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#21
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if the cam was coated with break in lube & you only hard started 5 or 6 times & ran at 500rpm for a few minutes, i dont think the cam/lifters are damaged, you should be able to fire it up & instantly go to the 2000-2500 rpm for 20-30 minutes & break it in properly. |
#22
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It's a Melling STP-1. Very tame, as we need the vacuum for power brakes, the AC controls and the factory Cruise Control. This car uses a lot of engine vacuum! I got it off of Rock Auto.
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#23
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ok just curious & making a suggestion the cam would probably be ok, its not like its a huge cam with high spring pressures that would scuff it up in such a short time. did you mean the MTP-1? dont see a stp listed for pontiac. & rock auto shows its out of stock... also consider new lifters if youre replacing the cam, they are just as important to break in to the cam.
looking at the specs, that is a very small cam, you could go quite a bit bigger in duration & lift & still have plenty of vac for brakes or a/c. im not sure what the engine specs are but for a 400 you could go a lot bigger to get more power & bigger rpm range & still have plenty of vac. im not a cam expert to give specific suggestions but maybe some others can suggest another cam or post a new question asking for recommendations based on the engine? |
#24
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Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#25
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What are the risks in running it? Immediate failure or premature wear later? When we did get it running right it sounded the best it ever has.
Sorry about the typo in the cam. It is the Melling MPT-1. And yes, it is mild. But the stock cam had 198 and 208 duration at .050. This one has 204/214. You'e also correct about the cost of gaskets, oil, filter, etc. I'm not kidding myself about the costs and time. Fortunately I do have a stockpile of that stuff. |
#26
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the chances are very minimal that the cam is actually bad from how you said it was run. there's a greater chance the cam is fine, at least if you ran it to the break in RPM/time asap after knowing it ran right. just a suggestion to at least try & break it in right but its your engine, money & time so totally your call.
also dont forget that if you do change the cam the lifters should be changed too, you cant or at least shouldnt try to run what are now used lifters on a new cam, you didnt mention the lifters in either of your replacing the cam comments so just want to be sure you know that. also before pulling the old cam it would be a good idea to confirm with RA if/when another MPC1 cam will be available, it says out of stock & with the recent cam core shortages there may not be another one available for quite some time, plan accordingly or look into another brand cam. that MPC1 is barely even a RV towing cam for a 400, would be a perfect time to consider another cam. comparing the stock cam to this one doesnt really address that a bigger cam, although still considered "small" with way more vac than needed for power brakes etc will perform better & still run very tame for a low comp street engine. not suggesting a big race inspired cam, just something more than a basically stock MPC1. these small stock cams were intended for emissions & MPG etc, much better "modern" cams out there. best of luck on whatever you decide to do. |
#27
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You want to install the cam with number one piston at top dead center (TDC) on the compression stroke. Since it's a four stroke the piston fires every other time the piston reaches TDC. Don't bother taking the valley pan off again just a waste of time. Stick your finger in the #1 spark plug hole and as it starts getting close to TDC you will feel the compression if you don't go around again it's impossible to not feel the compression if your on the compression stroke.
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Tim Corcoran |
#28
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.
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#29
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Well, I'm happy to report that we got it all back together, fired it up, and broke the cam in for 20 minutes. It seems to be OK. It was late so I shut it down right after. So we'll see after work tonight how it starts and runs.
Thanks again for everyone's help and comments. |
#30
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#31
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The original replacement one. It seems fine. We did install new lifters with it as well.
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The Following User Says Thank You to 66sprint6 For This Useful Post: | ||
#32
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For your own piece of mind, you may want to do this. Start it back up and run it another 20 minutes or so at a higher than normal idle speed, like 2000 RPM. Then while the engine is still warm, drop the oil out and the oil filter. Cut the oil filter off near the threads. Don't use a saw. You can punch a hole in it and then cut around it with tin snips. They make a tool for cutting filters, I am assuming you don't have one. It will be messy. Use a box cutter and slice the paper element down the length and cut across the area where you cut the can. Now extract the paper element and put on a clean rag and un-fold it. If you have a cam love failing, you will absolutely see the material in the oil filter. It will be dark gray and magnetic and their will be allot of it in the filter. If the filter is pretty clean and no gritty feel, and no material, your good to go. Very few new camshafts fail after 40-60 minutes of run-in time. Especially one with gentle stock lobes, little lift and weak valve springs. You should be just fine.
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The Following User Says Thank You to mgarblik For This Useful Post: | ||
#33
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i was going to suggest inspecting the flter but wasnt sure he would want to do that. also after running a fresh engine for the first time there can be other wear particles in the oil/filter that could be misleading. i use a strong magnetic drain plug that will show any magnetic metals easier than cutting open a filter.
besides finding it early on in a filter or magnetic plug, after a short time you will usually hear a slight tick start that adjusting will only stop for a short time then it comes back. |
#34
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Little known fact: Some gear sets are set up for dot to dot orientation , some down and down. When installing, be certin the gears are lifting #6 , and not lifting # 1.
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
#35
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When I had cam failures due to break in excessive wear, generally I knew in about 20 to 30 min. on the engine stand, that the cam would live or die.. Remember the no zddp oil days?
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
The Following User Says Thank You to KEN CROCIE For This Useful Post: | ||
#36
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Wow, that's a really small cam. You would have been safe with an OE 'more' performance grind, but your call.
.
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. 1970 GTO Judge Tribute Pro-Tour Project 535 IA2 http://forums.maxperformanceinc.com/...d.php?t=760624 1971 Trans Am 463, 315cfm E-head Sniper XFlow EFI, TKO600 extreme, 9", GW suspension, Baer brakes, pro tour car https://forums.maxperformanceinc.com...ght=procharger Theme Song: http://www.youtube.com/watch?v=7zKAS...ature=youtu.be |
#37
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#38
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he's past all that, said it was a timing or rotor position issue & is running good now with the original cam
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#39
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Yes, small cam for sure. For me, the price and availabity were big factors, along with guaranteed vacuum, which it has. This isn't the last engine for this car. Frankly, I would have switched out the whole engine, but there's nothing available and the rebuilders don't even return an enquiry. It's that bad. The cam improved it a little but it's still an old engine. So I'm usiing that good vacuum for now to eliminate it as an issue for restoring my A/C and cruise.
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#40
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Darby 74 Grandville 2Dr 455 c.i 4550# 2011 1.60 60 ft,7.33@94.55-11.502@117.74 2017, 74 firebird -3600 lbs (all bests) 1.33 60 ft, 6.314@108.39 9.950@134.32 M/T 275/60 ET SS Drag Radial 2023,(Pontiac 505) 1.27 60 ft, 5.97@112.86, 9.48@139.31.... 275/60 Radial Pro's |
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