How to rebuild a V8 - D.I.Y.

Any questions or suggestions regarding restorations
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Re: How to rebuild a V8 - D.I.Y.

Post by drgfinger » Thu 26 Jan 2012, 22:58

If detonation is a real problem in that your really fuxored up the build , then consider water/water+methano/methanol injection or an octane booster - but you building for a daily driver - so I doubt it will be an issue
At any rate , its not just total timing that counts , its the way the timing comes in et that can be modded to give both deccent throttle response and enough retard to stop pinging.
The nicest thing about smacking your head against the wall is........the feeling you get when you stop!!

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Re: How to rebuild a V8 - D.I.Y.

Post by Tony69 » Fri 27 Jan 2012, 00:49

V-Hatchi wrote: Earlier when I said ''manipulate'' the timing, I actually meant retarding it etc would rob me of torque low down etc, and to me that would have been the band aid. :cry:
Band-aid? Not at all, you cant expect to run a high comp mill and not run slightly more retarded than lets say an 8:1 motor, its almost a given with any high comp motor. It's not a simple matter of turning the dizzy either, you gotta tune each advance circuit individually, and tune it for running not revving. The aim is to tune for peak but safe performance. It's only if your pinging is severe that this wouldn't work out.
Listen to Rodney, seems like were making the same point.

Running meth sounds a bit hectic for a streeter 8O but I get what youre saying there Rodney, if all else fails I'd do the same I guess. I've heard boosters dont really work, but I honestly dont know. :? Never used octane boosters & hope I never need it. :cry:

There are many small things you can do that'll have minor effects on reducing spark knock, all of which will add up.
But lets first see if you are pinging or not. shall we? :lol:

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Re: How to rebuild a V8 - D.I.Y.

Post by V-Hatchi » Fri 27 Jan 2012, 06:49

Good morning Gentlemen,


That's for Nick !! :cry:

Why ?

Coz he's talking the talk but where's the f$$kin' build ? :lol: :lol: :lol: :lol:

Once again, good points. Thank you. :D

Squish at 0.04'' rings a bell. 8O

If it turns out that I've ''fuxored'' ( :lol: ) the engine, I'll be taking the meths myself !! :lol:

The intention today is to finish the block ! :D

The rear welsh plug is still not fitted, so I'll take the block off the stand to fit it, and fit the fly wheel at the same time.

I picked up the degree wheel and piston stop yesterday so I'll use that initially to check the cam timing is to spec.

Using the piston stop in the picture means I have to temporarily fit a cylinder head.
I can't fit them permanently until I get the new springs and replacement valves. :cry:

One could make up a piston stop that bolts to the deck, which is cheaper than buying one.
Also, printing a degree wheel from the Tavia website and gluing it onto a board of some sort would also work out lekker cheap.

So without further ado. :D
Degree wheel.jpg
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Re: How to rebuild a V8 - D.I.Y.

Post by F100-(351) » Fri 27 Jan 2012, 10:08

Neek, well done so far.

This has now become so technical I think I will go have some meths in any case, maybe then I will understand whats going on here.

I see a hard time coming 8O to anyone that is gonna work on my V8 because I have a hell of a lot of AMO to use against them :lol: to actually see if they are worthy working on it :P :D

Keep up the good work.

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Re: How to rebuild a V8 - D.I.Y.

Post by V-Hatchi » Mon 30 Jan 2012, 21:59

Howzit Charles,

Don't tell anyone, but I started drinking Meths 2 weeks ago already.
And I tell you what, it works, as I started understanding things once taking it !! :lol: :lol: :lol:

It's all Tony's fault !! :lol: :lol: :lol:

If you want to test someone, ask them what the ring end gaps will be, and what crank compression they suggest !!
But make sure you know the answer before asking !! 8O
If you get a blank look, give 'em some meths too !! :lol: :lol: :lol: :lol: :lol:

Anyway, good news, the block is 100% rebuilt, fuel pump etc attached and 2nd coat of nice dark blue hammerite applied. :D
The build seems like it took for ages but in fact it was relatively quick. It was the studying, humming and ha-ing that took long. 8O

I used to use loctite RTV gasket sealer, but I've never liked using RTV. :evil:

The pic below shows Gasgacinch, which I'd never heard of until Edelbrock recommended to use it on the intake gaskets with their Ally heads.

What a pleasure ! :D

It applies easily.
You can use it over and over again with the little pad that's inside the lid.
(Unlike the RTV which solidifies in the cap after the first use :evil: )
And, when dismantling parts, it comes off in seconds with thinners (or equivalent).
F$$kin' awesome stuff. Love it. :twisted:

I used something similar, locally made, when applying the lower inner door panels but I forget the name of it.

Edelbrock don't make Gasgacinch, Gasgacinch do, and they confirmed that it can be used on the fuel pump, front cover, water pump and oil sump. :D
I'll know soon enough if it works 100% !! :lol:

Last comments about compressions and degree wheels.

The degree wheel is an awesome tool !

Initially, it's simply to check what the cam manufacturer specified with regard to the cam.
So if it said Intake Centre line should be 106 degrees, you can check.
But also, which I hadn't thought of, one can check the specified durations and lobe lift too.

