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After speaking to our new mapping guru / race engine build advisor it's been brought to our attention something that will interest a few of you who are planning big power builds, certainly was a surprise to me too.
Basically it concerns the throwing of the gtir rockers on solid lift engines I.e ours.
I always was under the impression that the rocker arms misplaced and threw off the shims sideways at anything over or around 8k rpm
so a mis-shift, bouncing the car off the Rev limiter with incorrectly adjusted shims or weak valve springs would cause this.
Up to yet the problem has been partially resolved with fitting rocker arm stoppers which seem to do the job they were designed for but using these is not without risk as they can Infact cause damage to valves by holding down a valve rather than letting it bounce which could result in valve striking piston.
Now our new guy has pointed something out to me it's made me re-think my whole system regarding building heads
When a rocker throws off the shim / valve stem it DOES NOT come off sideways as I originally thought, it actually moves backwards and is thrown from the pivot ball from the rear of the rocker, the cam coming on to its profile as it strikes the rocker then helps it on its way to misplace.
Terry did explain to me how this can be avoided to an extent and certainly make it far less likely to happen on a race engine or fast road high performance engine.
The answer involves a fair bit of mathematics to do with axis points and the like, can't be assed to type all this tonight but certainly does make sense to me and will help in our future engine builds in order to make the head more suitable for higher revving applications.
He is also helping, showing me how to carry out necessary work in order to prep a fully worked head for race applications as well as giving me use of his in house engineering shop to carry out necessary machining
The man has some serious knowledge with the sr20det engines (as well as many other race engines) so it really is a massive boost to us and my new company to have this guy working with us advising / helping me in terms of how to make our engines stronger still.
I'm also receiving mapping lessons from him too (starting soon)
Turns out he is a massive name in Motorsport and has had years and years of experience both in race engine design and mapping of such vehicles, anything from top fuel drag cars, Btcc, wrc, and F1.
He played a major part in the design and build of the primers Btcc car and also mapped the grp A rally gtir driven by Andy Llewelyn back in the early 90s.
The mans been there and done it all
Turns out he's soon to be mapping a certain time attack car for guess what.........a so called tuner:lol:
I thought I knew a fair bit with regard to engine building,general mechanics and so forth (especially after 12 years of working on these cars) but turns out I know jack shit in comparison
Il of course pass on my new findings to help people on here should they need any info regarding their own builds but only by pm guys!
Basically it concerns the throwing of the gtir rockers on solid lift engines I.e ours.
I always was under the impression that the rocker arms misplaced and threw off the shims sideways at anything over or around 8k rpm
so a mis-shift, bouncing the car off the Rev limiter with incorrectly adjusted shims or weak valve springs would cause this.
Up to yet the problem has been partially resolved with fitting rocker arm stoppers which seem to do the job they were designed for but using these is not without risk as they can Infact cause damage to valves by holding down a valve rather than letting it bounce which could result in valve striking piston.
Now our new guy has pointed something out to me it's made me re-think my whole system regarding building heads
When a rocker throws off the shim / valve stem it DOES NOT come off sideways as I originally thought, it actually moves backwards and is thrown from the pivot ball from the rear of the rocker, the cam coming on to its profile as it strikes the rocker then helps it on its way to misplace.
Terry did explain to me how this can be avoided to an extent and certainly make it far less likely to happen on a race engine or fast road high performance engine.
The answer involves a fair bit of mathematics to do with axis points and the like, can't be assed to type all this tonight but certainly does make sense to me and will help in our future engine builds in order to make the head more suitable for higher revving applications.
He is also helping, showing me how to carry out necessary work in order to prep a fully worked head for race applications as well as giving me use of his in house engineering shop to carry out necessary machining
The man has some serious knowledge with the sr20det engines (as well as many other race engines) so it really is a massive boost to us and my new company to have this guy working with us advising / helping me in terms of how to make our engines stronger still.
I'm also receiving mapping lessons from him too (starting soon)
Turns out he is a massive name in Motorsport and has had years and years of experience both in race engine design and mapping of such vehicles, anything from top fuel drag cars, Btcc, wrc, and F1.
He played a major part in the design and build of the primers Btcc car and also mapped the grp A rally gtir driven by Andy Llewelyn back in the early 90s.
The mans been there and done it all
Turns out he's soon to be mapping a certain time attack car for guess what.........a so called tuner:lol:
I thought I knew a fair bit with regard to engine building,general mechanics and so forth (especially after 12 years of working on these cars) but turns out I know jack shit in comparison
Il of course pass on my new findings to help people on here should they need any info regarding their own builds but only by pm guys!
