110HP to 3100cc

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'66Monza
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110HP to 3100cc

Post by '66Monza »

I am new to this forum. I own a '66Monza 110hp w/4speed. I am now blowing quite a bit of oil, about a quart every 150 miles. I'm guessing the rings are shot. I am interested in this 3100cc conversion. I figure that for the money I'd spend to get the cylinders honed, get my heads redone since I'd have to take them off, I could just get the 3100cc work done. My question is, can I use the 110 heads I have, just have the shop do the necessary work on them, or do you have to get 140 heads? Also, since I was going this far, I figure I might as well get a new cam, with more oomph. Does anyone have any suggestions?
Thanks,
'66 Monza
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Scott H
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Re: 110HP to 3100cc

Post by Scott H »

Good question.
I don't know. I'm thinking the 110 heads and only two carbs won't flow enough to maximize all the benefits of the 3100cc's.
BUT, hopefully one of the engine builders on here will see this and give you more of a definitive answer.

I like the OT20 or the Isky 270 or 280 cam.
Scott
1960 Monza Coupe
1965 Evening Orchid Corsa Turbo (project)
1961 Rampside (project)
1964 Spyder coupe (patina car, running)
1964 faux Spyder (project/parts car)
1964 Monza (parts car)
1963 Monza (parts car)
miniman82
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Re: 110HP to 3100cc

Post by miniman82 »

On the other hand, if you keep a smallish cam and do some pocket porting, you'd have a hell of a stump puller for around town. HP is not always the name of the game after all, TORQUE is what gets you down the road.
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'66Monza
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Re: 110HP to 3100cc

Post by '66Monza »

I sent an email to Ray Sedman from American-Pi. He responded really quick! He said that you can use the 110 heads. He also explained a bit about cams. I didn't know that your tire size matters with this. I have the stock 13" Firestone FR380's on, so when I save up some more $$$ to get this done, I will have to talk to him about my driving, what I'm looking for, etc., he said.
Just thought I'd update you all.
Thanks
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Scott H
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Re: 110HP to 3100cc

Post by Scott H »

awesome glad you got hooked up
Scott
1960 Monza Coupe
1965 Evening Orchid Corsa Turbo (project)
1961 Rampside (project)
1964 Spyder coupe (patina car, running)
1964 faux Spyder (project/parts car)
1964 Monza (parts car)
1963 Monza (parts car)
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UNSAFE
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Re: 110HP to 3100cc

Post by UNSAFE »

I'm not an expert but here's my two cents worth as a 3.1 owner.

Don't even bother with the 3100 cc motor if you aren't going to use high performance heads . Even stock 140 heads are questionable.

If you want to pull stumps with your car just get lower gearing :cool: Or a 4X4 ::-):

I tried different size chokes in my Weber carbs when I first got them. In the case of Webers the "choke" is a removable venturi that allows you to alter the CFM.
When I tried 30mm chokes my engine sounded very peppy when revving it up but on the street it ran out of steam by 5000 rpm and didn't seem any more powerful than my old stock bore 140 .

When I went to 36mm chokes the motor really woke up and the difference was amazing. Now it will pull hard to 7000 rpm and has more "TORQUE" than with the 30mm chokes. This is obvious because the tires will go up in smoke if I punch it from a roll in first gear and it wouldn't do it with the 30s.

The whole torque Vs HP thing is pretty confusing anyway . HP is an imaginary number and torque is only a twisting force that doesn't represent any "work" done. It takes work to move a car.

It's not just the lack of carburation with the 110 heads but also the smaller valves and ports , especially the tiny exhaust tubes.

An engine is basically just a pump and like any pump if you restrict any part of the system you have resticted the output.

If you really want to hop up you motor --- spend the money on having the heads massaged and keep the stock cylinders. Just add some compression and a cam and you'll be better off. Even then you will have the option later on of going big bore.

