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Hello, I am brand new to this site so forgive me if I go into too much detail. I am working on my first project by myself. I bought an 85 chevy c10 with a 305 sbc and ZZ4 L98 heads. After tearing down the motor I found aftermarket pushrods (EnginePro 7.900") broke right through one of the rocker arms. Also the hydraulic lifters and cam were extremely worn out to the point that some of the lobes were almost completely circle and the lifters had bowsl worn into the bottoms. I looked at the pushrods and they are all good, no over wear or bent. So what I need to find now is a new suitable cam, lifters, rocker arms, etc. What I don't understand is how do I take the 7.900 pushrods into account when fitting the right cam, lifters, rocker arms? Right now Im looking at the COMP Cams extreme energy kit and the comp cams high energy rocker arms(http://www.summitracing.com/parts/cca-k12-268-4, http://www.summitracing.com/parts/cca-1212-16). I want to make sure that with this combination the valves don't make contact with the piston. I don't know which rocker arms to get mainly because there are 1.5:1 ratio and 1.6:1 ratio. How do you know which one is right? Also with the 7.900" pushrods (which are .1" bigger than stock) is that going to open the valves an extra .1"? plz help or explain this to me because ive done extensive research on specs and just forums and cannot figure out how all these things come together. Thank you
 

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your engine is toast and needs a complete strip and clean first and foremost. You need to find ot why the cam failed and fix that( or be smart and get a roller cam) If you never built an engine you will have quite a bit of reading to do as building an engine is not assembling a box of parts. You may end up buying new pushrods. Take it apart and find the problems then we can help you choose good and reliable parts. Tell us your total budget and time frame?

welcome to the forum
 

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Wrench Turner
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Like Vinnie said,that engine will need a complete tear down.It already has metal shavings floating around that have most likely already trashed the main/rod bearings & crank.Replacing the cam & lifters @ this point will only be a waste of time & money.
 

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Ok i may have made it soud a little worse than it is, maybe not. But a push rod punched a small hole through one of the rockers. Ive torn it all the way down to the block and it doesnt appear anything else is damaged. There was a bit of small shavings but they have all been removed. Ive checked the cylinder walls, etc and its all intact with no major scratches. Now the cam im sure is stock and has just been worn down. There are multiple lobes on it that are almost completely gone. Ill post pictures later but as of now i cant upload.
 

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Discussion Starter · #6 ·
What would be a good cam? I understand how the measurments work between the rockers and cams but what about the pushrods? If they are longer than stock it will add to the lift but is it multiplied by the rockers or no?
 

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Wrench Turner
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If that much damage has occurred to the cam,there are more than a few metal shavings.Inspect the crank & bearings.All oil galleys in the block & crank need to be brushed & flushed to insure all shavings are removed.Some of the shavings may be so small that you can't see them with a naked eye.Put some of the oil from the engine,if you still have some,into a clear container,then hold it up to the sunlight & you can see it.
 

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Wrench Turner
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What would be a good cam? I understand how the measurments work between the rockers and cams but what about the pushrods? If they are longer than stock it will add to the lift but is it multiplied by the rockers or no?
Pushrod length is adjusted to achieve the proper valvetrain geometry in a given set of parts.Not to add or take away lift.The ratio of the rocker arms will effect lift.If that is the original truck 305,your compression is in the 8.5:1 range.You will need something along the line of an RV type cam with short(probably less than 210*) intake duration for best results.
 

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Alright ill make sure I GI clean it. Anyways, im not trying to dump a fortune into this motor i know the sbc 305 is not a go to performance engine but its what ive got right now. ove got a budget of about 800 right now. Im trying to get at least 300 horses out of it. Not too far fetched from articles ive read
 

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Ok i may have made it soud a little worse than it is, maybe not. But a push rod punched a small hole through one of the rockers. Ive torn it all the way down to the block and it doesnt appear anything else is damaged. There was a bit of small shavings but they have all been removed. Ive checked the cylinder walls, etc and its all intact with no major scratches. Now the cam im sure is stock and has just been worn down. There are multiple lobes on it that are almost completely gone. Ill post pictures later but as of now i cant upload.
Frankly...You are in way over your head. Some of the things you have written has me shaking my head. If time is an issue, source another good running engine from a recycler. Often you can find someone on CL who has a running wreck or a runner the want to upgrade. If you have the time you've got a steep learning curve. One thing you probably dont understand at this point is that even one wiped cam lobe will clog the oil filter, once that happens the filter bypass opens up and sends unfilter oil with metal particles through out the whole engine.

I don't think 800 will repair this motor. You need at least 400+ in head work alone.
 

