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> Engine rebuild 1.8L to 2.1L, Daily driver with a kick!
ScottD914
post Apr 12 2009, 10:54 AM
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Gentleman (and Ladies): I'm wrapping up my frame/ body repairs on my '74 and turning my attention to my stock 1.8L carburated power plant.
With so many variables to consider, I thought I'd throw it out to you for your thoughts on a good combination. (IMG:style_emoticons/default/stirthepot.gif)
Starting with a stock 1.8L, the goal is build an engine with a balance of power and efficiency for a daily driver with a kick.
What I have found so far, for consideration is:

1. Increase displacement with a longer stroke: 71mm to 78mm (and corresponding
rods)
2. Larger P/C's from 90.5mm to 94mm (or 96mm)
3. Mild cam (Webcam 86a or 494)
4. Switch to dual carbs vs. the current single.

This combo would provide an increase from 1.827L to 2.165L
The questions that come up are:

1. Will this combo meet the goal?
2. Are 1.8L heads okay on this engine or do I need to find 2.0L heads?
(the 86a cam would require better valve springs I gather)
3. Should I lighten up the flywheel?

One other biggie, since I'm in the Northeast: Where can I have machine work done? Loads of places in CA, do I need to ship my heads and possibly the case out to CA or is there someone closer? There's a lot of wisdom and experience out there, any help would be greatly appreciated and might save me a couple bucks!

Thanks! ScottD (IMG:style_emoticons/default/aktion035.gif)
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underthetire
post Apr 12 2009, 11:38 AM
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I was told to start with a 1.7 case because of some additional webbing inside the case. Hopefully someone else will chime in that actually knows.

I also think that the 2 liter 3 stud head flows better. This I believe is the largest HP gain. Again, a motor guru will hopefully chime in.
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type47
post Apr 12 2009, 11:40 AM
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Carburetors and efficiency don't seem to go together to me. Microsquirt, stock stroke (starting with a 2.0L engine) and 96mm pistons with a Raby cam is the plan for my next engine.
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r_towle
post Apr 12 2009, 02:20 PM
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Lets start with some of the simple questions.
The 1.8 liter heads are the ones that have been used for hotrodding for many years. They have alot of meat to work with and they are less prone to cracking then the 2.0 liter ones.

Given that, the big difference is the location of the plug. H.A.M states that its worth at least 10HP to move the plug to the 2.0 liter location.

New valves and valve seats are a must. Plan to spend money on the heads. HAM is located in Georgia, use him for the heads.

For the heads and cylinder work..use HAM. He is on the east coast.

For the case, find a local machine shop to blueprint your case, or clean it up and ship it to HAM... I have had good success with local shops for the case work...its not rocket science. Do blueprint the case...ensure you have all your deck registers machined flat to the centerline of the case/crank. Have the shop measure up the crank journals BEFORE you do anything with the case...then decide from there.
These cases are fairly rugged and dont typically have the need for line boring, so dont believe it without VALID measurements to prove it...

Talk to Jake about some decent engine combos and think about buying a kit that is complete and proven.
Rich
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ScottD914
post Apr 12 2009, 06:11 PM
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Gentleman, Thanks for excellent starting points. I will definitely mic out the case carefully and look for signs of pounding in the mains to see if I need an align bore.

HAM sounds like the place to send the heads and I've heard that the old school sodium filled valves should be replaced with stainless steel. New guides an seats are a must, but the spark plug hole? That's interesting! 10HP! It's probably not that expensive to have done and they are likely cracked anyway.

What are your thoughts on a small flycut to increase compression ratio a bit? I don't what to push up to need a higher grade gas either.

Rich: your reference to "deck registers". Are you referring to the seating surface where the cylinders seat on the case?

I cracked open over a hundred cases over a brief span 30 years ago. Threw in new parts and down the road. This one will be interesting with an engineering background to add to the mix plus a healthy respect for cleanliness, precision and the time to do it right. Should be fun! Thanks for the advice. Now off on my hunt for HAM! ScottD
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Dominic
post Apr 12 2009, 06:44 PM
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Here are the websites you need for machining and parts:

http://www.aircooledtechnology.com/store/home.php

http://www.haminc.biz/


Also check out Jakes forums for info on your Type 4 build:

http://forums.aircooledtechnology.com/

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r_towle
post Apr 12 2009, 06:53 PM
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QUOTE(ScottD914 @ Apr 12 2009, 08:11 PM) *

I will definitely mic out the case carefully and look for signs of pounding in the mains to see if I need an align bore.

It rare to need to line bore a type 4 case. It is a much stouter design.

QUOTE

That's interesting! 10HP! It's probably not that expensive to have done and they are likely cracked anyway.

Plug location is all about the efficiency of the burn...look at the 1.8...its off center, it shrouds part of the valve.

QUOTE

What are your thoughts on a small flycut to increase compression ratio a bit? I don't what to push up to need a higher grade gas either.