To much extent the heads are what limits the power , the cubic inches only determine at what rpms the heads reach their limit. A 100 hp head will only make 100hp no matter how big the bore is. The bigger bore will just reach it's limit at a lower rpm.

Be sure to contact Michael Leveque at LeVair Performance & Restoration if you serious about a big bore motor !
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Kevin Willson
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miniman82
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Re: 110HP to 3100cc

Post by miniman82 »

UNSAFE wrote:The whole torque Vs HP thing is pretty confusing anyway . HP is an imaginary number and torque is only a twisting force that doesn't represent any "work" done. It takes work to move a car.
If you can't figure out fuel injection, it can be. :assault:

HP is TQ multiplied by engine speed, where TQ is the rotational 'strength' of the engine acting on the wheels via the transmission at a given RPM. (low RPM) TQ is more important on a street car, because it's the grunt force that gets you moving. No one with a street car cares how much HP an engine makes at 7000 RPM, because you usually don't leave every light at that RPM.

I used to like the whole 'rev the snot out of the engine' thing too, but I've since come to appreciate an engine that can do the same work while being more user-friendly and tame. Hence turbos. I personally don't like high RPM on the street anymore, though there is a certain 'swan song' to be heard with ITB engines.
To much extent the heads are what limits the power , the cubic inches only determine at what rpms the heads reach their limit. A 100 hp head will only make 100hp no matter how big the bore is. The bigger bore will just reach it's limit at a lower rpm.

But again you're forgetting TQ, it's not all about HP. Those same heads are going to make a much better around town engine than a 'hopped up' high-RPM engine you have to flog to get anywhere because they will make more TQ sooner, and that can give the impression of being very powerful early on in the rev range.

Perfect example is the 1915 I have in my Beetle.

If it were N/A and I wanted to make 150 TQ to the wheels, I would need a gigantic camshaft, huge heads, big carbs and a matched exhaust. All that and I would get the power (at 7500 RPM), but it wouldn't idle worth a piss and would get terrible MPG. I chose to turbocharge and the engine idles like a stocker, but will keep up with engines nearly twice it's size. If I didn't turbo, I would need a 2.3L to meet my goals and MPG would still be an issue.

As always it comes down to what you WANT, and what you LIKE.

Most people (sadly) only care what engines look and sound like, not what they actually DO, or how they are used to achieve a goal.
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'66Monza
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Re: 110HP to 3100cc

Post by '66Monza »

Thanks for all the info. Let me restate my situation. My 110- 4speed is blowing out oil like the leak in the Gulf. So bad that I switched to synthetic so I don't leave a cloud when going down the street. Since I have to have the cylinders done anyway, I was pricing things up and don't think it would really cost me anymore, less in fact, to just do the 3100cc jugs w/new pistons, and heads redone. I have to have the cylinders honed anyway, and for all I know some of my pistons are shot, so I figure why take a chance on all of that, just install new. Since I am going to go that far, I figured maybe I'd get the cam changed to, just to give me a bit more oomph!. I am not looking for a race car here. A bit peppier would be nice, reliable is the key. I want to rebuild the engine and never have to deal with it again. (I would hope). I know that 140 heads would be better, but they are also more likely to fail, correct?? I have other things I want to do with the car, such as two recovered seats, a better paint job.
I also understand that when this is installed, that it looks the same as a stock motor, which I like also.
So does this logic make sense to anyone??
miniman82
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Re: 110HP to 3100cc

Post by miniman82 »

You can always just do .040 or .060" over Corvair slugs, those make good power.
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'66Monza
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Re: 110HP to 3100cc

Post by '66Monza »

Yes, however, I will still have to get new pistons and rings, and no matter what, I think it's a smart idea to get my heads done since they have to come off, once you start adding all that up, American-Pi will do the heads and give you new jugs w/the 94mm Mahle pistons for $1575, I think that's cheaper than what you are suggesting. If all that I was going to do was hone the walls and get new rings, it would be the way to go. I don't want to get my cylinders done to have a valve seat start leaking oil or worse, fall out.
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