My engine specs were 100% spot on. Nice ! :D

The ignition timing goes hand in hand with the crank/cam timing and it only takes a matter of minutes to check.

In other words, it's an outside measurement of what goes on inside ! Love it ! :D

We've been talking about Dynamic compression, so I thought while the degree wheel is doing its thing, why not check when the intake valve closes.
Comp Cams states it closes at 54 degrees.
The degree wheel confirmed it. Nice again ! :D

So WTF exactly is static compression ratio (SCR), dynamic compression ratio (DCR) and crank pressure (CP)?

Say the volume of the combustion chamber in the head is 50cc, and the volume of the cylinder with the piston at BDC is 500cc (Top of piston at BDC to top of cylinder flush with the block face (deck) ).
Total volume = 500 + 50 = 550. Head volume divided by total volume = SCR.
So 50 divided by 550 gives 11.00 : 1.00 ratio.
SCR is the commonly used ratio and it means f$$k all to anyone on its own ! :evil:

In real life, when the piston is at BDC, a valve will be open. There's no compression, there can't be, as any pressure will escape through the space left by the open valve !!

So in real life, where and when is the compression ?

It's when the piston is moving up the bore, and both valves are closed !!

When the piston is at a certain height in the bore, the valves are closed, so this is the volume to measure, not when the piston is at BDC.
So say the volume in the cylinder is now 400. DCR will be (400+50) / 50 = 9.00 : 1.00.

Both valves will be closed when the intake valve closes ABDC.
The cam chosen will dictate when the valve closes !!
It's piss easy once you know !
As Tony said, you can have a 12.00 : 1.00 SCR with no detonation depending on the cam !
I didn't know that prior to Tony mentioning it ! Thank you Tony. :D

WTF is detonation.
It's pinging !
Basically a noise in your engine that sounds abnormal is trouble !
That's what detonation is !! :lol:
(Ok, not minor detonation, but we're generally speaking!)

My degree wheel, my new best friend ( :lol: ), confirmed that the intake valve closed at 34 degrees, so I measured the distance from the top of the piston at that point to the deck, punched the number into the lekker calculator spreadsheet, and voila, gave me the DCR previously mentioned.

(Tony, that just meant changing the stroke figure in the spreadsheet ! Nice 'n simple :D )

WTF is Crank pressure then ?

It's the pressure measured in the cylinder at the DCR level.

Personally I think the crank pressure is the figure to use, and that the SCR and DCR are just general guidelines.
If the crank pressure is too high, 95 octane RSA fuel will not like it, and guess what, detonation. :cry:
I reckon a CP of 180 will be friendly with 95 octane RSA fuel. 8O
We'll know soon enough !! :lol:

And lastly for now, there's a pic of timing tape which I got from Summit Racing.
It will look a lot neater on the damper than the marks painted on them at present. :D
Timing tape.jpg
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Gascacinch.jpg (115.42 KiB) Viewed 898 times
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Re: How to rebuild a V8 - D.I.Y.

Post by V-Hatchi » Mon 30 Jan 2012, 22:01

I nearly forgot to upload a pic of the completed block !

:lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol: :lol:
Completed block.jpg
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Re: How to rebuild a V8 - D.I.Y.

Post by HenryGaB » Tue 31 Jan 2012, 07:30

:cry: :cry: :cry:

We wanna see.....
Pure unadulterated power, now that is the life....
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Re: How to rebuild a V8 - D.I.Y.

Post by F100-(351) » Tue 31 Jan 2012, 08:58

Neek, I see the block is tucked in nice and cosy. Dont pamper it too much, you gonna feel too sorry to put it back in the truck once done :lol:

I take it that the Gasgacinch is available from most V8 spares shops ?

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Re: How to rebuild a V8 - D.I.Y.

Post by V-Hatchi » Tue 31 Jan 2012, 16:32

Well I won't be using the timing tape after all !!

I thought I'd clean the damper this morning, and because the multiple coats of paint were so thick, I thought I'd take a bit of paint off in order to accurately fit the tape.

+/- 5 years ago I thought the damper was matt black, hence the layers of paint on it.

What a nice surprise when the paint came off. :D
It took about 10 minutes to remove all paint, and a matter of minutes to clean the metal and give it a couple of coats of clear laquer. :D
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Re: How to rebuild a V8 - D.I.Y.

Post by V-Hatchi » Tue 31 Jan 2012, 16:42

Hi Charles, on the subject of pampering, I'm going to lay off the meths.
Girlfriend caught me talking to the block this morning !! :lol: :lol: :lol: :lol:

I'd be surprised if the V8 shops have got the Gasgacinch in stock, but it wouldn't be a problem ordering it I'm sure.

There's been mention of parts being made in China.
The pic below shows a chrome dizzy hold down clamp (the small one on the right).
I bought it to tart up the block about a year ago.
It's utter sh$t as it warps with the heat from the block. :evil:
Rather keep the original one !! ( I didn't ! :cry: :oops: )
The big one on the left is a Mr Gasket one that I'm gonna use.
Hopefully it doesn't warp.

Also, chrome water necks look nice, but they too warp and are utter sh$t !

The only thing that was cheap ass, and still works 100% is the oil dip stick ! :D
Dizzy hold down clamp.jpg
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