching all the parts. Which 350 cylinder heads do you have http://www.wallaceracing.com/head1.htm
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I have cast number 47.....
Few valves replaced new springs -guides-screw in studs n guild plates -cleaned n no cracks
Should be ready soon
 
they will fit the 400 block but they are small valve low compression heads
 
So I should just bore my 70 pont 350 instead of hunting down a 400....?
Bore hone replace cam bearings block cleaned crank clean n polished new pistons n rings
Do I need anything else...??
Also I'm cleaning n smoothing the valley and removing flash any thing else I should do...?
This is all on the 70 350 block........
 
that is your decision to make, the machine shop has to sonic test the 350 if you are going to overbore it, have you looked for a 400 block or complete engine. You could compare the cost of all the machine work on your current engine versus buying a complete 400.
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Ok update....
Not going with 400 because of my heads
Going to bore n hone the 70 350 block
In mean time I have started to clean n smooth the valley
Any thing else I can do while in there...?
Thank you
 
I have that book......
Basic disassemble and reassemble
Some basic tips and stuff
I read on internet about smoothing valley
Book doesn't mention that one....
Just a whizz wheel n lots of cookies till smooth..???
Dermal for corners n flash removal...
Wire wheel for heavy crap on outside....
The rest will clean up when machine shop cleans it....
I was just wondering about any thing else I can do...
 
Last edited:
By the "book" ......
Block stripped freeze plugs out
Trying to get all loose crap from water jackets.....
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Unless you are racing the car and need to make sure you have full oil return back to the pan cleaning up the valley will not gain you anything.
 
you seem to have everything covered, all new bearings, pistons, rings, crank polished, etc. For a daily driver thats about it. One thing you didnt mention, new oil pump, and water pump.
 
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