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Engine build experiences
https://www.ausmini.com/forums/viewtopic.php?f=2&t=83039		 Page 1 of 1
Author:  NickDole [ Tue Oct 08, 2013 9:01 pm ]
Post subject:  Engine build experiences
Hi,
I'm building an engine for a friends S. I'm a bit out of touch with a few things and would like some suggestions from those of you who have 'been there, done it and decided not to do it again because it didn't work."
Engine spec is
Thin flange 1275 block
Omega 1275 offset dish pistons at 60 over.
Stock S crank and rods, stock journals too, it was a low km car
Pierce head with non S type valves (small)
Titan belt drive
266 Kent cam
1.5 roller rockers
Maniflow 1 3/4 SU Manifold with twin HIF's
LCB Maniflow 1 3/4 with RC 40 system.
Light flywheel/pressure plate

It's a road car but not a daily. Trying to get to 100hp and still have an idle. :roll:
I will say the pierce head is not as good as I hoped. we bought it early on with little research. The inlet ports are too big and way too low (my opinion) Why they didn't lift all the ports up 15mm baffles me, the short side radius is not good. I've straightened out the casting lumps and made the best of a bad situation generally while trying to not enlarge the ports.
Questions are
Distributor. what's a good pick? I have used Bosch units modified by Scorcher in Vic years ago, they can still make me one, is there a better option? No crank triggers, my life is complex enough.
Compression ratio. I'm thinking 10.5:1 with the alloy head. Anyone had experience with this?
Cam timing. Card says 106. Suggestions? Some say advance it up. Experiences?
I have a set of HS4 SU's and the HIF 1 3/4's. Debating if the bigger carbs will be the go?
I would ask GR but I, like him, run my own business and I have severe guilt in calling him up to waste his time when "we" didn't spend any money with him. I will get you to run it in on the dyno GR but I'd like to get it close on cam timing and ignition adjust-ability before hand.
Author:  GR [ Wed Oct 09, 2013 5:18 pm ]
Post subject:  Re: Engine build experiences
HI NickDole
Iwon't bite if you ring,thoes heads are not that bad they work better if you put a 1.4 inlet valve in them, you get a much better seat and choke area doing that and in turn get a better short turn,dialing the cam in at 104/105 will work fine,scorcher make a good dizzy i get them put 7 to 8 degs in the dizzy and run about 16 deg static all in by 3500 rpm (engine rpm) this way your engine will idle off the advance and not by throttle opening this will help when you turn the motor off so it will not run on.
I like the single 1 3/4 su.
Graham Russell
Author:  awdmoke [ Wed Oct 09, 2013 5:41 pm ]
Post subject:  Re: Engine build experiences
The standard springs will not take 1.5 rockers.
Check the valve seat inserts while you have them out.
Author:  GR [ Wed Oct 09, 2013 5:55 pm ]
Post subject:  Re: Engine build experiences
HI AWDMOKE
All the 5 port heads i have done i did'nt have a problem with it was the 7 port you could not put any lift into.
Graham Russell
Author:  awdmoke [ Wed Oct 09, 2013 10:12 pm ]
Post subject:  Re: Engine build experiences
sorry Nick didn't say if it was 5 or 7 port.
I have a decent set of springs for my 7 port but the roller rockers won't be going on just yet.
Author:  GR [ Thu Oct 10, 2013 8:34 am ]
Post subject:  Re: Engine build experiences
HI awdmoke
What head are you running?
If it is a 7 port you will need longer valves not just springs.
Graham Russell
Author:  howey [ Thu Oct 10, 2013 10:32 am ]
Post subject:  Re: Engine build experiences
NickDole wrote:
The inlet ports are too big and way too low (my opinion) Why they didn't lift all the ports up 15mm baffles me, the short side radius is not good. I've straightened out the casting lumps and made the best of a bad situation generally while trying to not enlarge the ports.


I'm not a mini guru, quite the opposite actually, just getting in to them. If the ports are too big and the floor is too low, could you have the floor filled and reshape the ports yourself? That should also help your SSR problem, and allow you to dictate the size and position of your MCSA.
Author:  NickDole [ Thu Oct 10, 2013 11:05 am ]
Post subject:  Re: Engine build experiences
Thanks for the reply guys. GR you have never bitten in all the times I've called to ask you dumb ass questions that I'm too lazy to work out for myself!
I did drop a 1275 crank off to you for wedging in about 1995 and never got it back. I figured you had given me enough free advice over the years that donating a crank to the cause was part payment for my questioning...


Nick
Author:  NickDole [ Thu Oct 10, 2013 11:09 am ]
Post subject:  Re: Engine build experiences
Mine is a 5 port. The bigger inlet valve idea is good, the seats are smaller than the ports anyway.
I was talking TWIN carbs. Still a fan of the 1 3/4's?
If it was a race car I'd Bondo/epoxy the ports up. It's a road car and not mine. If the epoxy comes loose in a few years the owner would not be thrilled.


Nick
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