Low compression and low vacuum??? - Ford Mustang Forum
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post #1 of 19 (permalink) Old 08-06-2017 Thread Starter
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Low compression and low vacuum???

I am pretty stumped on this one. I just ran a compression test on the passenger side cylinders and they are all at 90# and holding steady. I thought that they were supposed to be closer to 165#. My vacuum was reading 9'' and it would bounce to 11'' but the engine was surging and I think that was causing the bouncing. The vacuum seemed to hold steady also, except for the surging idle.

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post #2 of 19 (permalink) Old 08-06-2017 Thread Starter
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I have a friend that lives in San Francisco and he owns a shop. He lives too far to have a look but he told me that it sounds like the timing chain is off. Come to think about it, when I got the car, the timing mark was lined up to 0 degress BTDC and when I adjusted it to 10degrees, it started to run rough. The engine dies when I pull the spout connector also... I am assuming that he is right and I need to have a look at the timing chain.

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post #3 of 19 (permalink) Old 08-06-2017 Thread Starter
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Sorry, I forgot to say that he suggested that the valves might not be adjusted properly... I'll buy some gaskets soon and check it out.
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post #4 of 19 (permalink) Old 08-07-2017
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Originally Posted by dustin2100 View Post
Sorry, I forgot to say that he suggested that the valves might not be adjusted properly... I'll buy some gaskets soon and check it out.
That's a possibility, if the valves were improperly adjusted that means that they
would be leaking because they are not fully seating when closed. They definitely
won't hold steady if that was the case. if you suspect the timing chain put a light
on it . If the timing mark is jumping then it is the chain if it is steady the chain is good.
and if the chain is good then it couldn't have jumped timing.
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post #5 of 19 (permalink) Old 08-14-2017 Thread Starter
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That's a possibility, if the valves were improperly adjusted that means that they
would be leaking because they are not fully seating when closed. They definitely
won't hold steady if that was the case. if you suspect the timing chain put a light
on it . If the timing mark is jumping then it is the chain if it is steady the chain is good.
and if the chain is good then it couldn't have jumped timing.
The previous owner installed a TFS top-end kit and I suspect that he didnt set the timing chain correctly. I wasnt trying to say that it jumped a tooth. I know that it is easy to set the timing chain but maybe he thought that he was "degree'ing" the cam or something? I had the valve covers off and I had my dad watch as I turned the engine by hand. He said that when the crank damper was at TDC, the valves looked out of time. He was a diesel mech for 12-13yrs, so he should be competent at this.
The previous owner did a great job at making the car cosmetically appealing but I think that he was not much of a mechanic. He did a paint job, new interior, Eibach suspension kit w/ sway bars, brake conversion, AOD trans rebuild, and a TFS top-end kit. I dont think that he took the original block out of the car at any time. It leaks pretty bad and the oil dip stick looks like it has been baked. I am ready to pull the engine block and bring it to a machine shop and get a 347 stoker with TFS specific pistons. Then, I will send my 170cc TFS heads into T.E.A for a port job and get it to 205cc for $1k. I already own the heads and the 11R205's cost about $2,400. The port job should get it close to the 11R's and be able to support a 347.
Trick Flow 205cc TW Cylinder Head | :: Total Engine Airflow ::
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post #6 of 19 (permalink) Old 08-15-2017
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Quote:
Originally Posted by dustin2100 View Post
The previous owner installed a TFS top-end kit and I suspect that he didnt set the timing chain correctly. I wasnt trying to say that it jumped a tooth. I know that it is easy to set the timing chain but maybe he thought that he was "degree'ing" the cam or something? I had the valve covers off and I had my dad watch as I turned the engine by hand. He said that when the crank damper was at TDC, the valves looked out of time. He was a diesel mech for 12-13yrs, so he should be competent at this.
The previous owner did a great job at making the car cosmetically appealing but I think that he was not much of a mechanic. He did a paint job, new interior, Eibach suspension kit w/ sway bars, brake conversion, AOD trans rebuild, and a TFS top-end kit. I dont think that he took the original block out of the car at any time. It leaks pretty bad and the oil dip stick looks like it has been baked. I am ready to pull the engine block and bring it to a machine shop and get a 347 stoker with TFS specific pistons. Then, I will send my 170cc TFS heads into T.E.A for a port job and get it to 205cc for $1k. I already own the heads and the 11R205's cost about $2,400. The port job should get it close to the 11R's and be able to support a 347.
Trick Flow 205cc TW Cylinder Head | :: Total Engine Airflow ::


I am sure that your father is a very competent mechanic but I have to ask
this. The TDC mark on the damper comes around twice, Was it on the power
stroke when he was looking at the valves?. They should both be closed. Even if
the cam was advanced or retarded the should still be closed at TDC. Unless
ofcourse the cam was installed way off but if that were the case it wouldn't
run at all.
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post #7 of 19 (permalink) Old 08-15-2017 Thread Starter
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Quote:
Originally Posted by squekster View Post
I am sure that your father is a very competent mechanic but I have to ask
this. The TDC mark on the damper comes around twice, Was it on the power
stroke when he was looking at the valves?. They should both be closed. Even if
the cam was advanced or retarded the should still be closed at TDC. Unless
ofcourse the cam was installed way off but if that were the case it wouldn't
run at all.
Right, the distributor was pointing at #1... Anyways, I have everything pulled off of the timing cover except for the harmonic balancer and I dont have a puller right now. I'll probably have the timing cover pulled off by tonight though.
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post #8 of 19 (permalink) Old 08-16-2017 Thread Starter
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Yeah, the timing chain and marks look OK. I was at a loss for a couple of hours until I realized that the harmonic balancer looks bad. It didnt look noticeably bad, but it was cracked and looks like the rubber is working it's way out.. I think that the balancer slipped the timing mark. Does this happen often? I wish that I didnt have to pull the timing chain cover to figure it out. The woodruff key was starting to shear and the balancer came off way too easily. Just a couple of turns with the puller and the balancer fell off and I think that it came off too easy.

