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MGB MGB 3 main engine porn

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Hap Waldrop

Hap Waldrop

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I sure would like to see more technical engine post here, heck more technical post about anything for that matter, so maybe I help can kick it off, a pretty picture always spike conversation. here's a MGB 1800 3 main head and set of rods I recently did for a fela in Texas, correct early MGB 3 main head fully ported and polished, with later style MGB valves, retainer,and collets, spo that way we could use the bigger 1.625" intake valves, HD valve springs, bronze guides, umbrella valve seals, instaed of those silly o-rings, and then a set of early 3 main connecting rods, I rebuilt, resized, balanced and ARP bolts installed, which is a bit creative job on 3 main engine's connecting rods. Enjoy,and hopefully topics like this can help for more technical post in this forum.
 

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BEAUTY!!!! Where do you source your bronze guides, Hap? Or do you machine 'em there?
 
Nicely done. One of these days I'll have a B engine for you to do, but not for a while.

Haven't had any technical questions lately, the car is running okay these days. Too busy driving it.
 
The bronze guides are available from all your normal sources, Moss, BPNW, now on a ported head like this, any head porter worth his salt is going to rework the guides, they are shortened, and reshaped, the exhaust are just bulleted on the end, I try to shape the entire section of the guides which extends into the port, on the intake, it is a bit more complicated method, I have lathe cutting tool I have custom shaped, so I can reduce the diameter in the port, and then radius back to it original diameter as it goes back into the casting of the head.
 
Thanks, Hap. We've needed a kick-start on the MG side for a while. Hopefully your post will help wake us up!

:cheers:
Mickey
 
Basil, yes I do my own port and polishing and own my own flow bench.


Scott the uprated umbrella seals are listed in Moss' cylinder head section for MGB, Gordon at the B Hive also keeps them in stock, they are the best ones I have found form the MGB, because they work with all dual spring set ups, and are easy to install, just slip them over the top of the guide, much like the ones used on Spridget A series engines.
 
Nice job!

I much prefer the MGB 3 main to the 5 main and raced with that engine for many years (until I went to the Twin Cam, ironically mine is a 5 main)
 
jimmie said:
hello iam new on here, trying to figer out how to talk to someone
Click to expand...

well this is one way. Another is to post at the new member introductions - tell us who you are and what ya got. (You might also want to post that info on the 'signature" of your profile.


You had, in another "tag on" post asked about brakes. If you want, start a new topic, tell us (again) what you have and what you need to know. Conversation starters are always a tad awkward without a topic.

That said, welcome, we' :cheers: re a friendly bunch here with a ton of knowledge. Are you restoring? repairing? regretting?

I have a Midget but visit the MG side as well as the Spridget posts.

cheers!
 
Bill,

Just got a '64 MGB with the 3-main. Why do you prefer the 3 main to the 5 main?
 
The 3 main is harder to source parts for and you have less choices, but it's good motor, the 5 main has way more parts choices, as for quality and performance upgrades and in many cases they cost less than the standard offering parts for the 3 main. TO each their own, but if sinking money into making a engine better, I'm going with the 5 main everytime.
 
marcm said:
Bill,

Just got a '64 MGB with the 3-main. Why do you prefer the 3 main to the 5 main?
Click to expand...

The 3 main versions run a bit more freely, although the factory never reflected any difference in the power outputs. They just feel better! And I've raced both 3 and 5 main, so have a personal basis of comparison.

What Hap says is correct though, parts are harder to get, and if I were building a pure race engine today I'd no doubt opt for the 5 main. But I have enough parts in the garage to keep my 3 main street cars going for another century or so!
 
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