so I broke "the belt"
10-24-2008, 10:09 AM
#61
Drifting
Thread Starter
It'll be inaccurate, because you have bent valves...
A compression test can help you diagnose a bent valve (because the combustion chamber won't seal tight). But, on these engines, you don't need to diagnose that - it's an assumption.
Right now, you're better off doing a visual inspection on the block/cylinder walls after you pull your head (the one with the bent valves) off.
A compression test can help you diagnose a bent valve (because the combustion chamber won't seal tight). But, on these engines, you don't need to diagnose that - it's an assumption.
Right now, you're better off doing a visual inspection on the block/cylinder walls after you pull your head (the one with the bent valves) off.
by the way, something I am unsure of: these are the "zero tolerance" engines? so the belt goes and the rest follows? something one of my co-workers mentioned. he also said that's why he likes domestic engines driven by chains. conversion?
10-24-2008, 12:10 PM
#62
Rennlist Member
The "zero tolerance" or "interference" engines offer higher performance through an increased compression ratio and longer valve duration.
There are "chain driven" engines that could also "interfere" if the chain breaks - but it is a less common occurrence. (I once had a timing chain in a bigblock 400 break... that stranded me in Nowhere, PA.)
But, your coworker is right, many of the domestic econo boxes have engines that do not bend valves when the timing belt breaks.
Perhaps you best solution is to go buy an old escort or something.
I'll wave when I pass you with my PORSCHE! 
There are "chain driven" engines that could also "interfere" if the chain breaks - but it is a less common occurrence. (I once had a timing chain in a bigblock 400 break... that stranded me in Nowhere, PA.)
But, your coworker is right, many of the domestic econo boxes have engines that do not bend valves when the timing belt breaks.
Perhaps you best solution is to go buy an old escort or something.
I'll wave when I pass you with my PORSCHE!
10-24-2008, 05:46 PM
#63
Drifting
Thread Starter
I am pretty commited to this car, and I want to work it/work on it
just neither me nor my dad have much of an idea as where to start, how to start about this
it doesn't matter how long this takes; and what are some improvements that can be made? I'm all down for some wrench time, so stop teasing/punning, lol
and I'm not looking to cheap out on anything, I want to do this right; my dad keeps hoping that we won't have to rebuild the head or have it done, but I'm coming from the same side as you guys: assume it's all f*cked up inside
he wants to do a leak down test and see if we are getting compression, and that it would tell us if anything is wrong inside mechanically - truth to this? and if not, please explain why not. because he keeps asking why it won't work, and only thing I can tell him is that's because valves are bent so you won't get accurate reading ...
just some help/pointers/ideas
and no, I'm not selling or parting out this car
but I AM looking for another/parts/roller/complete car on the cheap around my area
this is all in good fun right?
just neither me nor my dad have much of an idea as where to start, how to start about this
it doesn't matter how long this takes; and what are some improvements that can be made? I'm all down for some wrench time, so stop teasing/punning, lol
and I'm not looking to cheap out on anything, I want to do this right; my dad keeps hoping that we won't have to rebuild the head or have it done, but I'm coming from the same side as you guys: assume it's all f*cked up inside
he wants to do a leak down test and see if we are getting compression, and that it would tell us if anything is wrong inside mechanically - truth to this? and if not, please explain why not. because he keeps asking why it won't work, and only thing I can tell him is that's because valves are bent so you won't get accurate reading ...
just some help/pointers/ideas
and no, I'm not selling or parting out this car
but I AM looking for another/parts/roller/complete car on the cheap around my area
this is all in good fun right?
10-24-2008, 05:50 PM
#64
Drifting
Thread Starter
10-24-2008, 09:33 PM
#65
Apparently, more than one.The car is running fantastic, thanks for asking. Done for the season, which is probably a good thing as my car/track expenses were huge this year. I need a few months off to recover.
Good luck with the car repairs. Let me know if you get in a bind and need a hand.
