need basic head work... Rimco or headflowmasters?

Ghost Rider · Post by **Ghost Rider** » Tue Jun 10, 2003 2:49 pm

that would be a good option ray, but I think I will be going with 96mm pistons which can be found much easier... or are you suggesting haveing 96mm pistons made like the 1.7s? you lost me a bit...

raygreenwood · Post by **raygreenwood** » Tue Jun 10, 2003 8:48 pm

But for the cost I listed...the pistons will be MADE...CNC milled, to whatever diameter you want. Moving to 96's would be nice...you could either one if you are having pistons made. The purpose for having pistons made was to get the larger piston WITH the dome to match to 1.7 heads, as they were never made stock...that Iknow of. Be very careful when taking the 1.7 head out too far in diameter. It has avery large quench area. It will skyrocket your compression very fast, the larger the diameter goes. Then you will have to start cutting away the very parts that make it a good combustion chamber design, just to control compression. RAy

Ghost Rider · Post by **Ghost Rider** » Wed Jun 11, 2003 7:57 am

I think having the pistons built is for builders who are much more advanced than I am... I don't have the knowledge yet to be able to make those kind of decisions as to figuring what the compression ratio is/will be don't you think a good quality flat piston would be better for a newbie builder such as myself? Jake and yourself has the knowledge to properly lay out something like we are discussing here... I need something more like a kit....where I can't screw up a perfectly good engine by not really understanding something like quench area and compression ratio and the limits of each...

raygreenwood · Post by **raygreenwood** » Wed Jun 11, 2003 10:37 am

I think you are thinking this is too complicated. You will have to figure the compression even on a bone stock engine. The calculations are very simple and can be done on a calculator in 2 minutes. A domed piston IS stock on a 1.7. You will be making no decisions to have pistons made. Simply provide them with an old one and tell them the book measurementsform the factory manual for the cylinder diameter of the 93's or 96's. Chances are, They probably already have them...as you are probably not the first person to request this very piston to be made. They will dulicate what you give them with no effort of your own. Having pistons made is quite common. Also...what you will be able to buy these days for almost the same cost...will usually be brazilian...and of very suspect quality. If you want to use the 93mm...and make use of what the 1.7L head does the best...you really should have a domed piston like what came stock on it. But...they never made one in 93mm. Its as simple as sending the piston company an old 1.7L piston and saying....just like this...but with a 93mm outside diameter. They will do the rest. It is computer controlled milling. You get a much better piston...for about the same money. Send the jugs to rimco in California after you get the pistons...and have them do the honing. Then you are done. They can probably do the head work on opening up for 93's as well. This is all pretty easy..and is no more complicated than installing 96's from an existing kit. Ray

Ghost Rider · Post by **Ghost Rider** » Wed Jun 11, 2003 12:09 pm

ok, I get it now... I was just worried that a 1.7 type(domed) piston at 96mm with a 78mm crank would cause the compression ratio to be much too high for the heads to handle... what is the formula for compression ratio?

raygreenwood · Post by **raygreenwood** » Wed Jun 11, 2003 2:11 pm

Ok...you didn't mention a 78mm crank. That in itself is a complexity. There will be case clearancing issues most probably...but not huge issues. You will need to have spacers under whatever cylinders you desire to use...or you are going to hit the valves. The piston issue pales in comparison. You will need to think about whatever head you use...in relation to what comprression you desire, what valve clearance is available and what shims are available on the market to produce the desired cleances. Wether you use the 1.7, 1.8 or 2.0 heads...you will have the same issues when going to a stroker. Also..you had better think about which cam. There may or may not be lobe clearancing issues as well. What rods are you going to use? This is not a drop in bolt on set-up. Ray

Ghost Rider · Post by **Ghost Rider** » Wed Jun 11, 2003 3:17 pm

that's why I was looking harder at a kit... say from Mr. raby!! b/c I don't know any of that stuff! he sells 2270 kits on his site... 78.4mm crank and 96mm pistons, the rods, cam and spacers, whole bit... just add head work...

