Motor Building Secrets

[Morgan]

Install your head assembly with the motor on TDC and install the cam gear and cam chain with the lines level with the arrows on the cam tower. Install the cam gear bolts and the timing chain tensioner, extend the tensioner to ensure it doesn't skip timing when you roll it over. With your 8mm allen you used eariler, roll the motor over slowly 2-3 full rotations. Remove the head in the opposite order you installed it, and we are now ready to see what we have for Piston to Valve clearance.

 

When the head is removed you will be able to see that the valves have left their indentions in the modeling clay. Take note of the outer edge to make sure the valves are inside the valve pockets and not hitting. Next, cut the clay in half from intake to exhaust not from intake to intake. Dished valves must be checked against the lowest point at the rear of the valve relief. The center will give you a false reading. Take your calipers and measure the piece that is still on the piston and record. The absolute bare minimum is .050 on the intake and .070 on the exhaust. With this DASA LL piston our intake was .075 and the exhaust was at .096, adequate room on both sides, with slightly more to allow for even more to be cut off the head safely then we already cut off.

 

Wiseco and JE shelf pistons usually do not have the valve relief that CP shelf pistons do. Most CP shelf piston will allow .010-.015 off the cylinder and .015-.020 off the head with adequate piston to valve clearance.

[Morgan]

Try to get the cam info up sometime this week.

[bigcountrydude]

lol "secrets". great rightups. after what modifcations would you say you HAVE to check the the deck height? just before and after decking, and with long rod strokers?

[OTMTRX]

Good on you Morgan!

[ghott]

Fantastic write-up, can't wait for more!

[Dr. Beardface]

Great stuff!

 

Couple of questions if you don't mind. Do you stick with .040 on all your engines or does it vary by manufacturer/engine size? How much of an effect does this have on compression ratio, is the whole point of this to increase compression? What is the stock deck height set at?

[mx333]

Great Info there.

[TRX450Ryan]

Hey morg, after removing .010-0.015 from the cylinder, is it enough to worrry about it affecting the cam timing, and to degree it, or is it minimal at that amount of material removed?

[Wadezzz]

great thread very informative !!! i love reading stuff like this ! thanks

[450R]

I wish Morgan would come on and finish this thread... this is one of the best threads on building I've ever come across. The secrets of doing a top end like a pro.

[Wadezzz]

I was thinking the same thing ! o well mans prob only got so much time ya know

[chronicsmoke]

Bump for a very informative thread. Anything else to add!?

 

:popcorn:

[rexxtack]

Great write up.. Ill be staying tuned to learn more.