Review your goals of the motor. With the right camshaft you can go higher than most bench engineers think...its all about the camshaft/head combo.

QUOTE

Rich: your reference to "deck registers". Are you referring to the seating surface where the cylinders seat on the case?

Yes, this is the area that seems to be "off" when the case is blueprinted.
It requires a machine shop to find and fix correctly...

Rich
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ScottD914
post Apr 12 2009, 07:07 PM
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Thanks Rich, Lots to consider. Guess the 1st step is a tear down/ clean up to see what I have, should be interesting.
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Jake Raby
post Apr 12 2009, 07:47 PM
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QUOTE(ScottD914 @ Apr 12 2009, 06:07 PM) *

Thanks Rich, Lots to consider. Guess the 1st step is a tear down/ clean up to see what I have, should be interesting.


Yep, tear it down and then start the research... You should take at least 6 weeks to study the possibilities before buying a single part!!!

Tomorrow I'll chime in here with my thoughts on the tentative combo for your application..

That said, "its ALL in the combo!"..
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sean_v8_914
post Apr 12 2009, 09:29 PM
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teh 2.0 chamber is different shape also.
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Jake Raby
post Apr 13 2009, 05:58 AM
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QUOTE

With so many variables to consider, I thought I'd throw it out to you for your thoughts on a good combination.

Hopefully I can help.. These engines are all about their combinations and that goes right down to the assembly difficulty, not just performance.


QUOTE
Starting with a stock 1.8L, the goal is build an engine with a balance of power and efficiency for a daily driver with a kick.

>>>>>>Great. The 1.8 case can be made into anything, all the way to a 3.1 liter. I have a tech article on my forums about using the 1.7/ 1.8 cases for performance engines, you should check it out.

QUOTE
What I have found so far, for consideration is:

1. Increase displacement with a longer stroke: 71mm to 78mm (and corresponding
rods)

Choose the stroker crank carefully. The rod journals determine difficulty with assembly as well as strength. I'd suggest a 78mm crank with a Type 1 or Chevy rod journal and a set of clearanced rods to match.

QUOTE
2. Larger P/C's from 90.5mm to 94mm (or 96mm)

Go straight to n96mm and pay attention to the pin height and diameter of the pistons that you choose. This will determine compatibility with the rest of your parts.

QUOTE
3. Mild cam (Webcam 86a or 494)

These are both great base grinds, but neither have split duration. This is THE most important part of your combination and you MUST take it deriously. The key is a full valve train kit thats 100% compatible.

QUOTE
4. Switch to dual carbs vs. the current single.

HELL YES!

QUOTE
This combo would provide an increase from 1.827L to 2.165L
The questions that come up are:

With the 96s it would become a 2270, my most researched and favored combination. We get a minimumk of 150HP from this combination and generally 170-180 all very usable HP. The torque is astounding, usually 10% greater than the HP at peak and its totally flat. This is the best all around engine combination that can be built for money Vs HP Vs. longevity/ reliability

QUOTE
1. Will this combo meet the goal?

It has met the goals of hundreds of my Clients.

QUOTE
2. Are 1.8L heads okay on this engine or do I need to find 2.0L heads?

The 1.8 heads are OK.. BUT they are over 30 years old and were probably most effectiove over 20 years ago. You can do a plug relocate and some port work to them, but they'll never be as good as a set of new LE heads. If the castings need repair you may be close to the same cost as a new pair of heads after HAM finished them. (HAM does all my work on the new heads)

QUOTE
(the 86a cam would require better valve springs I gather)

Yes, and it is not the best cam for this application.

QUOTE
3. Should I lighten up the flywheel?

Yes, if you are willing to sacrifice some drive ability for some added throttle response.

QUOTE
One other biggie, since I'm in the Northeast: Where can I have machine work done?

Send it across the Mason Dixon line and we'll take care of it..

QUOTE
Loads of places in CA, do I need to ship my heads and possibly the case out to CA or is there someone closer?
Lots of people in California ship their projects here.. The volume of work that is done in Cali isn't what you are looking for.

QUOTE
There's a lot of wisdom and experience out there, any help would be greatly appreciated and might save me a couple bucks


I'll help you however I can.. Join my forums and start reading.. Also join the STF and read there.. You have lots of info to review before you are ready to open the wallet.
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ScottD914
post Apr 13 2009, 06:59 PM
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Gentlemen, Thanks to all, you've given me a lot to think about. I'd go right for the 3.1 L combo Jake mentioned if my pockets were deep enough, but reason has to enter in at some point.
I was going to keep the engine on its stand in the corner while I finished up my body work, but it sounds like I should take a weekend for engine disassembly to see what I've got.
Once I make a few decisions, I can ship parts off for machine work and use the wait time for body work. I'll post what I find and go from there. Thanks again. ScottD
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Jake Raby
post Apr 13 2009, 07:02 PM
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Very wise.. Tear it down, report back with pics and I'll tell you what you've got..

Jumping right in and spending big bucks on parts that aren't compatible happens all the time..
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