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Author Topic:   Not Quite Right
posted July 08, 2002 12:34 AM
My car when I rev it up a ways you can hear it missing not real bad but you can still hear it(its a little under powered on the track but you cant tell its missing) the thing is I can't find where its coming from. Last week I replaced Coil, Module, Cap and Rotor (all high perf.)and plugs. I checked all the wires resistance and they were all pretty close to the same numbers as new. Also rebuilt the carb, valve springs are only 3-4 weeks old(.504 lift) Can anyone point me in the right direction it's starting to get frustrating

posted July 08, 2002 02:43 AM
This may sound a little strange but run a compression check on that motor. I had an engine blow a head gasket between cylinders 3 and 5 one time. The amount of water I was getting on either cylinder was either none or next to nothing, because there wasn't any evidence of it, even after teardown. The engine would not run hot, but a power loss was evident and there was a slight miss that was hard to find. What I found was that both cylinders were sharing compression through the blown gasket and it was causing a power loss as well as the slight miss. Pretty much went through the same drill you did...cap, rotor, plugs, etc. I did find the problem before tearing the carb apart. A compression check on the engine should tell you if this could possibly be your problem. You might want to also run a leakdown test as well. This suggestion may seem a little weird, but you've pretty much all but eliminated the possibility of the problem being either spark or fuel, so I'd look for a compression gremlin now. Hope this helps and good luck to you!!

posted July 08, 2002 02:56 AM
Another possibility just crossed my mind. If you are using a toggle switch inside your car to switch the power on and off to your distibutor temporarily bypass the switch and connect the wires directly together. Rev the engine and see if you still have that miss. Sometimes a toggle switch will go bad and cause low voltage to the distributor, which can cause a problem similar to yours as well. You can also test the switch by turning it on and testing the voltage on either side of it with the engine shut off to see if you're getting all of the power through the switch. Do you run an alternator on your car? If not, you want to make sure your battery is hot enough. If you have low voltage at the battery you're not going to get it to the distributor. Also make sure you've got your tach hooked up properly because some tachs can be hooked up improperly and still work while drawing too much power and cause a low voltage problem. Oh, check your grounds on EVERYTHING. A bad ground connection can make you miserable. Just a few more things that you can check. Good luck!!

posted July 08, 2002 12:53 PM
No alt. but the battery is a fully charged 1000cca batt. Last week after we put all new electrical on we started it and it ran fine for about 30 seconds and started doing it again. We did a comp. check last week and they were all pretty close to each other. I will check out that toggle switch tommorow. Thanks

posted July 08, 2002 02:12 PM
This may seem a bit unlikely as you say your engine ran good for 30 seconds then the miss returned. But a friend of mine had been trying to trace a miss for some time, it turned out that the cam had lost a lobe. The miss was only noticeable when he reved it up though.
Just a thought.

posted July 08, 2002 09:09 PM
Here is something to look for. Pull your rockers and look at your push rods. I had a push rod go bad and I fought the car for 3 -4 weeks. I only noticed the miss under a load and discovered it at the track.

posted July 16, 2002 01:00 AM
Pulled the valvcovers sun. and I saw that two of the rockers had to much lash and it had crossed my mind that my cam was s.crewed then I did a compression test and found out that one cylinder was about 50 less than the rest. So I pulled the intake and looked at my lifters and noticed one was sank in the hole farther than it should be and one wasn't as far up as it should be and I knew the cam was trashed pull the lifter and I could see the cam was smoked. Then I decided to pull that one head, got it off and it had been burning water but I couldn't see anywhere is was blown out. The head bolts had water on them could it have worked its way up the bolts, the white goop wasn't on there anymore either.
Next I pulled the motor and pulled the number 5 piston (the hole with bad comp) and the piston was cracked in between the ring gaps, later I picked at it and I could pull pieces of the piston off of it. Also had 3 other pistons that were scuffed pretty bad around the tops and the sides of the pistons. Hmm what else oh yeah my other head gasked was the same way water burning but not as bad water came from the block side, and last but not least my fuel pump pushrod was bent???? My guess is that bolt sometime got pushed in too far. Anyways what the h@ll happened in there. Heads not torqued right, not enough sealant on them???
What about the cam its my 2nd this year. What are could be causes of that---- coil bind, lifters not rotating in the hole bad cams?
Here another question at full lift what is the minimum clearance there should be between the coils. Last cam was 504 with 550 springs.
Its been a bad year

posted July 16, 2002 09:29 AM
as for the water, have you checked your heads and block to make sure they are not warped. If they are no matter what gasket or torque you use you probably wont keep them sealed. Also have you checked your heads for cracks. Maybe they are cracked and letting water in and the gaskets are fine.

as for the cam. How are you breaking them in? What are you using for prelube? Are these solid lifters and what kind of spring pressures are you running?
If the lifter bores are scored and the lifters cant rotate then that will flatten a cam. if your springs bind that will also but i would think you would have bent pushrods as well. as far as min clearance i have always used .060 as a rule.
Are your springs 550 lift or 550 coil bind? If they are 550 lift then you should be alright. If they are coilbind then you are pushing it .550-.060=.490 lift.

Did you build this yourself or did someone else do it for you?

posted July 16, 2002 12:33 PM
Heads that are on there have been on there for a month and they were checked shortly before that. Springs say they are good up to 550 lift. Pushrods are straight I just checked them on some glass. Lifter holes look ok but I am going to take a hone to them to clean them up a little.
When we break them in we coat the cam well with cam lube. When we start it we take it to 2500-3000 for about 20-30 minutes. Should I be doing it differently? I don't have a clue about spring pressures but its the same type of setup I ran last year with no problems. Home built motor.

posted July 16, 2002 01:38 PM
Be careful with that hone make sure you dont enlarge the bores too much.

