What not to do when you buy an engine built by someone else

First, I have to say that I bought my Maverick because it has drag racing history all the way back to the 1979 Ponoma Winternationals where it raced in B/SM..............and because it is a Ford and still looks great for being 41 years young.
Now, with that said, maybe this will benefit some of you younger guys who are building your own motor or having one built.....................NOLAT, or Never Over Look Any Thing...................and ADCSEW...........Always Double Check Some Elses Work......................!!!!!!!!!!!!!!!!!!!

I bought this car with a CHP 408 stroker short block and the owner put a set of Roush/Yates heavily tweeked TFS-R heads on it........Maybe because I was really thinking this car was the perfect thing I was looking for, it sounded really strong...............leak down was right on, compression was where it should be for a 13/15:1 CR..................and the guy had Timing Slips to prove it.
I drove the car and scared myself by turning a 9.801 @ 133 in the quarter, so I thought WOW, it is as represented........................Well...........Not Quite!

As I am pulling the motor down to refreshen it over this winter getting ready for 2011 (it was built in 1999)..................when I took the roller rockers off I just placed them in the tray, then took the pushrods out and placed them in the tray and started to take the heads off.........................while looking over at the tray I notice wear patterns on the pushrods that looked a little strange....................so I pulled one out to look at it................then flipped the roller rocker over to look at the back of the trunion area.............what do I see but a wear spot, maybe .020 deep in the roller rocker................I match this up with pushrod and the pattern becomes "crystal clear".
The cam in the motor is a special grind Crower solid roller with .704 intake and exhaust.............and uses 1.6 ratio roller...all 16 rockers..............................now I look a the pushrods...............and on the side it reads..................9.000 .080...................the length of the push rods.....................OK, so what does all of this mean, well when I pull the inside of the motor apart what do you think I am going to find after all of that aluminum has gone through the motor????????????
The only good thing is the motor oil was changed after everytime the car was raced..but????????? Who ever put the heads and valve train on this motor missed one of the most important things you can do with a motor after it is assembled and the cam is degree'd in............how many of you actually degree the cam after you put it in to see where the real timing is??????????????????????????? Anyone!
Well after you degree the cam you need to check the valve train geometry to make sure nothing like this happens..................and if you have to ask why.................well, you need to start reading how and why to blueprint a motor. If you want your new motor that you have spent $$$$$ for to perform and produce HP realiably, you need to pay attention to the details!!!!!!
If anyone wants I will continue to tear the motor down and show pictures as I go and everyone will see why this is important...............and manditory on a race motor. I will also explain why it is important to degree a cam anytime you change one, and how to check rocker arm/push rod geometry so this won't happen to you.
The other thing I hear alot is that, well, geeeee............I sent the motor to a machine shop and he put it together for me.................well, if you would trust that person or shop with "Your Life", then I would say OK, but if not, you should be doubling checking his work, like checking deck height, piston to wall clearance, ring clearance, rod and main bearing clearance, rod end play, crank end play........................and if you say, well heck, I use plastigauge..................I say, plastigauge?..that was great 30 years ago.............but something you should know is that it can be between .001 to .0005 off............if that is good enough for you than you probably shouldn't read any further....................
So, this is the first installment of my indepth look at some of the things to do if you ever buy a used motor from somebody, or have a shop build you a motor...................check everthing at least twice, then do it again.
Here are some pictures of the valve train issue....................oh yes, the pushrods to not appear to be bent, but putting them in a lathe and using a dial indicator..................they are all about .0015 untrue, maybe good enough for a street low HP motor, but for a 450HP or above not close enough.
Stay tuned........................more to follow

 

So too much lift for the rockers? Does that mean that wrong rockers were used? Do high lift rockers come clearanced or something?

Im following along...

 

My guess is the push rods were too long which let them rub on the rockers at full lift or those are 1.7 rockers (cam designed for 1.6) which moves the seat closer to the fulcrum. I learned my lesson on this with my GTO. I didn't check the geometry and in less than 2500 miles I needed guides in the heads. Another expensive lesson but those are the ones you don't forget!

 

I wish my poorly assembled motor ran 9.80 But you got my attention. I love reading about motor builds, or um, un-builds.

 

No kidding!!!!:Handshake

 

MercGT73,

Like RMiller said, my first guess would be that the pushrods are too long by .020 or .030", but I will not know until I get the motor back together, degree the cam, then set up the valve train geometry using an adjustable push rod and a test valve spring (test spring) to find out the exact length pushrod I need.
No, most roller rockers to not come clearanced, because the pushrod isn't supposed to come that close rocker arm...........minimum distance should be around .050 and .080 would be better.
So, the cam card I have specifies the .074 lift with 1.6 rockers, and the Scorpion Rockers (I have never been a fan of these) are marked with 1.6, but I will check them when the motor gets back together and the cam is dialed in................but a standrard 1.5 is used in most motors, and when you use a 1.6 you get approximately 10% greater, which means the valve ramp opens faster, stays open longer, and closes faster............there is a lot more to a cam profile................but in simple terms it can wake a cam up by going from 1.5 to 1.6.

RMiller,

You could be right about the wrong length pushrods...................we will see.

