Teksid block Vs Stock 03 Cobra block - pics iside
- Thread starter MalcolmV8
- Start date
- Status
Good thread.:beer:
Who's doing your machine work? If they don't have a torque plate go somewhere else, if they have one that means they do enough mod motors to make that investment and are set-up for the job. I'm real selective about machine shops. My block goes to a toolmaker friend who checks the squareness and the linebore of the block then I have "his" numbers and ask for the "shops" numbers before they start any machine work. They are basically cross referencing each other and the machinist will know this beforehand and will be very careful knowing I have knowledge of the block geometry before they do. If the numbers are far apart there's a problem. After the bock is machined it goes right back to Keith who verifies the finished results and the shop will be know it's going to be checked before the engine is assembled which will provide a little more incentive for them to make sure the block was machined correctly. I am suspicious of the calibration of the measuring equipment and how much care the machinist puts into getting the measurements its very time consuming to do it right. I've worked closely with and in aerospace inspection dept's and have a deep respect for the kind of skill it takes to get accurate dimensions. After that you need to have confidence in the equipment and the machine operator. It sure looks pretty getting a freshly machined block but what your looking at could be worse than before if the shop was sloppy. Resently a friend brought a brand new block in to get clearance honed and the shop ended up punching it out with a .007" PWC! 
Then again some shops take great pride in their work and has good equipment The problem is finding them! They all talk-up their game, some places I could not run out the door fast enough :uh oh:
Not trying to scare anybody, just be very careful with this step and don't rush this, be skeptical, observant and ask lots of questions. This can make the difference between an engine that you can flog all day long and one that clocks out after a few hundred miles.
Then again some shops take great pride in their work and has good equipment The problem is finding them! They all talk-up their game, some places I could not run out the door fast enough :uh oh:Not trying to scare anybody, just be very careful with this step and don't rush this, be skeptical, observant and ask lots of questions. This can make the difference between an engine that you can flog all day long and one that clocks out after a few hundred miles.
awesome post malcom!
Who's doing your machine work? If they don't have a torque plate go somewhere else, if they have one that means they do enough mod motors to make that investment and are set-up for the job. I'm real selective about machine shops. My block goes to a toolmaker friend who checks the squareness and the linebore of the block then I have "his" numbers and ask for the "shops" numbers before they start any machine work. They are basically cross referencing each other and the machinist will know this beforehand and will be very careful knowing I have knowledge of the block geometry before they do. If the numbers are far apart there's a problem. After the bock is machined it goes right back to Keith who verifies the finished results and the shop will be know it's going to be checked before the engine is assembled which will provide a little more incentive for them to make sure the block was machined correctly. I am suspicious of the calibration of the measuring equipment and how much care the machinist puts into getting the measurements its very time consuming to do it right. I've worked closely with and in aerospace inspection dept's and have a deep respect for the kind of skill it takes to get accurate dimensions. After that you need to have confidence in the equipment and the machine operator. It sure looks pretty getting a freshly machined block but what your looking at could be worse than before if the shop was sloppy. Resently a friend brought a brand new block in to get clearance honed and the shop ended up punching it out with a .007" PWC!
Not trying to scare anybody, just be very careful with this step and don't rush this, be skeptical, observant and ask lots of questions. This can make the difference between an engine that you can flog all day long and one that clocks out after a few hundred miles.
It's a local place in KC, Mercer Machine, owned and run by Shawn Mercer. It's the same guy who did my machine work in 09. He did a great job back then and hopefully still does. Yes he uses torque plates and is fairly knowledgeable. Last time he even worked with me to get all my bearing clearances just right for the 10w30 oil I intended to run. He got my piston to wall clearances spot on too so I had no piston slap but no issues with highway pulls even balls out on spray. He's also the guy who double keyed my crank and lower pulley. He line honed, decked the block and all that good stuff. Every measurement I was able to check was in spec. I don't have machinist quality set of measuring tools but I have a fair amount and was able to check a lot of the work. Things like how straight he got the line hone for the crank I had to take on a leap of faith based on how well he did the rest of the work. As well as the balancing, I have no way of double checking he balanced stuff right.
The only sticky part this time around is I'm going with flat top pistons and comp stage 3 cams which means some valve reliefs for the intake valves. How to relay that to Diamond is going to be tricky. I don't want massive oversized reliefs killing my CR and I don't want to small to where I don't get my PTV clearance. Kinda hard to measure and figure out without assembling the engine and impossible to do till I've ordered the pistons and had machine work done. Chicken and egg scenario.
Having prior experience with a machine shop and having good results takes a lot of the worry out. I live in Los Angeles where shops are within a stones throw in any direction, visited quite a few and have gotten lots of referrals but I still haven't found my huckleberry. My block work is still a ways away and will need to throw a wider net.
Nothing scares me more in this engine then the relationship between 8 pistons, 32 valves and 4 cams. Add high lift cams and stiffer springs to the mix and it can get dicey. Having to add reliefs in the pistons adds a stress riser to both the crowns and the owner. It's the price you pay for the privilege of more flow thru the heads. I'm sure you will work through it in a methodical fashion. It's hard to beat a garage built motor as shop can't devote as much time and attention to the assembly. Engine work is a lot of fun though. Look forward to seeing your progress.
Malcolm, maybe I missed it. Are you just doing this as new "built" engine, or was there issues with the stock one? I don't recall seeing any threads about you having problems.
Great thread BTW.
Great thread BTW.
