The Rebuild Begins

[jpayne]

what Posh? scotties motel! Nah. Think me neighbour was murdered last night by the dwarf down the hall while spying on the grandpa/granny down stairs while he/she skinny dipped in the green pool, think more like my name is ea...justin..rl!
The plate thingamijig is bolted to the top of the block when boring to hold the deck true/square or something, just a rumour that I have heard 3 times from 2 different sources.
Had a good reputation 6 years ago and dont doubt it remains.
I always feel if I get good service or at least attention prior to ordering bying etc Ill happily pay more for it than shopping around dealing with ignorant, rude, who-needs-a-customer-anyway pricks
Justin

[wayovermyhead]

[jsa]

thanks

[Danny M]

How much compression has the engine got with which cylinder head and what fuel have you been using

[MK1_Oz]

[MK1_Oz]

Current plugs are NGK-R CR9EK so maybe a move to CR10EK is needed?

Also, I did not have the water line into the rear side of the block connected so no4 may have been getting hot. I will also look into getting this plumbed back in just in case (I cannot afford the fancy pants Holbay water system mods even though they look pretty!!!).

[PaulMK1]

I have never heard of anyone running 10's. I'm using 8's after fouling a few 7's.

But since I installed the MSDN I have not had any plug issues.

[MK1_Oz]

OK ta. Maybe 9's are fine then.

[wayovermyhead]

Sorry Danny was that question directed at me or Mk1_oz?

[Danny M]

No willy wonka

[MK1_Oz]

[Danny M]

If you've only got 10.8 to 1 just use an ap8fs if you've got a decent ignition or a ap7fs low grunt one

[gen mk 1rs2000]

ngk ??

[Danny M]

Yep

[MK1_Oz]

That's a standard diameter plug yes? I still have the smaller bike plugs. You have mentioned to me before about ditching the adaptors and bike plugs but what are the pros and cons of using each? Does it really make a difference? My plugs have twin electrodes which I could possibly see resulting in a smaller arc length and therefore a smaller initial flame front but Im guessing at that.

[MK1_Oz]

[Miniliteman]

[Miniliteman]

Just to add to the "confusion":
the calculations here are based on a symmetrical profile of the camlobes.
If these are a-symmetrical, then the timing of when full lift occurs and/or the LCA could be some degrees different w.r.t. the theoretical calculated ones.

A better illustration of overlap is the overlap at a lift of for example 0.01".
Besides the overlap, duration and LCA a cam can be defined by the timing at which both the inlet and exhaust valves are open the same amount (over here this is designated by the letter S).

If you have a symmetrical cam with timing of 40/80 80/40 then the overlap is 80 degrees, full lift is at 110 degrees ATDC and LCA is 110 degrees. The "S" number is 0.
S = ((80 - 40)/2 - (80 -40)/2)/2 .
Now if you take the GTS4 cam the S-number is
S = ((79 - 53)/2 - (89 - 43)/2)/2 = - 5 degrees.
A minus number here means the cam has more low-end power and sacrificing high-end power.

Hopes this makes some sense ...

[MK1_Oz]

Thanks Leon.........I think! More info to digest.

Maybe I need to ask a more basic question to help with your info above. When the numbers are presented as 53/79 89/43 I believe this has something to do with the opening and closing values of the inlet and exhaust valves. So the 53/79 means that the inlet opens 53 crank degrees before TDC and closes at 79 crank degrees after TDC???? Same applies to the exhaust figures?

The Vizard theory I have been reading comes from his 2011 update book "How To Build Horsepower" so not sure how out of date it could be? Seeing as he is now such an American the book focuses on yank v8 small and big blocks although several times in the book he makes similarities between the small block and Pinto motors stating that the theory relates to both.

[Miniliteman]

53/79 means that the inlet opens at 53 degrees before TDC and closes 79 degrees after BDC (bottom dead centre).
89/43 means that the exhaust opens at 89 degrees before BDC and closes 43 degrees after TDC.

Google camshaft timing and you get some clarifying pics:



Vizard wrote the book on the Pinto in 1984, the How to build horsepower book was first published in 1990.
As always "there are more ways than one to Rome" ...

The tuner that build the rallyteams BDG normally prepares KTM motorcycle engines. Several things that he designed for the KTM's he also used on the BDG with good effect.