Lancia Beta Forum

Technical stuff => Tuning and competition => Topic started by: 75coupe on May 09, 2014, 12:33:09 PM



Title: Guy Croft race engine build
Post by: 75coupe on May 09, 2014, 12:33:09 PM
Dear All,

Though I would post a few pics of my GC full race engine build. I built the bottom end, whilst Mr Croft modified/built the head and fitted the cams.

Spec:

2 litre 85mm bore, 2043cc, GC forged 11:1 pistons.
GC Forged race con rods.
GC Steel flywheel, 6 puck clutch
modified sump, VX oil pump
VX head, 43.5/36mm valves modified to full race spec
GC 4A race inlet cam with 11.8mm lift
GC 3D exhaust cam with 10.9mm lift
Twin 45 DCOE carbs with 40mm chokes on GC inlet
4-1, 1 5/8" bore header with 36" primaries
2 1/4" exhaust with single straight through muffler
Davies Craig electric water pump
MSD 6A multi spark capacitive discharge ignition
NGK B9EGV plugs
19 row oil cooler with remote filter, oil thermostat and Accusump
For Focus ST170 radiator
Daihatsu Charade alternator with toothed belt drive

PREDICTED POWER OUTPUT: 190BHP/154lb ft torque.
REV LIMIT: 9000RPM (although GC said it would be safe to 9500!!)



Title: Re: Guy Croft race engine build
Post by: 75coupe on May 09, 2014, 12:37:57 PM
Race rods & piston only 1kg, compared to OE which were 1.43kg ! The weight difference equates to leaving 1 complete OE piston & rod out! This important as the reciprocating mass needs to be less when revving to 9000rpm!


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 09, 2014, 12:51:12 PM
Setting ring gaps and fitting pistons to rods. The rings are CP race type and are very thin compared to OE type. They also have very low spring tension, meaning less friction on cylinder walls. it doesn't mean they don't seal well!


Title: Re: Guy Croft race engine build
Post by: HFStuart on May 09, 2014, 03:28:26 PM
Ahh, engine porn!

That must have cost a pretty penny - but then the quality of Guy's work is beyond reporach so if he predicts 190bhp that's that it will make.

When I've saved a few pennies and got bored of my 'only' 150bhp I will be buying some of those HC pistons myself!


Title: Re: Guy Croft race engine build
Post by: Hawk on May 12, 2014, 07:14:53 AM
naked engine - phwoar :)

that's a good saving on the rods and pistons - have you had the crank balanced?


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 07:47:33 AM
Hawk - yes crank, front pulley, flywheel (including clutch pressure plate) all balanced together.

Stuart - Don't ask about cost, but not as much as you would imagine. At the end of the day this engine will have been completely built for less than 5 grand (GBP)including ancilliaries. I did ALL the bottom end work myself though, as shipping a block and then complete engine back and forth from GB to Oz would have been as much again.....

As it happens I was lucky and managed to buy a nice useable VX head off Matt, a forum member, Thanks Matt!! Why a VX head? Well it has the nice big 36mm parallel throat inlet ports and 43.5mm inlet valves as standard, very similar to the Fiat 130TC head, so this means the cost of modification is less then with a standard Beta head with 42mm inlets

Now on with the story and next up some pics of the assembled block. I have built plenty of twin cam engines, but when you are playing with expensive parts you start questioning your own ability to do the job in case you stuff something up! In particular fitting pistons to rods with those horrible wire pin retainers, and gapping/fitting fragile piston rings, as you know it will cost.....

I did a "dry build" check, using an old head gasket I fitted the head and fitted cam belt, and turned it over two complete inlet/exhaust cycles to check valve to piston clearance at TDC. The cams in this engine have over 4.5mm lift at TDC compared to standard Beta that has less than 2mm...


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 08:03:24 AM
Good job I took the strainer off the oil pump....Otherwise my big ends would have not looked like they do below. I fitted the big ends and did a few rotations to check all was good and then took the cap off again on No.1 cylinder to check...


Title: Re: Guy Croft race engine build
Post by: Hawk on May 12, 2014, 08:30:06 AM
Keep the pics and info coming :)

I would love to drive a 190bhp Beta. 


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 08:30:42 AM
An uprated clutch and baffled sump finish the bottom end..."True TDC" marked on flywheel so ignition timing can be checked from gearbox inspection hole.


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 08:39:11 AM
Head finally goes on with uprated GC head gasket and bolts, cam belt on cams timed ...


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 08:48:21 AM
I decided to use an electric water pump instead of the original as this is supposed to free up a few BHP at high rpm, so had to make up an adapter plate to fit a water outlet.


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 09:01:39 AM
A view down inlet port with piston at TDC and valves on the "overlap". You can literally see straight through the inlet port into the exhaust port with these cams! It is this that gives the "cross scavenge" effect at higher rpm which helps draw charge in through the inlet tract so long as the exhaust system is tuned to match...


Title: Re: Guy Croft race engine build
Post by: HFStuart on May 12, 2014, 02:49:24 PM
Great posts and a clever mod with the pump housing - I've thought of one of those EWP setups myself - I think the Emerald ECU could control it too-  but mine has little trouble with temperature anyway so it not urgent but let us know how you get on with it.

