Hello everyone, been a follower of the HAMB for quite a while but have only just signed up. Im building a BB Olds 425 and have access to a new set of Jahns forged pistons, C-1171 H RP std, and have exhausted my searching for a catalogue which tells me the piston weights. I did read one of the Hamb posts where someone had a catalogue but at that point couldn't register in the group to find out. Gotta love bad internet. If anyone has a catalogue i could download or even a copy of the page with that piston information would be great. The pistons are still available but didn't want to miss out on the price. My email if permitted, is mjhvette@tpg.com.au, thank you, Marty.
You might try JE Pistons (you'll never guess what the "J" in JE stands for); they may have an old catalog in their files.\ I am Butch/56sedandelivery.
thanks 56sedandelivery, but before i was a member, i read one of the posts and there were a couple of guys who still had the jahns catalogues. by the way, the je numbers dont match the Jahns after searching high and wide. Ill see if i can reloacte the members that had the catalogues in the earlier posts, they may have been from a few years ago. cheers.
just found this on the site from 2010, "Jahns was a cast piston company (pretty rough too). Jahn Jr. wanted to get into the forging piston scene so they set up Jahns Engineering (later shortened to JE). This is were JE Pistons came from." so that must be the connection.
My 1969 Jahns catalog page says: #1171 is for 1968-69 400 & 455 High Compression with Deflector, Bore sizes 3.870, 3 1/8, 4 3/16 avail Compression Ratios 12:1, 13:1 1965-67 400 &425 Bore sizes 4", 4.057, 4 1/8 flat top is #1156 nowhere in these early Jahns catalogs does it give any more specific details such as piston weight also the C in front of the # means it's Cast. An F in front of the # would be Forged
thanksd for the info 1933_willys_77, Bit confused why your listing shows 3 bore sizes for each part number, but only 2 engine sizes. Here are some pictures of the box and pistons. definitely says forged on the box, so im hoping some more info might surface. Also asked to seller to measure the weight on a digital scale. Will ask him to check piston pin height and piston diameter also. herer
I have a set of Jahns pistons and rings still in the box # 8-1139-RP . Any info on these ? I know they are .040 over 289. Cast or forged ??
Jahns cast pistons were the cheapest on the market back in the 50's but their forged piston was a quality piece but quite heavy. What Jahns would do and nobody else did was to sell piston blanks. You could then machine the wrist pin hole to give the compression height your build needed and cut the ring grooves where you wanted them and the width you wanted.
I recently recieved a box of new jahns forged pistons. The box is marked 6-1143H 3 7/8 .060. Does anyone have an idea as to what they might fit? They are a small dome style piston. Thanks!
I believe 3 7/8" is a standard bore size for a 283 chevy; this coming from a Ford guy. Chevy guys will chime in quickly.
I'm curious why is the weight so important to you? I have a set of what I believe to be forged Jahns pistons .060 over 12:1 for a 65 Olds 425 but only have 7. The guy that had the engine had a rod let go and it busted up one of the pistons. In my case a single piston weight should try to come close to the other 7 but a full set of 8 the weight doesn't seem to be of concern. Also the pistons you have pictured are high compression like 12:1 because stock pistons had a deep dish. Also I see that the pistons are "std." do you have a standard bore 425 to put them in? Where are you from? PS I own a 65 Olds 88 w/a 425 cu in engine and am building a 425 Olds engine for it or what ever I desire. Pat
What's the pin bore diameter?? That info will lead to which engine family they fit. The distance from the centerline of the pin bore to the top of the non-domed section of the piston(known as "compression height") will also be valuable information leading to what they fit if nobody can ID the part number any longer. Yes, 283 and 307 SBC are two of the possibilities of 3-7/8" bore....but there are other makes too with bore sizes near that.. Pontiac 350 Ford FE/FT 330" medium and heavy duty truck International 304" Navistar
I have to learn to read ALL the posts, my reply was for Martin Hewitt then I find that was from 2018. Although I read sprint3 question I thought it referred to original posters query. In any case Sprint I can't help you, like Eric says check the dimensions. Pat
Pin is .927 or very close with my cheap azz calipers. From all measurements I am 99.9% sure they are for a .060 over 292 chevy
@sprint3 I did see your message earlier this week I've just been very busy lately. Yes they are 292 Chevy 6 cyl with 12:1 compression. That's all the catalog page lists.
I have a set of Jahns pistons numbered 1108C and looking for a catalog listing with dimensions and applications etc. Any assistance much appreciated.
Might as well jump on board here; I have a set of NOS Jahn's, cast pistons, flat top with two valve reliefs, for a STANDARD bore 265 Chevrolet, like there are any standard bore 265's left on the planet. And, I'll probably never use them, even though I have a 57, 265 block that is standard bore with hardly any ridge. Just too many projects going on, and I'm sure everyone knows what that's like. I am Butch/56sedandelivery.
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