JB Weld?!

[bholmes]

OOOook, I'm prob gonna get beat up for it....but has anyone used JB Weld on their ports? In my readings of either Grahm Bell or Jennings, I don't remeber which, but they talk about epoxying up your ports to lower/retard your port timing/opening. Any experience out there? My inclination is I wonder 1) the heat it sees and 2) how dissimilar are the thermal expansion rates of JB weld or epoxy and the aluminum of the cylinder.....any help out there?

[278]

First why are you trying to close up the ports? Ass far as JB weld, i think it would work and Ive heard of it being used but there is some better stuff. Talk to some builders and see what they use in the case halfs to epoxy and port match them. Also I cant remember exactly what it was, maybe this person will chime in, but there was a guy on here talking about a filler that they used on the cylinders of huge ships like oil tankers and stuff, that he suggested using so maybe thats something to look into too.

[broncbob]

I'd check what is used for port work, JB would work, but there is better stuff out there.

 

You had better make sure that you follow the instructions to the letter.

[bholmes]

I'm wanting to fill my ports because my banshee has to much power and scares me. LOL not really. I want to fill the tops about 2mm (i gotta do final calculations once i get all my parts in) to retard my port timing and then take some out of the bottoms to get my proper duration because i'm going to be using a 4mm stroker crank. Basically I'm wanting to time it like stock for the 4mm crank and proportional port area/displacement to the best of my ability. I have found some liquid steel stuff they use at a local power plant a friend can get me that I think I will end up using. It is supposed to be good enough to use on heat exchangers so I think I'll be OK. Thanks for the help guys.

[broncbob]

I have never seen epoxy in exhaust ports, only on the intake side.

[bholmes]

I don't think I said i was going to use it on the exhaust port.....but even if I didn't say it you read my mind LOL. Where have you seen it used? On the transfer ports only or transfer and intake? I'll have to look more into the exhaust port and see what I'm up against there. I'm not sure that having it open a little longer will hurt unless it's sucking unburnt fuel charge out.....hmmm any insight?

[papa_smurf49319]

ya i have some insight, send your damn cylinders out already. I know you gotta learn somehow, but i dont think reading a couple books and grinding away is your answer. You need to go to school, or find someone who has been in the biz for awhile and let them show you the tricks. Just because i read a book on regrinding camshafts and porting cylinder heads for small block chevys doesnt mean im going to attempt it. Your essentialy doing both, which can be very tricky. Trust me you will be much more happy sending your cylinder heads out and getting them ported. If your already contemplating using epoxy then your making mistakes. Trust me i never like to send anything out, or have anybody touch my stuff, i rebuild my own automatic transmissions, engines, manual transmissions, etc. But porting is a ART and im not that talented, and dont have anybody that talented near me to show me the tricks.

 

 

 

Just my two cents take it how you will

 

 

 

Cody

[broncbob]

I have never seen in in a 2 stroke, lots of it in heads for 4 strokes and car heads. It has all ways been used on the intake side, normally to change the height of the floor of the intake runners it up velocity through the port to try and get better than 100% V.E.

 

The exhaust side work is normally opened up as to match the header, and then some work around the valve and the bowl to increase flow to the max, and reshaping of the floor of the port doesn't include epoxy, as it's add to choke the flow up on the intake side.

[papa_smurf49319]

Exactly what broncbob said, at least on smallblock chevys there isnt a whole lot to be had on the exhaust port, the real horspower is in the intake side, you want as straight as possible shot to the combustion chamber without losing to much velocity ie air speed, you want to keep that up thats where the eighteen degree stuff is nice but expensive. None of this applies to the banshee except for the fact that i wouldnt wanna use jb weld or any epoxy for that matter anywhere near any type of extreme temperature.

[bholmes]

Trust me, if I had the cash I'd be sending my cylinder out. I prob shoulda stuck with a reg stroke crank, but they were the same price soooo oh well. Hind site it 20/20. I'm very confident in my ability to port regardless. I ported my YZ490 and came up with a pretty good result, more top-end than previous. May not have been perfect, may not have run as good as if I'd had it professionally done. I'm just trying to see what experience there is out there I might be able to glean some information from.

[278]

Trust me, if I had the cash I'd be sending my cylinder out. I prob shoulda stuck with a reg stroke crank, but they were the same price soooo oh well. Hind site it 20/20. I'm very confident in my ability to port regardless. I ported my YZ490 and came up with a pretty good result, more top-end than previous. May not have been perfect, may not have run as good as if I'd had it professionally done. I'm just trying to see what experience there is out there I might be able to glean some information from.

papa smurf is a good guy but he is being a little harsh. Porting can be done just dont expect as good of results as you would if you sent them out. Idk what type of riding you do but i think a trail port from Wildcard is around $230, and an aggressive dune port for a 4mil is around $270-280. Dont quote those numbers but im close with them, you can call Brandon and Shay and ask. The other good builders that i would send my stuff to ie. Herr Juggs and F.A.S.T. are close on pricing too. Just saying by the time you buy all the books, spend all the time learning and doing it yourself, plus buying all the right tools youll spend maybe 150-200, but I think youll be way happier sending them out. With that said if you really want to do them yourself all the more power to ya' eventually i will try some porting myself, but I did sned my cylinders to Wildcard and dont expect to get results even close. As far as advice... dont epoxy anything, not any of the 3 builders i named do this and they are considered to be some of the top builders. As far as builders who do "big block" banshees like K&T or RDZ i dont think any of them do what you are saying either. I would say you have alot to learn before you start grinding on your cylinders. You have to figure out what pipes your going to run, what kind of riding you do, what your other mods will be etc. there are alot of variables. Your not just removing material also you're re-shaping the ports. Im not a pro but if you figure out those variables i can help you. PM me if you'd like and maybe I can help you out with your porting

[bholmes]

I'll be running LRD pipes and silencers, wiseco 759 pistons, 4mm stroker crank, i'm gonna go ahead and use the base plate despite ridicule to save on machine work, running stock carbs and a toomy 2 into 1 open air cleaner. stock reeds and cylinder heads. I'll be running a 13/41 sprocket set up and 20" tires out back. I ride primarily tight east coast type woods and do some nice hill climbs. But I really don't care if it's ported for max power or my particular riding. A stock banshee engine with those mods runs good, I just want it to run good with more torque than before, I'm not doing a max effort port job or anything. My trails are tight and don't allow you to really open it up for very long before shifting, turning, braking etc. I just want it run GOOD.

[Ieat4strokes]

Id be more worried of JB weld breaking loose and getting sucked into motor = a very bad day! That stuff from my experience doesnt adhere to well and tends to break loose under constant contact with oil/gas....

[papa_smurf49319]

umm i think maybe your mistaken, ive used it on oil pump pickups in cars where there is a press fit, and seen many others use it in that particular application where it is constantly submerged in splashing oil, and it seems to hold up well there. I do get what your saying about it maybe breaking off in the intake side and going crazy in the engine though. Just saying i know it holds up to motor oil well.

[bholmes]

I spoke with a machinist that works on polaris and yamaha's (Rick Ritter of RCR) and he says on the stroker banshees that he does all I need to do is match my port bottoms to the top of the piston, and forget about the spacer plate (as i've been told before lol) and machine the head for piston clearance and he says the opening of the ports will be OK. He said that's more or less how he builds a stroker banshee with out major port mods. Sooooo no JB weld needed!