£5k seems pretty good value for that output

I'm familiar with the buy a VX head route from a forum member to get big valves- in my case thanks Eric  ;)


Title: Re: Guy Croft race engine build
Post by: 75coupe on May 12, 2014, 08:37:00 PM
One advantage with the EWP is that it will run on after shutdown to prevent heat soak, they make bold claims about it saving up to 8 BHP, however this was on a V8 motor, so if I gain a couple of BHP I will be happy.😊.

Wished I could fuel inject this engine, I'm sure it would then pass that double century mark....Historic racing rules  mean carbs it is, and for setup makes life a little easier.


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 13, 2014, 12:56:54 PM
To go with the engine I built a new 4-1 exhaust manifold
(http://img.tapatalk.com/d/14/06/13/eruryvys.jpg)(http://img.tapatalk.com/d/14/06/13/qetunega.jpg)(http://img.tapatalk.com/d/14/06/13/eqejaguj.jpg)


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 13, 2014, 01:00:36 PM
Engine in car(http://img.tapatalk.com/d/14/06/13/ynypa4e5.jpg)(http://img.tapatalk.com/d/14/06/13/sanavady.jpg)(http://img.tapatalk.com/d/14/06/13/epu6yby5.jpg)


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 13, 2014, 01:07:18 PM
Preliminary dyno run produced 155BHP at wheels in 4th gear which translates to 188BHP at flywheel. Dyno sheet went only to 7500RPM, but engine holds power to nearly 8000RPM before starting to drop off...

Still some fine tuning to do and revised Pipercross air filter to be fitted....Will post more dyno results soon, but pretty happy with result so far!(http://img.tapatalk.com/d/14/06/13/9u5a7ebu.jpg)


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 13, 2014, 01:17:16 PM
Turn the volume up for this one, flat out 4th gear at Lakeside raceway...

http://youtu.be/YHD5nUp5gAM

A few laps of the same short 2.4km circuit. Had a few issues changing gear due to the gear oil used with the LSD, which meant he synchro wouldn't work once hot, hence the missed gears a few times....rectified now waiting for next track outing...

http://youtu.be/BPOxb3nsFaA


Title: Re: Guy Croft race engine build
Post by: lbcoupe76 on June 13, 2014, 02:29:55 PM
Yeah baby, that's awesome. ;D


Title: Re: Guy Croft race engine build
Post by: swedgamma on June 13, 2014, 07:38:33 PM
What a fantastic sound,especially the fly-by noice!!And the engine didnt miss a beat either,Congratulations!

Urban(Swedgamma)


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 13, 2014, 09:47:27 PM
Thanks Guys, it is a bit nerve racking building a new engine only running it in for half an hour then running it flat out at 8000rpm round a race track....

The next engine build is a Guy Croft VX which should have 220BHP.....


Title: Re: Guy Croft race engine build
Post by: WestonE on June 15, 2014, 04:02:11 PM
Ian

I am delighted for you!! The car is sounding great and it looks like it is handling and braking well too. As the former owner of a 185 BHP GC engined Beta Spyder I know how great these cars can be.
Let me know when you want to know more about the VX build as I have the Volumetrico Montecarlo running and it first ran as a VX Montecarlo on Fuel Injection. I still need to complete the build of the VX FI Beta Spyder. I have all of the engine and gearbox parts including an inboard manifold with a flow deflector following flow bench development of the original horribly unbalanced manifold.

Cheers

Eric 


Title: Re: Guy Croft race engine build
Post by: 75coupe on June 16, 2014, 10:16:10 AM
Thanks for the kind comments Eric, I am hoping for a couple more BHP when I take it back to the dyno.

The suspension is still work in progress as I really need stiffer springs and some castor and a bit more negative camber on the front end to make the semi slicks really bite. Currently the geometry is no where near optimised for a race track anyway.

Very interested in the VX in board manifold mods. I have 2 VX's to build and considering fuel injecting the 2nd one.

I upset an Alfa GTV driver who has a supercharged fuel injected 2 litre twin spark (with Toyota SC14 blower) who couldn't shake me down the straights!!

He follows me out of pits in this clip:

http://youtu.be/_uz_b1ZwbWI


Title: Re: Guy Croft race engine build
Post by: andybeta on July 04, 2014, 11:37:10 PM
Turn the volume up for this one, flat out 4th gear at Lakeside raceway...

http://youtu.be/YHD5nUp5gAM (http://youtu.be/YHD5nUp5gAM)

A few laps of the same short 2.4km circuit. Had a few issues changing gear due to the gear oil used with the LSD, which meant he synchro wouldn't work once hot, hence the missed gears a few times....rectified now waiting for next track outing...

http://youtu.be/BPOxb3nsFaA (http://youtu.be/BPOxb3nsFaA)

2nd link is well worth viewing.


Title: Re: Guy Croft race engine build
Post by: Deltona on November 29, 2020, 02:58:35 PM
An old post I know, but still great to read! Can I ask what fuel (Mon/Ron) you used? Just wondering why 11:1 and think it maybe down to that perhaps?


Title: Re: Guy Croft race engine build
Post by: 75coupe on December 30, 2021, 11:57:36 PM
I havenít been in here for a while, but to answer the last question, 11:1 CR was chosen as you can still run 98Ron unleaded fuel without detonation problems.

The cams are very aggressive with big overlap so a high static CR is needed.

The car can run in ambient temps up to 40deg C over in Australia, but I have never had an issue with pump fuel. I use Shell V power or BP Ultimate.

I have also taken great lengths to ensure the carbs are fed with cool air straight from the front of the car.