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Mon Apr 06, 2015 12:32 pm

I have a beautifully built 2083cc engine in my 68 T34 auto. But, I am tired of trying to sort it out, it just gets too hot. I don't think it get's enough fuel, and I don't want to go to electric pumps, remote oil coolers, on and on.

When it is running good (before it gets hot) it's a blast..
I think it would have worked great in a manual square-back, but with the T34's cooling and the auto, it's too much.

SO -Here's the question can I just replace the cylinders and the piston heads and keep the rods and crank I have now? I'm thinking something just under 1.8 liter.

I don't have all the engine specs here at work, but I was thinking about all night and just want to see if that's a possibility.

Mon Apr 06, 2015 12:35 pm

Tell me more about your engine's specs. I run a 2332 on a stock fuel pump. There might be something small causing issues....

My guess is we can getting it running well with the details.

Mon Apr 06, 2015 12:51 pm

I did just get a rebuildable pump from ISP west.
Before I had a really nice one I was borrowing from Lee Hedges, that Pedro had rebuilt. In both cases I have run into vapor lock, more of less from the engine getting hot.

I replaced the stock Solex because they had altitude compensaters and you cannot change the jet sizes. I think I put .35s in. The new solexs and jets made a huge difference at idle. But, it still got hot.

The engine is a stroker with really low compression. The compression is low to help it run cooler. (Only 80-85psi)

It could have crap fuel in now. I'm going to drain it out and try that. There is not any junk in the fuel filter, so I don't think there is stuff in my tank filter screen.

I'm not much of a wrench, I'm just tired of coming home on a hook and not being able to enjoy this beautiful car.

Mon Apr 06, 2015 12:57 pm

you are running a two liter on stock 32mm dual carbs? if so, with bigger valves, you would need to do some heavy mods on the carbs... not impossible, but stock will run you lean quick.

Mon Apr 06, 2015 1:03 pm

They are stock, with the larger jets. I am starting to think the lower compression is an issue too because it does require more fuel. The valves are stock, polished and ported.

Mon Apr 06, 2015 1:10 pm

you venturies are way too small for that sized engine, even with stock valves.

Mon Apr 06, 2015 1:16 pm

Where do you find larger ones?

Mon Apr 06, 2015 1:20 pm

You will have to modify what you have or go with a different set of carbs. That engine really needs some 36mm Dellortos or 40mm Weber DCNFs. It is about getting enough air moving to get enough fuel delivered. With the stock carbs, even with bigger jets you still have a limited air signal, so the carbs aren't going to get enough fuel there...

Mon Apr 06, 2015 1:31 pm

Holy crap!! You have 80-85psi on a compression tester?? That motor must be a dog to drive. . . :roll: I consider a motor in need of a rebuild around 90psi

With a loss of CR comes a loss of efficiency within said motor. That motor sounds like it is completely mis-designed with parts that have no business being together.

Brian is right about the carbs. I would guess that after 3K rpms, you're carbs turn into a governor on a motor of that size. You should be running 40 Webers on a 2.0L to be adequate (44s for a performance built motor).

8:1 is the target I shoot for on street, DD motors. I have found that this is a nice target to get cool running, good mileage and good engine efficiency. I see people still using Berg semi-hemi heads that bring the CR into the 6.0-6.5 range and I have to shake my head. When a motor has too low of CR, they become un-tuneable and have a host of problems.

If you take the heads off and measure your deck and combustion chambers as well as see what you have for cylinder spacers, you may be able to remove some spacers and be O.K. This WILL change EVERYTHING (rocker geometry and push rod length required for certain), so everything must be re-checked just as with building any motor.

Consider using an electric rotary pump. Whisper quiet and they always work unlike the mechanical ones.

BTW, with a stroked 2.1L, you should see compression # around 140-150#. 8)

Mon Apr 06, 2015 1:34 pm

I want to stay with the solexs because I want the stock look -that's important to me.

I did find 34mm PDSIT Solex Venturi, 28mm that I can replace the stock ones with. Sounds like a good way to go regardless of what I do with the displacement.

Thanks for the suggestions Brian.

Mon Apr 06, 2015 1:49 pm

reay wrote: I want to stay with the solexs because I want the stock look -that's important to me.

I did find 34mm PDSIT Solex Venturi, 28mm that I can replace the stock ones with. Sounds like a good way to go regardless of what I do with the displacement.

