Just reading throught the forum and have come across this a fair few times, what is dowling and what does is it involve? Most of the time i see it associated with porting. Just wondering involves and what you achieve out of it.
Cheers
Gav
at the interface between the side housing and the rotor housing Mazda fitted a few dowels for alignment of the housings. My understanding of doweling the engine is that more dowels are fitted to help prevent any distortion when running high boost pressures and or horsepower.
I\'m sure someone else will chime in and provide more detail.
Ahh right i kinda of see, wonder if anyone else has pics of a "dowles" rotary so i can see where abouts this takes place.
Cheers
Gav
its as mike says. the engine block is made of 5 plates, two end plates, two rotor housings and a centre plate. They are flat and bolt together with 17 bolts that go through from the back to the front.
The bolt holes are a little bigger than the bolts so there would be nothing to stop the plates twisting if it wernt for the 2 dowels that mazda use. They fit snugly in plates in two of the bolt holes and the bolts go through them. The dowels that mazda use are only half length. one for the front of the engine and one for the back.
When they are dowelled by a tuner they will drill out more of the bolt holes, (maybe every other one) and fit dowels in them. This helps to stop the plates from twisting with large boost or BHP.
I\'m not sure if they use dowels that go from the front to the rear or if they do what Mazda do and make them half way. Would seem to make sense to use full length one though.
not an easy one to explain in writing, hope i\'m not teaching you to suck eggs and it makes sense
Ahhh i see, that totaly clears things up you guys now made it easy to understand...its pretty straight forward for what it does.:cool
Cheers
Gav
Dowel
Hi, when I dowelled my 13b in oz the builder drilled out all of the botl holes and then reamed them to suit the new bolts we had made. We used high tensile(not sure what it was called) steel rod to make our new bolts and they fitted very snuggly. The motor was also a 6 port. But that is neither here nor there. It also had mild porting and 3mm apex steel seals. I had intended to run alot of boost. Hope this helps. You could always just give carl hayward a ring, he can help where my dodgy explanations might be a bit vague.
cheers, michael.
Cheers guys, explaned it all, well what i needed to know anyway :) so rule of thumb really, going for big boost, get the engine dowled.:confused:
Gav
Here are some pics of the process. This was on a PP motor. It is not an easy task and not actualy necessary. My buddy/partner\'s motor is making over 800hp on a street ported motor without nitrous and is not pinned nor has any of the motors in his car ever been pinned.
(http://kgparts.com/images/Pinning/atlantic%20009.jpg)
(http://kgparts.com/images/Pinning/atlantic%20023.jpg)
(http://kgparts.com/images/Pinning/atlantic%20024.jpg)
(http://kgparts.com/images/Pinning/atlantic%20025.jpg)
(http://kgparts.com/images/Pinning/atlantic%20026.jpg)
(http://kgparts.com/images/Pinning/atlantic%20027.jpg)
(http://kgparts.com/images/Pinning/atlantic%20028.jpg)
(http://kgparts.com/images/Pinning/atlantic%20029.jpg)
(http://kgparts.com/images/Pinning/atlantic%20031.jpg)
hmmm...would not let me post all my pics in one thread. here are a few more....
(http://kgparts.com/images/Pinning/atlantic%20032.jpg)
(http://kgparts.com/images/Pinning/atlantic%20033.jpg)
(http://kgparts.com/images/Pinning/atlantic%20034.jpg)
(http://kgparts.com/images/Pinning/atlantic%20035.jpg)
(http://kgparts.com/images/Pinning/atlantic%20036.jpg)
(http://kgparts.com/images/Pinning/atlantic%20037.jpg)
(http://kgparts.com/images/Pinning/atlantic%20038.jpg)
(http://kgparts.com/images/Pinning/atlantic%20040.jpg)
Wow 800 bhp :D that is some serious peice of kit your using there, is to drill out the holes for the dowels or just to check the size/diameters etc.
Gav
WOW, very cool photos. Thanks for them. Would you be able to give us a bity more info on your friends motor? Like, how long it lasts with 800hp cursing through it? I know loads of engines in oz with similar ourputs and I know how long they last with dowling. So I would be very curious to know. Does he drag race or do some other form of racing with it?
Thanks again. michael.
Dowling can help a motor that detonates in that the forces involved can be enormous.Not that you deliberately tune an engine to det but if it does for some reason then it can at very high outputs look after it.
Also there are some motors that even with stock outputs have been known to crack where the stock dowels locate in the end plates.These engines are running stock ecu and ancillaries.
Regards
Carl
nice piccies, very interesting to see some of the work that goes into these engines, usually we just get to see the bling shots of the end product. In my humble opinion these are much more interesting :cool
Just for interest, there is also a shallow dowelling technique sometimes used (i.e. I have 64 dowells in my engine!) - however I believe it isn\'t the best way to do it. The full dowells through the engine are better.
But as rxrotary2_7 has mentioned, it is possible to produce huge hp without dowells (AVENGE/Marty Heards 8.0second Datsun with a 13B twin turbo engine is a good example - made 900+ on an engine dyno).
Some pics here of the shallow dowell technique:
.
..
Hi Glen,
On mine I have dowelled all the way through with one piece dowells the whole length so in effect my engine could become a structural member in a car such as a single seater.
Nice pics BTW.
Regards
Carl