Sorry I wasn't clear, I meant that from your calculations you would be .080 and that's not ideal. .045 would be better by far but a lot of 292's ran around with .080 Quench. I am guessing between the compression and quench 10 HP. 159 vs 169****uming a 500 holly 2bll. Just a guess....
If it were mine I'd never accept 0.080 quench. Also if it were me in your shoes I'd never accept additional charges for dis and re****embly. To me 0.080 quench is a***** up. And and and this is so easy to catch. Takes about 3 seconds on a calculator to be able to foresee a possible issue. Maybe a full min. To calculate a deck cut and be at least in the zip code of correct. Takes 30 mins to do a mock up and actually physically measure what the correct cut on the deck should be. But I'm not you and you aren't me. But that's my opinion. Want an*****ogy or two,,, Putted off the green Missed the backboard Throwing a hot dog down the hallway Again my opinion your mileage will vary
This is frustrating. Now I don't know if I need to call him back and actually get stern and tell him to fix the block without an extra charge (in which an arguement will probably ensue and he won't do that) or just accept the .080 quench and run the motor as is and keep the situation calm. I don't want to make this into a bad experience and I'm not an engine building expert but is .080 quench really that bad? Am I really being screwed here or am i just losing a tiny bit of horepower? This thing doesn't make a whole lot of hp to begin with and I just want to have a nice daily driver quality motor for my car and then POSSIBLY turbo it in a few years if ever.
I'm curious about the pistons you used? maybe I could get this engine out of the machine shop now and then wait a couple months and save up the money to swap the pistons out later to improve the quench AND the compression ratio at once.
I understand the difficult position you are in and without being in on all the discussions I would rather not advise you how to deal with your machinist. If I was a machinist the last thing I would want is my customer calling me and telling me what some guys on a message board said. The power difference is about 6-10 HP for .5 compression and the quench, and probably a bit of fuel mileage. Tight quench engines are more efficient at part throttle and require less timing. It's your call, not a life changing thing, a bit nicer easier to tune engine.
That is a good bit of difference to me and it still seems important overall to get the compression up higher to help with the camshaft choice. I will be at the shop tomorrow to see everything and talk to him in person and see what happens. I found a set of forged pistons that are $600 with wrist pins and rings. They only come in .040 over bore though and mine was only bored .020 so there again I would have to have more machining done to the block for those to fit. All I found at summit racing was cast pistons. http://12bolt.com/250292_products/292_forged_pistons I will print this webpage out and bring it to him and see what he says.
Ok, but you would probably want to wait till you get those pistons to cut the deck. Have you checked into the Lump Port mod? http://12bolt.com/lump_head_information Hoop
Yes i will definitely will wait for those if I decide to go that route. I have looked into the lump port mod several times and it has benefits, but I don't think I would personally have to go that far and actually install them since the flow difference with them installed seems unneccesary for me and my HP goals. The charts seem to show that cutting the bolt boss out and increasing the valve sizes alone would give a pretty nice increase in hp and tq and I would be pretty happy with around 250 hp and the better tq curve. plus not having the lumps installed would save a lot of money, somewhere around $400. At this point though, they already ordered the new valves and installed new seats, and springs and everything. I would pretty much have to sell this head to someone else and find another head to rework with the larger valves.
I had my head redone on my 292. Those motors were in wheat trucks, combines, so forth The low compression is so they will run off mudwater gas, drip gas if need be. I hope it works out for you. Sounds like you will be fine.
The pistons on my site 12bolt are made with a taller compression height to get you within .015 of the deck. So very little cutting of the deck is needed to "zero" deck the block. They are also lighter and stronger than those cast stock type pounders. I would not deck a block .050. The head , yes, but that would be max for street use. Your stock type pistons have a 30CC dish, try finding either pistons made for LPG or use mine. The dish used in mine is 18CC.
WOW, quite the site there. Wish it, and the net, had been around when I built my six. Almost makes me want to do one again. Way back when I did mine, no one wanted a six, and those that had them were putting in V-8's, especially the boxy Nova/Chevy II guys. At the time I had collected 6 of the small chamber 194 heads, I used one on my 250; the rest ultimately found their way into the trunk of a hulk car to add weight to it for scrap (which was very little then also). Like a lot of things, I should have kept them. I even have the Hot Rod Magazine with the Turbo Tornado F-85 I saved for just that article, and John Dianna's 56 Chevrolet Sedan Delivery Junior Stocker, along with the open drive line conversion for early Chevy's (three saves in one magazine!). I have bookmarked your site for future reference. Thanks, Butch/56sedandelivery.