10-24-2008, 09:40 PM
#66
Rennlist Member
I don't think a compression test is a good idea.
For it to work, the valves have to be working in synch with the pistons - so it draws air throught the intake valve, the intake valve closes, then the piston compresses air.
Also, because of the valve movement, there is always a valve or 2 open at any given time. If you start turning the cam shaft, then, when you do your next crankshaft rotation, the pistons will hit a new set of valves...
I suppose you could get around this by pulling the cam box and letting all the valves shut... But, by then, you're only 30 minutes from having the whole head off - then you can do a visual inspection (looking for marks on the pistons and looking for valves that aren't seating.
I understand the logic of the leak down test - to see if the rings are in good shape. My understanding is that for a leak down test to be valid, the engine has to be at operating temp and have everything fully lubricated - which your engine won't be.
Plus, with a leak down test, you'll get to a cylinder with bent valves, it will leak, and you still will not know the condition of the rings... so it's a waste of time.
Just my 2 cents.
(And, you'd better bet your bottom dollar that a Cosworth engine is an interference engine!)
For it to work, the valves have to be working in synch with the pistons - so it draws air throught the intake valve, the intake valve closes, then the piston compresses air.
Also, because of the valve movement, there is always a valve or 2 open at any given time. If you start turning the cam shaft, then, when you do your next crankshaft rotation, the pistons will hit a new set of valves...
I suppose you could get around this by pulling the cam box and letting all the valves shut... But, by then, you're only 30 minutes from having the whole head off - then you can do a visual inspection (looking for marks on the pistons and looking for valves that aren't seating.
I understand the logic of the leak down test - to see if the rings are in good shape. My understanding is that for a leak down test to be valid, the engine has to be at operating temp and have everything fully lubricated - which your engine won't be.
Plus, with a leak down test, you'll get to a cylinder with bent valves, it will leak, and you still will not know the condition of the rings... so it's a waste of time.
Just my 2 cents.
(And, you'd better bet your bottom dollar that a Cosworth engine is an interference engine!)
10-24-2008, 09:48 PM
#67
Drifting
Thread Starter
Jim - I talked to that seller, he wants $500 for the parts car - no engine and frame damaged in front; a little much and it has nothing I need - car is a 1987 (from that other Roman)
lol Van thanks for that explanation! I keep telling my dad the same thing - why not just open it and take a look at it; he's afraid that its a very costly job, and it's cold, and we will need new light, heat, lots of tools; he just doesn't want this car to turn into the "audi project"
but I really want to do this. Plus my cars are taking up the garage space. One of them will have to vacate the spot so my mom can park her car inside during winter.
sidetracked. I was also wondering what else could I do while rebuilding? company I work for has oil, salt, vacum hardening machines; stress relieve ovens, 3 cryo machines; sandblasting machines (tables), glass bead blaster; I know customers that do plating, and make parts out of pretty much any material
so I'm open to some ideas here
raise the RPM to 8K+? lol
lol Van thanks for that explanation! I keep telling my dad the same thing - why not just open it and take a look at it; he's afraid that its a very costly job, and it's cold, and we will need new light, heat, lots of tools; he just doesn't want this car to turn into the "audi project"
but I really want to do this. Plus my cars are taking up the garage space. One of them will have to vacate the spot so my mom can park her car inside during winter.
sidetracked. I was also wondering what else could I do while rebuilding? company I work for has oil, salt, vacum hardening machines; stress relieve ovens, 3 cryo machines; sandblasting machines (tables), glass bead blaster; I know customers that do plating, and make parts out of pretty much any material
so I'm open to some ideas here
raise the RPM to 8K+? lol
10-24-2008, 09:55 PM
#68
Rennlist Member
Sky's the limit! Cryo treat and shot peen your new lightweight, knife edged 3.0 liter crank and titanium connecting rods... Use dual valve springs and titanium retainers/keepers... High compression pistons... You can get that thing up to 8k RPMs easily, and probably make 250 or more HP!
