Photos are of a 308 Holden. that had similar work done to our story.
Old school is definitely back in fashion, from a good old solid reliable and much loved 350 Chev, 351 ford Clevo or windsor to a rock solid holden 308.
Here in Australia when we are playing old school this is what we seem to love playing with.
Quiet simply we Aussie's love bang for our buck ! ( apart from a good beer or a good Bundy rum.)
So in this Blog I'm going to share some trade secrets and tips on getting the most out of your best mate in the shed:
Ok lets start, the old girl is tired: bit slow, low on compression, you have thrown a carby kit, plugs, leads, dizzy cap and points at her and she still doesn't want to tune up as good as she used to ?
1st point and most important point is times have changed dramatically and older parts are now more expensive to purchase new. Labour is more valuable and knowledge is your engines biggest improvement and your hip pockets saviour !
So we have stripped, " say your 70's 350 Chev " down. for your HQ Holden Monaro: it needs to be cleaned. so it looks like brand new. acid bathing parts and ultra-sonic cleaning the bits that do not like acid. removing (rust,scale,paint,grease,carbon and chemical sealants) internally where you can't see and externally.
you want it to sound tough but with drivability and have some Balls about it but not too crazy.
So we look at cylinder heads and cam packages ? to suit individual needs.
Lets say we want originality good performance and turn key she starts:
Rather than going to town lashing out of some nice polished alloy heads ( which the choice is yours you can if you wish, it all comes down to what you want to spend $$$. )
But in this case we reco your original heads. clean them up and open the ports a little, insert the valve guides and machining the seats to correct angles to take an over sized valve, 0.8mm to 1.mm approx is usually a very comfortable zone. we check our surfaces and they look not too bad so we only decide to take enough off to get them perfectly flat again in this case 0.002" - 0.004". valve heights are also checked and valves machined to suit if required also.
So heads are then prepped painted and finish assembled with new stem seals and springs, retainer collet's as per our cam kit package.( later on mentioned. )
Bottom end, machining wise measure up crank, it is at std "Yea-Haa", we grind the crankshaft to .020" thou on the main and big end bearing. As the old crank had some wear and grooves.
The block bores measures up after being cleaned at std size with about 0.004" ware and some marks in it. " woo-hoo ! " lets go out to .020" over size on our pistons, to keep our numbers all fairly even on the spec sheet. ( not that this matters, but looks cool on paper.)
Set up, Bore & hone the engine block to .020" over size. lets go some nice flat top pistons raise that original compression a little bit.
Lets now have a look at the surface of the engine block where the heads bolt down to your head gasket mating surface ? looks a tad crappy. ( Ok lets plan and return to that later).
check our connecting rod big ends ( where the bearings clamp. ) looking for shape under clamping force. As we learned earlier our crankshaft had grooves and marks in it, the big end bearings would have been bad and could have affected the connecting rods. so before we spend the time and money re-shaping our con-rods lets check to make sure they are straight not bent of twisted.
So we now set up and reshape each individual con-rod as they pass all other tests apart from a couple of rods being a little out by a few thou on the big end area.
lets pop a new piston on our con-rod and dummy assemble our bottom end carefully.
Now we can check our piston height and all of our specs and realize we have 0.023" block deck height clearance.
So remember our top of engine block that looked average and needed machining ? This means we can take a little more off than just a couple of thou to clean it up, but say with still good valve clearance, lets machine 0.013" from the deck surface (engine block face area. ) This very safely raises our compression a tad more and also adds to our bang for our buck theory.
Now everything has been machined and ready to go together lets check our list of parts.
full rebuild kit including :
* pistons and ring set @ 0.020"
* new main bearings and con-rod big end bearings @0.020"
* new camshaft bearings std.
* new valve set @ over sized
* new timing chain kit.
* new oil pump assembly.
* new cam-shaft kit stg 3 old school terms. with springs and retainers.
* new hydraulic lifter set.
* new push rod set.
* new welsh plug set.