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Hello, I am brand new to this site so forgive me if I go into too much detail. I am working on my first project by myself. I bought an 85 chevy c10 with a 305 sbc and ZZ4 L98 heads. After tearing down the motor I found aftermarket pushrods (EnginePro 7.900") broke right through one of the rocker arms. Also the hydraulic lifters and cam were extremely worn out to the point that some of the lobes were almost completely circle and the lifters had bowsl worn into the bottoms. I looked at the pushrods and they are all good, no over wear or bent. So what I need to find now is a new suitable cam, lifters, rocker arms, etc. What I don't understand is how do I take the 7.900 pushrods into account when fitting the right cam, lifters, rocker arms? Right now Im looking at the COMP Cams extreme energy kit and the comp cams high energy rocker arms(http://www.summitracing.com/parts/cca-k12-268-4, http://www.summitracing.com/parts/cca-1212-16). I want to make sure that with this combination the valves don't make contact with the piston. I don't know which rocker arms to get mainly because there are 1.5:1 ratio and 1.6:1 ratio. How do you know which one is right? Also with the 7.900" pushrods (which are .1" bigger than stock) is that going to open the valves an extra .1"? plz help or explain this to me because ive done extensive research on specs and just forums and cannot figure out how all these things come together. Thank you
Read through all of the posts, this sounds like a lubrication problem or an excessive valve spring pressure problem, or a constant over revving problem. Long pushrods have nothing to do with adding lift they are used especially with extra long valve stems, high ratio rockers, and or high lift cams to properly place the rocker contact point on the valve stem tip.

Lubrication would be no oil, not enough oil, wrong oil, seldom changed oil. Pluged oil lines, inadaquate filtration, issues with the oil pump, issues with oil control in the pan which are usually related to inadaquate bottom end preperation and too much RPM.

Excessive valve spring pressure especailly when mixed with incorrect rocker to stem alignment eats parts very quickly the lifters and cam take a huge beating as do the rockers sometimes the studs and stud bosses.

Another is constant high RPM usage or overrevving especially where the oil pan and lower end is not prepared to manage oil control. High RPMs put a lot of oil into the engine that gets trapped in the windage and does not return to the pan and oil pump pick up. This takes a highly effective windage tray, a passenger side oil stripper, and a pan with dams and guides that keep the collected oil at the pump's intake. Without this the oil just doesn't return in sufficient quanities to prevent the pump from mixing air and oil which then causes failures along the lubrication system and especailly hydraulic lifters which will pump down beating the crap out of the lifters and lobes.

Bogie
 

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Trust the advice given

If you don't think it is as bad as these guys are describing, then remove the three soft plugs in the front of the block behind the cam gear and the three plugs at the rear of the engine and see what comes out.

Your block needs to be cleaned properly, otherwise it will be a re-do in a short period. Also, you can mess around disassembling your oil pump and inspect or just trust that you need a new one. As mentioned, if the oil filter bypassed for any length of time, then this is a mess.

Best advice, go to talk to a couple of local machine shops and get the block cleaned and prepped properly. If the cylinders are good, then this is pretty cheap. A new set of cam bushings and take them your crank to have it checked/polished/cut if needed and cleaned. Otherwise, find another motor.

$800 is somewhat tight of a budget. If you can get away without boring and new pistons, then maybe, by the skin of your teeth. Personally, I wouldn't expect it, but it is possible.

Best of luck - Jim
 

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. The guys are giving good advice... the rod and main bearings may be showing copper instead of silver babbit and have high clearances from fine metal particles running through the oil... they might fail in less than 5,000 miles... especially as engine performance is increased...

. As Joker was getting at, we don't start with pushrods and build an engine around them... the old ones are prolly damaged on the ends, anyways... we build the engine right and then LAST add the proper length of pushrods... new Summit pushrods only about $30/set...


. That XE268 230/236 cam will act kinda like a race cam in a 305" engine... not much torque till 2500-3000 RPMs... need to twist up RPMs to make power... a smaller Summit K1103 214/224 cam/lifters would save some money for other repairs and give better all around performance... especially for truck usage... and exceed your power HP goals... the -113 aluminum heads are good for 350-380 HP, but will need flat top or minidomed pistons for higher compression ratio in a 305" to make good HP...



. I'd go the 1.6 rocker arms... at this performance level, these would be sufficient:


http://www.summitracing.com/parts/sum-g6801


. Those -113 heads sometimes have only loose 'assembly plates' instead of true pushrod guideplates, so:

http://www.summitracing.com/parts/sum-g6451/overview/

https://web.archive.org/web/20130728193710/http://www.ryanscarpage.50megs.com/combos11.html (scroll down to Combo #83 for 214/224 cam performance)


. Check valves/valve seats/valve guides for wear/leaking... check valve springs for proper pressures... about 90-100 lbs. at 1.700" seat height... 260-280 lbs. at 1.200" open height... (base level stock springs 60-80 seat, 180-200 open too weak) (too strong springs damage the cam/lifters)

. We assemble the engine with soft modeling clay on top of one piston to determine how far the valves push into it... turn engine over slowly by hand, stop if feeling any parts contacting... some good reading:

https://www.google.com/?gws_rd=ssl#q=engine+quench

https://www.google.com/?gws_rd=ssl#q=building+first+engine
.
 
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