I did notice that when I first got the car that the timing was set at 0 degrees instead of 10.
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post #9 of 19 (permalink) Old 08-16-2017 Thread Starter
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Quote:
Originally Posted by squekster View Post
I am sure that your father is a very competent mechanic but I have to ask
this. The TDC mark on the damper comes around twice, Was it on the power
stroke when he was looking at the valves?. They should both be closed. Even if
the cam was advanced or retarded the should still be closed at TDC. Unless
ofcourse the cam was installed way off but if that were the case it wouldn't
run at all.
Sorry that I didnt clarify. He was looking at the mating cylinder to watch the valves move.
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post #10 of 19 (permalink) Old 08-22-2017 Thread Starter
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I thought that I would give an update on my situation. I pulled the timing chain cover off to inspect it and the harmonic balancer came off in my hand without a puller! The woodruff key has been chewed up too. I thought that I was going to be able to look at the camshaft and see identifying marks but I couldnt, so I have a mystery cam. I really think that the camshaft has been the root of all of my problems! I dont know if it was supposed to be degree'd or what, but I am ready to take it to the machine shop and get a new rotating assembly along with a new cam.

The nose of the crankshaft has been rounded off and it is pitted and that is why it will not hold the harmonic balancer anymore. I am not sure how it happened and I have not seen this before, but I am not putting my engine back together as is...

I dont plan on going overboard with this build but I do want a stroker kit. I am leaning towards a 331 over a 347, because I dont plan on buying a different set of heads. I do have TFS 170's and I thought about sending them to T.E.A sometime in the future but not right away.

Here is my question, should I let the machine shop order my kit? I know that they will probably charge more but I will get what I need as far as compression ratio ect. Sorry for rambling but I am excited and I have the money to get this started, the machine shop let me make payments lst time.
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post #11 of 19 (permalink) Old 08-22-2017 Thread Starter
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Here is the ticket from my last build that is in my sig. I really felt like that they "Got me" on the stock camshaft that I didnt ask for! It could have been my fault because I really didnt know what to ask for back then, it was several years ago and I have been to ASE classes since then.
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post #12 of 19 (permalink) Old 08-22-2017 Thread Starter
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There is a Dart Sportsman block on Craigslist right now and it looks like he is willing to take a loss on it. It has never been assembled or machined, but I could have a finished short block for less than what the parts for the Dart block would cost. I really dont think that I would need this block but it is fun to imagine... I have a friend that is determined to set me up with forced induction, but that wouldnt be anytime soon... The rotating assembly in the ad has a 4.030 bore. Isnt it a 4.125 bore block?

https://oklahomacity.craigslist.org/...265220191.html
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There is a Dart Sportsman block on Craigslist right now and it looks like he is willing to take a loss on it. It has never been assembled or machined, but I could have a finished short block for less than what the parts for the Dart block would cost. I really dont think that I would need this block but it is fun to imagine... I have a friend that is determined to set me up with forced induction, but that wouldnt be anytime soon... The rotating assembly in the ad has a 4.030 bore. Isnt it a 4.125 bore block?

https://oklahomacity.craigslist.org/...265220191.html
Using the part # in the ad,the block currently sits with a 4.000" bore.You would have to get a machine shop to bore it 0.030" over,in order to use the rotating assembly listed.If you were to leave the block as it sits now and install the crank & rods with the kit + buy pistons to match the 4.000" bore,you would have a 327ci engine.
If you bore the block 0.030" over and use all of the components listed in the ad,you would have a 331ci engine.Eventhough the block is at 4.000" now,it can be safely bored to 4.125" to increase ci.
If you were to bore the block to 4.125" and use the crank & rods from the kit listed then buy pistons to match the new 4.125" bore,you'd have a 347ci stroker.If you swapped the 3.25" stroke crank with a 3.40" stroke crank,you'd have a 363ci engine.

BTW- most 302 blocks can only be bored to 4.060",but its not safe to go above 4.040" due to their thin cylinder walls.Overheating can occur above a 0.040" overbore.The Dart block has alot more metal,4 bolt mains,etc which safely allows it to be bored more.


You can use the following formula to calculate ci displacement:
B=bore S=stroke Pi=0.7854 N=# of cylinders

B (x) B (x) S (x) Pi (x) N= ci displacement

Example 1:
4.000 x 4.000 x 3.25 x 0.7854 x 8= 327ci

Example 2:
4.030 x 4.030 x 3.25 x 0.7854 x 8= 331ci

Example 3:
4.125 x 4.125 x 3.25 x 0.7854 x 8= 347ci
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Get an estimate from the machine shop and compare it to the various "kits." http://www.adperformance.com/index.p...roducts_id=211
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post #15 of 19 (permalink) Old 08-23-2017 Thread Starter
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I really think that the Dart block was just a daydream. It would be cool, but I would have to spend so much more money... I think that I will get a fun to drive 331 and let the shop pick out the kit. I dont want to be "that guy" that brings the wrong rotating assembly in and cant return it or something. I wanted higher compression but I dont know exactly which pistons to get +11cc or +16cc, you know what I mean. They are going to balance the engine also.

While I have the engine out, I will freshen up the trans also. I dont know if there are any AOD guys here, but I am kind of excited for this one. I had a T5 in my '95 that is in my sig... Anyways, I am looking at doing the reverse clutch drum with a mechanical diode and get rid of the sprag. Plus, it will give me more clutches and a bigger over drive band.

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