I don't know enough about all of the clearences to judge anything... I am new at this... but I want to be thinking about this for a year or 2 to work out all the details first... when I first posted this thread I was just trying to get an idea of what I should do to make due for another year(or 2) and we've gotten off onto what to do in a year...

raygreenwood · Post by **raygreenwood** » Wed Jun 11, 2003 5:30 pm

AH!...Yet another facet...hee hee. Ok....if you get one of Jakes kits, you will still need to know all of that stuff...which is not as much as it sounds. Face it! You are going to have to learn IT! With Jakes kit, everything has been pre-assembled at least once.....out to the heads. At that stage, you will be providing the heads to the kit...yes/no? That means he has set a deck height in the pre-assembly for the compression based upon...what? Does he need your finished heads in advance? That would be the best way. I would still start with the 1.7. It will save you some money, it would get new seats and valves, it would have plenty of metal to do better port work and come out with a head similar in displacement to the 2.0...and be much better than the 1.8. Ship him the head...then he knows the valve margins and the displacemnet to set your kit up with the proper shims. You will still need to measure clearance when you build it...and calculate clearance and compression. Even though Jake is the best...just assembling a kit without measureing those things is a 100% recipe for disaster. Ray

Ghost Rider · Post by **Ghost Rider** » Wed Jun 11, 2003 5:49 pm

yea, I was planning on him doin all of the head work... I will get the heads worked for now... just to get the 1.7 working and I do plan to learn how to measure all of this stuff and how to do all of it... a 2056 or 2270 kit really appeals to me because it's one of those things: you only think you know it until you do it once... or twice

but I see completely what you are saying... maybe the best of both worlds that we've discussed is 96mm pisons with the 1.7 dome and a 71mm crank! with a nice cam and ports too though!

btw... who do you know that does heads in Dallas... I called one place and they wanted 400-500 to do them!!!

hell! MOFOCO will completely rebuild them for 175 each!!! who do you trust in dallas/ft.worth?

Bleyseng · Post by **Bleyseng** » Wed Jun 11, 2003 7:01 pm

Send the heads to be rebuilt by HeadflowMasters in Calif. Save yourself some grief! It not done right the babies will drop a valve seat on you.

Geoff

Ghost Rider · Post by **Ghost Rider** » Wed Jun 11, 2003 8:40 pm

do they have a website? or a number... my problem is I want to know at least ballpark pricing... I don't want to be thinking... oh 200 will do it and it end up costing 500+... I can't afford that right now... in a couple months maybe...

raygreenwood · Post by **raygreenwood** » Wed Jun 11, 2003 9:04 pm

I don't know a single soul in Dallas that works on type 4. My brother does fabulous cylinder heads. He did mine. But he is also not cheap. He has been porting race heads for about 20+ years. He does the seats....with a heavy interference fit, has a flow bench and dyno...and is a mechanical engineer...with a specialty in airflow. He has a heavy schedule though. I will ask him what they would run. He would be worth it...but I suspect that he may be more than you want to spend. He is in the middle of a pair of 327's right now. One of them is for the fastest corvette in its class in the country (cannot remmeber what class...but its a gorgeous car) and thats about a $20K+ engine. But...there is only so much that you can do to the type 4's as is...so I will ask.
As far as the valve seats dropping....I have never dropped one. I also have neer overheated any of my engines. Most every dropped seat I have seen was overheated grossly and repeatedly. But since there was a suspect year or two from the factory, concerning proper intereference fit...no one is exactly sure if thar may be in the mix. Mostly it is becasue overheated causes a loss of elasticity in the aluminum around the seats. But yes...if its done incorrectly...they can for sure fall out. Thats wh the best insurance is to replace the seats on any head and do it right. Ray

Ghost Rider · Post by **Ghost Rider** » Thu Jun 12, 2003 6:56 am

well the place in Hurst yesterday is mainly a 911 shop... so I don't know if I trust them with type 4's... I don't have a dropped valve... I just think it's a bit burned b/c I had an exhaust leak... I may go with MOFOCO or another place that Knight's Foriegn Auto Parts recommended... they work on a lot of VW's and porsches.. but they are hard to get in touch with... but bus' are their specialty... so they have seen plenty of type 4 engines...

Ephry73 · Post by **Ephry73** » Thu Jun 12, 2003 7:29 am

Ray did bring an interesting point acrossed(well, several)

What if you were able to have a 2lt piston made with the dome on it, instead of the flat top, and use the 1.7 litter head(which has almost the same chamber shape as the 1.7, but i believe it doesn't have the "dimple" for the dome...

Highes CR, and good exhaust with updated valves and port jobs should not be anythng less than fun....

E

Ghost Rider · Post by **Ghost Rider** » Thu Jun 12, 2003 10:37 am

oh yea... I agree... a 2.0L (71mm stroke, 94mm bore) with ported 1.7 heads(maybe to stock 2.0L sizes or a little higher?) and domed pistons may be they perfect 2.0... (probably producing 130-140hp!!) but the increased compression worries me a bit... will the heads need to be "freshened" every 30k miles? or will this be a 100k engine like a stock 2.0 is? wouldn't a 2056cc or 2270 with a lower compression producing 130-140 last longer? compression makes heat and heat bad?!