 New Motor + Hot Running = ?, Advice, help, suggestions? |
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| Jake Raby |
 Aug 25 2009, 10:35 AM
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#21
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Engine Surgeon  Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States  |
What did the CR end up being? What cam does it run?
Unless these engines have huge deck height, super enlarged chambers or low CR coupled to a bigger cam they generally like 28 degrees. To optimize an engine takes experimentation or a trip to a dyno with an operator that has some sense. |
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| jhadler |
Aug 25 2009, 12:00 PM
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#22
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
QUOTE(Jake Raby @ Aug 25 2009, 08:35 AM)  What did the CR end up being? What cam does it run? Unless these engines have huge deck height, super enlarged chambers or low CR coupled to a bigger cam they generally like 28 degrees. 9:1 CR. FI grind webcam (73 if I recall). 96 mm KB P&C's. 0.016" deck height. Intake valve clearance to piston top: 0.22" Exhaust valve clearance to piston top: 0.33" Piston ring end gaps: 0.020" (measurements made by a friend) Melling oil pump. Tuna Can sump extension. Welty oil pressure relief pistons. Euro race headers, ceramic coated. Stub pipes port matched with heads. Stock D-Jet. Stock Ignition. That pretty much sums up the build. -Josh2 |
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| Jake Raby |
Aug 25 2009, 01:57 PM
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#23
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
WOW!
You only have .016 deck height?? The piston to valve clearance you state is also way too tight on both the intake and exhaust valves. If those clearances are that tight cold, what do you think they are doing hot and fully expanded? With that tight of deck your engine might like as little as 2^* advance, but you'll be colliding pistons to the heads at any kind of revs once the engine is fully expanded.. The least deck I have ever successfully ran was .021 and even then it was knocking the carbon off the chambers and piston tops. |
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| jhadler |
Aug 25 2009, 02:11 PM
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#24
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Okay, now I'm sweatin' bullets.
These were the numbers provided to me the friend who was building the motor. If you can give me ball park numbers what you think they SHOULD be, I will confirm that these were the actual numbers taken. Car is on hold until then. Have I already wasted it? (IMG:style_emoticons/default/sad.gif) (IMG:style_emoticons/default/sad.gif) (IMG:style_emoticons/default/sad.gif) -Josh2 |
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| jhadler |
Aug 25 2009, 02:50 PM
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#25
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Waiting for my friend to call me back with actual number he recorded during the build...
Feeling nervous... -Josh2 |
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| jhadler |
Aug 25 2009, 03:54 PM
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#26
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Okay, now he -thinks- that it was more like 0.032" deck height. He hasn't checked his notes, but will let me know when he does.
Now, about the valve to piston clearances. Jake, I thought that .22" and .33" valve to piston clearance was pretty large. It's a stock combustion chamber, 59.5 cc's each (measured by the head builder - professionally built heads - years before this build). Is this motor reasonable? Or am I just a bozo in a world of hurt now, and should give up and buy a miata? (kidding about the miata...). -Josh |
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| jhadler |
Aug 25 2009, 06:36 PM
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#27
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Well... He looked for his notes and couldn't find anything.
Sigh... I'll be taking the motor out, and pulling the heads... After re-measuring the deck height, and if the pistons and heads pass visual, would it be reasonable to slide a .020" gasket in there? 0.030"? (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) -Josh2 |
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| jhadler |
Aug 25 2009, 06:49 PM
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#28
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
That being said...
Should I run a head gasket, or shim the jug? If head gasket, copper or ??... humbled and sadly asking for advice... -Josh2 |
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| Jake Raby |
Aug 25 2009, 07:27 PM
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#29
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
So is that clearance .022 or .220?? Huge difference!
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| gregrobbins |
Aug 25 2009, 08:20 PM
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#30
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Member: Team NARP Group: Members Posts: 1,515 Joined: 23-March 04 From: Arizona Member No.: 1,844 Region Association: Southwest Region |
No on the head gaskets, the factory recommended against that years ago.
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| jhadler |
Aug 25 2009, 08:43 PM
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#31
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
QUOTE(Jake Raby @ Aug 25 2009, 05:27 PM) So is that clearance .022 or .220?? Huge difference! 0.220" -Josh2 |
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| byndbad914 |
Aug 25 2009, 11:20 PM
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#32
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shoehorn and some butter - it fits Group: Members Posts: 1,547 Joined: 23-January 06 From: Broomfield, CO Member No.: 5,463 Region Association: None |
man, I would think 0.220" is more than plenty, tho' if Jake thought you said 0.022" I can see why he would freak out (IMG:style_emoticons/default/laugh.gif)
I used to run as tight as 0.100" on intakes but no less than 0.125" on exhausts on full race, domed 9500 rpm V8s, and as low at 0.080" on ti intakes one time against my wishes but the engine owner went for it as he found the heads on a Th and was racing Friday, and we ended up not having any issues. side note... Ti expands less than stainless steel (8.5ppm/C for Ti v. around twice as much 15-17ppm/C for stainless steel) and I knew that at the time, so I was sorta willing to take the chance but was sweating bullets with him road racing the next day at no less than 6500rpm and shifts around 9K on that engine (IMG:style_emoticons/default/smile.gif) |
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| jhadler |
Aug 25 2009, 11:25 PM
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#33
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
I think it's the deck height value that Jake jumped at. And somehow, even though it had been measured, it got overlooked.
Plan at this point is engine out, heads off, shims on, and all back together again... -Josh2 |
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| byndbad914 |
Aug 25 2009, 11:31 PM
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#34
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shoehorn and some butter - it fits Group: Members Posts: 1,547 Joined: 23-January 06 From: Broomfield, CO Member No.: 5,463 Region Association: None |
QUOTE(Jake Raby @ Aug 25 2009, 12:57 PM) ...The piston to valve clearance you state is also way too tight on both the intake and exhaust valves. If those clearances are that tight cold, what do you think they are doing hot and fully expanded?... snipped that from a post above and he also asked about 0.220 v 0.022 which was a piston to valve #... that is what I was referring too (IMG:style_emoticons/default/smile.gif) It seems to me he like neither the piston to valve nor the deck height. I think piston to valve seems totally reasonable unless I am missing something that is somehow specific to T4s. I know nothing about T4 deck ht specifics. |
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| jhadler |
Aug 29 2009, 06:35 PM
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#35
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Learning experience here... cliche central.
you get what you pay for... no such thing as a free lunch... buy cheap, buy twice... want something done right, do it yourself... My friend was well meaning, and I really greatly appreciate his work. But there are enough questions about the measurements made during the build (even one would be too many), that I have no choice but to pull the motor and tear it down. Hopefully, it means nothing more than adding the right shims to get enough deck height and valve clearance. But suffice to to say, it's gotta happen before I turn the key again. Here's what I have gathered... Deck height: 0.010 - 0.012 per inch of bore. That means at LEAST 0.037 deck height up to a minimum of 0.045. That is way more than the 0.016 that was measured. -Josh2 |
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| jhadler |
Oct 19 2009, 03:37 PM
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#36
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Yeah... Finding out that tearing down the motor is a certainty. Motor's on the engine stand now, finding loose this, and loose that. And that's still outside the motor.
Bottom end at this point is suspect too. It's all gotta be torn down. That being said... What's the desired bearing clearance that I should strive for when everything goes back together? I hope to pull the heads in the next couple days. Hopefully metal-to-metal contact was avoided. Any bets? -Josh2 |
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