Ants delco twin cam gemini

[delcowizzid]

yeah the OTHER vid was a laugh LOL

[antus]

yeah my mates commentary is a crack up!

[antus]

Got this one back on the road, and now have the naw_7s wideband installed and connected to the delco. The tune can be cleaned up some more from here.

wideband.png (12.55 KiB) Viewed 12432 times

[antus]

Its been a while since this thread was updated. This car has been off the road with head gasket failure (again, suspect the quality of the gasket being the fault) and so I have decided that MLS gasket, and then boost was the way to go. The commonly available permaseal ones dont seem to be tough enough to last with the thin spacing between cylinders 1&2.

A custom run of G200W MLS gaskets has been completed, and one has been purchsed. Im waiting for it to arrive but this is a pic of the actual item. Some time in the next few weeks I'll get the head off, check that its still straight and good and get this installed. Then after its proven ok NA start looking at the boost. Also have a 2 bar map on the way, a 4 cylinder DFI ignition module, a suitable intercooler, and a custom laser cut exhaust flange though that'll have to be made in to a turbo manifold.

[Holden202T]

you right theres bugger all meat there!

[antus]

Im trying to get the car ready for the bay to birdwood cruise 2011 next sunday, so pulled the head off to see whats going on. To my suprise the head gasket was fine! It had sealed well, and after a bit of a baking looked much better than I expected. So the question became what is wrong? Stripped down the head and found oil starvation at the exhaust cam, along with a stuffed bearing and damage to the cam. Being a twin cam replacement bearings are not available (though Im still looking).




Fortunately I was able to source another 2nd hand cam, and a couple of 2nd hand bearings. Not ideal, but good enough to get things fixed up. I took the head to a local engine shop to get another opinion on it and get it cleaned/fixed up. He told me and showed me that I had a huge amount of play in the exhaust valves, especially #1 under the stuffed bearing. Also one of the exhaust valves was starting to leak. He told me that I'd probably gotten to it just in time, but it was well on the way to major failure.

Then on the block, I had massively seased bolts on the water pump. So bad we literally had to smash and cut the pump off. The spacer between the head and the pump had been leaking too, and the whole area was a mess. We managed to get it this far, but needed professional help.



So I called up Dr Bolt, and 3 hours later he'd visited my house, got the spacer off, got the 4 bolts out and cleaned up the threads, and welded a crack in the spacer




So that still needs a clean but should be going back together this weekend.

Then the engine shop and advised they had completed the work. Top job from Knight engines. IMHO.

Code: Select all

hot wash
dismantle & inspect
replace camshaft rockers/buckets
bead blast
reface valves
k-line guides - exhaust only
cut valve seats & vac test - performance seats
mill head
line bore cam tunnels - exhaust only
groove cam journals for improved oil flow
set valve clearances - shim type
mild pocket port
R&R oil gallery plugs
clean & assemble

The mild port will change the tune, with an expected 10% extra flow (ballpark). So the plan this weekend and next week is to get everything back together, get the wideband on it, fix up the tune and things should be looking good!

[Holden202T]

if your getting oil starvation to the head, just check all the oil gallieres arn't blocked before the head going back on, i'd hate to see you do the same thing to it again!

[antus]

Yeah it was just the front exhaust one, and its a common fault with this engine. Apparently the oil feed is not upgraded enough from the push rod days of the engine, and the oil flow is borderline from factory.

It says here http://www.gseriestwincam.info/twincam/ ... ?f=1&t=464 to put a groove in the journal to improve the flow and and a drilled out grub screw in the feed to compensate and restrict it some. But the engine builder shook his head and said the groove was a good idea, but the restriction was not. He figured when there is a known problem more oil=better. So I took his advice and got the groove, but did not re-restrict the flow elsewhere. That should stop it failing in the same way.

[Holden202T]

yeah well unless your emptying the sump there can never be too much oil

[antus]

I took this car up to geminats 2013 over easter. Great time, and it also included a hillclimb event at ringwood park. Heres my the best lap in the coupe. 1080p quality if you go full screen and select it.

[youtube]http://www.youtube.com/watch?v=h_Q4nOStgE8[/youtube]