Ryan,

Don't get me wrong, I have seen CHP (Coast High Performance) put together some awsum short and long blocks so as I pull the shortblock apart I expect everthing to be the way it should be, but I do know that the customer ordered this cam specific for the motor as CHP did have to special order it from Crower in 1999.
I am saying that the valve train was poorly put together though, and taking a look at these TF-R heads, they have almost the same size exhaust and intake port sizes as a set of stock early Boss 302 heads, the intakes on a Boss 302 were 3.8 sq Inches, and on these heads they are 3.4 sq Inches..............the exhaust ports are round and exactly the same size.....................Large!
Oh, the other thing when I pulled the motor down, I noticed the throttle cable was hanging up on the throttle stop and not allowing the secondaries to fully open...................so maybe the ole girl had a little more left after all........................for a 3325lb with me and fuel she didn't do to bad.......................we will see if we can't do better......maybe.

 

I'm curious to learn how to set up the valve geometry. But I do have to comment on CHP. I don't know much but I know they had
HORRIBLE customer service and sold me wrong parts. I bought all the parts for a long block from them in 2006 and their workmanship on the machined shortblock was pretty bad according to my machinist who I had go over the block. The intake they sold me wasn't the right one that I was supposed to have and I'm sure there is other stuff that I just don't remember now.

 

Mashori,

I can't really talk about CHP because I haven't dealt with them for over 10 years, but the motor was put together in 1999 and pushed the ole Maverick to a 9.801....................so they must have done something right initally because the motor hasn't been apart since then.
When I called them to find out information on the motor, they were certainly nice and gave me as much information as they could find. Not sure what issues you had, but as I said before, if you recieve parts, pieces, or whole motors........................check, check, check everything to make sure you are getting what someone said they are giving you. If you don't have the proper equipment to do that, find someone you would trust your life with, borrow the tools and have someone teach you how to use them.........................it does take time, but checking everything yourself....................unless you have $100 dollar bills falling out of your pockets.....................can be fun and certainly will give you an appreciation of what it takes to blueprint a motor............IMHO

If you would like me to run through setting up a valvetrain I would certainly be happy to, but I will not have pictures until I start assembling the motor...................as you need to have the shortblock together and preferably have the heads in place after you have checked piston to valve clearances and degree'd the cam..................Just let me know.

 

If you never checked the pushrod geometry (wear pattern at the valve tip) then you're making wrong assumptions, just as the builder did. My first assumption is the cam lift is too high for the pushrod/rocker combo. But without knowing what the wear pattern is at the valve tip, that's all it is.........an assumption.

 

baddad457,

When I purchased the car and ran a leakdown/compression test this was done visually.....................the only way to check this tip pattern is to have the motor apart...........use machinest dye and see where the tip contacts the valve stem................I certainly agree with your thought process.........................but when I did the leakdown/compression I did watch the tip action while the owner cranked the engine over with the remote starter..................it looked like the rocker tip was fairly well centered and did move out slightly toward the outer edge of the vavle stem and then returned.....................which is pretty normal if the valve train has been set up correctly.................so I didn't think too much about it......until I am dissassembling the motor.
As for the wear pattern at the tip, I think is should be pretty close.......as for any wear indication on the stems.................there is none that can be seen. The other part of the equation is the spring installed height and coil bind height.......................I know for a fact that there was no coil bind but not sure what the installed height is supposed to be. When I take the heads apart I get this information and also check spring pressure to make sure it's close to spec.............around 617lbs.
So you are right, assumptions are just that, ASWAG.

 

1.6 is the standard rocker arm ratio for a small block Ford... isn't it? Why would you want a 1.5?

 

I hate to be a smarta$$ but I have only put together one engine, and I spent a LOT of time working on the valvetrain geometry. Found that I had a reduced base circle grind on my exhaust valves, had to use lash caps to make up the difference, etc. I put at least 15 hours into checking, rechecking, and putting sillyputty in the cylinders to check for clearance before I ever tightened it down and tried to run it.

I would expect the experts at a shop to do as well, or better, than myself.

This is just a careless error and should have been caught WAY before it was started up. Before the valve covers went on, even.

 

You would think that the push rod length would have to be pretty far out, for them to rub the inside of the rockers like that. Or when they were assembling it, and turning it over by hand, you'd notice some binding? It's alot of work to get the geometry right, I made a pushrod length checker, and still ended up buyin 4-5 sets, before I was really happy.
What make are those rockers? I wonder if they are not rated for the lift of the cam?

 

PaulS,

Yes, a 1.6 is a standard Ford, I was just making an anaology of the 1.5 to 1.6. Sorry for not making that clear....................

Scooper,

Well, I believe that the owner bought the short block direct from CHP and put the valve train and heads on himself......................this is what I was told.

Dave,

I remember helping a friend build a 408 stroker awhile back and he used the Edelbrock heads and .650 lift cam and I think the pushrods were around 8.75 or so.................(mine are 9.080" long and although I have a 9.5 deck height these just sound long). My friend used some Harland Sharp shaft mounted roller rockers..................better stabiltiy and less flex than stud mounted rockers............and you don't need a rocker girdle either.
As I said earlier, the roller rockers are marked 1.6 and are Scorpion which I have never thought were good quality rockers...........so, maybe I think about the Harland Sharp units, but less pushrods they are about a grand, and I need to sort out why the pushrods were making contact with the rockers..........................We will see

 

1.5 would move the pushrod out and away from the rocker, possibly enough to fix the contact problem between the two.