casting # head

[datzenmike]

210 head was 38.5cc the closed chamber head is 41cc so there is a small drop in compression.

[Dantheman]

Thanks, yes I did read up on that, any idea on the amount of drop in compresion? And I guess that would be a wash in reguards to the more agresive cam and bigger valves. Again, I guess it will be put aside untill I rebuild an engine. While I am dreaming here, Would the 38 su set up work well along with a flat top piston?

[ggzilla]

38 mm work well with a stock engine

[Laecaon]

A flat top piston will raise the compression too! And that is a good thing.

 

Flat tops and closed chamber should result around 9.4:1 or better...

 

38mm SUs came stock on certain editions of cars with the L16 and L18. I just put them on my engine, a bored out L18 with flat tops, and the SUs run great!

[datzenmike]

Stock L16 compression is..................... 8.58.

Using an open chamber head............... 7.72

Running a closed chamber head.......... 8.21

 

 

Keep the stock 210 head and swap an L20B or A-87 cam into it. Look in the middle of the cam and it should have the square bumps as shown below. If you find a head with this cam remove the rockers in proper order and keep with that cam.

 

[Dantheman]

Yes the cam looks like that. I will take your advice. I will leave the head alone for now and swap the cam.

[datzenmike]

And rockers.... keep in order. If the cam comes without them it's ok.

 

 

YOU KNOW NOT TO REMOVE THE CAM SPROCKET WITHOUT FIRST BLOCKING THE TENSIONER SO IT DOES NOT FALL OUT???????

 

Very important and will save you half a days work and a few gaskets..

[Dantheman]

The head has valves installed, but thats it. Was also given a box of extra parts. When i change the cam, i was planning on using the rest of existing valvtrain in my running 210 head

[Dantheman]

Had another question on the a87 head i got. I just took the valves out and inspecting things. My intakes are measuring at 1.73", and exhaust at 1.38". Intake port is at 1.50". Looks like some milling has been done. Want to measure combustion volume to see. Question is, is this too much for my l16. Kind of fantacy thoughts.

[datzenmike]

For best results the engine size, RPM range used, valve size and port size are matched to have maximum flow speed. The faster the air flows the better, but must not restrict the flow and make the motor work to pull air in. If you run with massive port sizes the air speed drops and you will loose some efficiency. Now if you plan to rev a lot higher with a hotter cam and have multiple carbs then the extra port size will work and the air speed will be high enough.

 

NOTE:

There is nothing wrong with a larger port size, the engine will work fine it's just not ideal for a strictly stock use motor.

[Dantheman]

May build an engine later, but day dreaming a bit on just a top end on the current l16. If I were to consider the head on this one, I would need side draft I assume. Given the size of the intake port and valve, I assume to loose velocity, thus loosing torque at the lower rpm range. Best remedy would be displacement, right? I am probably answering my own question.

[TFM1066]

Caution!!!  check to make sure what the exhaust valve sizes is, the 35mm/1.38 exhaust valve may contact the deck and/or cyl bore if you plan on running the A87 cyl head, on a L-16.

[Dantheman]

Thanks for that. I would be running stock l20 cam, so no extreme lift, but still unsure on degree of milling to head. I am guessing the block has not been changed from stock. The numbers all match id tags. With dished pistons the only concern would be contact with the bore if it has been heavily milled.

[datzenmike]

Had another question on the a87 head i got. I just took the valves out and inspecting things. My intakes are measuring at 1.73", and exhaust at 1.38". Intake port is at 1.50". Looks like some milling has been done. Want to measure combustion volume to see. Question is, is this too much for my l16. Kind of fantacy thoughts.

 

http://community.ratsun.net/topic/358-how-to-cc-your-cylinder-head-for-free/

 

If you have a stock open chamber A87 head the larger compustion chamber will drop the compression of an L16 to 7.72. You can simply mill the head and remove the same difference in cc's between the 210 and the A87 chambers. My figuring shows about .55cc per tenth of a mm removed. So 7cc would be about 1.4mm or 0.055" perhaps a fair amount to remove. A closed chamber head is smaller so the difference is less, only 3cc or so and because of the chamber shape more difficult to guestimate.

[Dantheman]

Thanks, read your post you linked and makes sense. My a87 is closed chamber and looks to have had been decked or just a clean pass on it. So after checking to see how much has been taken from it , I can assume one more squaring in would only put it closer to the stock 38.5cc on the 210 head. If I follow the info given. I don't think a tiny bit of compression loss will kill it. Hoping the + will out weigh the -. Is this an out of line reasoning?

[ggzilla]

Yeah,.you are just guessing. CC the head, it only takes 15 minutes and a $2 syringe from a local feed store.

[datzenmike]

Only thing for sure is the chamber won't be larger than 41cc. Just for fun I figure that 0.020" or .5mm should remove about 3cc of combustion chamber bringing it close to the 210. (very rough and making some assumptions)

 

Yes, CC the head.

[Dantheman]

Thanks gentlemen. I will post tomorrow.

[Dantheman]

Have not had time to get needed items for testing head volume test but did a compression check. I have an old tester that needs a new rubber tip, but used any way. So here what I found.  I was hoping for better but not shocked. Holes 1 and 2 read 145 and 150 and 3, 4 where at 185. First off the 185 psi seems high, second, not pleased on the difference between front and rear of motor. Going to perform a leak down and see if it is in the head which I can swap any way or the bottom end, and this will leave me looking for a l18 or l20 block.

[ggzilla]

It's not the head. Head problems won't cause a compression reading like that. Read the compression testing section of your repair manual.

 

It is the rings. Do the wet compression test to confirm it. Or do a blowby test.

[Dantheman]

The compression check was only taken to further know what I have to work with and if it would be worth puting a better flowing head on it. The block may still be good. I wont know until I do a blowby test. Just seemed strange to see consistent number readings 1,2 and the same at 3 and 4 but separated by 30 points. I am hoping for leaking valves up front or maybe a head gasket. I an not a mechanic but like the learning process. Thanks for your input.

[ggzilla]

That is a fairly common compression test result, having two cylinders high and two cylinders lower.

 

 

> The compression check was only taken to further know what I have to work with

 

You won't know what you have to work with if you don't do the wet compression check. Those figures are bad, but there is a small chance it is not the rings. Wet check will tell you.