I don't know any engine builder worth his salt that would build .080" quench into an engine, that's just wrong. He should be responsible for pulling it down now (at his expense) and getting the quench to between .035" and. 045". He should know better, simple as that. Duke
FWIW, there are many older engine designs and truck engines which came from the factory with pistons .080" in the hole and 7.5 and lower compression. That's the way it was back in the day. On a pretty much stock rebuild, the shop orders the parts and sets bore and bearing clearances and bolts it all together. It is not usual to even measure deck clearance when rebuilder pistons are used. They are what they are and it is what it is. If the rebuilder was just told general directions, bore it, mild cam, be glad he was proactive enough to tell the customer what compression he'd be getting with that combo. Many shops would have just bolted the head on it and sent it out the door. If the goal is a custom build with a specific compression ratio desired at the end, put it in writing so the estimate will reflect trial****embly, CCing head and block and calculating compression ratio. Shop hours is shop hours. Expect to pay for them Bottom line - what did the customer provide as to written directions and outcomes and what did the written estimate say the builder would deliver? As far as what he said/she said on the phone, it never happened. Go over what it is/where it is now, state clearly the compression ratio desired and start negotiating in good faith and in writing and it's lessons learned. jack vines.
Main thing is, you are probably double the original power now. Get it together, get it sorted and enjoy that sweet ride ( I am watching your build). You may love it where it is, or you may decide to go for more in the future. As you learn through each stage tuning would be a good place to maximize the driveability. A well executed package of carburetion, and timing control will make more than 7 HP difference and pay off in motoring pleasure and economy.
Perhaps it varies by region or by shop ,,, Rebuilder style pistons have a lower compression height. And , there is only one reason for this , only one. To bring piston height back to stock after decking the block. There is no sense or reason to install rebuilder style if there is no intention to deck the block, none that makes any sense anyway. This********* of "you get what you get" and "it is what it is" wouldn't be acceptable around here. I'm sure it is in some places though, and those are the places that should be avoided when quality and craftsmanship are valued. A block that is not being decked doesn't need rebuilder style pistons and they shouldn't be used in that situation. Not every block get decked or needs it, but the rebuilder style piston and decked block have a "glove -n- hand" relationship.
Does not fly around here, either. Any shop that did work that sloppy would be long out-of-business. Word gets around fast, real estate is very expensive, and poor quality work will put you under, here, in a heartbeat. It is not the job of the customer of a machine shop to ride-herd on the machine shop about every little detail. That is the machine shops' job. Machine work is not a guessing game. Engine building is not a guessing game. Every shop I deal with provides a detail report, of every single dimension, and specification. That is the standard I expect, and will not accept work without it. I have been doing this since the 80's. I have never seen or worked with a shop that just bolted on the head and sent it out the door. That is simply not acceptable.
They are Sealed Power pistons that came in the rebuild kit, .020 over You are pretty close to telling what happened in my case. My issue is that I never got anything in writing from the beginning. I know we talked a lot on the phone (while i'm at work on lunch break) and I know I told him that I would like a higher compression ratio but I suppose I was not adamant about reminding him of this fact. Then the block was in the process of having the cracks welded up,which was done elsewhere, and then brought back to the machine shop and they started on the block finally. It took a few weeks to get to this point and it was a big deal to me wondering if the guy welding the cracks up would be able to pull it off... especially the crack in the side was questionable to the welder which worried me. At this point I had spent $75 for clean and magnaflux, and then I bought the engine for $100 last year, and this welder was going to charge a couple hundred for fixing the cracks. I was just hoping I hadn't wasted $175 on the engine so far. The point is that this got me away from thinking about the compression ratio issue all together and when the welder did call me a week later and told me that he was very happy with the repair then I was relieved to hear it and just glad i didn't have a giant $175 paperweight. The machine shop started their work and ordered a master rebuild kit with the camshaft I chose and then****embled the short block at some point about a week and a half later. I wish he would have presented me with possible options about the comp ratio needing to be higher before they had****embled but I do understand that they are not necessarily going to think that my boring 292 truck motor would be something that a customer would want to go wild with.