* new harmonic balancer.
New engine full gasket & seal set including:
* head gaskets.
* manifold gaskets
* timing cover gasket
* front crank seal.
* neoprene replacement rear main seal.
* new sump gasket.
+ other related gaskets for std assembly.
Now to get engines rotating assembly balanced: crankshaft, con-rods, pistons, harmonic balancer, flywheel etc.
Why balance an engine ?
As a nice balanced engine can pick you up to 20-40 rwhp, in some cases +more with the right set up.
They also run smoother, can use less fuel, but under acceleration usually produce's smooth clean crisp power.
Now everything is balanced lets get this engine built:
Our block is now painted, welsh plugs installed & sealed, cam bearings installed with correct tooling (yes there is a correct tool and procedure),
engine cleaned internally again with solution and lint free clothes , repeating this with ever part as installed.
Main bearings laid and anti ware additives coated on bearings, crankshaft installed along with con-rods with pistons etc. All with correct recommended torque settings, marking each bolt and nut every time a torque stage is met. If there are 3 stages your bolts should display 3 marks when finished.
Cam shaft bearing coated, Cam shaft lobes coated in anti-ware solution and installed. ( this is vital some vehicle especially with solid lifter type cams, if the vehicle does not start and gain oil to the rotating parts right away can rub out and damage a cam lobe while you struggle to find your starting fault. ) LUBE IS KING !
Lets install our new timing chain kit, due to new cam etc most after market kits are adjustable for large timing variances. We have our cam specs and install our gears where required, set up our dial gauge and degree wheel and dial in our cam shaft to perfect specs. ( some times this can take up to a over an hour depending on the engine and perfection etc. )
An engine with a camshaft not dialed in properly will never perform as great and it then wastes all of your time and money doing all the other little mods you have done along the way.
Now hydraulic lifters installed. The Lifter question is " most people say these days do not pre soak in oil." ( sorry I'm old school I still do). But only when the manufacturer says not too that i do not. )
Cylinder head surfaces cleaned multiple times and deck surface. lay gaskets with no additives ( good quality new gaskets usually have their own curing properties. ).
NOW time to torque down your head bolts, this is old school Chev, this means most bolts go into a coolant/water galleries. (They must be sealed.) Usually Hylomar, or aviation sealant by Permatex is great. And you can never use too much.
If you were building something where your bolts do not enter coolant it is recommended to use a product like arp thread lube or a little oil on threads and under the bolt head between the washer.
Ok time for push rods now our push rod length requirements have changed we have to dummy assemble some of our rocker train to measure and order the correct length push rod. ( which we had done earlier and yes there are special tools that can be used to do this. )
We assemble all of our rocker train, torquing, set loads or clearances as all required.
Now the fun part ? lets rotate our engine by hand. lol if you are a little of a dare devil place your thumb over the plug hole and feel the compression. lol ( yeah - now we are excited).
Lets now finish by fitting all of our final covers such as sump, timing cover, harmonic balancer and wait inlet manifold. ( oh - oh ) inlet manifold. remember we have taken some off the faces of our cylinder heads and some off the block deck face. Our old school manifold is not going to seal at this pitch.
Time to sit the gaskets down and do some measurements. In some cases the manifold has to now be set up in the mill and machined on the bottom and both head port sides to the correct angles. Keep in mind this is always bare minimum, try and let the gaskets take up where they can within reason for a nice seal. As this could affect how you distributor sits and seals also if you take too much off. ( These are all variables in which most times do not affect a build, but i am letting you know the possibilities.)
Manifold machined and installed. All up this engine is ready to be fitted to the vehicle by either our technicians or the vehicles owner. depending on circumstances.
Now i know what your next question is PRICE $$$
As all builds are different and individual needs are catered for the above mentioned scenario would set the Chevy lover back approx $6500.00
Well I hope this blog has been informative and helped with some of your questions about building your engine here on the Sunshine Coast QLD Australia.
Thank you for taking your time to read :
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