683 replies to this topic

[LC69GTR]

What have you done seen it last night and all looked good.

[Heath]

A bit of secret squirrel stuff I suspect

[rodomo]

Secret squirrel is sorta right.

There was a secret test day recently, I thought I'd do a track day and sort the car out as I have done quite a few things to it.

1. Head shaved, still not enough comp. so out came the motor, block decked and a freshen up. (I've only ever had the sump off before, never the head or pistons)

2. Bigger front brakes, VL Turbo/ VN V8, bigger rotors and aluminium ribbed calipers, upgraded front pads.

3. More neg. camber and more castor.

4. Stiffer front springs.

5. Port matched, hand finished, extractors.

6. Delete factory ignition switch and replace with master switches, upgrade wiring to coil.

I entered the FFCC cup day sprint at Sandown, the plan was to bed the brakes in, run the motor in, and make any adjustments as necessary. More of a test and tune than to compete.

Unfortunately, the engine now produces too much horsepower and the head tried to jump off the block.

Attached Files

•  Head gasket 001.jpg   85.33K   119 downloads
•  Head gasket 006.jpg   88.74K   110 downloads

Edited by rodomo, 20 November 2009 - 12:37 AM.

[rodomo]

So what is the arrow actually pointing to? Is that where the head gasket is leaking?

Leaking? That's where it spat out the side!
AND I had retensioned it.

[rodomo]

what brand gasket? Mason, made by Permaseal I think?was the block surfaced? Yes, as mentioned above, the block was decked.
what bolts? The same ones that came off.

O.K, I'll fess up.
The HEAD gasket wasn't the problem.
The dick HEAD behind the wheel was.

The problems were 2 fold.
2 lean
2 much advance
2 dopey to bring it in and have a fiddle.

Consequently, the car did 2 laps.

What you see in the pic is the result of detonation.

[rodomo]

About time you showed up!

Still the Holley and Varajet manifold.

[rodomo]

But!
It's all back together, 2 sizes up in the main jets (armed with a further selection to choose from) and the dissy has been re-graphed.

(I've learned a lot about H.E.I dissys in the last 2 days )

If the rain stops I will be trying to beat 1:16.83 at Calder tomorrow.

[TerrA LX]

(I've learned a lot about H.E.I dissys in the last 2 days )

Did you keep the vac ad?
if so, Whats its total?
Whats your total all in and at what rpm?

[Heath]

And the rain ain't a stoppin, regardless of how much everyone wants it to. Grrr!

[rodomo]

The day was washed out DAMMIT!
An hour and a half return to Calder from here.
Entry fee will be refunded though.

No more club racing this year on the calendar.

Maybe Winton fun day 13th December? Winton or bust? That's got a ring to it.

[rodomo]

I can't find ^^^that^^^ on the Winton site?

[rodomo]

Did you keep the vac ad? No. it's never been connected
Whats your total all in and at what rpm? 40 @ 4000, way too much

A bit of a lead up to the day:
Build engine, fit, mod extractors, get running, cool down overnight, re-tension head, re-adjust valve clearances (it's still running standard 202 bridged rockers that I shim adjust)

Running again, get side tracked, fit big brakes (which included a hub seal mod as they spat grease onto the discs last time at Calder), fit heavier front springs, do lower control arm mods (camber/castor) toe-in, replace rear pads, alter switches and wiring........basically everything listed above..........and forget all about dissy and carby

Trying to do too much at once, not to mention the other R & D stuff

Advance was:
9 @ 600
18 @ 1500
24 @ 2000
28 @ 2500
30 @ 3000
34 @ 3500
40 @ 4000

Edited by rodomo, 22 November 2009 - 01:02 PM.

[Heath]

Ohh shit so you hired the trailer and drove out there etc to find out it was cancelled? When you called me up I just assumed you had forgotten about it the day before because it was canned

[rodomo]

Rob,
your not still running 40 deg all in are you?

No and I asked Stu yesterday and the compression is in the mid 10's. 10.3 or 10.5 he can't remember himself, it was 6 months ago now.

A bit of Googling and reading here (Thanks oldjohnno) and the magic figure for an engine with good comp. is 26 - 28 total maximum advance from what I can gather, all in by 3000 - 3500 rpm.

Here's what I found/done.

The dissy in the car is -
GMH part number - 92014170
Bosch part number - 9230064708

I have 2 of these and I'm pretty sure they are off carbied 3.3's
These advance figures (from above) were found using a tacho and a timing light:
Advance was:
9 @ 600
18 @ 1500
24 @ 2000
28 @ 2500
30 @ 3000
34 @ 3500
40 @ 4000

Using the RoDoMo DISTO-GRAPHER, I was able to confirm that this dissy has 34 crankshaft degrees advance built into the mechanical advance.





I have another dissy here that I pulled out of a VK E.F.I Calais that I am pretty sure was original.

GMH part number - 92017790
Bosch part number - 9230064720
(I have spoken to another forum member that has a different part number again on a H.E.I dissy. Maybe 2850??)

Anyway, using the DISTO-GRAPHER, I found this dissy has only 24 degrees mechanical advance at the crankshaft built in. I couldn't use it though, it is pretty much stuffed.

This pic is of the lower shafts from the 2 dissys, you'll notice the different lengths in the slotted holes for the advance stops.



So I welded up the slotted holes in the original lower shaft and then filed them back and using the DISTO-GRAPHER, acheived 18 degrees mechanical advance at the crankshaft.

18 degrees advance at the crankshaft means 9 degrees at the dissy shaft for anyone considering this type of mod.




I kept checking the stops to make sure I wasn't filing too much out of one side and not the other.



I assembled it with the same springs and weights and this was the result:
6 @ 800 (static)
8 @ 1200
12 @ 1500
20 @ 2000
24 (maximum) @ 2500

Maximum advance in too early.

So I pulled it apart again had a look at the springs and what they were doing and when again using the DISTO-GRAPHER.

The secondary spring was basically doing nothing till right at the very end.

I pulled a couple of dissys apart and compared springs:



1 = E.F.I dissy springs.
2 = Original to this dissy springs.
3 = Points dissy springs.

I fitted the points springs and gave the secondary spring post a bit of a "tweak" in as the secondary spring is so much shorter.

These are the new figures:
6 @ 800 (static)
8 @ 1200
11 @ 1500
13 @ 2000
16 @ 2500
18 @ 3000
24 (maximum) @ 3500

I reckon I'm in the ball park now and might have room to move with the static timing???

[Heath]

Awesome, bit harder to comprehend it all over the phone LOL

[TerrA LX]

It is amazing how different two similar dizzys can be inside, I have found quite a few myself.
Well done Rob, should make a big difference.