Right now i believe that I want to just pick up the block as is. It will be a few months or more before I will be bolt the head onto it permanently and I'm thinking that I might just wait and save more money for a different set of pistons that have a higher compression height than these "rebuilder" pistons I apparently got. tlowe races these engines and said that he would NOT deck the block .050 to fix my problem so i will just wait a while and come back to this issue later. Plus If i pay the shop the 3 hrs labor to disassemble, machine and clean and reassemble the block, then I would still have stock cast pistons :/ I would rather put that money towards forged pistons instead since I can just take the rods and pistons out of the block myself and have the pistons swapped on the rods by a shop for a lot less money and then I would reinstall them. I'm not an engine builder professionally but this seems like the best thing I can do at this point. At worst, I wasted $150 on the cast pistons and maybe I can sell them to someone else later. Seems like an acceptable "learning cost" to me for my first engine build.
I did print out a bunch of info about removing the bolt bosses from the siamesed intake ports and brought it with me to show him yesterday. It was funny, the day before I had told him to NOT****emble the head yet and he told me that was not a problem. When I got there yesterday and we walked back to where the head was and we found the guy back there was in the middle of****embling my head! I thought to myself "I'm not paying for that labor!". The owner told him right there that we were not****embling that yet. The worker definitely seemed frustrated about this in a kind of whiny little kid way with his body language which very unprofessional in my opinion. I don't know what might have possibly made him mad earlier that day or whatever but I was not happy to have this guy working on my stuff at all with the way he acted while i was there. This is a RACING ENGINE shop where most of their work is local race car teams and I can only speculate that he might hate working on my dumb 6 banger or something and only wants to work on the big bad blower stuff.... Anyway, so me and the boss and worker are all looking through what I printed out and I talked about cutting the bolt bosses out and the lump installation and then I asked them "have y'all ever seen or done any of these 6's like this or anything?" and they said nope! I should have known but i had to make sure at this point. The cylinder head looked really good and everything was done to it so far that I asked. I am going to have them cut out the bolt bosses and counter-bore the floor of the intake to install a short bolt. The boss and I went into his office and spoke about the push rods and other things i still need to buy and I mentioned that his worker seemed mad and I don't want someone like that working on my stuff. He told me that he was personally going to do the additional machine work and reassemble it. Yes there will be a small bolt head sticking up but that is much better than the full bolt boss and it should still help a good bit with my larger camshaft. I decided not to do the lumps as well in order to keep the costs down and also because I am not racing this engine. I know they are beneficial but not needed for my relatively tame engine in my opinion at this time.
Yes I was wondering about that too at the shop. The factory pistons have a D shaped dish so i don't understand why these are a full dish. That made the quench area smaller for sure.
Here is a pic of the Ross Pistons, notice the quench/squish pads. As the piston approaches TDC this directs the charge toward the center of the chamber. This charge motion plus the shorter distance for the flame to travel is all for the good. The last thing you want with pistons down in the hole is a big old bowl. Even the stock pistons at least have the pads. Stock piston Sealed Power Cast stock replacement would perform better
Sorry for the delay in responding. My pistons are from Tom Lowe, and his spec, with the 18cc dish. Posted using the Full Custom H.A.M.B. App!
You are fretting about to many things at once, pull back and think it over. Thank the shop for the work they have done, take it home and look it over for a week or so. And think about this, you will never feel 5 or 10 hp difference driving on the street, so quit shooting for a magic hp number. I have drove a guys 500 hp {engine dyno numbers) car that wouldn't spin the tires from a dead stop! He wanted 500 hp, so the shop got it done, the power band was so high and so narrow, the car was slower then the stock engine was in everyday driving. Go back to a stock type cam to recover some compression, or look for one with less overlap, and stay away from the 194 inline head, yes they give better compression, but the ports need a ton of work just to get up to where you stock head is. Joe
Thought the target was 200 hp and I got that from the first post. The 10 difference of 159 or 169 isn't any where near 200. It's around 20% off give or take. Kind of like dropping one cylinder off of a 6 cylinder and running on 5 of them but that's only 16.xx %.
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