Everything you have said sounds good. Next time you put it together check each lifter as you put it in and see if it spins freely or catches in the bore.

What kind of cam lube do you use?
What oil did you use during breakin?
What kind of cam is it?
Did you have trouble getting it fired the first time... did you do a lot of cranking on it?
Do you have shims under the valve springs to stiffen them up?

posted July 16, 2002 10:19 PM
The big cam break in!!! I have lost a few cms over the last 8 years most i think was from to much spring pressure for break in. If you talk to some they say pull the inner spring out and others say use a 1.2 rocker arm?? Wich do you do? Anyone that has pulled the springs off a head while the heads are on the motor and in the car can tell ya its a PAIN!! With the amount of cams i have lost i think i may have found somthing that helps with the break in of a cam..... they call em
Direct Lube lifters that have a hole in the bottom to feed oil to the cam lobe all the time. I lost 1 cam at the start of the season and that is when i went to the direct lube and have pulled a lifter since and the cam still looks like it did when it went in and when we check the lash it has been dead on. I am not telling you to run right out and buy them, but i can tell ya i will never put a cam in without them!!

posted July 17, 2002 12:01 AM
What kind of cam lube do you use? LUNATI
What oil did you use during breakin? 10W-30
Did you have trouble getting it fired the first time... did you do a lot of cranking on it? NO FIRED RIGHT OFF
Do you have shims under the valve springs to stiffen them up? NO
I have always just used my same setup maybe thats my problem
where do you get those lifters at and what do they run for price

About the head gasket deal the bolts seemed to be pretty easy to break loose. I should've checked the torque but I was in a hurry and didn't know I had a gasket problem. If the head was warped wouldnt the water be mainly on the head side instead of mainly on the block side. Also these heads are two single heads with the same numbers paired up. So I wouldn't think it would be kind of funny for both of them to be warped. Anyone have insite on why the white goop on the bolts were gone and the bolts had water on them?? Thanks for the help so far.
p.s. building it tommorrow

posted July 17, 2002 09:53 AM

The lifters dirtracer is talking about i have seen for as little as 80 up to 150$. They are great for really radical cams but we have also used standard lifters on our motors and had no problems either. If you can afford them then i think they would be worth looking into.
This is a solid lifter cam right??

I think part of the problem is your oil. You need to use something heavier than 10w30. With the spring pressures used to run high rpms with solid lifters the 10W30 doesn't stick well enough to protect the cam and lifters. Try using a good quality straight 30wt or 40wt or 20w50 and see what happens. Also try adding a bottle of GM EOS (engine oil supplement) they add this to all new cars to aid in breaking in the cams.
Is this the same oil you use run after break in? Most guys I know are running 20w50 and some even straight 50wt.

As for the head i am still thinking about that. What did you use to seal the bolts? As for it being gone most of it will get scraped off as the bolt is threaded in there will only be a little bit left in the threads. Where was the water on the bolts? on the threads or up higher on the shank?
I usually use pipe thread sealant or similar.
What gaskets are you using and what are you torqing them too?

posted July 17, 2002 01:24 PM
Solid Cam
That oil is just for breaking in the motor I was always told to use thinner oil to break it in to wash some of the junk that might be floating around dirt, steel shavings etc. I usually run racing 20-50. Usually just use the cheap-o gasket set. I have felpro head gaskets this time we'll see if its any better. Checked heads with a straight edge and they look perfect, but I don't know how acurate that would be.
I use the thread sealant from Napa little white bottle with white goo. I don't remember the exact name of it.
Don't remember head torque right off the top of my head I usually look it up in my engine book. There is water on all of the bolt
Thanks again

posted July 17, 2002 04:10 PM
If you ran any amount of time with water , or especially anti-freeze going into the pan, you may see all types of strange failures like wiped bearings, bad cams, etc. Anything but oil in the pan is very bad news.

posted July 17, 2002 08:13 PM
I got the lifters from competion products, they had a add in the stock car book and they were $89 a set. Like i said im not saying run right out and buy them but it oils the lobe all the time and for the $$$ i thought it was well worth it.

posted July 17, 2002 11:30 PM
I built a motor this year that used a midwest motor sports cam. Lost a lobe after one night of racing. My friend also built a motor using a midwest cam. He also lost a lobe after one night of racing. We both broke the motors in just like we have in the past. Will never use a midwest motorsports cam again.

posted July 17, 2002 11:54 PM
Monster I figured the same so I am doing a complety rebuild. I might try those lifters next time I put a cam in which better be next year If it happens again this year I'll just say to heck with it and put in one of my new stock hyd. cams in. Good dry slick cam lol

posted July 18, 2002 12:46 AM
I talked to Rick from Midwest Motorsports at a trade show here in OKC, and alot of the things they sell as far as cams and rocker arms, are actually from Crane Cams from what he told me. Both of the motors I have built for our cars have midwest cams in them, and knock on wood we havent had any problems.

posted July 21, 2002 09:36 PM
We have about .030 clearance between coils. What do I need to do to get more .600 lift springs? Is that my problem??

posted July 22, 2002 01:25 PM
a lot of the mail order house cams are made by elgin if you compare the specs from speedway, midwest etc you will see the cams are identical usually reboxed for sale also
ive read where a major company in tenesee
grinds very few cams but sells quite a few boxes. also if you are on budget try blue racer cams they are owned by crane and even have the same website.

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