Type 4 Engine build basics, Best approach on rebuild options Options

[TomL]

I am hoping to build a good, solid, higher performance Type 4 which will be used as a daily driver, touring car and perhaps an occasional AX. I have some questions.
1. Are all type 4 engine cases identical? If so, why are "GA" cases preferable?
2. What practical difference is there between a 78.4 stroke crank and an 80mm crank--since the 80mm seems to be more prevalent and a little less expensive?
3. Which is the most preferable bore--94mm, 96mm or 103/4mm?
4. Is there any practical difference between standard 2.0 sized crank journals and chevy sized?
5. Can 1.8 heads be "massaged" enough for decent performance?
6. Pure speculation--What kind of HP might I expect out of an engine with: 80mm stroke, 96mm bore, a moderate cam, re-worked 1.8 heads (8.5 or 9:1CR) and carbs?

Thanks for any answers you can give
TomL

[Jake Raby]

Bill speaks from experience...

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1. Are all type 4 engine cases identical? If so, why are "GA" cases preferable?

The GA case is not magical.. All TIV cases are virtually the same, and can have parts swapped and interchanged from 1.7-2.0. I actually prefer the 1.7 cases for reasons that most people would not understand. My 3 liter is built on a 1.7 case-

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2. What practical difference is there between a 78.4 stroke crank and an 80mm crank--since the 80mm seems to be more prevalent and a little less expensive?

Thats all according to how easy you want the engine to be assembled. I prefer the 78.4mm crank with my TI rod journal mods coupled to a 5.4" Type 1 rod with standard clearancing. This is easy to assemble and offers an excellent rod ratio with ease of assembly. My parts make this a DROP IN affair with only minimal hand clearancing. The 78.4 crank with its 2.165" TI rod journal is the strongest you'll find.

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3. Which is the most preferable bore--94mm, 96mm or 103/4mm?

If you go above 96mm Nickies cylinders are an absolute requirement unless you have a desire to toss your reliability and longevity away. In most cases cast iron cylinders in the TIV are toast at 10K miles, generally warped and tapered. Most engines won't see 5000 miles with them without cylinder/head leakage. Stay away from big bores, especially if you don't have the 2K + it'll take to create a set of heads to feed the HUGE bore.

I worked for 7 years non stop to make TIV combos that work efficiently alkl while using the 96mm bore and it's longevity and reliability benefits. Wise men take advantage of this-

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4. Is there any practical difference between standard 2.0 sized crank journals and chevy sized?

>>Yep, both in diameter and width and more importantly bearing composition. The stock 2.0 journal has a bi-metal composition and is horrible for performance applications the stock rod length is also inadequate for any strokes over 74mm unless they are low revving engines (primarily for Bus applications) The stock rods and their journals should be avoided at all costs for stroker engines-

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5. Can 1.8 heads be "massaged" enough for decent performance?

>Yep, but a plug relocation is good for 10% more power alone...

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6. Pure speculation--What kind of HP might I expect out of an engine with: 80mm stroke, 96mm bore, a moderate cam, re-worked 1.8 heads (8.5 or 9:1CR) and carbs?

My 2316cc kit makes a soild 180HP and 185 TQ with the "New Generation" heads employed (they are now a standard on all kits larger than 2056cc) This is up from 170 HP with the 7440 heads that we superceded. The 2316 kit has all the parts clearanced, balanced and indexed and even prepped for assembly if you opt the service. The 2316 is one of my easiest kits to assemble, 3 weeks ago one customer assembled one in a weekend and fired it up, drove the car the following Monday- He started Friday @ 4 Pm!

The nice thing about my kit is the fact that I can dictate everything right down to jet sizes and ignition timing, simply because its an engineered, heavily developed engine that I have dynoed dozens of.

It's impossible to buy the components to assemble a like engine individually for a lower price, then you'll still need to clearance and balance the parts and won't get any support because it took 10+ suppliers to get you the parts to complete the project.

Its all about compatible parts... I can make it fall together as easy as a correctly built stock engine. That 180 HP number is not a guess.