Engine was still running like a champ. I rebuilt my stock engine in 09 after doing about 10 back to back highway pulls and scuffing cylinder #4. I lowered the CR with larger dish pistons and hated it every since. Killed throttle response, HP, and gas mileage. Yeah I don't care about gas mileage but with such a tiny tank and long trips to E85 pumps it becomes an even bigger issue.
So recently I've been pondering upping the CR and then I decided I wanted cams but that would kill my already horrible DCR. So this was on the back burner and something I was itching to do.
So my son is 14 now and obsessed with cars and engines. He spends hours on youtube learning how pistons, valves, turbos and everything else works and then comes and asks me a million and one questions. More recently he's been asking me to buy him a fox body to start working on, he's dying to get his hands dirty. Well I'm not ready to have extra cars laying in the driveway just for him to work on lol. So I made him a deal. Tear down my Cobra engine and rebuild it under my supervision and we'll see about his own car when he's a little older. Of course myself and some buddies had to pull the motor from the car. After that he took over. He tore the whole thing down to bare block while I sit back and watch and explain. It's hard for me to just sit back and watch because I love this stuff but he's learning and doing a great job.
So yeah I figured why rebuild with the cast iron block and that's why we picked up the teksid aluminum block for the new build. This time I'm doing flat top pistons, comp cams, long tubes and such. Looks like we found a local guy to port the heads too but I want to go over and see some of his work before we commit to that.
I'm excited, looking forward to the crisp responsive throttle and love the sound of cams
Awesome, and that's great about your son. My oldest, who's a lot older than yours is the same way. In fact, just a few months back he bought some special 2L Honda motor, built the crap outta it and swapped it into his Civic. N/A, not turbo like yours.
Very cool. It's nice to have the same interests and do stuff together like that.
So we tackled the timing cover bolt issue today. Here you can see the freshly drilled hole next to the one that was already there.
So one important thing I had NO idea and have not seen anyone mention is when you drill and tap a hole for this timing cover bolt you drill right into a coolant passage
I had no idea that was going to happen. Had I shorted the bolt about 1/8th of an inch and slightly short drilled the hole I would have been fine.
This arrow shows you which coolant passage I'm talking about.
Here's looking up inside that coolant passage. See the hole where I drilled all the way though?
Anyhow here's tapping the thread with the timing cover in place to make sure I was dead centered and perfect.
All done and the bolt fits in now.
Really wish I knew about the depth issue and didn't go into the coolant jacket. Not to a big a deal I suppose. I just have to remember to use a good thread sealant on the bolt threads and it should be fine.
So one important thing I had NO idea and have not seen anyone mention is when you drill and tap a hole for this timing cover bolt you drill right into a coolant passage
I had no idea that was going to happen. Had I shorted the bolt about 1/8th of an inch and slightly short drilled the hole I would have been fine.
This arrow shows you which coolant passage I'm talking about.
Here's looking up inside that coolant passage. See the hole where I drilled all the way though?
Anyhow here's tapping the thread with the timing cover in place to make sure I was dead centered and perfect.
All done and the bolt fits in now.
Really wish I knew about the depth issue and didn't go into the coolant jacket. Not to a big a deal I suppose. I just have to remember to use a good thread sealant on the bolt threads and it should be fine.
The block measures exactly 3/4" thick at the spot you have to drill. You could safely drill 1/2" or even 9/16th. Heck even 5/8s if you're careful. Then just shorten the bolt accordingly.
Very nice progress so far.
I should also add you want to tap an M8 x 1.25 thread. I'll go back and update the very first post as I make progress with the differences and resolutions so eventually the very first post will be a complete set of differences and how to overcome them for anyone doing a search.
Malcolm, Be wary of the local head porter. Some have focused on a particular head or heads and have developed their procedures over time with their flow bench, previous knowledge and cutting heads apart. They may have some of the best flowing heads around. Others think they understand what needs to be done, but lack the knowledge of the head and bench testing to make real improvements. They can make the head weaker, reduce velocity and flow less because of this lack of testing and experience.
I would ask anyone you are considering what the heads flow at 28" of water at various lifts (up to your intended lift for sure) and how many mod motor heads they have done. A good porter would be able to tell you flow numbers without hesitation, and you can compare these numbers to others. You can also have yours verified after porting. All of the major CNC porters for our heads claim similar numbers at similar lifts and port CCs. If your local ported is much higher then those, he is fibbing!
I would ask anyone you are considering what the heads flow at 28" of water at various lifts (up to your intended lift for sure) and how many mod motor heads they have done. A good porter would be able to tell you flow numbers without hesitation, and you can compare these numbers to others. You can also have yours verified after porting. All of the major CNC porters for our heads claim similar numbers at similar lifts and port CCs. If your local ported is much higher then those, he is fibbing!
Thanks for the heads up. Will do. A local guy had his heads ported there and claims he picked up 70 rwhp from it. That's what perked my interest. I still need to meet this porter and get first hand info on his work and numbers etc.
Great info in this thread.
Addressed the timing chain tensioner pins tonight. Used this awesome kit from Cobra Engineering. Apologies all pics tonight were right under the shop lights which were way to bright over exposing all pics like I had an over powered flash on. whoops.
It came with two different inserts. One snugged the drill bit exact and the other the tap so you'd be perfectly square both drilling and tapping the new threads.
Here's tapping the threads
All done with heavy duty pins in place.
It came with two different inserts. One snugged the drill bit exact and the other the tap so you'd be perfectly square both drilling and tapping the new threads.
Here's tapping the threads
All done with heavy duty pins in place.
- Status
Users who are viewing this thread
