2.0 Type IV Vintage Race Engine Options

[jdahl]

I'm building an engine (2 actually) to run in my 914 for SVRA Group 3 road racing. I've done a lot of research, built a spreadsheet, shopped around, done more research, etc. Before I start spending money on parts, I would appreciate any experienced advice/critique of my build(s).

Conservative
Bore 94 mm - flat top Type 1 "stroker" pistons 35mm pin height
Stroke 71 mm
Rods 5.325"
Heads 59 cc, 2.0 42/36 valves, single valve springs (porting/polishing TBD)
Rod Ratio 1.905:1
Deck Height .04" (1mm)
Compression Ratio 8.5:1
Cam 86a

Creative
Bore 95 mm - 14cc custom dome pistons 25.8mm pin height
Stroke 71 mm
Rods 5.7"
Heads 56 cc, 2.0 44/38 valves, double valve springs (ported/polished)
Rod Ratio 2.039:1
Deck Height .04" (1mm)
Compression Ratio 11.5:1
Cam 86b/c or 163/86b

Induction Weber 40 IDF
Exhaust Kerry Hunter 1.5" header

Again, I appreciate any and all constructive feedback.

[Brett W]

I'm building an engine (2 actually) to run in my 914 for SVRA Group 3 road racing. I've done a lot of research, built a spreadsheet, shopped around, done more research, etc. Before I start spending money on parts, I would appreciate any experienced advice/critique of my build(s).

Conservative
Bore 94 mm - flat top Type 1 "stroker" pistons 35mm pin height
Stroke 71 mm
Rods 5.325"
Heads 59 cc, 2.0 42/36 valves, single valve springs (porting/polishing TBD)
Rod Ratio 1.905:1
Deck Height .04" (1mm)
Compression Ratio 8.5:1
Cam 86a

Please No. No reason to re-engineer the wheel. That cam is a baby and needs more compression, Unless you are going to turn a zillion RPM there is no need to run a rod that long. The engine will be a dog everywhere.

Creative
Bore 95 mm - 14cc custom dome pistons 25.8mm pin height
Stroke 71 mm
Rods 5.7"
Heads 56 cc, 2.0 44/38 valves, double valve springs (ported/polished)
Rod Ratio 2.039:1
Deck Height .04" (1mm)
Compression Ratio 11.5:1
Cam 86b/c or 163/86b

Induction Weber 40 IDF
Exhaust Kerry Hunter 1.5" header

Again, I appreciate any and all constructive feedback.

If this is truly a race motor and not a wanna-be race motor, use a solid combination that has proven its reliability for decades. Again no reason to reinvent the wheel. Start with the following:

71mm Counterweighted crank

96mm Keith Black or forged pistons with stock pin height. (You can get tricky here if you want and run smaller wrist pins, but that typically means custom pistons and special rods) Don't use the Hastings junk rings, go low tension on the rings. If you do custom pistons, go 1.0mm or less on ring thickness and 1.2mm on the oil rings. Compression needs to be in the 11:1+ range, depends on what you can get to clear the valve lift

Bore the stock 2.0 cylinders as they are better quality than the garbage for sale new.

Rods, Run the stock rods with ARP bolts or buy a nice set of SCAT lightweight rods. (stock rods are really heavy)

Cam: Web 86B/163 on a 102-104 centerline, to keep it easy, You could go bigger but you get into sprint race motor territory and the cam is hard to setup. Only use Web cams (although Elgin has done some interesting stuff)

Call Len and get him to port a set of heads, replace guides, replace seats, etc. Expect to spend over $1000 to get a good set of heads done with new valves, new springs, Titanium retainers, bronze guides etc. Expect that stock heads will be junk and start with the new castings. Have him do all the tricks, small stem valves, small plugs, etc. These will be real money and they will be where the power is made.

Carbs (if you have to run them) 44IDF Webers 36mm Chokes

Header, Tangerine if he still makes it or a custom copy of the Finch header. Kerry makes a nice street header, but not a good race header.

If you want to get really silly with it:

100+mm Nickies and custom pistons. Use the most current design strutted piston they offer. Stick with JE or Wesisco for custom pistons. Maybe CP if they will work with you.

Stroker crank. take the engine out to 2318ish. You know the Datsun guys will be running 2.3 stroker motors.

If you want to race a T4 there really isn't a cheap way to do that. It will take work and you will blow a few pieces to bits. These engines don't make good race motors. Not trying to burst your bubble, but having been down this road, you will find the six is cheaper and faster in the long run. The four is a good street engine, but when you start asking it to go racing, its a grenade.

[stugray]

If you want to race a T4 there really isn't a cheap way to do that. It will take work and you will blow a few pieces to bits. These engines don't make good race motors. Not trying to burst your bubble, but having been down this road, you will find the six is cheaper and faster in the long run. The four is a good street engine, but when you start asking it to go racing, its a grenade.

I think it is important to find out WHAT KIND of "racing" the OP is interested in.
I was actually really interested until I read the last paragraph.

The type IV is the cheapest engine in my vintage racing group.
I cant think of an engine that is as fast as the 914-4 that costs less.

You can DEFINITELY make more HP with a type-IV than a 914-6 motor for the same money.
HP costs MORE with a 6 than with a 4 - period.

For what it would cost to rebuild a 6 to stock specs, I could build a type-IV from the ground up and get 130 hp.

Here's mine (vintage rules, so ~stock displacement):
Stock 2.0L crank & rods
Stock 2.0 Heads cut ~.020 for 10.5:1 CR (mine are single spring, would do double next time for higher RPM)
Keith Black 96mm pistons w/ hasting rings
Webcam 86b w/ new lifters
Deck ~.030
Mallory Unilte w/ optical pickup
MSD-6AL
Weber 40 IDFs
Kerry Hunter header (would do Tangerine but $$)

In my race group there is a 2.0L type-IV 4-cyl that consistently beats ALL of the other small bore cars INCLUDING a 914-6.

[ChrisFoley]

...
Here's mine (vintage rules, so ~stock displacement):
...
Keith Black 96mm pistons ...

I thought Vintage Production cars are limited to 1.4mm overbore.

[stugray]

...
Here's mine (vintage rules, so ~stock displacement):
...
Keith Black 96mm pistons ...

I thought Vintage Production cars are limited to 1.4mm overbore.

Unknown to me when I built my first engine.
I will fix that on the next build, but as a rookie, they did not penalize me (yet).
I am in 81 D-prod. with a 71 2.0L.