Thanks for the suggestions Brian.

I would consider building a 1776cc motor if you plan to stick with those carbs. This will give you a boost over stock yet not be choked with too little carb.

Mon Apr 06, 2015 1:55 pm

Can you post up the specs of your motor again for us here?
2083?? :?

Did i read that right - stock carbs on a big stroker?
That will require a bit of finageling by an experienced tech to get right.
Too low of compression can also have it's own set of issues..
Combined with your auto trans, it would likely be very difficult to get smooth/cool.

Again, need the whole story to make an intelligent suggestion..

However, since this is the Internet, and more specifically The Samba,
I'll make a WAG as to what to recommend! :D

Having seen a bit about your motor before, I remember it having a relatively mild spec, that was suited to your application.
So I'll go with it..

Because you are asking the carburetors to provide fuel delivery too far from their original design parameters, you are having problems.

Rather than go back smaller, or changing your motor itself,
I purport that installing a pair of small dual-throat carbs would be your ideal solution.
I.E. a pair of Dell 36s, or Weber 36s (or 40s - Webers run smaller than Dells for their size).

With smaller carbs, and the correct small venturies, you could have a motor that is very tame, idles smoothly, works with your auto trans, gives better mileage, runs cooler, and makes more power.
Yes, cake, and eating it.. Except for the costs, both initial, and set-up.
Plus a bit more noise, especially on open throttle.

About the 'smoother' part; this would be a lot smoother. Two single-barrel carbs can get a bit cantankerous at idle/low speed, on even mild/small motors.

Webers/Dells are so finely adjustable, that they can be tuned to make nearly anything run perfectly.
A lot of work/skill to set up, but, once set - forget.

Plus, you would not have to remove/disassemble your motor.

Provided it's otherwise correct, again, Please let us know.

Really wish you lived closer;
Have a wideband O2 sensor and a variety of jets to try here.
For some of us, tuning a set of Italian carbs is our idea of a good time! :D

Mon Apr 06, 2015 1:58 pm

Oh, stock look. Didn't see that.

There's a great thread about building a box for bigger carbs running here right now.
Maybe you could talk W1K1 into building you a box that looks like a stock cleaner?

Or, better yet, you could hang your stock cleaner on the wall, so you could enjoy it every day, not just when your engine compartment was open? :lol: :lol:

Mon Apr 06, 2015 2:02 pm

wow..
Thanks for the input. one problem with the Dells or Webers is the kick down set up. I'll post my specs when I get home, but you guys have given me alot to think about!

Mon Apr 06, 2015 2:09 pm

Another factor is your exhaust.

If you are running stock heat exchangers and mufflers,
You are definitely choking off the exhaust, causing the heat to stack up inside the motor.
1776 is generally considered the limits of the stock heaters.

Unless you want to run a header, (maybe VST exhaust - looks near stock) going back to mild is the wise choice.

You can build a really, really nice smaller/mild motor.
With a counterweighted crank and a dynamic balance job,
a smaller motor can be built to a 'sweetness' level that would not leave you wanting for power...

Mon Apr 06, 2015 2:13 pm

I guess another question to ask would be if you have the original numbers-correct engine case for the car.

A car that nice, with originality in mind, having the OG case changes what you would want to do strategy-wise..

Food for thought.

Mon Apr 06, 2015 2:18 pm

Unfortunately, the original case was cracked.
It is a NOS AS41 that's been cut.

Mon Apr 06, 2015 2:48 pm

I would suggest you run the dual 36 dells or 40 webers and forgo the stock look for that sized engine. The other possibilities with the 40 DCNF carbs is that they are shorter than the Weber IDF and you might be able to modify the underside of the stock air cleaner to mount to the carb tops with some creativity.

Mon Apr 06, 2015 3:31 pm

Wouldn't a 68 have come with factory FI?

Max

Mon Apr 06, 2015 3:33 pm

let me start by saying im not a motor head but have been through some motor issues myself lately. I built a 1914 and it was running hot, really hot. once i got the motor into the right hands they showed me some diferences in parts i was useing. My heads were cheap castings and were not allowing enough air though to cool.

I had issues with the case on the 1914 and decided to go back to stock with there recomeneded heads. I have to say the first time i drove it was 2 hours away and it drove great and cool.

Just throwing it out there heads are something to concider as well as everything else mentioned.

good luck.