It's all about budget...
Isn't Chris White out near you? Take a day trip and visit his shop and introduce yourself. Not only will he be able to give you ideas, but you might be able to use him, or his contacts, for things like a head job.
Tell your dad: you learn by doing. And, you're never too old to learn. And throw in that it'll be a good "father-son" project. How can he refuse?
It's all about budget...
Isn't Chris White out near you? Take a day trip and visit his shop and introduce yourself. Not only will he be able to give you ideas, but you might be able to use him, or his contacts, for things like a head job.
Tell your dad: you learn by doing. And, you're never too old to learn. And throw in that it'll be a good "father-son" project. How can he refuse?
10-24-2008, 10:30 PM
#69
Burning Brakes
Buy the head gasket kit from someone like EBS. It will contain everything you need to reseal the entire top end. The head will need an R&R, should be $500ish if the springs and valves are good, or $1000 if you need to source that stuff. I'd also do all the belts and injector seals while in there. This can all be done with the motor in the car, although it's a lot harder.
Also, if you go this far and are ambitious you may consider doing the rod bearings and oil pan gasket so she will last a long time. Oh, and then the clutch...
Also, if you go this far and are ambitious you may consider doing the rod bearings and oil pan gasket so she will last a long time. Oh, and then the clutch...
10-24-2008, 10:39 PM
#70
Drifting
Join Date: May 2008
Location: New Paltz, NY
Posts: 2,364
Likes: 0
Received 0 Likes
on
0 Posts
dude... the valves are bent. sorry tough luck. the cylinders are probably fine.
you need about 5 types of tools to take the head off.
its simple, if your dads afraid too do it then just do it yourself.
Again..... there is no way too see if the pistons/rings are ok(but the most likly are) unless you take the head off.
you need about 5 types of tools to take the head off.
its simple, if your dads afraid too do it then just do it yourself.
Again..... there is no way too see if the pistons/rings are ok(but the most likly are) unless you take the head off.
10-24-2008, 10:42 PM
#71
Drifting
Join Date: May 2008
Location: New Paltz, NY
Posts: 2,364
Likes: 0
Received 0 Likes
on
0 Posts
Tell your dad: you learn by doing. And, you're never too old to learn. And throw in that it'll be a good "father-son" project. How can he refuse?
10-24-2008, 10:50 PM
#72
Drifting
Thread Starter
lol 
EBS?
and I'm just throwing ideas out there myself, I got access to some neat stuff that I could do
my dad was wondering what is the position of valves in this engine? aparently in some they are facing up, in others they are facing down
better yet, a picture of an open head with valves would be nice
and then, where would be a good place to get vavles from? which timing belt kit? aparently there were 2 waterpumps or something? also someone said something about updating one of the rollers to a later style or something (cant remember)
EBS?
and I'm just throwing ideas out there myself, I got access to some neat stuff that I could do
my dad was wondering what is the position of valves in this engine? aparently in some they are facing up, in others they are facing down
better yet, a picture of an open head with valves would be nice
and then, where would be a good place to get vavles from? which timing belt kit? aparently there were 2 waterpumps or something? also someone said something about updating one of the rollers to a later style or something (cant remember)
10-24-2008, 11:09 PM
#73
10-24-2008, 11:23 PM
#75
Intermediate
Join Date: Jul 2007
Location: Central Coast, California
Posts: 28
Likes: 0
Received 0 Likes
on
0 Posts
This is purely for my curiosity...if he wants to up the power, what about shaving the head and increasing compression ratio a bit? Would you need a adjustable cam shaft pulley, or does it matter?
I'm a student trying to graduate soon, so I haven't had time to take care of my early '85. But when I start work on it again, this is something I'd like if possible...
and on a similar note, what about euro pistons. I can't find those anywhere!
I'm a student trying to graduate soon, so I haven't had time to take care of my early '85. But when I start work on it again, this is something I'd like if possible...
and on a similar note, what about euro pistons. I can't find those anywhere!